EPA-AA-SDSB-84-01
Technical Report
The Feasibility, Cost,
and Cost Effectiveness of
Onboard Vapor Control
Glenn W. Passavant
March 1984
NOTICE
Technical Reports do not necessarily represent final EPA
decisions or positions. They are intended to present
technical analysis of issues using data which are
currently, available. The purpose in the release of such
reports is to facilitate the exchange of-' technical
information and to inform the public of .technical
developments which may form the basis for a final EPA
decision, position or regulatory action.
Standards Development and Support Branch
Emission Control Technology Division
Office of Mobile Sources
Office of Air and Radiation
U. S. Environmental Protection Agency
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Table of Contents
Page
I. Introduction 1
II. Technological Feasibility 1
III. In-Use Performance of Onboard Systems 7
IV. In-Use Emission Control Effectiveness 10
V. Costs of Onboard Vapor Recovery ....13
VI. Cost Effectiveness 21
VII. Leadtime Requirements 24
VIII. Onboard Control Versus Time 27
IX. Conclusions 33
References 35
Appendix A: "Recommendation on Feasibility for Onboard
Refueling Loss Control," February 1980.
Appendix B: "LDV and LOT Operation and Usage Characteristics"
Appendix C: Tables from "Manufacturing Costs and Automotive
Retail Price Equivalent of Onboard Vapor Recovery
System for Gasoline - Filling Vapors"
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I. Introduction
This report updates the previous analysis of the
technological feasibility, in-use effectiveness, cost, and cost
effectiveness of an onboard vapor recovery system for
controlling refueling emissions from gasoline-fueled motor
vehicles. The last report in this area is dated February
1980. In that report it was concluded that onboard vapor
recovery was feasible for light-duty vehicles (LDVs). However,
some question remained about the feasibility for other types of
gasoline-fueled motor vehicles and the cost effectiveness of
controlling refueling vapors through the use of an onboard
system.
Therefore, this report addresses the feasibility of
control for other gasoline-fueled motor vehicles (light-duty
trucks (LDTs) and heavy-duty gasoline-fueled vehicles (HDGVs))
in addition to LDVs, and also examines those factors related to
cost effectiveness. The feasibility is examined for HDGVs, but
the cost and emission reduction impacts are not determined.
However, cost-effectiveness values similar to those calculated
for LDVs and LDTs would be expected.
This report begins with a discussion of the technological
feasibility of onboard control, and this will be followed by _a
calculation of the in-use effectiveness of onboard control
systems. After reviewing and updating the previous estimates
of the costs of control, the cost effectiveness of an onboard
strategy will be calculated. In addition, a fifth section of
the report estimates the leadtime necessary to implement
onboard controls, and the last section estimates the time
required for an onboard strategy to achieve control of a
substantial portion of in-use refueling emissions. A summary
of the overall conclusions closes the report.
II. Technological Feasibility
A. Introduction
The bulk of the experimental work in the area of onboard
vapor recovery has been performed by the American Petroleum
Institute (API) and their contractors, Exxon, Mobil, and
Atlantic Richfield (ARCO). They completed a vehicle
demonstration of onboard vapor recovery in October of 1978[1].
The results of that study strongly suggest that onboard
controls are feasible and effective in controlling gasoline
refueling losses from low- to mid-mileage LDVs, with only a
negligible impact on a vehicle's ability to comply with current
exhaust or evaporative emission standards.
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Following the release of the API work in 1978, EPA
solicited comments from the motor vehicle industry concerning
the cost and technological feasibility of onboard controls for
LDVs and LDTs. These comments were incorporated in EPA's
analysis of the API vehicle demonstration program (This
report is presented in Appendix A, "Recommendation on
Feasibility for Onboard Refueling Loss Control," dated February
1980.)[2] The judgment that onboard vapor recovery is
technologically feasible for gasoline-fueled motor vehicles is
based largely on this analysis of the API work and the
technological feasibility comments submitted by the motor
vehicle industry. In the remainder of this section, the
information leading to the conclusion that onboard control is
feasible for LDVs is reviewed, and the feasibility of
controlling LDTs and HDGVs is discussed.
B. Review of LDV Feasibility
1. New System Performance
The onboard contol effectiveness of new systems is based
on the results of the API vehicle demonstration program. This
program consisted of SHED tests of the entire system minus the
filipipe seal (the fillpipe was plugged) and bench SHED tests
of the ARCO rotary fillpipe seal. These tests showed that
refueling emission control efficiency ranged from 98.2 to 99.3
percent for both total HC and benzene, with an average value of
98.9 percent. [3] Based on these results, a control system
efficiency of at least 98 percent is judged to be
representative of potential new vehicle control for the
canister/modified fillpipe and seal system evaluated by API. A
diagram of the system evaluated by API is given in Figure A-l
of Appendix A.
2. Mechanical Durability
EPA's 1980 report summarized the ARCO API durability data
on the nozzle/fillpipe seal effectiveness. These data were of
necessity derived from an accelerated test program, and
therefore concerns about seal durability over time could not be
addressed. After completion of the original work for API, ARCO
installed a fillpipe cone seal (Figure A-6 of Appendix A) in a
company vehicle and monitored seal effectiveness over 26 months
and approximately 54,000 road miles near their Harvey, Illinois
facility. During the 26 months, the seal was exposed to
environmental extremes representative of most of the
continential United States.
ARCO tested the seal effectiveness by measuring the HC
concentration at the fillpipe/nozzle interface each time the
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vehicle was refueled. At periodic intervals the seal
effectiveness was checked by measuring the leak rate past the
seal using a specially designed nozzle to pressurize the system
with nitrogen. The pressure check tests were performed at
system pressures corresponding to 5, 10, 15, and 20 inches of
water, at which the seal effectiveness was still 99 percent. A
pressure of 4-5 inches of water is typical for a normal fuel
fill. Therefore, the ARCO data indicate excellent sealing
capability over time. Overall, seal effectiveness was better
than 99 percent after two years of service using unleaded fuel,
and 99 percent effective after an additional 11,000 miles using
a high concentration (20 percent) methanol/gasoline blend.[4]
The ARCO in-use data suggest that effective, durable,
low-cost fillpipe seals (rotary seals or cone seals) are
feasible for LDVs for in-use service to at least 50,000 miles
over a two-year period. The available data is not conclusive
as to which type of seal is preferable. The important
question, which has not been fully addressed, is whether the
fillpipe seal will be effective throughout the full useful life
of a vehicle. Remaining effective implies no significant
deterioration, contraction, or expansion problems under normal
environmental conditions such that the seal fails to achieve-a
leak-free connection with the fuel nozzle, or the nozzle cannot
be inserted through the fillpipe seal at all. At this time,
durability data do not exist out to the full average life of a
typical LDV, 100,000 miles (10 years), or 120,000 miles (11
years) for LDTs. However, the durability data up to 65,000
miles indicate no reason why the seal would not continue to
perform over its full life. Given this durability data to
65,000 miles, the relative simplicity of the system design, and
the nature of its use, it is reasonable to project that
full-life performance should occur.
3. Effect on Gaseous and Evaporative Emissions
The work conducted by API indicated that purging the
refueling vapors had no significant effect on exhaust
emissions. However, it should be cautioned that the tests were
conducted on 1978 and earlier model year vehicles which had
emission levels higher than today's new vehicles. Also, test
procedures for measuring refueling emissions have not yet been
fully developed and it should be recognized that the test
procedure requirements for purging the vapor recovery canister
could impact exhaust and evaporative emissions. However, it is
expected that through proper design of the onboard control
systems (taking into consideration appropriate purge
requirements), increases in exhaust or evaporative emissions
can be avoided.
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C. Feasibility for LDTs and HDGVs
Even though the API feasibility evaluation project
involved only LDVs, onboard control technology should be
directly and fully adaptable to LDTs. LDV and LDT fuel systems
are practically identical, and both use similar hardware to
comply with the 2.0 g/test evaporative emission standard. The
primary difference between LDVs and LDTs is in the fuel tank
specifications. Analysis of 1984 certification information and
discussions with the manufacturers indicate that, on average,
LDT fuel tanks are about 25 percent larger than LDV fuel tanks,
and about 20 percent of LDTs use dual fuel tanks. A larger
volume fuel tank would require more charcoal in the canister to
accommodate the increased volume of refueling vapors, and LDTs
using dual fuel tanks may require a separate onboard control
system for each tank. However, neither of these differences
has an effect on the conceptual design or technological
feasibility of an onboard control system.
The above considerations apply equally to many of the
smaller HDGVs (those less than 1-4,000 Ibs gross vehicle weight
(GVW)). Approximately 65 to 70 percent of all HDGVs are
essentially LDT derivatives.[5] These HDGVs are essentially
the same as their parent LDTs in their basic chassis, body and
powertrain designs, but have been classified as HDGVs for
purposes of emission control because their GVW, frontal area,
or curb weight are just above the LDT/HDGV cut-off points.
Although these characteristics would have an effect on exhaust
emissions, they would have no effect on the ability to comply
with an onboard vapor recovery requirement. The key parameter
which influences feasibility is fuel tank volume. Most of
these smaller HDGVs have fuel tank sizes similar to the heavier
LDTs, so the onboard systems used on LDTs could be applied
directly to the smaller HDGVs. For those smaller HDGVs with
larger fuel tanks, larger charcoal canister volumes could be
utilized.
The application of an onboard control requirement to many
of the larger, heavier GVW HDGVs is somewhat more complicated.
HDGVs in this group are sold in many different configurations
with different fuel tank sizes and locations. Also, many of
these HDGVs are sold initially as incomplete vehicles by the
primary manufacturer to a secondary manufacturer. In the most
common case, the primary manufacturer produces the chassis and
the secondary manufacturer adds a payload-carrying device. In
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some cases, the overall vehicle fuel capacity is increased by
the secondary manufacturer. In these cases a problem might
arise because the primary manufacturer would have to certify
the onboard control system before it was sold to the consumer,
but the secondary manufacturer could affect the integrity of
the system. Many of these problems are similar to those
encountered and resolved in the recent HDGV evaporative
emissions final rule, which suggests that implementation
problems can be solved. Also, for the foreseeable future,
these heavier GVW HDGVs will be using leaded fuel and will not
have a filler neck restrictor. Thus, the onboard control
system for these HDGVs would require the additional hardware
associated with the filler neck restrictor already present on
vehicles using unleaded fuel if they were to use fillpipe seals
similar to those used on LDVs and LDTs.
Although application of an onboard control requirement to
the heavier HDGVs is not as straightforward as for the lighter
weight HDGVs and may be more costly, there does not appear to
be any technological reason why onboard control would not be
feasible for the heavier GVW HDGVs. One possible approach for
applying an onboard control requirement to HDGVs if costs wer'e
excessive, would be to require control for the lighter weight
HDGVs (under 14,000 Ibs GVW) and defer control for the heavier
weight HDGVs (over 14,000 Ibs GVW).
D. Safety Considerations
In addition to concerns about the performance and
durability of onboard control systems for LDVs, LDTS, and
HDGVs, there are some potential safety considerations which
require evaluation. If a blockage of some type occurs in the
line from the fuel tank to the charcoal canister, pressure
buildups within the system may lead to damage of the fillpipe
seal and possibly a spurt of gasoline from the fuel inlet.
Second, if the automatic shut-off of the gasoline nozzle fails
to operate properly, an overfill of the tank could occur which
also could result in damage to the fillpipe seal and a spurt of
fuel. Third, there is also the possibility that a failure of
the vapor/liquid separator and rollover check valve in the line
from the fuel tank to the canister and an improperly operating
automatic gasoline nozzle shut-off could lead to a tank
overfill and fuel flowing up the line and poisoning the
canister.
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These problems could likely be resolved with a pressure
relief valve which would vent vapor or gasoline overpressure to
the environment should problems occur. However, prototype
pressure relief systems have not been fully developed and
failure modes have not yet been adequately identified and
evaluated. Also, increasing the diameter of the vapor line
from the fuel tank to the charcoal canister and increasing the
vapor flow capacity of the vapor/liquid separator and the
rollover check valve should decrease overpressure problems.
Thus while some questions relative to the safety of an onboard
system remain unanswered, any problems should be solvable with
direct engineering effort.
E. Summary
The work conducted through API and later by ARCO suggests
that onboard control is technologically feasible for LDVs, and
evidence is that in-use durability of these systems should be
excellent. Due to the fundamental similarities between LDVs
and LDTs, onboard control should also be feasible for LDTs. In
fact, the onboard systems would likely be nearly identical with
the possible exception of charcoal canister size.
The demonstrated onboard technology also appears adaptable"
to HDGVs. For those HDGVs of less than 14,000 Ibs GVW (65-70
percent of all HDGVs), the application of onboard technology
would in all likelihood essentially be accomplished through an
extension of LOT systems. The only major difference might be
larger canister sizes to accommodate the larger fuel tanks used
on some of these HDGVs. Onboard systems for the heavier HDGVs
(those whose GVW exceeds 14,000 Ibs) would be somewhat more
complicated and costly, but nevertheless appear practicable.
It should be possible to minimize any effect of an onboard
vapor recovery requirement on exhaust and evaporative emission
levels through the proper design of the onboard system.
There are some potential safety considerations which must
be identified, evaluated, and resolved. However, it is likely
that these can be adequately addressed through the use of a
pressure relief valve within the fuel delivery system.
Although control systems could be applied to HDGVs, we
have not quantified the costs, benefits, and cost effectiveness
for these vehicles at this time. HDGVs comprise only about 3
percent of the gasoline-fueled vehicles produced each year and
represent on the order of 5 percent of annual nationwide total
gasoline consumption.[6] The remainder of this paper
concentrates on the costs, benefits, and cost effectiveness for
LDVs and LDTs.
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III. In-Use Performance of Onboard Systems
A. Introduction
Losses in the effectiveness of in-use onboard systems can
occur through two mechanisms: tampering or deterioration of
the efficiency of the system. Tampering occurs when
individuals purposely disable part or all of the onboard
control system. Tampering could occur with the fillpipe seal
and the charcoal canister and related hoses. System
deterioration occurs when control efficiency of the onboard
system declines with mileage and/or time. Either mechanism
renders the onboard vapor recovery system partially or
completely ineffective. The projected effects of these
mechanisms on onboard system performance are discussed below.
B. Tampering
1. Fillpipe Seal Tampering
It is possible that fillpipe seals could be subject to
tampering similar to that reported for the tampering with
fillpipe restrictors in vehicles using unleaded fuel, since
violation of the leaded fuel restrictor would also destroy the
vapor recovery seal. Fillpipe tampering data is available from
the National Enforcement Investigations Center (NEIC).[7]
These data show substantial differences in fillpipe restrictor
tampering in areas which have inspection/maintenance (I/M)
programs versus non-I/M areas and different levels of fillpipe
tampering for LDVs and LDTs. (See Figure B-l of Appendix B.)
A linear regression of this fillpipe tampering data versus
mileage for 1982 produces the following results:
LDVs; I/M Areas: TAMP = -1.43 + 1.14(M)
Non-I/M Areas: TAMP = -0.78 + 1.65(M)
LDTs; - I/M Areas: TAMP = 3.55 + 1.14(M)
Non-I/M Areas: TAMP = 10.6 + 1.65(M)
Where:
TAMP = Tampering incidence expressed in percent at a
particular vehicle mileage.
M = Mileage/10,000 miles.
It should be noted that the tampering increase rates (the
change in tampering incidence with mileage) for LDVs and LDTs
are the same. This was taken to be the case because the size
of the LOT sample was too small (323 LDTs versus 1,999 LDVs) to'
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allow meaningful rates to be determined. However, the LDT data
were used to derive a mean tampering level for LDTs at the
average LDT mileage, with the LDV tampering rate being applied
to that single point.
However, these tampering rates are conservatively high for
the late 1980's and beyond when an onboard vapor recovery
requirement might be implemented. The primary motive for
fillpipe tampering is to permit the use of somewhat less
expensive leaded fuel in LDVs and LDTs designed to use unleaded
fuel. The tampering rate itself depends on the availability of
leaded fuel, the leaded to unleaded fuel price differential,
and the actual difficulty and other effects of the tampering
process itself. The tampering rates given above are based on
data gathered in the Summer of 1982, when leaded fuel was
readily available at a differential of about five cents per
gallon and fillpipe tampering was a relatively simple process,
usually with no effect on the integrity of the filler neck
itself.
However, in the late 1980's and beyond, leaded fuel will
be generally less available due to lower overall demand, and
with less demand it is possible that the leaded to unleaded
fuel price differential would decrease. In addition, there
were only a handful of I/M programs in place in 1982 when this
data was gathered. As more I/M programs are implemented over
the next few years tampering should decrease. Perhaps most
importantly, the onboard control requirement could be
implemented with a certification performance standard such as
the parameter adjustment requirement for carburetors on
gasoline-fueled vehicles. This requirement would force the
design of filler neck restrictors and fillpipe seals which are
a more integral part of the fillpipe, thus reducing the
accessibility and success of tampering. Therefore, it is
reasonable to project that fillpipe tampering will decrease
markedly by the later 1980's. After briefly considering the
rate of tampering with charcoal canisters and hoses, a
composite tampering rate will be determined for LDVs and LDTs
if fillpipe tampering is reduced by 50 percent due to the
reasons discussed above.
2. Charcoal Canister and Hose Tampering
Tampering with the charcoal canister and related
connecting hoses would also destroy the effectiveness of an
onboard vapor recovery system. Since the control approach
expected by EPA assumes an integrated onboard/evaporative
emissions control system, currently available data on tampering
with evaporative emission systems (canisters/hoses) would be
directly applicable to onboard controls as well. Evaporative*
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emission control system tampering rates are also available from
the National Enforcement Investigations Center (NEIC) for
1982. [7] The tampering rates are different for LDVs and LDTs,
but not different in I/M versus non-l/M areas, since the
evaporative emissions control system is normally not checked
during I/M. (See Figure B-2 of Appendix B.) A linear
regression of this most recent (1982) NEIC evaporative
emissions control system tampering data provides the following
results:
TAMP = -0.55 + .360(M)
TAMP = 2.85 + .360(M)
TAMP and M are as described previously above, and the
explanation regarding the derivation tampering incidence and
tampering rates for LDVs and LDTs is also applicable.
3. Composite Tampering Rates
It would be convenient to have composite tampering rate
equations for LDVs and LDTs for • computing the in-use emission
reductions expected from an onboard vapor recovery system".
Since tampering with either the fillpipe seal or the
canister/hoses would disable the vehicle's onboard system, the
slopes and intercepts of the different tampering equations
given above could simply be added for LDVs and LDTs
respectively. However, this would overstate the total effect
of tampering, because some vehicle owners tamper with both the
fillpipe and the charcoal canister and hoses. Since disabling
either would eliminate the effectiveness of onboard control,
just adding the equations would lead to some double counting.
To determine the degree of overlap in tampering, the
National Enforcement Investigations Center data discussed above
was analyzed. After the overlap tampering was accounted for, a
linear regression of the combined data sets was conducted and
the following regression equations were obtained:
LDVs; I/M Areas: TAMP = -1.47 + 1.442(M)
Non-I/M Areas: TAMP = -1.52 + 2.114(M)
LDTs; I/M Areas: TAMP = 6.42 + 1.442(M)
Non-I/M Areas: TAMP = 13.67 + 2.114(M)
The tampering levels in I/M and non-I/M areas can be
weighted (40 percent I/M and 60 percent non-I/M) according to
the fractions of the U.S. population residing in the two types
of areas. The results of this tampering rate weighting are
shown below.
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LDVS; TAMP = -1.5 + 1.8452(M)
LOTS; TAMP = 10.77 + 1.8452(M)
The weighted composite tampering rate equations given
above are based on current tampering rate data. As was
discussed above, it is likely that tampering will decrease in
the future, thus improving the overall in-use effectiveness of
an onboard vapor recovery program. To estimate this potential
decrease in tampering, the portion of the above composite
tampering rates associated with the fillpipe will be reduced by
50 percent. The portion of the composite tampering rate due
solely to tampering with the fillpipe was taken to be the
difference between the composite rate and the tampering rate
associated with the evaporative HC control system. The result
of decreasing this difference by 50 percent is shown below.
LDVs: TAMP = -1.0 + 1.1026 (M)
LDTs: TAMP = 6.81 + 1.1026 (M)
These projected weighted composite tampering rate
equations will be used in calculating the in-use emissio~h
reductions for onboard vapor recovery control. These equations
will be taken as applicable to 1988 and later model year LDVs
and LDTs.
C. Deterioration
As was discussed above in Section II.B.2., the ARCO seal
durability data show no deterioration of the onboard vapor
recovery system effectiveness with mileage. This is consistent
with historical EPA certification information which shows that
the efficiency of evaporative emission control systems (which
are similar to vapor recovery systems), do not deteriorate with
mileage. Limited in-use testing of LDV and LOT evaporative
emission systems shows that these systems do function as
designed. At the same time, some small loss of effectiveness
with mileage, on the order of a few percent, would appear
reasonable due to contamination of the charcoal, channeling,
aging, leaks, etc. With no data, it is not possible to
estimate this loss quantitatively. However, the tampering
rates of the previous section appear large enough to overwhelm
any expected loss in efficiency due to deterioration. Thus,
the losses in system effectiveness due to tampering will be
taken to include any losses due to deterioration.
IV. In-Use Emission Control Effectiveness
An estimate of the annual or lifetime HC emission
reduction potential of vapor-controlled LDVs and LDTs is a
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function of annual or lifetime mileage, the vehicle's fuel
economy, the uncontrolled refueling emission factor, the
control system effectiveness, and an adjustment factor that
accounts for a loss of effectiveness in-use, (i.e.,
tampering). This relationship on an annual basis is expressed
below:
HC = (VMT)(EF)(NSEFF)(NTAMP)
MPG
Where:
HC = Average annual HC emission reduction per vehicle,
grams.
VMT = Average annual mileage, miles.
MPG = Average in-use fuel economy, miles per gallon.
EP = The uncontrolled refueling loss emission factor, or
4.54 g of HC per gallon of dispensed gasoline.
NSEFP = Onboard control system efficiency of new vehicles-,
or 0.98.
NTAMP = An adjustment factor which discounts for in-use
tampering. NTAMP equals (1-TAMP) for any given year.
Estimates of in-use (over the road) fuel economy for new
LDVs and LDTs are based on projections of fleetwide
improvements for 1988 and later years. Annual vehicle miles of
travel estimates are those used in the EPA emission factors
program.[8] This information is contained in detail in
Appendix B. The new vehicle control system efficiency of 0.98
and the range of tampering rates as a function of mileage were
discussed above.
The uncontrolled refueling loss emission factor (4.54 g
HC/gal) is based on recent work conducted by the California Air
Resources Board (CARB).[9] This figure is 11 percent larger
than the emission factor contained in the EPA emissions factor
document (AP-42). [10] The CARB emission factor was selected
over the AP-42 emission factor for three reasons. First, the
EPA emission factor document expressed uncertainty about it's
emission factor value. Second, the CARB factor is based .on
data at least 5 years more recent than the AP-42 emission
factor. And third, an increase in the emission factor can be
explained by the steady increase in gasoline volatility
(expressed as Reid Vapor Pressure) over the past 10 years.[11]
In fact, information recently submitted to EPA by General
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Motors indicates that 4.54 g/gal may be conservatively low for
today's commercial gasolines.[12]
This equation and these factors may be used to estimate
the lifetime emission reductions for LDVs and LDTs. For any
given model year, the only variable would be the fuel
consumption. The remaining factors for each year of the
vehicle life can be determined and summed to get a single
factor representative for the entire vehicle average lifetime.
Using an average lifetime of 100,000 miles for LDVs and 120,000
miles for LDTs, and assuming that the tampering occurs at the
midpoint in each year, the lifetime HC reduction can be
calculated for any model year.
AL
HC ftonsi - (NSEFF) (EF) <^ (VMT . NTAMP )
HC (tons) - (453.6) (2foOO) (MPG) ^ x x
Working through the mathematics of this calculation, the
following equations have been determined for calculating the
lifetime tons of HC emission reductions for LDVs and LDTs..
These are based on an average lifetime (AL) of 100,000 miles
for LDVs and 120,000 miles for LDTs.
LDVS: HC = «4683
MPG
LDTS: HC = -5095
MPG
With these equations, the average lifetime in-use HC emission
reductions from onboard vapor recovery for any model year LDV
or LOT can be determined using the in-use fuel economy
estimates .in Table B-3 of Appendix B. For example, for 1988
model year vehicles, LDV and LOT reductions of 0.0178 and
0.0264 tons respectively per vehicle, would occur. These will
be used in a later portion of the analysis to calculate the
cost effectiveness.
In addition to computing the annual or lifetime emission
reductions on a per vehicle basis, the nationwide annual
reduction in the overall HC emission inventory can also be
estimated. Determining the reduction in the annual HC
inventory for any given year is a relatively straightforward
calculation involving the annual gasoline consumption of
vehicles employing onboard controls, the emission factor, andv
the in-use control efficiency of those vehicles. The annual
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gasoline consumption of controlled vehicles is a function of
their total registrations, fuel economy, and the annual miles
of travel. These can be expressed mathematically as shown
below.
IR = (EF) (NSEFF) ^ | REGxzSRxzNTAMPxzVMTxz
(453.6) (2,000) z=!
s\ £j
REGyz SRy2NTAMPy2VMTyz
MPGyz
The variables are the same as identified above, and as noted
below:
x = LDVs
y = LDTs
z = time (years)
IR = annual HC inventory reduction (tons)
REG = new registrations of gasoline-fueled LDVs or LDTs in
each year z=l,n
SR = new vehicle survival rate of gasoline-fueled LDVs or
LDTs in each year
The values for these variables are given in Appendix B.
Working through the calculations above, the following
annual inventory reductions are projected from all in-use LDVs
and LDTs with effective vapor recovery systems.
Annual Reductions (tons)
1988 1989 1990 1995 2000
41,200 77,500 108,400 213,300 257,500
One can see that as a greater portion of the LDV and LOT fleet
employs onboard control, the annual reduction in refueling
emissions becomes substantial.
V. Costs of Onboard Vapor Recovery
Two new sources of information on .the costs of onboard
vapor recovery hardware have become available since the
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preparation of the last estimates shown in Appendix A. The
first is a June 1983 draft report entitled "Manufacturing Costs
and Retail Price Equivalent of On-Board Vapor Recovery System
For Gasoline-Filling Vapors," prepared by LeRoy Lindgren under
contract to API. The second is a January 1984 cost estimate
presented by API in their final report on the cost comparison
for Stage II versus onboard control of refueling emissions.
The information contained in Lindgren's report was one input
used by API in their most recent cost estimates for onboard.
No updated cost estimates from the auto industry were available
for this analysis.
In this section of the report, the Lindgren hardware cost
estimates will be reviewed and discussed first. This will be
followed by a discussion of the onboard cost estimates
developed by API and an update of the estimate of the cost of
an onboard vapor recovery system for a current technology LDV
or LOT. This section will close with a discussion of the sales
impact of an onboard control requirement.
A. Lindgren Report
The Lindgren report to API provides an estimate of both
the manufacturer (or vendor) cost and retail price equivalent
(or customer cost) of a complete onboard control system. The
estimates of these two costs are $12.95 and $29.85,
respectively. Tables 1 through 6 of Appendix C (taken from
Lindgren's draft report) contain the bases for these costs.
Lindgren estimated hardware costs for the system
demonstrated by API in 1978. This system is shown in Appendix
A, Figure A-l. This system was a fillpipe seal, additional
charcoal canister, and separate plumbing for the evaporative
emissions and onboard recovery systems. Lindgren attempted to
update these designs for changes in LDV engine and emission
control technology which have occurred since 1978. However,
this was not done properly in every case, and costs for
components already on current technology vehicles were
attributed to the cost of an onboard vapor recovery system.
For example, costs were included for a leaded fuel restrictor
and modifications related to the electronic control unit, both
which would be present on current vehicles.
Although most of Lindgren's component manufacturing costs
appear reasonable, there are two other major deficiencies in
the analysis. First, arithmetic errors were made in several
places in the analysis, and an error was made in calculating
the costs after corporate and dealer markups were added. A
markup factor of 2.3 was used instead of 1.8 as specified by
Lindgren in his report. As was mentioned above, Lindgren
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-15-
estimated a customer cost of $29.85. Correcting these errors
and applying Lindgren's 1.8 standard markup factor brings the
customer cost down to $24.06. Second, based on previous
analyses of Lindgren's cost methodology, standard absorbed
overhead and profit absorption rates appear to be used at the
corporate and dealer levels, rather than incremental rates.
This results in a substantial overestimation of the
contribution of overhead and profit to onboard control costs.
As will be discussed below, it is believed that an incremental
approach to corporate and dealer overhead and profits is
appropriate for emission controls, resulting in a markup factor
of 1.27 rather than 1.8. Using this incremental markup factor
brings Lindgren's estimate to $17.72.
Thus, Lindgren's cost estimates cannot be used directly
here, but will have to be modified to include only the costs of
components incremental to those already on current technology
LDVs and to more accurately reflect appropriate corporate and
dealer markups. This process is described in the next section,
after a review of the cost estimates released by API.
B. API Cost Estimates
In their recent final report comparing Stage II and
onboard costs, API presented their updated cost estimates for
onboard controls.[13] API did not present
component-by-component cost estimates, but only a fleetwide
average cost of $13.43. This estimate included different
canister sizes for LDVs and LDTs and the need for two canisters
on some vehicles. The fleetwide average estimate was
calculated using a cost of $12.07 for LDVs or lighter LDTs with
one canister, $14.47 for LDVs or lighter LDTs with two
canisters, and $20.87 for all heavier LDTs. These costs were
then weighted 70 percent, 20 percent, and 10 percent,
respectively, representing the projected portions of the total
vehicle population. When system development and certification
costs are added, this cost rises to $15.26 per vehicle ( 1983
dollars).
The API cost estimates did not include a retail markup
because they were not certain about what markup figure was
appropriate or how the vehicle manufacturer or dealer might
choose to absorb or pass on costs. If the markup factor of
1.27 is applied, a fleet average cost of $19.38 per vehicle is
obtained. In the section which follows directly, it will be
seen that the marked up API figure is in the range of the
updated estimate of this report.
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-16-
C. Updated Estimate
1. Hardware Costs
The cost estimates here are based on an integrated
evaporative emissions and onboard control system as opposed to
the separate systems on which the Lindgren and API cost
estimates are based. This design is expected to be the
approach preferred by the manufacturers because it makes
optimal use of limited underhood space, simplifies the design,
and reduces cost. The key feature of this design is that one
large charcoal canister can be used for evaporative emissions
and onboard control rather than two separate canisters.
The first step in developing the updated cost estimate was
to decide on what components would make up the system. The
components selected were mostly the same as those used in the
API demonstration program and priced by Lindgren. However,
there are several important differences. First, as was
mentioned above, an integrated onboard/ evaporative emissions
control system was assumed, thus ~ eliminating obvious
redundancies between the two systems. Second, the cost of a
pressure relief valve was included which might be necessary as
discussed previously in Section II. D. And, third, the
components which are present on current vehicles but were not
present on the 1978 vehicles used by Lindgren were excluded.
Once the components of the system were determined, vendor and
retail price equivalent cost estimates were developed using,
and in some cases modifying, the manufacturing cost estimates
provided by Lindgren.
The expected components and their costs are summarized in
Table 1. The vendor costs include material, direct labor, and
direct overhead and have been multiplied by a factor of 1.4 to
account for indirect overhead and profit at the vendor levels.
The 1.4 factor for vendor allocation and profit was taken from
Lindgren's methodology and represents a standard absorbed
overhead rate and rate of return for this industry. These full
rates are appropriate here because the production of the
emission control equipment is the primary business activity for
the vendor and is not incremental in nature.
These vendor costs were then multiplied by 1.27 to
estimate the corresponding retail price equivalent, accounting
for corporate and dealer overhead and profit. Lindgren applied
a factor of 2.3 to account for these factors, though this
appears to be an error, since his own methodology specifies a
factor of 1.8. The 1.8 factor appears, again, to include a
standard absorbed overhead rate for both manufacturer and
dealer and standard profit margins for both. These figures are.
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-17-
Table 1
Onboard Vapor Control Hardware Costs
(1983 dollars)
Component or Assembly
Charcoal Canister LDV/(LDT)
Purge Control Valve
Liquid Vapor Separator
Fillpipe Seal
Pressure Relief Valve
Hoses/Tubing
Miscellaneous Hardware
Vehicle Assembly
Systems Engineering/Certification
Incremental Costs
Vendor
$3.99/(7.83)
0.74
0.71
1.12
0.44
1.90
0.40
LDV Totals:
LOT Totals:
Vendor
Vendor
Retail Price
$5.07/(9.94)
0.94
0.91
1.42
0.56
2.41
0.51
1.00
— 0.50
$9.30 Retail $13.32
$13.42 Retail $18.19
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-18-
not appropriate here because adding emission control equipment
is only incremental to the primary business of assembling
automobiles, and overhead and applied assets are not entirely
variable with respect to vendor cost, but have significant
fixed components. This is particularly true for the dealer,
who would experience almost no effect due to the added
equipment. The 1.27 factor is the result of an incremental
analysis of corporate and dealer overhead and profit which was
performed as part of a recent EPA mobile source regulatory
analysis for LDVs and LDTs.[14]
The size of the carbon canister in Table 1 is that
associated with a fuel tank which would give an in-use driving
range of about 300 miles. Using the in-use fuel economy
projections of Appendix B (Table B-3) for 1985-90, LDVs would
require an average fuel tank size of 10-13 gallons, LDTs would
require an average fuel tank size of 14-18 gallons. To be
conservative, in each case, the higher end of the ranges in
fuel tank sizes was used to size the canisters.
As shown in Table 1, an onboard vapor recovery system is
expected to carry a consumer cost of $13.32 for LDVs and $18.19
for LDTs. Those LDTs using dual-fuel tanks (approximately 20
percent) may require two separate onboard control systems for a
total cost of $36.38. This is a conservative assumption since
costs could likely be reduced by using one large charcoal
canister rather than two separate canisters.
A fleetwide estimate for all LDVs and LDTs can be
determined by sales weighting the costs given above. Using the
projected sales for 1988 from Appendix B (Table B-3), and
assuming 20 percent of LDTs have dual-fuel tanks, the fleetwide
average cost is calculated to be $15.08 as shown below. For
future calculations this cost will be rounded to $15 per
vehicle.
(10.582M) ($13.32) + (2.768M) ( (.8) ($18.19) + (. 2) ($36.38))=$15.08
13.35M
This estimate of $15.08 is comparable to API's estimate of
$19.38 after application of the 1.27 markup factor and
Lindgren's estimate of $17.72 after corrections and using the
1.27 incremental markup factor. The main reason for the
difference between this estimaJbe_and those developed by API and
Lindgren is because >^E_PA^' assumed an integrated
onboard/evaporative emission control approach as opposed to two
separate systems.
2. Differences Between Past and Current •• EPA N Cost
Projections '' ' -
EPA's February 1980 report projected a fleet average cost
of $19.70. When inflated to 1983 dollars, this cost becomes
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$26 per vehicle. There are three reasons for the overall
decrease of $11 between this cost estimate and the previous
estimate.
First, the 1980 projection used a 1.8 retail markup
factor. As discussed above, it is now believed that a 1.27
markup factor is more appropriate; this change alone accounts
for approximately 70 percent of the cost difference.
The second reason is related to changes in system mixes.
The 1980 projection assumed higher costs in some cases due to
the use of two canisters rather than one larger canister, or
due to a manufacturer not choosing an integrated
onboard/evaporative emissions control approach. This accounts
for another 23 percent of the difference.
Third, there have been changes in the components
anticipated to make up an onboard control system and the prices
for some components (notably the fillpipe seal). This accounts
for the remaining 7 percent of the cost difference.
3. Fuel Economy Impacts
As was stated in the previous EPA report (Appendix A), the
implementation of an onboard vapor recovery requirement would
not be expected to impact LDV or LDT fuel consumption.
Hydrocarbons retained by the onboard canister represent about
0.1 to 0.2 percent of vehicular fuel consumption. The use of
this fuel by the engine could thus be expected to decrease fuel
consumption by this amount. However, the additional fuel
needed to transport the added weight of the onboard system is
also in this range. Thus, no net change in fuel consumption is
expected.
4. Overall Cost Estimate
As discussed in the previous two sections, the updated
LDV/LDT cost estimate is about $15 per vehicle and there is
adequate explanation as to why this cost is well below that of
February 1980. However, there are still reasons to believe
that the total cost of onboard control could be somewhat
greater than $15 per vehicle.
One, this figure includes primarily hardware cost and
excludes any costs associated with possible fuel tank
modifications, modifications to the vapor line and rollover
check valve between the fuel tank and the vapor canister,
modifications to make the fillpipe more tamper-resistant, and
general packaging costs to fit the integrated
onboard/evaporative emissions control system into the vehicle.
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Also, there may be some cost related to manufacturer-specific
electronic control unit (ECU) modifications. For example, some
manufacturers may desire to use specific canister purge cycles
which may require reprogramming or modification of their ECUs.
Finally, since the actual pressure relief valve discussed above
has not been identified, there is some uncertainty in the cost
for that component.
Two, except for the allowance of a dual system for LDTs
with two fuel tanks, the system considered herein is somewhat
ideal. Completely integrated onboard/evaporative emission
control systems are assumed in every case, and this simply may
not be possible. For reasons of canister production economies
of scale, underhood packaging restrictions, or for unique
vehicle models, manufacturers may choose a non-integrated two
canister system similar to those considered by API. As was
discussed above, a non-integrated system would increase the
costs over those shown in Table 1.
Three, in the final analysis, the actual canister size and
purging system will depend on the details of the test procedure
implemented to measure compliance with an onboard vapor
recovery requirement. Factors such as the degree of
interaction between the evaporative emissions and onboard test
procedures and whether the charcoal canister would have to be
purged during the exhaust emissions test will affect the size
of the charcoal canister and the complexity of the purging
system. These in turn would affect the overall cost of the
onboard system.
To account for these and other potential costs, a range of
$15-25 per vehicle will be used rather than the single cost of
$15 per vehicle. While the final cost is expected to be closer
to $15 rather than $25, the use of $25 as an upper limit will
allow the sensitivity of any subsequent decisions to this cost
to be addressed.
D. Impact On Sales of LDVs and LDTs
An average purchase price increase of $15 to $25 is
expected to have no discernible impact on the sales of LDVs or
LDTs and, therefore, no effect on the profitability of the
companies comprising the regulated industry. The "own price
elasticity of demand" for LDVs and LDTs (that ignoring any
crossover purchases in other vehicle classes) is approximately
-1.0, which means that for each 1 percent increase in price,
sales drop 1 percent. With the price of an average new LDV or
LOT now exceeding $10,000, a $15 to $25 first price increase
would be predicted to decrease sales by no more than 0.15 to
0.25 percent. However, there is some question whether the
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-21-
elasticity of demand is even meaningful in measuring the sales
impact of a $15 to $25 increase. Such an increase would tend
to be lost in the annual price increases occurring at the time
of model year introduction.
Furthermore, onboard controls are not expected to affect
operating and maintenance costs, nor significantly affect the
owner's experience of refueling. Thus, there should be no
non-economic resistance which will affect sales or
satisfaction. In the long term, an onboard vapor recovery
requirement should have no perceptible impact on the sales or
profitability of either the manufacturers or dealers.
VI. Cost Effectiveness
The cost effectiveness of onboard control can be
calculated using the LDV and LDT in-use emission reduction
equations developed in Section IV and the range in the average
costs of control calculated in Section V. The in-use emission
reduction varies with each model year' s.vehicles depending on
the fuel economy, and the average cost varies somewhat based on
relative sales of LDVs and LDTs. The 1988 model year will be
used here, since it is possibly the first model year in which
an onboard requirement could be implemented.
Referring to Appendix B (Table B-3) , the 1988 LDV and LDT
fuel economies are 26.30 and 19.28 mpg respectively, and the
sales are 10.582 and 2.768 million, respectively. Using these
fuel economy figures, the lifetime reduction for LDVs is 0.0178
tons and for LDTs the lifetime reduction is 0.0264 tons. Sales
weighting these figures, the fleetwide average lifetime tons
reduction is 0.0196 tons. Dividing these figures into the
range of fleet average weighted cost of $15-25 per vehicle,
yields an average lifetime cost-effectiveness value of $766 to
$1,277 per ton. As shown in Table 2, this cost-effectiveness
value falls in the range of values for other mobile source
related HC. control strategies, though nearer the end.
On an annual basis, the cost effectiveness is somewhat
larger. Using a 10-year vehicle life for LDVs and LDTs, a 10
percent discount rate, and assuming payment in mid-year,
annualization of the $15 to 25 lifetime cost yields an annual
cost of $2.34 to 3.90. Assuming annual mileage is constant for
the ten years, the 0.0196 fleet-weighted lifetime tons
reduction converts to 0.00196 tons annual emission reduction.
The annual cost effectiveness is then about $1,194-1,990 per
ton. The simplifying assumption of constant annual mileage
results in a slight overestimation of this figure, since annual
mileage is higher early in the vehicle's life. Nevertheless,
this provides a valuable additional way of looking at the cost'
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-22-
Table 2
Cost Effectiveness of Mobile Source HC
Control Strategies (1983 $/ton) [1]
Control Strategy
Cost Effectiveness
HDGV Evaporative Control
HDGE Useful Life
LDT Useful Life
LOT Statutory Standard
HDDE Statutory Standard
HDDE Useful Life
Interim High-Altitude Standards
Onboard Vapor Recovery (with evap. benefits)
LDV Statutory Standards
Motorcycle Standards
Onboard Vapor Recovery (w/o evap. benefits)
I/M
Auto Coatings
Transit Improvements
$112
$100-200
$406
$207
$319
$323
$416
$435-725
$508
$616
$766-1,277
$943
$1,301
$15,767
[1] Short ton
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-23-
effectiveness of an onboard requirement, especially when the
cost effectiveness of an onboard requirement is compared to HC
strategies where the cost effectiveness is calculated on an
annual basis.
This estimate of the cost effectiveness of onboard vapor
recovery only considers the emission reductions derived from
eliminating refueling losses. However, preliminary data from
EPA's emission factors program indicates that in-use
evaporative emissions appear to significantly exceed the
evaporative HC standard. This occurs primarily because in-use
fuels typically have higher volatility than the fuel specified
for certification testing and, therefore, produce larger
amounts of evaporative HC which cannot be adsorbed by the
current charcoal canisters. Preliminary estimates of the level
of these excess evaporative emissions can be made using the
data currently available from EPA's evaporative emission
factors testing program which is now in progress. This program
involves evaporative emission testing using Indolene
(certification) and commercial fuel in carbureted and
fuel-injected vehicles. Based on preliminary data from this
program, it is estimated that LDVs have evaporative emissions
in the range of 0.23 to 0.44 g/mi using commercial fuel arid
0.16 to 0.24 g/mi using certification fuel, yielding an excess
in the range of 0.07 to 0.20 g/mi. A best estimate at this
time based on this preliminary data is evaporative emissions of
0.33 g/mi using commercial fuel and 0.20 g/mi using
certification fuel, for an excess of 0.13 g/mi. Although data
is not available for LDTs, one would expect results in the same
ranges since LDV and LOT evaporative control systems are very
similar. Simply multiplying the best estimate of these excess
evaporative emissions by the average lifetime for LDVs and LDTs
(100,000 and 120,000 miles, respectively) and converting to
tons yields lifetime excess emissions of 0.0143 tons for LDVs
and 0.0172 tons for LDTs. The fleet-weighted LDV/LDT per
vehicle excess would be 0.0149 tons of HC lifetime or 0.0015
tons annually.
Since refueling only occasionally coincides with the
occurrence of evaporative emissions, the larger charcoal
canister associated with an integrated onboard/evaporative
emission control system could also control these excess
evaporative emissions at little or no extra cost. Adding these
benefits to those from onboard control improves the cost
effectiveness by approximately 43 percent. If all excess
evaporative HC emissions were controlled, the lifetime cost
effectiveness of onboard control would become $435 to $725 per
ton and the annual cost effectiveness would become $678 to
$1130 per ton.
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-24-
As indicated above, the in-use evaporative emissions data
is preliminary as all testing has not been completed. As
additional data become available, it will be possible to make a
firmer estimate of excess in-use evaporative emissions.
However, regardless of the magnitude of excess in-use
evaporative emissions, the onboard control system does have the
potential to control a large portion of these excess
emissions. This additional HC control, if credited towards
onboard control, would improve its cost effectiveness. While
not central to the issue of controlling refueling emissions
through onboard vapor recovery, this potential for control of
excess in-use evaporative emissions provides an additional
perspective on the value of implementing an onboard vapor
recovery requirement.
VII. Leadtime Requirements
If an onboard vapor recovery requirement were implemented,
it is estimated that approximately 24 months of leadtime would
be necessary before the systems could be required on production
LDVs and LDTs once a rule is promulgated. This leadtime
estimate is based on engineering judgment, and on leadtimes
necessary in similar, previous EPA rulemakings. These include
the original 1978 6.0 g/test LDV/LDT evaporative emission
standard which was implemented in just one year, the 1985 HDGV
evaporative emission standard which will be implemented with
two years of leadtime, and the 1981 2.0 g/test LDV/LDT
evaporative emission standard which was also implemented in two
years. The two-year leadtime estimate to implement an onboard
vapor recovery program is based on the following considerations.
A program to comply with an onboard requirement would
first include approximately six months for the
vendors/manufacturers to develop and optimize working prototype
systems applicable to all of their different vehicle models.
Next, initial verification of the fillpipe seal and pressure
relief valve durability could be conducted in two months or
less under laboratory conditions. However, purge system
optimization and optimization and proveout of the integrated
onboard vapor recovery/evaporative emissions control system
would require some vehicle testing, as would verification of
the efficiency and durability of the fillpipe seal and pressure
relief valve. This vehicle testing would require four to six
months, based on manufacturer estimates for similar in-vehicle
testing programs. Thus, prototype testing and proveout is
estimated to take 12 to 14 months to complete.
Although many of the components of an onboard system would
be "off-the-shelf" or readily fabricated from existing
production tooling, some tooling changes would be necessary for'
some components, such as larger charcoal canisters. However,
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the critical items in terms of production tooling are the
fillpipe seal and pressure relief valve. If the fillpipe seal
and pressure relief valve used are some form of currently
available component, then only the question of capacity
exists. Capacity is necessary to meet long term demand in
excess of 13 million units per year. If the vendors and
manufacturers ultimately settle on prototype designs which
would require significant tooling changes or completely new
production, or if current production capacity is insufficient,
then longer tooling leadtimes may be required.
In any event, commitments leading to production tooling
changes could probably be made after the initial laboratory
verification of the fillpipe seal and pressure relief valve
durability. If vendors/manufacturers are able to use seals
similar to those used in the 1978 vehicle demonstration program
and an acceptable pressure relief valve is available, then
total tooling leadtimes of three or four months would be
necessary. If fillpipe seals and pressure relief valves must
be procured from modified tooling, then leadtimes of six to
eight months are reasonable. If new tooling must be developed,
then leadtimes for tooling will require approximately 12 months
or perhaps longer. Thus, the range for tooling leadtimes i-s
three months to one year or more, depending on the source of
the fillpipe seals and pressure relief valve. Assembly line
tooling changes would be handled during normal model year
changeover, and thus would have no effect on this estimate.
Finally, some time would be required to allow for the
normal EPA certification process. It normally requires a
manufacturer 10 to 12 months to certify its entire product
line.[15]
Given these estimates of the leadtime necessary for
development, laboratory testing, in-vehicle testing, tooling,
and certification, Figure 1 shows how these different estimates
were put together to arrive at a leadtime estimate of two
years. The critical path on this figure is 6 months for
development, 2 months for laboratory testing, 4 to 6 months for
in-vehicle testing, and 10 to 12 months for certification.
Presuming that tooling commitments can be made after the
laboratory testing is concluded, tooling is not a critical path
even if the fillpipe seal and pressure relief valve required
new tooling. Tooling would only become a concern if
commitments were delayed until after the completion of
in-vehicle testing (12-14 months).
In summary, a leadtime period of two years appears
reasonable to implement an onboard requirement. Of course, the
model year of implementation for an onboard requirement would,
depend on when a final rule was promulgated.
-------
Figure 1
»
Onboard Vapor Recovety Leadtime
I
Certification
I
to
If If If
Current Tooling Modified Tooling New Tooling
3~4 mo- 6-8 ,mo. 12 mo.
1 1
Tooling
Lab
Prototype
I
Development
Testing In-Vehicle Testing
-t-
FRM
Promulgation
12
MONTHS
15
18
21
24
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-27-
VIII. Onboard Control Versus Time
When considering the implementation of onboard controls,
it is of value to determine how much time would be required to
gain control of a majority of the annual LDV and LOT gasoline
consumption. This, of course, depends on the vehicle scrappage
and replacement rates, the annual vehicle miles of travel and
the vehicle fuel economies. Consequently, the portion of total
LDV and LDT fuel usage (and accompanying refueling emissions)
which would be controlled as a function of time beginning with
the model year of implementation is estimated below. For this
analysis it is assumed that implementation begins in the 1988
model year.
A. Total Fuel Consumption
To determine the portion of total LDV and LDT fuel
consumption controlled as a function of time the controlled and
total LDV and LDT fuel consumption must be estimated by
calendar year. A total gasoline consumption by a specific
model year's vehicles in a given calendar can be derived using
the expression given below:
GC - (REG)(SR)(VMT)(VMTGR)
(MPG)(ODOM)
where:
GC = gasoline consumption (gallons)
REG = new vehicle registrations for that model year
(function of model year)
SR = survival rate of new vehicles in the calendar year of
interest (function of age)
VMT = average annual mileage of the vehicles (function of
age)
VMTGR = growth rate in average annual mileage of the vehicle
(function of model year)
MPG = new vehicle in use fuel economy (function of model
year)
ODOM = Usage pattern factor to account for the different mix
of urban/rural driving and average daily mileage on
average in-use fuel economy (function of age)
Data for the input parameters described above sis provided-
and referenced in Appendix B. However, a few explanatory notes
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are appropriate. First, the approach used here models total
LDV and LOT fuel consumption using twenty model years of LDV
and LOT registrations (e.g., 1988 fuel consumption would be
modeled using registrations from 1988 to 1969 inclusive) .
While it is recognized that there are a small number of LDVs
and LDTs older than 20 years still in-use, their contribution
to total fuel consumption is relatively insignificant due to
their low registrations and average annual VMT. Second, Table
B-2 contains average annual VMT data for LDVs and LDTs. This
data is applicable for pre-1982 model year LDVs and LDTs. For
1982 and later LDVs and LDTs, average annual VMT was projected
to increase at a rate of 0.8 percent per year for LDVs and 0.4
percent per year for LDTS. [16] Last, calculation of fuel
consumption included a usage pattern factor (ODOM) to account
for the fact that the mix of urban/rural driving and the daily
vehicle miles of travel both change as an LDV ages, and this
affects the in-use fuel economy in any given year of a
vehicle's life. This applies to LDVs only. [16]
Given this data, total LDV and LOT fuel consumption in any
given calendar year can be calculated by simply determining the
fuel consumption of each model years LDVs and LDTs in the year
of interest and summing the consumption from each model yearrs
LDVs and LDTs to derive a total. This method of calculation is
shown mathematically in the expression given below:
V 7 (VMT GRv
v, z _ v , z _ v ,
(MPG^x)(ODOMVfZ)
(REGt,x)(SRt,z)(VMTt,z)(VMT GR
(MPG )
t, x
— r --
v = LDVs, t = LDTs, x = model year, y = years,
z = vehicle age
In this method of calculation y = 1 would be the calendar year
of interest, and all data used would begin with that year and
then going back 20 years. Total fuel consumption would be
determined by summing the consumption of the most recent 20
model years LDVs and LDTs in the calendar year of interest.
B. Controlled Fuel Consumption
Calculation of the controlled fuel consumption requires
only two additions to the discussion given above. First, since
controlled consumption is not assumed to begin until 1988, the
period over which controlled consumption will be calculated
varies from 1 model year in 1988 to 13 model years in 2000 (or
presumably longer were more data available with which to,
calculate controlled consumption after 2000). Second, as was
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-29-
discussed previously, tampering with the fillpipe or
evaporative emission system will eliminate the control
effectiveness of the onboard vapor recovery system of those
vehicles. Thus, the fuel consumption of tampered LDVs and LDTs
must be factored out. This can be accomplished using the NTAMP
factor described previously. NTAMP is a function of mileage
and is different for LDVs and LDTs. For any given mileage in
the life of an LDV or LOT, NTAMP = 1-TAMP, where TAMP is the
percentage tampering calculated using the projected composite
tampering rate equations given in Section III.B.3. The mileage
used in the tampering rate equation for each model years LDVs
and LDTs includes the growth rate decribed above for LDVs and
LDTS.
Controlled fuel consumption in any calendar year is then
the sum of the fuel consumption of each model year's
non-tampered LDVs and LDTs in the calendar year of interest.
This method of calculation is shown mathematically below. The
only difference between this and the previous expression is the
limits on the summation and the inclusion of the tampering
factor.
Controlled = (REGV,X) (SRVyZ) (VMTVyZ) (VMTGRV/X) (NTAMPv/m)+
(MPGVfX) (ODOM^)
(REG t,x> (SRt,2> (VMTt,z> x)(NTAMPt,m>
(MPG )
t, x
C. Discussion of Results
The portion of the total LDV and LOT fuel consumption
controlled in any calendar year, 1988 or later, can now be
calculated. Figure 2 compares LDV and LOT gasoline consumption
which would be controlled by an onboard vapor recovery
requirement to total LDV and LOT gasoline consumption, assuming
onboard controls were first introduced with 1988 model year
LDVs and LDTs. Table 3 is a tabular summary of the graphical
information presented in Figure 2. This data shows that
control of 50 percent of all LDV and LOT fuel consumption would
be achieved 5 to 6 years after introducing an onboard vapor
recovery requirement and control of more than 84 percent of all
LDV and LOT gasoline consumption would be achieved by 2000 (13
years after control is implemented). Without tampering,
control in the year 2000 would exceed 92 percent; control of
approximately 8.5 percent of consumption is lost due to
tampering.
In terms of the separate LDV and LOT fleets, control of 50
percent of LDV fuel consumption would be achieved in about 5
years and by 2000 89 percent of LDV gasoline consumption would
-------
-30-
Table 3
Gasoline Consumption of Non-Tampered Vehicles
With Onboard Emission Control
Compared to Total Vehicle Fuel Consumption
LDV Gas Consumption (billions of gallons)
Total LDV LDV Gas Consumption
Year Gas Consumption Controlled Vehicles Percent Control
1988
1989
1990
1991
1992
1993
1994
1995
1995
1997
1998
1999
2000
Year
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
49.0
48.0
46.9
45.9
45.0
44.0
43.1
42.3
41.6
41.0
40.5
40.2
40.0
LOT Gas
Total LOT
Gas Consumpt
24.4
24.0
23.4
23.0
22.7
22.4
22.2
22.1
22.1
22.0
22.0
22.0
22.2
6.0
11.3
15.8
19.8
23.2
26.1
28.4
30.3
31.9
33.1
34.2
34.9
35.5
Consumption (billions of gallons)
LDT Gas Consumption
ion Controlled Vehicles Percent
2.4
4.5
6.3
8.0
9.5
10.9
12.1
13.2
14.2
15.0
15.8
16.5
17.0
12.2
23.5
33.7
43.1
51.6
59.3
65.9
71.6
76.7
80.7
84.4
86.8
88.8
Control
9.8
18.8
26.9
34.8
41.9
48.7
54.5
59.7
64.3
68.2
71.8
75.0
76.6
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-31-
Table 3-Cont'd
Gasoline Consumption of Non-Tampered Vehicles
With Onboard Emission Control
Compared to Total Vehicle Fuel Consumption
LDV and LPT Gas Consumption (billions of gallons)
LDV &
Total LDV & LDT LDT Gas Consumption
Year Gas Consumption Controlled Vehicles " Percent Control
1988 73.4 8.4 11.4
1989 72.0 15.8 21.9
1990 70.4 22.1 31.4
1991 69.0 27.8 40.3
1992 67.7 32.7 48.3
1993 66.4 36.9 55.6
1994 65.3 40.4 61.9
1995 64.4 43.5 67.5
1996 63.6 46.1 72.5
1997 63.0 48.2 76.6
1998 62.5 49.9 79.8
1999 62.2 51.4 82.6
2000 62.2 52.5 84.4
-------
80 *
70 .
60 .
50 ,
CO
c
o
3 40
W
C
o
HJ
30
20
10
A
-32-
Figure 2
Controlled vs. Total Gasoline
Consumption for LDVs and LDTs
1988 - 2000
Total Consumption
Controlled Consumption
Controlled Consumption
Controlled Consumption
LDV & LDT
LDV
LDT
1 1 1 1 f. » 1 i 1 1 1 «
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 -2000
-------
-33-
be controlled. For LDTs, 50 percent control would require 6
years and 77 percent control would be achieved by 2000.
This method of determining the time for achieving control
of refueling emissions differs slightly from that used by
Lindgren,[17] which estimated the fraction of the vehicle
population which would be equipped with onboard gasoline vapor
controls over time. The fraction of dispensed gasoline
controlled is more appropriate than the fraction of vehicles
controlled, since refueling loss emissions are a function of
the amount of gasoline dispensed and not simply a function of
the number of vehicles in the fleet.
IX. Conclusions
The data from the API demonstration program and the
manufacturers' previous comments both indicate that onboard
control of refueling emissions from LDVs, LDTs, and lighter
weight HDGVs should be technologically feasible using a
fillpipe seal and an integrated onboard/evaporative emission
control system. Onboard control should also be feasible for
the heavier HDGVs, but the systems used on heavier HDGVs would
be somewhat more complex and costly. The implementation issue's
for the control of heavier HDGV refueling emissions could be
worked out in a manner similar to the approach used in the
recent HDGV evaporative emissions final rule, so control of
virtually all of the gasoline-fueled motor vehicles may be
possible. Implementation of an onboard requirement should have
a negligible impact on the vehicle's exhaust emission levels.
An in-use control efficiency of 98 percent is expected,
with negligible deterioration for a well-maintained vehicle.
Using the tampering rates expected in the late 1980's and
beyond, owner tampering with the filler neck restrictor and the
charcoal canister could reduce the average lifetime efficiency
to 91.8 percent for the sales-weighted fleet of LDVs and LDTs.
Using 1988 projected fuel economies for LDVs and LDTs, the
fleet average lifetime reduction in refueling HC emissions is
.0196 tons per vehicle.
An integrated onboard/evaporative emission control system
is expected to carry a fleet average cost of $15 to $25 per
vehicle, although the average should be nearer $15.
Implementation of an onboard requirement would not increase
lifetime operating or maintenance costs. At $15-$25 per
vehicle, an onboard requirement would have no perceivable
impact on manufacturer or dealer sales.
Using the costs and emission reduction benefits mentioned
above, the sales-weighted lifetime cost effectiveness for-
-------
-34-
onboard control is $766 to $1,277 per ton of HC controlled.
The annual cost effectiveness is $1,194 to $1,990 per ton of HC
controlled.
The larger charcoal canister of an integrated onboard/
evaporative emissions control system could potentially control
excess in-use evaporative emissions. If the preliminary best
estimate of these benefits is added to those achieved by
onboard control, the lifetime cost-effectiveness values fall to
$435 to $725 per vehicle and the annual cost effectiveness
becomes $678 to $1130 per vehicle.
An onboard requirement could be implemented two years
after promulgation of a final rule. Control of refueling
emissions from 50 percent of the total annual nationwide LDV
and LOT gasoline consumption could be achieved in five years.
Control of refueling vapors from more than 84 percent of total
annual nationwide LDV and LOT gasoline consumption could be
achieved by 2000.
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-35-
References
1. "On-Board Control of Vehicle Refueling Emissions
Demonstration of Feasibility," API Publication No. 4306,
October 1978.
2. "Recommendation On Feasibility For On-Board
Refueling Loss Control," U.S. EPA, OMSAPC, February 1980.
3. See reference 1, p. 25.
4. Letter, F. L. Voelz, ARCO to E. P. Crockett, API,
January 14, 1982, and follow-up telephone conversation between
M. Reineman, U.S. EPA and F. L. Voelz, ARCO, August 18, 1983.
5. "Staff Report, Issue Analysis - Final Heavy-Duty
Engine HC and CO Standards," U.S. EPA, OANR, QMS, ECTD, SDSB,
March 1983.
6. "Transportation Energy Data Handbook," Sixth
Edition, ORNL-5883, Oak Ridge National Laboratory, 1982.
7. "Motor Vehicle Tampering Survey - 1982," U.S. EPA~, "
National Enforcement Investigations Center, Larry Walz,
EPA-330/1-83-001, April 1983.
8. "Draft Mobile 3 Documentation," data provided by
Lois Platte, U.S. EPA, OMS, February 14, 1984.
9. "A Report to the Legislature on Gasoline Vapor
Recovery Systems For Vehicle Refueling at Service Stations,"
California Air Resources Board, March 1983.
10. "Compilation of Air Pollutant Emission Factors,
AP-42, Supplement 9," U.S. EPA, OAQPS, July 1979.
11. "Trends in Motor Gasolines: 1942-1981", E. Shelton,
et al, U.S. Department of Energy, DOE/BETC/Rl-82/4, June 1982.
12. "Decision: Vapor Recovery Control Strategy,"
General Motors Corporation briefing to EPA, February 3, 1984.
13. "Cost Comparison For Stage II and On-Board Control
of Refueling Emissions", American Petroleum Institute,
January 1984.
14. See for example the Regulatory Analysis and Summary
and Analysis of Comments prepared in support of the light-duty
diesel particulate regulations for 1982 and later model year
light-duty diesel vehicles. Both are available in Public'
Docket No. OMSAPC 78-3.
-------
-36-
References (cont'd)
15. Trap Oxidizer Feasibility Study", U.S. EPA, OANR,
OMSAPC, ECTD, SDSB, March 1982.
16. "The Highway Fuel Consumption Model - Ninth
Quarterly Report, prepared by Energy and Environmental
Analysis, Inc., for U.S. Department of Energy, February 1983.
17. "Manufacturing Costs and Automotive Retail Price
Equivalent Of On-Board Vapor Recovery System For
Gasoline-Filling Vapors," Leroy H. Lindgren, Consultant, Draft
Report, June, 1983.
-------
APPENDIX A
Onboard Technology Assessment
-------
December 1978
Recommendation on Feasibility
for
Onboard Refueling Loss Control
NOTICE
Technical Reports do not necessarily represent final EFA decisions
or positions. They are intended to present technical analysis of
issues using data which are currently available. The purpose in
the release of such reports is to facilitate the exchange of tech-
nical information and to inform the public of technical develop-
ments which may form the basis for a final EPA decision, position
or regulatory action.
Standards Development and Support Branch
Emission Control Technology Division
Office of Mobile Source Air Pollution Control
Office of Air, Noise and Radiation
U.S. Environmental Protection Agency
-------
I. Introduction
Refueling loss hydrocarbon emissions, estimated to be in the
range of 4-5 g/gallon, can be controlled by use of control equip-
ment at the service station (Stage II control) or by use of control
equipment in the vehicle (onboard control). As required by the
1977 amendments to the Clean Air Act, the Emission Control Techno-
logy Division (ECTD) of EPA has reviewed and analyzed available
data on the feasibility and desirability of onboard refueling loss
control which will be discussed in this report. This information
will be combined by the Office of Policy Analysis with available
Stage II control information to provide the basis upon which the
Administrator may choose the best of the two strategies.
II. Summary of Conclusions and Recommendations
Several hardware demonstrations and paper studies, Ref. 1, 2,
have been conducted to determine the technical feasibility and cost
effectiveness on onboard refueling loss control. Much of the
current information is from the American Petroleum Institute (API)
onboard demonstration program, Ref. 3. Other current information
was obtained from motor vehicle manufacturers in response to a June
27, 1978 Federal Register (43FR 27892) request for relevant informar
tion. These demonstrations and analyses deal with the state-of-
the-art emission control technology.
Analysis of this information supports the following conclu-
sions:
1. Onboard refueling loss control is feasible for light-
duty vehicles;
2. The most probable control system uses hydrocarbon adsorp-
tion on charcoal (the same strategy that is used for evaporative
emission control);
3. Control effectiveness can be as high at 97% but depends
especially upon the vehicle fillpipe/service station nozzle inter-
face and upon control technology design;
4. An analysis of data from three fillpipe/nozzle concepts
(fillpipe seals, nozzle seals, and combination fillpipe/nozzle
seals) shows that the effectiveness of all three concepts is
approximately equal. Durability effects have not been extensively
evaluated, especially for the nozzle seal concept;
5. A vapor/liquid pressure relief valve is required tb
protect the integrity of the vehicle fuel tank during the refueling •
process. The pressure relief valve can be designed to function on
the fuel nozzle, or it may be incorporated as part of the fillpipe
-------
-2-
seal mechanism, which would be sealed-off by the fuel cap during
vehicle operation. Durability effects have not been evaluated for
either the fillpipe or nozzle pressure relief. ECTD recommends
that the fillpipe/nozzle seal and pressure relief be located on the
vehicle if onboard controls are required.
6. Cost to the consumer for control of refueling losses on
light-duty vehicles will probably range around $17/vehicle. The
$17 estimate does not include costs for a seal or pressure relief.
Cost for a seal and pressure relief, if used on the vehicle, is
estimated to be about $2.70. The cost of a seal on the nozzle
should be the same as the cost for a Stage II nozzle. Except for
the as yet undefined durability of the interface seal no mainte-
nance costs are expected;
7. The feasibility of controlling refueling loss emission
from gasoline fueled trucks and diesel fueled vehicles has not been
evaluated to date. Technical feasibility and cost effectiveness of
controlling these sources should be determined;
8. Minor increases in CO exhaust emissions seen for some of
the vehicles can probably be controlled by minor changes to either
the refueling loss control system or to the exhaust emission
control system. The ability to certify a vehicle to a 3.4 g/mi CO
standard to 50,000 miles should not be seriously impaired;
9. The use of a bladder in the fuel tank appears to be a
viable alternative control strategy, but some problems exist and
technical feasibility is yet to be demonstrated.
10. Considering the lead time needed for regulation develop-
ment and review within EPA and the lead time required by the
industry for development and application of technology, implemen-
tation of onboard controls cannot occur before 1983.
ECTD recommends that the choice between onboard control and
Stage II control of refueling loss emissions be based upon the
relative cost effectiveness of the two strategies for the same
overall level of control and air quality considerations.
It is recommended that methods of reducing the cost of onboard
refueling control systems be examined by considering tradeoffs
between control system capacity and cost. It may be possible to
sacrifice some capacity that is only required under infrequent
conditions and achieve proportionately more significant cost
savings.
The feasibility and desirability of control of refueling
losses from light and heavy-duty gasoline fueled trucks and from
diesel fueled vehicles should be considered. EPA should support
the development of the bladder tank alternative for refueling loss
-------
-3-
control strategy. If regulations are to be developed for onboard
refueling loss control, a certification test procedure must be
developed.
III. Review of Available Information
The data and information summarized in this section are based
on material submitted to EPA by the American Petroleum Institute
and information received in response to a request for information
(43FR 27892) published on June 27, 1978. The API material, Ref. 3,
is the result of their most recent study to assess onboard techni-
cal feasibility and compare the cost effectiveness of onboard
refueling controls and Stage II controls. This study was initiated
at the urging of EPA. Respondents to the Federal Register notice
include General Motors, Ford, and AMC. The API, GM, and Ford
information contain data from tests with onboard control hardware.
All respondents, with the exception of AMC, submitted information
on the cost and the desirability of onboard control systems.
1. API Onboard Study
The API Onboard Control Study was structured to address
questions regarding onboard feasibility which were posed to API in
a December 1977 meeting with EPA. The API study consisted of thrse
tasks: a vehicle concept demonstration, a fillpipe/nozzle concept
demonstration, and a cost/benefit analysis. Exxon Research and
Engineering Company and Mobil Research and Development Corpora-
tion were the API contractors for the vehicle concept demonstra-
tion. Atlantic Richfield Company was the API contractor for the
fillpipe/ nozzle concept demonstration. Exxon R & E completed the
cost/benefit analysis for API.
The vehicle concept modification task had the following design
objectives:
1) Minimum 90% overall refueling vapor recovery.
2) No significant effect on exhaust emissions.
3) No significant effect on evaporative emissions.
4) Design should be durable, practical, and safe.
The fillpipe/nozzle demonstration had the following objec-
tives:
1) 90% overall vapor control.
2) Compatible with existing vehicle population.
3) Compatible with existing Stage II nozzles.
4) Design should be durable, practical, and safe.
-------
-4--
A review of the three API "contractor's activities is presented
below.
Test procedure guidelines for the API work were discussed at a
meeting with API on March 15, 1978. Important procedural guide-
lines which resulted from that meeting are summarized as follows:
Fuel specification; Indolene unleaded test fuel was used for
all exhaust, evaporative, and refueling loss measurements.
Dispensed fuel quantity; Test vehicles were refueled to 100Z
of capacity from a condition of 10Z tank capacity.
Fuel tank temperature/Dispensed fuel temperature; The dispen-
sed fuel temperature was selected to be representative of summer
refueling conditions in Los Angeles during the month of August, or
about 85°F. The fuel temperature in the tank was also selected to
be 85*F. Thus, the refueling was isothermal.*
Purge Cycle; For the purposes of the API study, the only
driving cycle which was used for purging the refueling loss can-
ister is the LA-4 cycle.
Individually, these test procedure guidelines are considered
to represent real world situations in a high oxidant forming.
location, e.g., Los Angeles during the month of August. Collec-
tively, these guidelines imply that the API vehicles demonstrated
the feasibility of onboard control systems in an approximate worst
case condition. This reasoning is consistent with earlier EPA
recommendations that API err on the conservative side during
their study. For example, Exxon used the following test sequence
to quantify the exhaust emissions interaction between the refueling
control system and the exhaust emission control system:
1) Load ECS (Evaporative Control System) canister to break-
through .
2) Condition the vehicle by driving 2 LA-4's.
3) Soak vehicle overnight.
4) Load RCS (Refueling Control System) canister to break-
through.
*This represents a conservative situation as survey data, Ref. 4,
show that nationwide dispensed fuel temperatures are typically
lower than tank fuel temperatures, thereby representing a vapor
shrinkage situation during the refueling process.
-------
-5-
5) Condition the vehicle by driving 5 to 6 simulated city
driving days (4.7 LA-4's with one hour hot soaks in between and a
diurnal at the end of the day) to consume 90% of the fuel in the
tank.
6) Drain the fuel tank.
7) Block RCS canister line.
8) Fill tank to 40%, unblock RSC canister lines.
9) Conduct diurnal evaporative test in SHED.
10) Drain tank to 10%.
11) Bring fuel tank liquid and vapor to equilibrium at 85°F
(shake the vehicle to accelerate the equilibrium process).
12) Refuel the vehicle to 100% in SHED with 859F fuel.
13) FTP
14) Hot soak evaporative test in SHED.
Obviously, these test procedures do not lend themselves to a
routine laboratory certification test procedure. They do, however,
permit an approximation of how an onboard control system would
function in a severe "real-world" situation.
Exxon
Exxon assumed the responsibilty for modifying four test
vehicles. Their vehicles included the following:
1978 Chevrolet Caprice
1978 Ford Pinto
1978 Plymouth Volare*
1978 Chevrolet Chevette
All vehicles are designed to comply with 1978 California
exhaust and evaporative emission standards (.41 HC, 9.0 CO,
1.5 NOx, 6.0 Evap).
* Vehicle subsequently dropped from test program because of high
baseline NOx levels.
-------
-6-
Table 1
FTP Exhaust and Evaporative Emissions - Caprice
Baseline Configuration
Modified Configuration
Percent
n=4
Ave.
S.D.
n=4
Ave.
S.D.
Change
FTP Exhaust
Baseline Configuration
Modified Configuration
n=4
Ave.
S.D.
n=4
Ave.
S.D.
Exhaust (g/mi)
HC CO
0.345 6.48
0.033 0.56
0.338 7.10
0.010 0.59
-2 +10
Table
and Evaporative
Exhaust (g/mi)
HC CO
0.187 1.70
0.021 0.10
0.217 1.83 '
0.006 0.12
NOx
0.95
0.06
0.86
0.05
-10
2
Emissions
NOx
0.77
0.01
0.79
0.07
Diurnal
n=3
0.8
0.4
n=3
1.1
0.3
- Pinto
Diurnal
n=3
1.0
0.2
n=3
0.9
0.3
Evap. (g)
Hot Soak
2.1
0.4
2.1
0.2
Evap. (g)
Hot Soak
2.5
0.3
2.4
0.5
Total
2.9
0.8
3.1
0.4
+7
Total
3.5
0.4
3.3
0.7
Percent Change
+16
+8
+3
-6
-------
-1-
Table 3
FTP Exhaust and Evaporative Emissions - Chevette
Exhaust g/mi)
Baseline Configuration
Modified Configuration
Percent
n=3
Ave.
S.D.
n=3
Ave.
S.D.
Change
HC
0.27
0.02
0.26
0.05
-4
CO
3.7
0.32
3.6
0.28
-3
NOx
1.09
0.04
1.13
—
+4
Evap. (g)
Diurnal Hot Soak
n «* 4
0.8 2.6
0.36 0.79
0.3 1.2
0.08 0.15
Total
3.4
1.03
1.5
0.15
-56
*FTP + 3 Hot Start LA-4s
-------
-8-
Table 4
Engine-Out Emissions - Caprice
FTP
HC
Baseline Configuration n=5
Ave. 1.28
S.D. 0.05
Modified Configuration n=5
Ave . 1 . 29
S.D. 0.09
Percent Change +1
*FTP + 3 Hot Start LA-4s
Engine-Out
Baseline Configuration
Modified Configuration
(g/mi) City Driving
CO NOx HC CO
26.42 1.17 41.86 733.86
0.72 0.04 2.00 39.27
32.04 1.17 42.32 853.52
2.4 0.04 1.90 61.51
+21 — +1 +16
Table 5 -
Emissions - Pinto
FTP (g/mi)
HC CO NOx
n=34
Ave. 1.83 52.7 1.25
S.D. 0.06 1.2 0.08
n=4 '
Ave. 1.77 60.1 1.12
S.D. 0.09 0.8 0.04
Day* (g)
NOx
38.68
1.17
41.34
3.17
+7
Percent Change
-3
+14
-10
-------
Table 6
Refueling Loss Measurements
Caprice
Pinto
Chevette
Potential HC (g)
93.4
91.0
89.3
Ave. 91.2
51.0
59.3
53.1
Ave. 54.5
62.5
65.5
60.1
64.6
Ave . 63 . 2
SHED HC (g)
0.4
0.4
0.3
0.4
1.0
1.3
1.1
1.1
0.5
1.5
1.1
1.6
1.2
Percent Control Effectiveness
99
98
98
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-10-
Table 7
Benzene Emissions
Potential Benzene Emissions*SHED Measurements (ppm) Measured Loss*SHED Measurements (ppm)
Caprice
Pinto
3.0
2.7
*A11 refueling at 85*F, RVP 9 lbs.t Benzene content 0.7%.
<0.05
<0.05
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-11-
The Caprice is a conventional oxidation catalyst vehicle,
while the Pinto is a three-way catalyst vehicle with feedback
carburetor control. Vehicle descriptions and complete refueling
loss control system descriptions are presented in Table A-l and
Figure A-l of the Appendix. The refueling loss canisters in the
Caprice, Pinto and Chevette are described as follows:
RCS
Vehicle Carbon Volume Carbon Mass Carbon Type* Location
Caprice 5.01 1800 g BLP-F3 Underhood
Pinto 3.04 1100 g BLP-F3 Underhood
Chevette 3.04 1100 g BLP-F3 Trunk
* Same carbon currently used for controlling evaporative emissions.
The Exxon exhaust and evporative emission test results which
compare baseline and modified versions of the Caprice, Pinto and
Chevette are summarized in Tables 1, 2 and 3. Engine-out data are
summarized in Tables 4 and 5. Refueling loss effectiveness test,
results are summarized in Table 6. All Exxon refueling emission
tests assumed a no-leak seal at the fillpipe/nozzle interface. In
laboratory practice this was achieved with leak free connections
from the fuel nozzle to the fillpipe.
Benzene emissions were measured during the refueling loss SHED
tests with both the Caprice and Pinto. These results are summari-
zed in Table 7. The Exxon data indicate that benzene control is
directly proportional to refueling loss control effectiveness,
although current benzene levels in the SHED are at the detectable
limit of the instrumentation.
Table 8 presents Exxon's manufacturer cost estimates for
onboard control systems for the 1978 Caprice and Pinto. These
estimates do not include the costs for fillpipe sealing devices and
pressure reliefs, and this hardware represents an additional cost
of approximately $1.50 (manufacturer's cost) per vehicle. Exxon's
cost estimates assume an estimated $.50 credit for downsizing the
ECS canister, which in the two canister system, controls only
carburetor losses. Exxon estimates the incremental cost of two-
canister refueling control systems to range from $8.25 to $10.53.
This estimate includes the above mentioned $.50 credit but does not
include the $1.50 cost for the fillpipe seal and pressure relief.
The corresponding cost range for single canister refueling control
systems is $6.75 to $9.00. For light-duty trucks, Exxon estimates
a cost range of from $12 (large single canister) to $20 (two
separate refueling loss canisters or multistage purge systems).
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-12-
Table 8
COST ESTIMATES FOR ONBOARD SYSTEMS(1)
Charcoal(2)
Canister and Valves
Tank Modifications
Hoses and Tubing
Assembling and Ins
(§ $20.00/hr.
Credit for Downsized
s(3)
(4)
)
talling(6)
ed (7)
>1 Systein '
Caprice
$4.96
2.50
0.50
1.57
1.50
$11.03
$0.50
$10.53
Pinto
$3.03
2.00
0.50
1.72
1.50
$8.75
$0.50
$8.25
(1) Estimates are made for cost to manufacturer for large volume
production.
(2) 1800 g for the Caprice canister, 1100 g for the Pinto
canister at $1.25/lbm (Calgon BPL-F3 carbon).
(3) Plastic container and valves.
(4) Larger size float/roll-over valve.
(5) 3/4" vapor line from fuel tank to canister, 3/8" purge line.
EFDM tubing for vacuum control lines.
(6) Additional 4.5 minutes labor at $20/hour.
(7) Reduced size evaporative control canister.
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-13-
Exxon estimates the average, cost for onboard control systems
to be $9/vehicle. This is based on the following assumptions:
1) Onboard systems are designed to control refueling emis-
sions from light duty vehicles with an average fuel tank size of 17
gallons refueled to 100% capacity from a condition of 10% tank
capacity. The onboard systems are designed to control hydrocarbon
emissions at a level of 6 g/gal.
2) 70% of light-duty vehicles and single tank light-duty
trucks are assumed to use single canister (evap + refueling)
systems.
3) 30% of light-duty vehicles and single tank light-duty
trucks are assumed to use two canister systems.
4) Light duty trucks with dual or large fuel tanks consti-
tute approximately 10% of the light-duty vehicle light-duty truck
population.
In summary, Exxon finds that onboard refueling controls for
light-duty vehicles are a technically feasible, practical, and cost
effective alternative to Stage II vapor recovery. They are of the
opinion that the same may also be said for light-duty trucks.
Mobil
Mobil R&D has modified a 1978 Pontiac Sunbird for control of
refueling losses. This vehicle has a three-way catalyst with a
feedback carburetor control system, and is certified for complaince
with California exhaust and evaporative emission standards.
This modified vehicle uses a single canister which contains 1550
grams of Calgon BLP-F3 carbon. The complete vehicle and refueling
loss control system descriptions are presented in the Appendix.
Table 9 presents comparisons of exhaust and evaporative emissions
from the Sunbird for the baseline and modified configurations; a
summary of the refueling emission data is presented in Table 10.
Similar to Exxon's findings, Mobil states that their test
results have demonstrated that onboard controls are a feasible and
desirable method of controlling refueling losses from light-duty
vehicles and light-duty trucks.
Atlantic Richfield Company
One of the requirements for the operation of an effective
refueling loss control system is the existence of a no-leak seal at
the fillpipe nozzle interface. Atlantic Richfield (ARCO) has
developed working prototypes of fillpipe seals and nozzles. ARCO
has investigated three types of sealing systems. They included:
t
1) Modification of the vehicle fillpipe to achieve a seal
when used with conventional lead-free nozzles.
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-14-
Table 9
FTP Exhaust and Evaporative Emission Comparisons — Sunbird
Exhaust (g/mi)
Baseline Configuration
Modified Configuration
Percent
n=9
Ave.
S.D.
n=6
Ave.
S.D.
Change
HC
0.39
0.03
0.40
0.03
+3
CO
6.41
0.91
6.35
0.74
-1
NOx
0.98
0.07
0.99
0.03
+1
Diurnal
n=2
0.87
030
n=4
0.72
0.23
Evap. (g)
Hot Soak
1.12
0.13
1.27
0.37
Total
2.00*
0.34
2.11
0.56
+6
Includes five tests at low mileage where individual diurnal and hot soak results are not available.
Table 10
Refueling Loss Measurements — Sunbird
Fuel Dispensed (gal)
16.4
15.3
16.9
17.1
HC Collected in Canister (g)*
85
73
113
109
Refueling Emissions
SHED Measurements (g/gal)
0.18
0.02
0.44
0.36
Control
Efficiency (%)
97
99
94
95
Canister purged from a nominal working capacity load of 210 g.
Fuel of nominal 9 Ibs. RVP.
8 gpm refueling rate, using modified Stage II nozzle.
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-15-
2) Modifications to both the fillpipe and lead-free nozzle.
3) Modification of a Stage II vapor recovery nozzle.
A description of each type of seal and a summary of the
durability data collected with each system are presented below:
Fillpipe seals; Two types of fillpipe seals have been ex-
amined. They are a rotary grease seal (similar to grease seals
used on rotating machinery shafts), and a doughnut shaped seal.
The material types for these two seals are a compounded nitrile and
thermosetting urethane, respectively. More complete descriptions
of these seals, including durability data, are found in Figure
A-5 and Tables A-2 and A-3 of the Appendix. Appproximately thirty
days of durability tests with both types of seals have demonstrated
that the rotary seal is more effective, basically due to the
absence of expansion problems when exposed to gasoline liquid and
vapor atmospheres. The seal effectiveness of the prototype fill-
pipe and nozzle hardware are determined by a bench test apparatus
which pressurizes a particular system and measures the resulting
leak rates. Seal effectiveness calculations are determined by
dividing the leak rate by a nominal fueling rate (assumed to be 7.5
galIons/min.). Durability tests conducted with the rotary seal
have demonstrated that the rotary seal is effective after 700-1000
nozzle insertions, which correspond to the life of the vehicle^
Combination fillpipe/nozzle seals; These systems consist of
connecting parts on both the fillpipe and nozzle. Figure A-6 is an
example of a prototype design evaluated by ARCO. Durability test
results with these systems are similar to results obtained with the
rotary seal.
Nozzle Modification; Working prototypes of vapor recovery
nozzles, modified for refueling loss control, have been developed
by OPW and Emco Wheaton and evaluated by ARCO for effectiveness and
durability. These nozzles are designed to seal on standardized
fillpipes. The modified vapor recovery nozzles incorporate a
pressure relief valve, which is located at the vapor return exit or
cast into the nozzle body, which is designed to open at approxi-
mately 14-17 in. water pressure*, thereby permitting the nozzle
to refuel onboard control vehicles and in-use vehicles. Nozzle
durability data are very limited but one nozzle has been inserted
and latched 7500 times, representative of a year's service at a
high volume station, and showed a seal effectiveness of greater
than 99%.
ARCO concludes that the preferred seal techniques are either
the fillpipe seal method or the combination fillpipe/nozzle seal.
Refueling loss control systems designed by Exxon and Mobil are
designed to operate at fill pressures of less than 4 in. of water
pressure.
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-16-
No statements are made as to the desired location of the pressure*
relief mechanism.
2. Vehicle Manufacturer Comments
General Motors
GM's March 1978 submission to EPA, Ref. 5, presents a summary
of their work on the control of diurnal evaporative emissions and
refueling losses through the use of fuel tank bladders. Their
information represents the most complete study of bladder tank
feasibility known to EPA. Regarding bladder tank feasibility, GM
admits bladder tanks have the potential for a substantial amount of
emissions control, but they are of the opinion that the technical
problems which must be solved before bladder tanks are capable of
demonstrating the same degree of control effectiveness as carbon
adsorption systems, do not permit this technology to be considered
applicable in the same time frame as the other candidate control
technologies, including Stage II control methods. The March 15
submission states that the major problem with controlling evapora-
tive and refueling emissions with the bladder tank is the formation
of gasoline vapor mixtures from dissolved air in gasoline. The
temperature at which the vapor pressure of the dissolved air equals
the partial pressure of air in the vapor space (bubble formation)
is known to be very sensitive to the quantity of dissolved air- in
gasoline. Other design problems include pressure relief valves,
and a puncture resistant fuel gaging indicator.
The March, 1978 submission presents calculations showing that
the additional weight of the components of an onboard control
system would cancel out any potential energy saving which would
result from the combustion of the refueling vapors.
The June, 1978 submission, Ref. 6, is basically a cost effec-
tiveness study comparing onboard and Stage II cost effectiveness.
GM's March, 1978 submission estimates the cost of typical
carbon adsorption onboard control systems to range from $11 for
single canister systems, to $15 for two-canister systems. The GM
estimates represent costs to the consumer. The June, 1978 submis-
sion indicates that these figures must be increased by $5-$9 per
vehicle to cover the costs for an enlarged vapor/liquid separator
and additional carbon. Thus, GM's estimates are now $16-$24 per
vehicle. These estimates do not include costs for fillpipe seals
or pressure reliefs as GM assumes that this hardware would be part
of the service station fuel dispensing equipment.
GM has stated that both onboard and service station controls
are technically feasible methods of reducing refueling loss emis-
sions. However, GM's cost effectiveness calculations find onboard
controls to be much less cost effective than Stage II vapor re-
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-17-
covery. Rather, GM emphasizes certain technical concerns which
they say are not fully addressed by the API study. According to
GM, these include API's unsubstantiated support for the onboard
fillpipe seal and pressure relief (lack of adequate durability
results), an unknown CO penalty for light-duty vehicles (no sensi-
tivity data relating CO to test procedure differences), and un-
proven feasibility for trucks. .
GM is of the opinion that accelerated laboratory durability
tests are not sufficient to prove that proposed elastomer type
seals will be effective in the extreme usage and environmental
conditions of the real world, particularly when considering a ten
year average lifetime for a light-duty vehicle.
Ford
Ford has submitted test results from four 1978 model year
vehicles (three non-feedback systems and one feedback control
system) modified for refueling loss control. These vehicles are
described in detail in Table A-4 in the Appendix and in their
submission to EPA, Ref. 7. The purge control systems for these
vehicles are shown in Figures A-7 and A-8 in the Appendix.
Ford estimates the cost to the consumer of onboard controls to
range from $15-$20. They note that the $15-$20 estimate does not
include additional expense for such items as: packaging costs,
incremental labor costs, or the costs for additional exhaust
emission control, such as feedback control over a wider air/fuel
ratio range.
Recent Ford material, Ref. 12, suggest that the cost of
onboard systems may range from $30 to $253. The $30 estimate
includes costs over the original $15-20 estimate, including costs
for such items as vehicle modifications to package onboard systems,
incremental assembly, and material substitution. The $253 estimate
includes the cost for a feedback fuel system and electronic con-
trols for vehicles which are not planned to be equipped with these
control devices.
On the basis of their in-house test results, Ford has conclu-
ded that onboard controls are not technically feasible for light-
duty vehicles.
American Motors
AMC has submitted a letter to EPA, Ref. 9, which states their
concerns with the possible use of onboard controls. They state
that packaging concerns, reduced quantities of purge air from.
downsized engines, and compliance with stringent evaporative
emission standards are unresolved technical issues which have not
been addressed by the API work to date.
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-18-
AMC does not find that API has demonstrated light-duty vehicle
technical feasibility.
IV. Analysis of Available Information
1. API Work
Exxon
Exxon R&E appears to have done a credible job in character-
izing the components of a hydrocarbon adsorption system. An
examination of the results from baseline tests and tests with the
modified Pinto (3-way •»• feedback carburetor system) show small but
finite increases in engine-out (14Z) and tailpipe (8Z) CO emis-
sions. HC, CO, and NOx emissions are still well below statuatory
emission levels for low mileage vehicles. Engine-out CO emissions
from the Caprice are approximately 20Z higher than baseline test
results; tailpipe CO emissions are approximately 10Z higher than
the baseline results. No increase in tailpipe CO was observed
during tests with the Chevette. Exxon suggests that differences in
CO emissions for the Caprice and the Pinto can be further reduced
by minor modifications to the refueling loss control system or the
exhaust emission control system, although this has not been demon-
strated.
Figure A-2 shows canister purge as a function of time.
Although the data are bench test results, the results are also
representative of actual control system purge data. It is signifi-
cant to note that the refueling loss canister is essentially purged
to its working capacity after three LA-4 driving.days. This
implies that the refueling control/exhaust emission interaction is
likely to be less in a typical driving day than Exxon has measured
using conservative test methods, which required running a cold
start FTP immediately after a 90Z refueling.
ECTD expects that refueling loss control systems will result
in slightly higher CO feedgas levels. Exxon estimates that the
average increases in CO feedgas between refuelings will be approx-
imately SZ for non-feedback control systems and less than 3Z for
feedback control systems. ECTD has no other data concerning either
the magnitude of the average CO feedgas penalty or the resulting
effect on catalyst durability. It is ECTD'a opinion that the Exxon
estimates are reasonable and that these additional CO penalties
will make it more difficult for vehicle manufacturer's to certify
some engine/families to the 3.4 g/mi CO standard. The higher CO
levels somewhat reduce the margin available to allow for exhaust
system deterioration over 50,000 miles.
ECTD finds that light-duty vehicles equipped with onboard
systems are capable of meeting a 2 gram evaporative emission
standard.
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-19-
An analysis of the control effectiveness of benzene emissions
during refueling, Table 6, indicates that charcoal canisters can
control in excess of 99% of the uncontrolled benzene emissions.
Exxon conducted additional tests with the Caprice and Pinto using
indolene test fuel with a high benzene content (4.2%). The results
from these five tests with the modified vehicles support the
earlier findings — benzene emissions are controlled in excess of
99% during refueling.
Packaging refueling loss control systems is a difficult
problem, but definitely not an insurmontable one. The refueling
loss canister is located behind the rear seat and above the rear
axle in the Caprice, and in the engine compartment of the Pinto.
It is Exxon's opinion, and ECTD agrees, that it is possible for
manufacturers to locate a refueling loss canister on downsized
vehicles without major engine compartment or sheetmetal modifica-
t ions.
The feasibility of refueling loss controls for light-duty
trucks has not been evaluated by Exxon, but they are of the opinion
that refueling loss control is feasible for light-duty trucks by
using larger control systems and more sophisticated purging con-
trols (refueling loss control canisters for each tank and/or two
stage purging systems). It is ECTD's opinion that the control of-
refueling losses from light-duty trucks needs to be demonstrated,
especially the ability to comply with a 2 g evap standard, before
onboard controls are judged to be effective for these vehicles at
the costs Exxon has estimated.
Table 8 shows Exxon's detailed manufacturer's cost estimates
for refueling control systems which have two canisters. ECTD finds
these cost estimates to be reasonable for onboard systems designed
to control 100% of refueling emissions from 90% fill conditions.
Exxon estimates the average manufacturer's cost for the light-duty
truck and light-duty vehicle population to be about $9. That
number is derived as follows:
Assumed % of
Average Cost Population
One-cansiter vehicles* $7.88 70
Two-canister vehicles* $9.38 20
6,000 to 8,500 Ibs. trucks** $16.00 10
Weighted average $9.00
* Includes light-duty vehicles and light-duty trucks under 6000
GVW - average fuel tank size = 17 gal.
** Average fuel tank size » 35 gal.
The charcoal cost per gallon of tank volume is assumed to be about
$0.20.
-------
-20-
The $9 incremental manufacturer cost may be translated to a
consumer cost estimate of $16.20 by multiplying the manufacturer's
cost estimate by a factor of 1.8 (Ref. 10, EPA Report "Cost Esti-
mations for Emission Control Related Components/Systems and Cost
Methodology Description" by Rath and Strong, March 1978). The 1.8
factor is in general agreement with previous EPA studies, such as
the EPA Report, Ref. 11, "Investigation and Assessment of Light-
Duty Vehicle Evaporative Emission Sources and Control," June 1976,
which used a manufacturer to consumer cost factor of 2.0. The
$16.20 estimate is in good agreement with consumer cost estimates
submitted by GM ($16-$24) and Ford ($15-$20). It is possible to
further reduce the cost of an onboard system by trading off some
degree of refueling loss control effectiveness.
Exxon has designed refueling loss control systems based on
conservative criteria, and thus a different set of design criteria
will afford reductions in the cost of onboard control systems.
Texaco has submitted data (Figure A-ll) Ref. 12, which relates the
number of light-duty vehicle refuelings and the percent of tank
fill. A reasonable design criterion is to size the refueling
canisters to control 90% of nationwide refueling emissions.
Calculations (Figure A-12) show that 90% control can be achieved, .by
designing systems to control 100% of refueling emissions from fills
to 63% of fuel tank volume. If onboard control systems are d_e-
signed to control emissions from refueling to 63% of tank capacity
rather than 90% of tank capacity, the Exxon estimate of $9 per
vehicle can be reduced by $1.60 as the result of reduced charcoal
quantity. This cost reduction is proportional to the reduction in
carbon bed volume. The net effect of this design change is a cost
reduction to the consumer of approximately $2.88. Changes in
design specifications such as the 90% fill requirement may afford
additional cost reductions for other control system components as
well as a general reduction in the problem of packaging onboard
control systems.
ECTD estimates the consumer cost of light-duty vehicle onboard
control systems designed for maximum control effectiveness to be
about $17. This estimate does not include an estimate for the cost
of the fillpipe seal or pressure relief valve. The $17 estimate is
based on Exxon estimates-, which when translated to consumer costs,
are in agreement with consumer cost estimates provided by GM and
Ford.
Exxon estimates the manufacturer's cost for a fillpipe seal
and onboard pressure relief valve to be approximately $1.50. ECTD
estimates the consumer cost of an onboard fillpipe seal and pres-
sure relief to be approximately $2.70.
Mobil
Comparisons of baseline and modified vehicle test results
indicate that Mobil R&D is able to add refueling controls to the
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-21-
1978 Pontiac Sunbird (3-way * feedback carburetor system) without
adversely affecting exhaust or evaporative emissions. No changes
in engine-out or tailpipe CO emissions are observed. Evaporative
emissions are also unchanged, with both baseline and modified
vehicle test results near the 2 g evaportive emission level.
It must be emphasized, however, that Mobil and Exxon use
different test procedures for measuring the refueling control/
exhaust emission interaction. Mobil's test procedure consists of
the following sequence of events:
1) Load canister to approximately one-half of working
capacity.
2) Condition vehicle by driving two simulated city driving
days (4.7 LA-4's with one hour hot soaks in between and a diurnal
at the end of the day).
3) Drain fuel tank to 10% of volume.
4) Refuel to 90% of volume in SHED.
5) Conduct hot start emission test.
6) Soak vehicle for 11 hrs.
7) Conduct diurnal evaporative test in SHED.
8) FTP
9) Hot soak evaporative test in SHED.
Steps 1, 2, and 5 are the important differences between the
test procedures used by Exxon and Mobil. Mobil starts their test
sequence with a canister loaded to one-half of working capacity,
versus a saturated condition for the Exxon procedure. Mobil purges
the refueling loss canister with two LA-4 driving days, versus the
Exxon method of purging by running a series of LA-4 driving days
until the fuel tank reaches 10% of capacity. Mobil runs a hot
start emission test prior to the FTP; no such additional condition-
ing is used in the Exxon test sequence. It is ECTD's opinion that
the the Mobil test sequence, particularly the addition of a hot
start exhaust emission test, will result in a less severe refueling
control/exhaust emission interaction. This is due to the smaller
quantity of hydrocarbon which is purged during the cold start FTP
when using the Mobil test sequence. The actual emission sensi-
tivity to various test procedure arrangements has not yet been
determined.
Atlantic Richfield Company
ARCO states that the fillpipe modification approach and the-
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-22-
combination fillpipe/nozzle seal concept are the preferred tech-
niques for achieving a no-leak seal. This recommendation is not
supported from an analysis of leak rate and durability data because
the test results show that seal effectiveness among all three
concepts are equal. Cost estimates for the three designs have not
been submitted. ARCO is continuing to collect field durability
data on their prototypes, but the lack of a more extensive durabil-
ity demonstration under simulated conditions of real world usage
makes it questionable to assume that their seals will function as
well in the field as they have in the laboratory.
In particular, ARCO has not adequately addressed the issue of
onboard pressure relief valves versus liquid pressure relief valves
located on the fill nozzle. Pressure relief valves are necessary
to prevent over-pressurization of the fuel tank in the event of a
failure of the automatic shutoff on the fill nozzle. For the
purpose of fuel tank integrity in the event of a vehicle crash,
NHTSA recommends that the pressure relief not be located on the
fuel tank. However, a relief valve might be incorporated safely
with a fillpipe seal mechanism, which would be sealed-off by the
fuel cap during vehicle operation.
The achievement of a safe and durable seal at the nozzle
fillpipe interface is critical to the performance of an onboard"
refueling loss control system. ARCO has demonstrated that the
effectiveness of fillpipe seals, combination seals and nozzle
seals are equal; but, the design, locations, and durability of the
pressure relief valve have not been adequately addressed.
Conceptually, a pressure relief may be designed to function
properly when located on the vehicle or on the nozzle. However, if
refueling losses are controlled on the vehicle, it is recommended
that the fillpipe/nozzle seal and pressure relief valve also be
located on the vehicle. Locating all parts of an onboard system on
the vehicle will prevent the potentially serious problem of refuel-
ing a controlled vehicle without protection from overpressurization
(no relief valve). Administrative and certification concerns also
suggest that onboard controls are practical only if the seal and
pressure relief are located onboard.
An alternative technique of achieving a seal at the fillpipe/
nozzle interface is the liquid trap or submerged fill. This seal
concept has not been adequately investigated. Submerged fill
offers the potential for significant advantages in terms of simpli-
city of operation and durability (mechanical, magnetic, or elas-
tomer type seals are avoided). It is ECTD's opinion that the
submerged fill concept should be investigated. Submerged fill (and
seal techniques investigated by ARCO) must be evaluated in the
context of a complete refueling and evaporative emission control
system. This includes incorporating features to provide adequate
thermal expansion capability and rollover protection while still
permitting normal safe refueling.
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-23-
2. Vehicle Manufacturer Information
General Motors
General Motors has several reservations concerning the appli-
cability of onboard controls, citing such things as: the uncer-
tainty of the effectiveness of fillpipe/nozzle seals, potential
cost increases associated with exhaust emission control systems
which must be designed to control increased CO emissions, negative
fuel penalties which are the result of this increased emission
control, and the long lead time which is required to obtain a
substantial reduction in atmospheric hydrocarbon and benzene
loading. However, with the exception of GM's concern with using
accelerated laboratory tests to assess fillpipe/nozzle seal dura-
bility, these reservations are not detailed in their submissions.
GM has stated that refueling losses can be controlled on the
vehicle Cfeasibility for trucks has not been demonstrated) or at
the service station. GM's disagreements with controlling refueling
emissions with onboard controls are primarily based on the issue of
cost/effectiveness.
GM's March, 1978 submission to EPA presents a summary of their
work on the control of diurnal evaporative emissions and refueling
losses using fuel tank bladders.
It is EPA's opinion that the theoretical control effectiveness
of evaporative and refueling loss emissions using bladder tank
technology is high and that these problems can be solved. It is
recommended that bladder tank feasibility be researched by funding
a bladder tank hardware demonstration contract.
The March, 1978 submission presents calculations showing that
the additional weight of the components of an onboard control
system will cancel out any potential energy saving which results
from the combustion of the refueling vapors. ECTD agrees with
this analysis.
The June, 1978 submission is basically a cost effectiveness
analysis comparing onboard controls with Stage II controls (balance
displacement and vacuum assist systems). GM estimates that onboard
control systems, effective with the 1982 model year, will range
from $16 to $24. These figures are about $5 to $9 higher than the
March, 1978 estimates due to higher estimates for larger canisters
and a new vapor/liquid separator. GM assumes that the seal at the
fillpipe/nozzle interface will be obtained using modified vapor
recovery nozzles. GM does not include seal costs in its estimate.
They assume these costs will be the same for either Stage II or
onboard controls and, hence, leave these costs out of their analys-
sis of both options. General Motor's onboard cost estimates are
costs to the consumer. These estimates are based on cost? for
hydrocarbon adsorption systems which control evaporative and
refueling emissions with one canister (cheapest) and systems which
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-24-
use two separate canisters for containing evaporative (diurnal and
hot soak) and refueling emissions (most expensive). The GM cost
estimates are consistent with Exxon's manufacturers cost estimates
for onboard controls. As discussed earlier, it is possible to
design cheaper refueling loss control systems by not providing 100%
control of refueling emissions under worst case conditions. If the
design criterion of 100% control for a 90% refueling is changed to
100% control for a. 63% refueling, it is possible to reduce the
required working capacity of the charcoal canister, thus reducing
the average system cost to the consumer by about $3.00.
GM does not find that onboard controls are feasible for the
1982 model year, although their cost effectiveness analysis
calculations are based on the assumption that onboard control could
become effective beginning with the 1982 model year. It is ECTD's
opinion that onboard refueling loss controls cannot be implemented
prior to 1983 model year. GM did not comment on the feasiblity of
refueling loss control's for light-duty trucks and heavy-duty
gasoline powered vehicles.
Ford
Ford emphasizes that the refueling loss/exhaust emissions
interaction is a function of the test procedure and that the
differences between emissions interactions measured by Exxon and
Mobil are due to test procedure differences. This statement is
correct, although the actual emission sensitivity to the test
procedure is unknown.
Ford attributes the high CO effects, which they have observed
with both conventional oxidation catalyst systems and three-way
plus feedback carburetor systems, to the presence of refueling loss
controls. However, the reason for their high CO emissions is due
to a non-optimally designed system for controlling the hydrocarbon
purge rate. Ford uses a manifold vacuum controlled purge system,
which results in cold start hydrocarbon loadings that are two to
three times higher than results obtained with venturi vacuum
controlled systems (Exxon system). This is the reason the Ford
results are so high, particularly engine-out CO emissions. Ford
maintains that refueling loss control systems produce peak enrich-
ment effects equal to two air/fuel ratios, which is beyond the
capability of their current feedback carburetor control system.
Exxon has demonstrated, however, that venturi vacuum maintains the
air/fuel ratio within the control limits of the feedback control
system. Problems with the existing Ford feedback control system
are likely to be the result of response time problems, not control
range problems.
Some of Ford's concerns with onboard refueling control sys-
tems, such as packaging, weight of onboard systems, and the design
of vapor/liquid separators have been examined during the API study
and shown not to be significant problem areas. Other concerns with
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-25-.
onboard controls, including system durability, onboard feasiblity
for light and heavy duty trucks, and high altitude feasibility,
have not been adequately addressed in any of the information
submitted to ECTD. It remains ECTD's judgment that these issues
need further examination, particularly before onboard controls are
determined to be feasible for light and heavy-duty trucks. Al-
though onboard durability data are not available, ECTD finds that
onboard control systems should be as durable as current evaporative
emissions control systems, which last for the lifetime of the
vehicle.
Ford estimates the consumer cost of onboard controls for
light-duty vehicles to range from $30 to $253. EPA estimates that
the consumer cost of onboard control systems will be about $20
(includes $2.70 for the cost of an onboard seal and pressure
relief).
American Motors
AMC's concerns with the use of onboard controls are addressed
to the issues of exhaust and evaporative emissions interactions,
feasiblity of vehicles using small engines, costs, and light-duty
truck feasibility. With the exception of feasibility for light-
duty trucks, AMC's concerns have been examined in detail by the API
study. EPA's analysis of that data is that refueling loss controls
are feasible for light-duty vehicles aC a consumer cost of approxi-
mately $17.
V. Conclusions
Feasibility
An Analysis of the available informatio-n has shown that
onboard refueling loss controls are feasible for light-duty
vehicles designed to meet low exhaust and evaporative emission
standards (0.41 HC, 3.4 CO, 1.0 NOx and 2.0 Evap.). However, the
feasibility for light-duty trucks, particularly the assurance that
onboard control systems are compatible with a 2 gram evaporative
emission standard, has not been established. Feasibility for
heavy-duty gasoline vehicles has not been established. tf
An analysis of information and test data presented to EPA
regarding the control of light-duty vehicle refueling emissions
offers the following conclusions:
1. Onboard control systems in laboratory use situations can
control in excess of 97% of the uncontrolled hydrocarbon refueling
losses.
2. The same systems in laboratory use situations can control
in excess of 97% of the uncontrolled benzene refueling losses.
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-26-
3. Test results from two light-duty vehicles equipped with
three-way catalysts, feedback carburetors, and prototype refueling
loss systems show that tailpipe CO emissions range from a 0 to 8%
increase.
Test results from the same vehicles show that engine-out CO
emissions range from a 0 to 14% increase.
4. Emission data from two conventional oxidation catalyst
equipped light-duty vehicles show that tailpipe CO emissions
range from a 0 to 10Z increase.
Data from one of the conventional oxidation catalyst vehicles
show that engine-out CO emissions increase by 10 to 20Z.
5. The addition of refueling loss controls to light-duty
vehicles does not significantly affect evaporative emission losses.
6. Minor increases in CO exhaust emissions seen for some
vehicles can probably be controlled by minor change to either the
refueling loss control system or to the exhaust emission control.
system. However, the addition of refueling loss controls will
likely make it more difficult to certify some vehicles to the 3.4
g/mi standard at 50,000 miles.
7. Onboard controls do not affect vehicle fuel economy.
8. Onboard controls do not affect vehicle driveability.
9. Refueling loss control systems for light-duty vehicles
are estimated to add $17 -to the vehicle sticker price. The $17
estimate does not include the costs associated with the fillpipe/
nozzle seal or pressure relief valve. The consumer cost of a seal
and pressure relief in the fillpipe is estimated to be about $2.70.
The cost of a seal on the nozzle should be roughly the same as the
cost for a Stage II nozzle. However, it is recommended that all
components of an onboard control system be located on the vehicle.
Lead time
Onboard refueling loss control can be implemented for 1983
model year light-duty vehicles, provided that potential problem
areas such as the design and development of effective fillpipe/
nozzle seals and pressure relief valves do not require additional
hardware demonstration programs. It is anticipated that the
fillpipe/nozzle seal and the control feasibility for light and
heavy-duty trucks are issues which can be resolved during the NPRM
process.
ECTD estimates that a minimum of two years lead time will be
required by manufacturers for development (purge system optimiza-
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-27-
Quarter;
Develop Certification
Test Procedure
Continued Study of
Fillpipe/Nozzle Seal
Concepts
Decision on Seal
Concepts
EIS, EIA, NPKM
Preparation
Publish NPRM
Final Rule
Manufacturers
Lead Time
Figure 1
Lead Time
Calendar Tear
1979 1980 1981
I34I1234I1234I1234
1982
1234
1983
12341
(Decision to publish service station nozzle
requirements or put seal on vehicle)
1983 MY
-------
-28-
tion, design and verification of fillpipe seal mechanisms) and
production tooling changes (tooling associated with fabrication and
relocation of new evaporative control components). These estimates
are based in part upon data provided by manufacturers relating to
carburetor tooling changes, and in part upon data supplied by GM
relating to retooling changes for body panel modifications.
Additional time will be required for EPA to develop a certification
type test procedure and issue regulations, however, the certifica-
tion procedure development can overlap the production tooling lead
time. Therefore, the projection is that an NPRM can be published
late in 1979 with final rules promulgated by 1980 with the earliest
possible implementation date being 1983. (See lead time chart,
Figure 1).
Compliance Costs
ECTD estimates that certifying light-duty vehicles for compli-
ance with a refueling loss standard will require an additonal
one-half person-year at the EPA-MVEL. This is based on an estimate
of 100-150 refueling loss tests per year. Facility modifications/
equipment procurements will cost from $30K to $80K.
A potentially significant impact on refueling loss compliance
costs is Inspection/Maintenance testing of light-duty vehicles.
EPA has not developed, and is not aware of, a valid I/M test for
determining the performance of evaporative emission control sys-
tems. Monitoring the performance of in-use refueling loss control
systems will be difficult and cumbersome. At this time, it may be
assumed that the onboard compliance costs associated with an I/M
test will be equal to the cost of Stage II enforcement.
VI. Recommendations for Future Work
1. ECTD recommends that additional hardware testing be
conducted to determine the optimal fillpipe-nozzle seal. Addition-
ally, the operation and durability of a fillpipe or nozzle pressure
relief must be demonstrated. The use of an onboard liquid trap
seal (submerged fill) as an alternative to elastomer type seals
should be investigated.
2. ECTD recommends that additional hardware testing be
conducted to assess the feasibility of controlling refueling losses
on light-duty trucks and heavy-duty gasoline powered trucks.
3. ECTD recommends that the need for controlling refueling
losses from diesel powered vehicles be investigated since these
vehicles are predicted to represent a substantial fraction of the
entire motor vehicle population in the 1980's.
4. ECTD recommends that the bladder fuel tank be investi-
gated as an alternative to carbon adsorption technology. It
is ECTD's opinion that the theoretical control of evaporative and
-------
-29-
refueling loss emissions with bladder tanks is high and that
technical problems can be solved. It is recommended that bladder
tanks feasibility be researched by funding a hardware demonstration
contract.
5. Finally, ECTD recommends that methods of reducing the
cost of onboard refueling control systems be examined. Such
studies should be directed toward tradeoffs between level of
control effectiveness and cost. It may be possible to sacrifice
control capacity that is required under only infrequent conditions
to achieve a proportionally more significant cost savings.
-------
Bibliography
1. "Control of Refueling Emissions," Statement by General Motors
Corporation, June 11, 1973.
2. "Control of Refueling Emissions with an Activated Carbon
Canister on the Vehicle - Performance and Cost Effectiveness
Analysis," Interim Report Project EF-14, prepared for the
American Petroleum Institute, Washington, D.C., October 1973.
3. "On-Board Control of Vehicle Refueling Emissions - Demonstra-
tion of Feasibility," API Publication No. 4306, October 1978.
4. "Summary and Analysis of Data from Gasoline Temperature Survey
Conducted at Service Stations," Radian Corporation, Austin,
Texas. Prepared for the American Petroleum Institute, Wash-
ington, D.C., November 1976.
5. "General Motors Commentary to the Environmental Protection
Agency Relative to On-Board Control of Vehicle Refueling
Emissions," March 1978.
6. "Suppplement to General Motors Commentary to the Environmental
Protection Agency Relative to On-Board Control of Vehicle
Refueling Emissions," June 1978.
7. "Ford Motor Company Response to EPA Concerning Feasibility and
Desirability of a Vehicle On-Board Gasoline Vapor Recovery
System."
8. "Ford Motor Company Position Concerning Feasibility and
Desirability of Vehicle On-board Refueling Vapor Control
Systems," November 6, 1978.
9. AMC letter to Paul Stolpman, August 3, 1978.
10. "Cost Estimations for Emission Control Related Components/Sys-
tems and Cost Methodology Descriptions," Rath and Strong,
Inc., Lexington, Massachusetts. Prepared for the Environ-
mental Protection Agency, Ann Arbor, Michigan, March 1978.
11. "Investigation and Assessment of Light-Duty Vehicle Evapora-
tive Emission Sources and Control," Exxon Research and
Engineering Company, Linden, New Jersey. Prepared for the
Environmental Protection Agency, June 1976.
12. Texaco statement submitted to Paul Stolpman, July 18, 1978.
-------
APPENDIX A-l
The Appendix contains detailed descriptions and data from the
test vehicles and fillpipe/nozzle seals which were used in the most
recent testing and evaluation of refueling loss control systems.
Exxon
Table A-l presents a description of all Exxon test vehicles.
Figure A-l is a schematic of the basic control system designed for
the Chevrolet Caprice and the Ford Pinto. The refueling emissions
(RCS) canister controls both refueling emissions and diurnal
evaporative emissions; the evaporative emissions (ECS) canister
controls carburetor hot soak losses. Exxon investigated several
different purge mechanisms, including combinations of manifold
vacuum and venturi vacuum, and two stage purge control valves
controlled by fuel volume, but venturi vacuum, which is propor-
tional to engine air flow, is the most effective purging method.
Exxon's control system is designed to maintain the total purge air
volume (RSC + ECS) equal to the purge air volume of the unmodi-
fied vehicle's evaporative control system.
The air bleed control valve, shown in Figure A-l, is necessary
because the RCS canitser is purged more efficiently (higher hydro-
carbon purge per unit volume of air) than the unmodified ESC
system, thereby resulting in richer A/F mixtures. This air bleed
may not be necessary for other vehicles with feedback carburetor
controls.
Figure A-2 is a plot of the RCS canister purging as a. function
of time. These data are based on consecutive LA-4 driving days.
As noted, the RCS system is purged at a rate of about 4 litres/
min., which corresponds to a total canister purge volume of about
40 litres during an LA-4 driving cycle.
Mobil
Specifications for the vehicle Mobil has modified for refuel-
ing loss control are summarized as follows:
Vehicle: 1978 California Pontiac Sunbird
Engine Size: 151 cu. in. L-4
Interia Weight: 3000 Ibs.
Emission Control System:
Exhaust: 3-way catalyst with feedback carburetor,
EGR
Evaporative: Carbon canister
-------
A-2
Fuel Tank Capacity: 18.5 gallons
The production vehicle is modified for controlling refueling
emissions by enlarging the existing carbon canister, (one canister
controls refueling, diurnal, and hot soak loss), enlarging the
vapor line between fuel tank and canister, redesigning the vapor/
liquid separator, and installing a purge control orifice between
the canister and intake manifold. A schematic of the Sunbird's
control system is shown in Figure A-3. Various flow control
orifices were inserted in the canister purge line but best results
are obtained with an orifice of 0.100 in. diameter. Mobil uses
1550 grams of Calgon BPL-F3 carbon for their control system, which
assumes a 20Z safety factor. This quantity of carbon is based on a.
90% fill of the 18.5 gallon tank, and assumes a hydrocarbon loading
of six grams per gallon of dispensed fuel. The working capacity of
the canister is approximately 240 grams. The basic components of
the canister control system are shown in Figure A-4. The ported
vacuum purge control valve is from a 1978 Chevrolet Impala evapora-
tive canister, while the two fuel tank vapor valves (two are
used to reduce the pressure drop during the refueling operation)
are carburetor bowl valves from a 1978 Impala. Using two fuel tank
vapor valves results in fillpipe pressures as low as two inches of
water pressure during refueling. The fuel tank vapor valves are
also controlled by manifold vacuum such that the vapor valves
are closed when manifold vacuum is present at the control port.
Atlantic Richfield Company
Figure A-5 shows the fillpipe seal which ARCO has developed
and tested for durability. Tables A-2 and A-3 are typical of the
durability results obtained with this seal. Figure A-6 is an
example of a prototype combination fillpipe/nozzle seal which has
been developed and evaluated by ARCO.
Ford
The vehicles which Ford has used for refueling loss testing
are shown in Table A-4. A single 4.35 1 canister is used in the
Mustang, while a duel canister system, 829 ml and 3.4 1, are used
for controlling carburetor vapors and diurnal/refueling losses,
respectively, in the Pinto. The purge systems for the Mustang and
the Pinto are shown in figures A-7 and A-8.
Figures A-9 and A-10 are plots of canister loading versus test
procedure sequence. These plots indicate that Ford's refueling
loss control system is quite sensitive to the particular test
procedure which is used to quantify the refueling control/exhaust
emission interaction.
-------
A-3
Table A-l
Vehicle Descriptions
Make
Model
Engine Displacement/
Configuration
Control Systems
Fuel Tank
Capacity
(gallons)
Chevrolet Caprice 5.0 litre (305 CID)/V-8
Ford Pinto 2.3 litre (140 CID)/L-4
Plymouth Volare 3.7 litre (225 CID)/L-6
Chevrolet Chevette 1.6 litre (98 CID)/L-4
Ox. Cat., AIR, EGR
3-Way, Ox. Cat.,
AIR, EGR
Ox. Cat., AIR, EGR
Ox. Cat., AIR, EGR
21.0
13.0
18.0
12.5
-------
Table A-2
FILLPIPE MODIFICATION
ROTARY SEAL-CR 7538
LEAK RATE AS AFFECTED BY
FILLNECK PRESSURE AND WEAR
NO. OF SPODT
INSERTIONS
0
100
100
100
100
100
• 100
100
100
100
100
TYPE
SPOUT
Smooth
Rough
Smooth
Rough
Smooth
Rough
Smooth
Rough
Smooth
Rough
CUMULATIVE
INSERTIONS
0
100
200
300
400
500
600
700**
800
900
1000
FT3/MIN
@ 5" W.C.
0
0
0
0
0
0
0
0
0
0
0
LEAK *
@ 15" W.C
0.001
0.001
0.001
0.001
:, o.ooi
_ 0.001
0.001
0.001
0.002
0.002
0.002
* Leak rate average of six nozzle insertions.
** Expected number of insertions during vehicle life.
RGJ:ip
7/13/78
-------
Table A-3
FILLPIPE MODIFICATION
ROTARY SEAL-CR 7538
EFFECT OF LIQUID AND VAPOR GASOLINE
SOAK ON SEAL ID AND LEAK RATE*
HOURS OF
LIQUID
SOAK
0
16
35
TOTAL WEEKS
OF VAPOR
SOAK
0
0
0
2
3
4
5
6
7
8
SEAL
IDrIN.
.712
.712
.711
.705
.699
.701
.703
.698
.693
.691
FT3/MIN
@ 5" WC
0
0
0
0
0
0
.001
0
0
.001
LEAK**
3 15" WC
0
0
0
0
.001
.001
.001
0
.001
.002
* Vapor and liquid soak at 72°F.
** Leak rate average of nine nozzle insertions.
RGJ:ip
7/13/78
-------
Figure A-l
EVAPORATIVE AND REFUELING EMISSIONS CONTROL SYSTEMS
REFUELING AND
DIURNAL VAPORS
PURGE
CONTROL
VALVE
RESTRICTION
CONTROL VACUUM
CARBURETOR VACUUM PURGE
RESTRICTION
VENT
CARBURETOR BOW
AIR BLEED
CONTROL
VALVE
MANFOLD VACUUM
PURGE
ECS CANISTER
REFUELING EMISSIONS
CONTROL CANISTER
-------
- 8 -
carburetion, a. technology expected to appear in most cars after 1981
to meet tailpipe emission standards.
On-board control systems have been installed on the Caprice
and on the Pinto.
Systems on the Caprice and Pinto
Figure 4 shows a diagram of the RCS and ECS systems installed
in the Caprice and the Pinto.
The RCS canisters are cylindrical two-pass containers with
vertical vents. Purging is conducted in the direction opposite to the
adsorption of hydrocarbons (countercurrent). The Caprice and the Pinto
contain approximately 1800 g (5.0 £,) and 1100 g (3.0 &) of Calgon
BPL-F3 activated charcoal correspondingly. This carbon is currently
being used in the Ford ECS canisters. The RCS canisters are designed
to trap all losses from the fuel tank: diurnal losses and refueling
losses. In the modified cars, the ECS canister is dedicated to trap
carburetor bowl emissions only. Since the diurnal vapors are no longer
directed to the ECS canister, restrictions were added to the ECS purge
lines to reduce the purge rate and thus the air intake to the engine due
to canister purging.
The RCS canister is purged by vacuum generated by the air
venturi at the carburetor throat. Taps were drilled in the carburetor
**
for that purpose. Carburetor venturi allows purging at a rate proportional
to the power-output of the engine.
To prevent purging during a. cold start, when the catalyst, is
cold, purge control valves which are opened by control (ported) vacuum.
are installed on the RCS purge lines. The ported vaccuin signal operates
-------
Figure A-2
PURGE @ 4 LITRE/MIN. WITH DIURNAL ADDITIONS
ADSORPTION TO 35 g. FROM BREAKTHROUGH
3.5 litre Canister (BPL-F3)
320
300
280
1 1 LA-4 » 40 litres » 10 min. DD
L 5 LA-4'a » 1DD» 50 min. L
1
\ >
-\ 6
GRAMS
Purged Diurnal
89 11
34 14
29 20
32 22
32 24
33
"od
~
n
u
4-i
V)
•r4
«
c
o
260
240
, 0)
i J 220
:' 3
200
180
160
lst
g.
158 g
capacity
1 1
™ 60
1
90
i
120
i
150
i
180
i i i
210 240 270
-------
i Figure A-3
ONBOARD SYSTEM TO CONTROL REFUELING EMISSIONS
Control
Vacuum'
Lines
Flow Control
Valves
Carburetor
Intake Manifold
Carburetor Bowl Vent
Engine
Canister Purge Line
With Flow Control Orifice
Fuel Tank Vapor Line
Vapor-Liquid
Separator
(5/8" l.D.)
Carbon Canister (4.4 L)
Sealing
Nozzle
Fuel Tank
-------
Figure A-A
Refueling System Carbon Canister
Sunbird
Carb. Bowl
Fitting
Chevy Purge
Valve, Drilled
To 0.180"
Carbon
//////// / / /I/ / / / / // -l/8" Plexiglass
• T'dla. x!3/4" long
Plexiglass Tube
-------
Figure A-5
FILL PIPE MODIFICATIONS
ROTARY SEAL
ROTARY SEAL
TRAP DOOR
LEAD RESTRICTOR
FILL PIPE MODIFICATIONS
ROTARY SEAL
TRAP DOOR
SPOUT
LEAD RESTRICTOR
-------
Figure A-6
NOZZLE / F1LLPIPE MODIFICATION
CONE SEAL
LEAD RESTRICTOR
TRAP DOOR
SPOUT
DISK
LATCH COLLAR
CONICAL SEAL
NOZZLE / F1LLP1PE MODIFICATION
CONE SEAL
LEAD RESTRICTOR
TRAP DOOR
SPOUT
LATCH COLLAR
CONICAL SEAL
-------
ON BOARD VAPdJTRECOVERY SYSTEM
VACUUM ACTUATED PURGE
VALVE AND TANK VAPOR
INLET VALVES ARE SIMILAR
TO CURRENT PURGE VALVES
Mustang 8Z18 & 8Z19
System A
TANK VAPOR INLET VALVES
VACUUM CLOSED
PURGE VALVE WITH
0.180 IN ORIFICE
VACUUM OPEN
SERVICE STATION
NOZZLE
FILL PIPE OPENING
THIS VALVE CONTAINS
A .OV? IN. BY-PASS
.ORIFICE FOR TANK RUNNING
LOSES
GARB BOWL
VENT CONNECTION
PURGE LINE TO
PCV HOSE
GARB BOWL
VENT LINE
PURGE SIGNAL
TANK VAPOR
LINE 7
TUBING
(REPLACES CONVENTIONAL
TUBING)
•tf350 ML CARBON VOLUME
OPEN CELL FOAM
WIRE SCREEN
FIBERGLASS '
8 IN.
DIA
CANISTER (REPLACES CONVENTIONAL CANISTER)
ENGINE COMPARTMENT MOUNTED
FUEL TANK
£
-------
UN BUAK1J VA
PINTO 8E79 & 8E12H
System B
PURGE LINE TO PGV HOSE
GARB BOWL VENT LINE
VAPOR PURGE
TO PCV LINE (
THRU BOTH .090"
& .085" ORIFICES
PURGE SIGNAL
i PURGE LINE
PURGE
SIGNAL
.085"
(PROD. VLV.)
\.090" REMOTE PURGE VLV.
3»*00 ML CARBON VOL
925 ML CARBON VOL. '
I/
ATMOS.
TANK VAPOR
LINE
FILL PIPE
FUEL TANK
"8
H
ID.
oo
-------
(•
Procedure #2 Set 2
• Mustang 5.CL (8218) 1973 1*9 States
Date 7-17-73 Test 29 . .
U350 nl Canister, Tank St Garb. Ecwl w/.lSO" Purge Orifice,
| Grass of Vapor Purged (-)j Absorbed (+)
'Figure A-9
I +55 I -98 I +27 1 -50 1 +35 I -38 I +39 1+8 I.+95
' -1*6
•1
X
si
St.
£
h
4)
•P
O
|
•a
o
I -7«f 1 +18 !
Productic:
^ " .Feedgas
Gas7iS~CO " 15.9
ON BOARD SIS. Bag 1,23:3 CO Gas. 205
Bag 1 CO C-ss. 1 1^3
Bag 1 CO- Gcs. I 05
BASELIJS SB. Bag 1,243 CO Gas. • 118
CO 9A
r-f O
r-i r-l S
Cj «H 3
•H t< n
*» a
•ri ^-5.0
s. °
H a
o S
5 o
I I
•3 a
^ ^
CM C3 •
oS
So
&-.VO
C^ ^j
-o 2
S3 3
01
PO 03 ^
=«a O 5S
^ -H lf\
OS rH Ai
d I d
'-i O rH O
^ -
01
C
o ._
n 3
00 I
a
s
o
o
Test Sequence
-------
M
-1 116
t,
01
•p
o
•a
o
I 1
. .
i • ' Procedure #3 3et 2 . ;
• Muatang 5.0L (8Z19) 19?8 1*9 States ! • ' '
! Date 7-8 & 9-78 Tost //l»f, 15 : ' ' : '
H350 ml Canlater, Tank & Garb. Bowl Vapora w/,180" Purge Orifice
I Grains of vapor, Purged (-), Absorbed (+)
I +30 I -33 I r?7 I -**5 1+22 14-3 I -1? ! +13 I >
t t t : t t t '> t t
•a
•H
+>
p§
PH w
U)
»R
-J- IV,
(X
-* 0)
^ M
I-1* Pi
r-t 4>
i-| tj
•H 3
Ui in
01
»R
ONfV,
1«
•H O
ca W
W
I CO
o
W-^
r-l O
r-J CO
l^»
CO
! o
+»
*fl
H-aJ
1
^ M
w U
, U I
tiS
w o
a
S-y
W ra
o
h01
fl£
H W
CO
,
•s
M
(D
Teut Sequonco
-------
Figure A-11
DISTRIBUTION OP GASOLINE PURCHASES
100
co
co 80
<
X
o
CE
r>
a.
2:
uj
o
IT
111
O.
Ul
20
**•••••••«
-»-
10
•*
****
._» »- »—___„__»_ „_—J__—• 1 -___<_ -_« _ 1
20 30 40 BO 60 7O BO 00 |OO
PERCENT OF TANK CAPACITY
-------
Figure A-12
REFUELING EMISSIONS CONTROLLED
100
a
o
oc
2
O
O
w
z
o
UJ
3
flC
O
UJ
oc
eo
eo
40
20
10 20 3O 40 60 6O 70 00 00
REFUELING TEST REQUIREMENT FOR NO EMISSIONS. % of TANK CAPACITY
—»
100
-------
W//7?
APPENDIX B
Stage II Energy Penalties and Credits
Total energy credits of the three Stage II systems can be calculated
by subtracting energy requirements of the three systems from the energy
value of the recovery credits derived in Section II A of this paper.
Energy penalties are calculated for each system below:
Balance
The balance system uses no energy to displace vapors back to the LIST.
It simply uses physical laws. In a recent paper by the San Diego Air
Pollution Control District, however, it was noted that the certified
balance system is limited to pump at 8 gallons per minute and thus the
pump would operate for a longer period of time.- This statement was
2/
supported by Trueman Miller of Red Jacket.— The company had calculated
the energy requirements of both the balance and the aspirator assist systems.
Their calculations showed energy to run the pumps as 1848 KWH per year
for a 100,000 gallon per month station. An uncontrolled station of the
same size was estimated at 1275 KWH. The difference is 573 KWH or 230 KWH for
the typical station of 40,000 gallons per month. Total energy credit it
689 -f gallons/yr x 125,000 BTU - 230 KWH x 3411 BTU
gal. KWH
= 86.125 x 106 - 78.45 x 104
= 85.34 x 106 BTU
]_/ San Diego APCD, "APCD Response to Comments Related Ninety-Five Percent
Vapor Recovery," August 14, 1978.
2.1
- Kleeberg, C.F. telephone conversation with Trueman Hiller, Red Jacket
Corporation, September 6, 1978.
- 689 = 40,000/1000 x 12 x 8.85 (Ibs of hydrocarbon vapor recovered per 1000
gallons pumped) x 1 (conversion from Ibs to gal; see Petroleum Facts and
6.17
figure, 1975).
-------
Aspirator Assist
The Red Jacket aspirator assist system uses about 10 percent of the
pumped gasoline to create vacuum in its aspirator. This means that 10
percent more gasoline must be pumped at these stations, resulting in an
energy penalty.
Mr. Hi Her estimated a 100,000 gallon per month station using aspirator
assist would require 1864 KWH per year. Total energy penalty is 1864-1275 =
589 KWH/yr or 236 KWH/yr for the typical station of 40,000 gallons per
month. Both this estimate and the balance system estimate of energy penalty
should be considered high since typical conventional station pumps are seldom
operated at capacity of 12 gallons per minute.
Thus the energy credit for the aspirator assist is:
732 gal/yr x 125,000 BTU - 236 KWH x 3411 BTU
gal. KWH
= 91.5 x 106 - 80.5 x 104 BTU/yr
= 90.7 x 106 BTU/yr
Vacuum Assist
According to the manufacturer, the Hasstech vacuum assist system
requires 1.4 KWH for each 1000 gallons of gasoline pumped to operate the
vacuum pump and a small spark igniter in the incinerator. The gasoline vapor,
once ignited, is self-sustaining in its combustion.
-------
Thus, the vacuum assist has an energy penalty of:
480,000 gallons/yr x 1.4 KWH = 672 KWH
1000 gal BTU
Total energy credit is:
359 y gallons/yr x 125,000 BTU's -
gal
= 44.875 x 106 BTU
229.3 x 10^ BTU
yr
- 229.3 x 104
=42.58 x 10 BTU/yr
Energy Summary
Table 1 summarizes energy credits of the three options:
Table 1
Energy Credits of State II Systems at Typical
Retail Stations
i
Net Energy
Credit
Recovery Credit Penalty lf)6 RTI,, ,
System (1Q6 BTU's/yr) 1Q4 BTU's/yr IU blu s/yr
Equivalent
Gasoline Credit per
1000 gallons pumped
Balance 86.125
Aspirator
Assist 9.15
Vacuum
Assist 44.875
78.45 85.34
80.5 90.7
229.3 42.5
1.42
1.51
.71
4/ Credit is given for only 50% of gasoline recovered.
-------
Taking the equivalent gasoline credit estimates from Table 1 above
and combining them with the regulatory options defined in Section III of
this paper, the following energy savings estimates can be made for the
period 1982 - 1995.
Table 2
Equivalent Cumulative Gasoline Saved
(Millions of Gallons)
(1982 - 1995)
Option Balance Aspirator Assist Vacuum Assist
10 0 0
II 328 348 164
III 0 0 .0
IV 328 348 164
V 1716 1826 858
VI 1887 2006 943
VII 1887 2006 943
The data show that the energy savings of efforts to control refueling
vapor losses range from as low as zero equivalent gallons for the onboard
systems to as much as 2.006 billion gallons (9,350 barrels per day) for
a national Stage II program.
-------
APPENDIX C
Stage II Costs
-------
3 Nozzles
ITEM.
EQUIPMENT COST
P1p1ng/Trenchi ng(i ncludes
installation)
Nozzles
Hoses
•
Flow Limiter
Recirculation Trap
Aspirators
Vent Pipes
Valves, Arrestors, Hoses
Blower, Burner, PV Valves
Drain Check Valves
SUBTOTAL FOR EQUIPMENT
INSTALLATION COSTS
System Testing
Travel
Nozzles and Hoses
Dispenser Components
Vent Pipe Modifications
Secondary Unit
SUBTOTAL FOR INSTALLATION
TOTAL
BALANCE
3850
5105
Included in the cost shown for valves,
arrestors and hoses.
'included in cost of "Aspirators"
EXISTING STATION '
ASPIRATOR VACUUM
3850
6045
3200
335
90
75
75
-
-
-
-
4425 • .
600
50
30
150
-
-
680
265
90
-
b
560
200
- ' -
-
4965
600
50
30
300
100
-
1080
250 .
a
_
.
-
-
585
3300
7335
600
50
30
375
-
2205
3260
10595
-------
ITEM
EQUIPMENT COST
Piping/Trenching(includes
installation)c
Nozzles
Hoses
• •
Flow Limiter
Recirculation Trap
Aspirators
Vent Pipes
Valves, Arresters, Hoses
Blower, Burner, PV Valves
Drain Check Valves
SUBTOTAL FOR EQUIPMENT
INSTALLATION COSTS
System Testing
Travel
Nozzles and Hoses
Dispenser Components
Vent Pipe Modifications
Secondary Unit
SUBTOTAL FOR INSTALLATION
TOTAL
3 Nozzles
BALANCE
2120
2695
600
75
675
ASPIRATOR
2120
560
200
3235
600
150
100
850
NEW STATION
VACUUM
1760
335
90
75
75
. 265
.90
-
b
250
a
-
585
3300
5895
600
180
2205
2985
3370
4085
8880
Included in the cost shown for valves,
arrestors and hoses.
Included in cost of "Aspirators"
'551 of Piping/Trenching costs of exi stingos tat ions-.
-------
ITEM
EQUIPMENT COST
Piping/Trenching(includes
Installation)
Nozzles
Hoses
•
Flow Limiter
Recirculation Trap
Aspirators
Vent Pipes
Valves, Arresters, Hoses
Blower, Burner, PV Valves
Drain Check Valves
SUBTOTAL FOR EQUIPMENT
INSTALLATION COSTS
System Testing
Travel
Nozzles and Hoses
Dispenser Components
Vent Pipe Modifications
Secondary Unit
SUBTOTAL FOR INSTALLATION
TOTAL
6 Nozzles
BALANCE
4700
6855
Included in the cost shown for valves,
arresters and hoses.
Included in cost of "Aspirators"
Existing Station
ASPIRATOR VACUUM
4700
8145
3850
670
180
150
150
-
"
-
•
5850
600
50
55
300
-
-
1005
530
180
-
b
1130
200
-
*
6740 .
600
50
55
600
100
-
1405
500
a
_
-
-
990
3300
8640
600
50
55
600
-
. 2205
3510
12150
-------
6 Nozzles New Station
ITEM BALANCE ASPIRATOR VACUUM
EQUIPMENT COST . .
Pi ping/TrenchIng(includes 2585 2585 ' 2120
installation)c
Nozzles 670 530 500
Hoses 90 90
• •'
Flow Limiter 150 b
Recirculation Trap 150
Aspirators _ 1130
Vent Pipes . i00
Valves, Arrestors, Hoses _ . 990
Blower, Burner, PV Valves _ . ' 3309
Drain Check Valves _ _
SUBTOTAL FOR EQUIPMENT •
3645 4435 6910
INSTALLATION COSTS
System Testing 600 600 600
Travel -
Nozzles and Hoses - -
Dispenser Components 150 . 300 300
Vent Pipe Modifications _ _
Secondary Unit _ _ 2205
SUBTOTAL FOR INSTALLATION
^5Q 900 3105
TOTAL
4395 5335 10015
Included in the cost shown for valves,
arresters and hoses.
Included in cost of "Aspirators"
C55% of Piping/Trenching costs of existing ^stations v "
-------
ITEM
EQUIPMENT COST
Piping/Trenching(includes
installation)
Nozzles
Hoses
•
Flow Limiter
Recirculation Trap
Aspirators
Vent Pipes
Valves, Arresters, Hoses
Blower, Burner, PV Valves
Drain Check Valves
SUBTOTAL FOR EQUIPMENT
INSTALLATION COSTS
System Testing
Travel
Nozzles and Hoses
Dispenser Components
Vent Pipe Modifications
Secondary Unit
SUBTOTAL FOR INSTALLATION
TOTAL
9 Nozzles
BALANCE
Existing Station
ASPIRATOR
5560
1000
270
225
225
-
'
7280 ' -
600
50
80
450
-
1180
8460
5560
800
270
-
b
1690
200
8520
600
50
80
900
100
1730
10250
VACUUM
4500
750.
a
1485
3300
10035
600
50
80
900
2205
3835
13870
Included in the cost shown for valves,
arresters and hoses.
^Included in cost of "Aspirators"
-------
ITEM
EQUIPMENT COST
Pi pi ng/Trenchi ng(i ncludes
installation) c
Nozzles
Hoses
•
Flow Limiter
Recirculatipn Trap
Aspirators
Vent Pipes
Valves, Arrestors, Hoses
Blower, Burner, PV Valves
Drain Check Valves
SUBTOTAL FOR EQUIPMENT
INSTALLATION COSTS
System Testing
Travel
Nozzles and Hoses
Dispenser Components
Vent Pipe Modifications
Secondary Unit
SUBTOTAL FOR INSTALLATION
TOTAL
9 Nozzles
BALANCE
3060
4645
600
225
825
5470
New Station
ASPIRATOR VACUUM
3060
1690
100
.5785
600
450
1050
2475
1000
135
225
225
800
135
-
b
1170
a
-
.
1485
3300
8430
600
450
2205
3255
6835
11685
Included in the cost shown for valves,
arrestors and hoses.
Included in cost of "Aspirators"
c55% of Piping/Trenching costs of existing stations
"
-------
ITEM
EQUIPMENT COST
Piping/Trenching(includes
Installation)
Nozzles
Hoses
•
Flow Limiter
Recirculation Trap
Aspirators
Vent Pipes
Valves, Arresters, Hoses
Blower, Burner, PV Valves
Drain Check Valves
SUBTOTAL FOR EQUIPMENT
INSTALLATION COSTS
System Testing
Travel
Nozzles and Hoses
Dispenser Components
Vent Pipe Modifications
Secondary Unit
SUBTOTAL FOR INSTALLATION
TOTAL
12 Nozzles
BALANCE
6200
9250
Included in the cost shown for valves,
arresters and hoses.
'included in cost of "Aspirators"
Existing Station
ASPIRATOR VACUUM
6200
12135
5020
1330
360
300
300
-
-
-
-
8490 ' -
600
50
no
600
-
-
760
1055
360
-
b
2260
200
- • .
-
10075
600
50
no
1200
100
-
2060
1000
a
-
-
-
-
1980
3300
11300
600
50
110
1200
-
2205
4165
15465
-------
12 Nozzles
New Station
ITEM
EQUIPMENT COST
Pi pi ng/Trenchi ng(i ncludes
installation)
Nozzles
Hoses
• •
Flow Limiter
Recirculation Trap
Aspirators
Vent Pipes
Valves, Arresters, Hoses
Blower, Burner, PV Valves
Drain Check Valves
SUBTOTAL FOR EQUIPMENT
INSTALLATION COSTS
System Testing
Travel
Nozzles and Hoses
Dispenser Components
Vent Pipe Modifications
Secondary Unit
SUBTOTAL FOR INSTALLATION
TOTAL
BALANCE
ASPIRATOR
VACUUM
3410
1330
180
300
300
5520
600
300
900
6420
a
3410
1055
180
2260
100
7005
600
600
100
1300
8305
Included in the cost shown for valves,
arresters and hoses.
'included in cost of "Aspirators"
C55% of Piping/Trenching costs of exi-sting, stations.
2760
1000
a
1980
3300
9040
600
600
2205
3405
12445
-------
3 Nozzles
BALANCE SYSTEM ASPIRATOR ASSIST VACUUM ASSIST
Nozzle 110 90 8Q
Replacement
Nozzle 90 60 30
Maintenance
Hoses 25 . 25 25
Aspirator 45
Maintenance
Vacuum Assist Processing 330
Unit Maintenance
225 - 220 ;-. 465
-------
BALANCE SYSTEM ASPIRATOR ASSIST VACUUM ASSIST
Nozzle 225 180 165
Replacement
Nozzle 180 120 60
Maintenance
Hoses 45 45 45
Aspirator 90
Maintenance
Vacuum Assist Processing 330
Unit Maintenance
450 435 .600
-------
BALANCE SYSTEM ASPIRATOR ASSIST VACUUM ASSIST
Nozzle
Replacement
Nozzle
Maintenance
Hoses
Aspirator
Maintenance
Vacuum Assist Processing 230
Unit Maintenance
680 655 740
340
270
70
270
180
70
135
250
90
70
-------
12 Nozzles
BALANCE SYSTEM ASPIRATOR ASSIST VACUUM ASSIST
Nozzle 450 360 330
Replacement
Nozzle 360 240 . 120
Maintenance
Hoses 90 90 90
Aspirator 180
Maintenance
Vacuum Assist Processing 330
Unit Maintenance
900 870 870
-------
Additional Stage II Cost - "Adverse Grades"
As Exxon U.S.A. has pointed out, there are a certain number of
service stations where the height differential between the top of
the underground storage tanks and the farthest island from the tanks is
insufficient to permit laying vapor recovery return piping with the
proper slope. (See Sept. 1 "Supplemental Comments", Attached, at page 4).
At such locations, installation of sump systems is necessary to accomplish
proper return, to the underground storage tank, of liquid accumulations
in the vapor return line. The impact of this fact on the total costs of
a Stage II recovery program depend, of course, on the number of stations
affected, and the average cost per affected station. There follow
estimates of these parameters, together with an explanation of how
Stage II total cost figures should be revised in light of these estimated
values.
Stations Affected -- The best estimate at the moment appears to be about
20%. Estimates range from a high of 34% submitted by Exxon to a low of
2% submitted by Gulf. The most reliable estimates were deemed to be
those of ARCO (10-15%) and Union (15%), as these majors have already
undertaken the task of correcting the (improperly installed) piping at
their stations in San Diego and other areas of California where systems
were installed several years ago. The 20% figure was chosen, rather than
the overall average (16%) or the average of the Arco and Union estimates
because, as Exxon argues, the extent of the phenomenon is likely to be
greater in areas outside California. (California, whence the presently
available estimates are derived, requires that underground storage tanks
be buried at a minimum of four feet. A survey of six major cities outside
-------
California indicated that all followed the National Fire Code which
requires only 3 foot burial).
Costs
Balance System — Exxon's suction-type sump system costs $50 for the
sump tank and fittings, $3 (installed) per foot for connecting pipe,
and $50 for installation of the sump, connection of the pipe to the UST,
and incremental engineering costs. . Although Exxon argues an average
run of 60 feet from the low point (point at which sump is installed)
to the UST, this estimate is inflated. Exxon's estimate assumes pipe
must be sloped @ 1/4" per running foot, whereas CARB requires only
1/8" per running foot, and purports to include the effect of situations
where the station building comes between the UST's and the farthest _
island. Measurements (by Bill Repsher) at a large local gas station
with an island on the other side of the station building from the UST's
indicate that a forty foot run will represent an extreme case (assuming
3/8" slope per running foot). Since it appears that the sump can be
located within 20 feet of the UST in a large number of instances, 30 feet
is deemed a good estimate of the average run. Accordingly, the total
average cost for an Exxon-type system, usable with manifolded balance
systems, comes to $190.
For non-manifolded balance systems, the sump must be connected
to all three vapor return pipes coming from the far island (typically,
all three products at the far island will be affected). This will add
$50 to the cost of the system.
-------
Aspirator Assist — Because aspirator assist systems recirculate product
in the vapor return line, a larger sump tank is required, at $75 total
cost. In addition, the flow possible with a suction system is inadequate
and a device must be attached to the submersible turbine pump to provide
the proper draw. This device costs $65 (installed) on a Red Jacket
submersible turbine pump (STP) and $150 (installed) on other types of
STP's. The average cost (weighted according to market share) is $100.
An aspirator sump system must use larger diameter pipe than a balance
system, the cost estimated to be $3.36 per foot (installed).
The cost of adding sumps to an aspirator assist system at one
facility thus come to $975. This represents 3 times the cost per
product (3 will be affected), which cost breaks down as follows:
$ 75 - Sump Tank
$ 50 - Installation of sump, etc. (see Exxon system)
$100 - piping
$100 - uphill eductor
Vacuum Assist System - Since vacuum assist systems use manifolded piping
and do not return product thru the vapor lines, an Exxon-type system can
be used.
No incremental cost will be incurred with a vacuum assist system, however.
These systems will be able to substitute the sump system for an existing
feature whereby liquid is returned by pipe from the station low point to
the LIST. Elimination of the piping and trenching cost associated with
this item will offset the costs of the sump system.
-------
To determine balance system costs, assume 60% of stations non-
manifolded and 40% manifolded.
% of stations affected = 20%
Balance
60% non-manifolded cost = $240
40% manifolded cost = $190
Aspirator
Additional cost @ 20% = $975
Vacuum Assist
No incremental cost
-------
IfH/Jf
APPENDIX
Bases and Assumptions Underlying Figures
Appearing in Tables 16, 17, 18, 20, 21,
23, 24, and 25 of §VII of Decision Paper
-------
TABLES 16, 17 and 18
Misinstallation
Stage II -Nature of defect is improperly laid piping
resulting in lack of proper drainback of condensed vapors
and, thereby, in excessive back pressure in vapor return
system.
GARB estimated that a minimum of 30% of the balance
systems in California were misinstalled. CARS Staff Report
Accompanying Proposed Revisions to ARE Suggested Vapor
Recovery Rules, October 22, 1977, at p. 10. (This number
was confirmed as a reasonable estimate by Dick Smith of San .
Diego APCD in phonecon with Bill Repsher, MSED).
It was assumed that the major oil companies who have
been involved with Stage II in California would learn from
experience and be able to cut the number of misinstallations
in half. (It was not believed that a lower figure could
be achieved due to difficulties in supervising the large
number of contractors involved in an en masse installation
of Stage II systems.) It was assumed that independents and
smaller concerns would experience the same installation
problems as were experienced in California. As 61% of
stations fly the brands of majors, 20% represents a weighted
average of expectable misinstallations for balance systems.
-------
-2-
It was assumed that three-fourths (15%) of these
misinstallations would cause only minor vapor recovery
problems. It was assumed that the other 5% of misinstal-
lations would cause back pressure problems serious enough
(given that newer balance system nozzles are equipped with
back pressure shut-off devices) to interfere with dispensing
of product. It was assumed that, as a result, dealers would
disconnect vapor return hoses or remove nozzle bellows, in
order to be able to dispense product. Accordingly, to avoid
double-counting of this phenomemon, this 5% was only listed
under the "Tampering: Nozzles, Hoses" category.
The companies who produce the Red Jacket and Hasselman
vacuum assist systems have adopted the practice of certifying
installation contractors, with installation training a
prerequisite to certification. Accordingly, it was assumed
that, for these two systems, the misinstallation rate could
be reduced by 50% again over the balance system rate. As in
the case of balance systems, the majority of misinstallations
were assumed to be of the moderate effect variety, with a
small percentage assumed to be severe enough to prompt
tampering. (These latter were likewise listed under "Tampering
Nozzles, hoses".)
-------
-3-
The average effect of a moderate type misinstallation
on the vapor recovery potential of the balance system was
assumed to be in the range of 20%. For aspirator and
vacuum-assist systems, the effect was assumed to be somewhat
(15% and 10%, respectively) less as these systems operate on
negative pressure and are thus less sensitive to moderate
increases in vapor return line back pressure.
The effect on recovery efficiency of any misinstallation
sufficiently severe to prompt tampering is deemed to be
100%, as the forms of tampering needed to cope with severe
build-ups of back pressure (namely, disconnection of vapor
return hoses or removal of nozzle bellows) would result in
complete loss of vapor recovery.
Onboard - Misinstallation of the vapor recovery processing
(hoses, canisters, purging system) portion of an onboard
control system was assumed to consist of crimped and non-
connected hoses and incorrect canisters based on the
experience of MSED's Inspection/ Investigation section with
current evaporative canister systems. The .5% misinstallation
rate estimate is also based on I+I's experience with evapor-
ative canister systems. It was assumed that 50% of the
defects would be non-connected hoses, with a 100% effect on
recovery efficiency, and 50% would be crimped hoses and
incorrect canisters with a (moderate) 20% average effect on
recovery. 50% x 100% +50% x 20% gives the 60% (weighted -
average) effect on recovery efficency.
-------
-4-
It was liberally assumed that addition of a fillpipe
modification to the onboard system would increase the
misinstallation rate by 100% (to 1%). It was assumed that
the added defects would consist of improper placement of
the fillpipe sealing device or some minor damage to the
device, with an overall average effect on recovery efficiency
of 20%. The 40% recovery decrement in Table 2 represents
the weighted average of the processing and fillpipe
portion recovery decrements—i.e., 50% x 60% + 50% x 20%.
IMPROPER MAINTENANCE
A. Nozzles
Stage II -From October 2nd thru 5th, MSED personnel visited
106 service stations in the District of Columbia, where a
Stage II vapor recovery regulation is in effect, but where
enforcement is understood to be minimal. Each vapor
recovery nozzle at the stations visited was examined and its
condition noted. If the nozzle had any defect in the
faceplate or bellows (e.g., rip or tear) which would affect
recovery efficiency, the size of that defect was recorded.
198 first-generation, Emco-Wheaton Model 3003 nozzles-
were inspected. So far as bellows and faceplate construction
is concerned, these nozzles are similar to the nozzle
presently certified by CARB for use with balance systems,
I/ These nozzles bear the Emco-Wheaton part No. "A303".
-------
the exception being that the CARB-certified nozzle has a
20% greater bellows area on its unleaded version. Of the
198 nozzles examined, 73 had defects deemed sufficiently
substantial to affect vapor recovery efficiency. The
frequency of occurrence of this failure mode was determined
by dividing 73 by the total number of vapor recovery
nozzles which should have been in place and functioning at
the stations concerned. This figure comes to 198 plus 20,
the number of conventional nozzles which were being used
illegally (see Nozzles:Tampering section below). The
frequency of improper nozzle maintenance thus came to 33-%.-
Allowing for the fact that state-of-the-art balance system
unleaded nozzles have a 20% greater bellows area (and
therefore, increased potential for damage), it was
conservatively estimated that 35% of balance system nozzles
would exhibit a recovery-affecting defect in a voluntary
compliance situation.
The defects observed in the A 3003 nozzles were of two
types—faceplate rips and bellows rips. Four of the 73
nozzles exhibited defects so major that a 100% loss of
recovery efficiency was assumed. . In the remaining 69
defective nozzles, there were 51 instances of faceplate'
defects deemed minor enough to have only a marginal effect
(assumed to be average in the range of 10%) on vapor recovery
-------
-6-
efficiency. In the 69 nozzles, there were also 22 instances
of bellows rips/ with an average effect on recovery
2 /
efficiency of 30%—' . The weighted average effect on
recovery efficiency of the defective nozzles was thus
calculated to be:
Weighted Average , . . .
Efficiency Reduction = 51—x x 10% + 22—' x 30% + 4 x 100% = 22%
Per Defective Nozzle ——^—--
2/ The average bellows defect was determined to be a rip of
1.3 inches in length. The average reduction in system
efficiency resulting from such a defect was determined
by calculating the ratio of emission flow through such
a rip to the uncontrolled emissions generated during a
refueling. This calculation' was made as follows:
Efficency
Reduction = Er = Q
(as a fraction) Qo
where Q=volumetric flow of vapor out of rip [ft3/sec]
Qo=total uncontrolled emissions available at 6
gal/min (.0134 ft3/sec) dispensing rate.
(It was assumed that Q/Qo would be roughly the same at
other dispensing rates).
Restating,
Er= A xV
.0134 ftVsec
where A = area of rip, and
V= velocity of emissions passing through the rip
(ft/sec)
The standard rip was ajudged to be of rectangular shape
with width equal to 1/32 x L, where L is the length of
the rip. (The proportion of width to length is based
on the engineering judgment that a 2 inch rip would
have a 1/16 inch cross-section.) The velocity of flow
out of the rip is expressed by the formula for flow
from a sharp-edged orifice at low pressure drops,
namely— (footnote continued on next page)
2A/ Does not sum to 69 due to fact that 4 nozzles exhibited
both types of defect.
-------
-7-
2/Continued from A-6
V = c, 2Ap
f
where c, = coefficient of discharge of a sharp-edged
orifice
P- density of gasoline vapor
&P = pressure drop across the orifice (rip)
Thus, restating -
.0134 ft /sec. U p
I ^
L, as noted, was measured to be 1.3 inches.
Cd = .60 Source: Marks, Mechanical Engineers Handbook
(5th ed.), p. 239.
/= .09821b/ft3 The vapors were assumed to be a _
mixture of 40% air, and 60% propane.
Sources of densities: 41 Fed. Reg. 48053; Marks,
op.cit., p, 1909.
= .1 inch of water. This is believed to represent a
conservative estimate ofAP. According to data in
CARB Exec. Order No. G-70-17, certified balance
systems operate roughly at .3"A? at 6 gal. per
min. flow rates. It is known that a rip would
reduceAP, and it is believed that a reduction to
.1 inches water for a 1.3 inch rip if anything
overstates the case.
Accordingly,
Er=.0313 x (1.3" x 1 ft)^C .60 X 12 x.l" H_0 x 5.20 Ib (F)/ft2
(12 in)2 | f Z d"H20)
.0134 ftVsec. -
11 (.0982 lb(M) X (lb(F) sec )
ft 3 (32.2 lb(M) ft)
-------
-8-
The expectable rate of defects in aspirator and vacuum-
assist nozzles (in a voluntary compliance situation) was
determined by examining 233 OPW-7V-A nozzles at District
service stations. The bellows design of the 7V-A nozzle is
similar to that of Red Jacket and Hasselman system nozzles.
The differences are that the bellows on a Red Jacket nozzle
has a roughly 50% greater area than that of the OPW-7V-A and
the Red Jacket nozzle does not employ a faceplate; the
Hasselman nozzle, on the other hand, employs a different
type of faceplate (concave metal instead of flat rubber^
than the 7V-A nozzle.
The number of nozzles with defective bellows was
determined to be 15. The percentage of nozzles exhibiting
this failure mode was determined to be 6% by dividing 15
by the number of vapor recovery nozzles examined (233)
plus the number of illegal conventional nozzles (11)
observed at the relevant stations. Based on the 6% rate,
it was estimated that aspirator nozzles would exhibit
about a 9% defect rate (because of the larger size bellows
-------
-9-
and because of the lack of a faceplate, which probably
serves to protect the bellows somewhat from abuse), and
about 6% for the vacuum assist nozzle (the same as for the
OPW-7V-A).
The average size bellows defect in the OPW-7VA nozzles
was determined to be a rip of 1.6 inches in length. Because
assisted systems operate at negative pressures, it was not
believed that there would be any appreciable vapor flow
through a rip of such size in such systems. However, it is
believed that there would be a loss of vapor scavenging"
ability for these systems at the vehicle fillneck owing-to
inflow of ambient air at the rip—' . The effect on the
vacuum-assist system's scavenging ability was assumed to be
in the minor range and was assigned a value of 5%. The
effect on the scavenging ability of the aspirator assist
was assumed to be greater, though still small, and was
assigned the value of 10%.
3/ The Installation Manual for the Red Jacket Aspirator
Assist system, for example, indicates that a small
leak at the fillneck-nozzle interface would permit
additional air to enter the aspirator, creating vapor
growth and thereby decreasing slightly the normally
small interface vacuum. Installation Manual, Red
Jacket; Aspirator-Assist Product, Sept. 15, 1978,
at p. 2. It is obvious that ambient air entering
from a rip would cause a similar reduction of
the interface vacuum due to the resultant vapor
growth at the aspirator.
-------
-10-
Onboard - For the nozzle modification case (hereafter,
"nozzle case"), it is assumed that the nozzle needed for a
tight seal would be comparable to that used in a balance
system. Accordingly, the onboard nozzle case numbers are
identical to those used for balance systems in the voluntary
compliance mode.
For the fillpipe modification case, it was considered
whether any loss in vapor capture efficiency could be
expected at the interface of the fillpipe seal and conventional
nozzle as a result of worn and/or deformed nozzles. MS-ED's
Fuels Section indicated, however, that substantially worn
and/or deformed nozzles are relatively rare and that, in any
event, virtually all wear and damage occurs in the outermost
3/8 "of the spout. The materials submitted by API indicate
that the interaction between the fillpipe seal and nozzle
would occur substantially farther up the spout than that.
See, e.g., Fig 3A in ARCO portion of API Publication No.
4306, October 1978. Accordingly, the nozzle-maintenance
failure mode was not included in the analysis of the onboard-
control modified-fillpipe case.
B. Hoses
Stage II - The nature of the defect is kinking and flattening
with resultant increase of back pressure in the vapor return
line. MSED's survey found a defect rate of roughly 32% in
-------
-11-
hoses at District of Columbia service stations. This
compares to a 29% defect rate determined by the California
Air Resources Board in a 1977 survey of stations in the Bay
Areai/.
The hoses involved in the surveys were full-length (12
foot) hoses and, as vacuum-assist systems utilize this
length of hose, the expectable rate of hose defects with
such systems was deemed to be in the 25% range. A reduced
rate of occurrence (10%) was assumed for balance and aspirator
systems, owing to the fact that these systems, as certified
by CARB, employ vapor return hoses only 8 feet long and_thus
less susceptible to being run over by cars—one of the
causes of hose problems. The hose defects found by MSED
personnel ranged from minor kinks to virtually total "crushes"
(collapsed hoses). It was conservatively estimated that the
average constriction would cause the same sort of moderate
reductions (20%, 15%, and 10% for balance, aspirator, and
vacuum-assist systems, respectively) in recovery efficiency
as would occur with back-pressure build-ups in misinstalled
systems (non-severe cases).
4/ Report: Harmon Wong-Woo to William Lewis, Subject:.
Field Survey of Bay Area Air Pollution Control District's
Phase II Vapor Recovery Program; March 10, 1977.
-------
-12-
C. Processing Unit
The Hasselman vacuum assist system processing unit
consists of an electrically-powered blower, an electronically-
ignited incinerator, and a control apparatus consisting of
a number of solenoids and valves. While the system is
believed generally reliable, the electronic and mechanical
parts are, obviously, subject to wear and malfunction.
Accordingly, it was assumed that there would have to be
some average downtime associated with these units. In
lieu of hard information about the durability of the
processing units, a nominal 2% rate was chosen. It was
assumed that 50% of the downtime would be downtime of the
blower, with resulting 100% recovery efficiency loss, and
50% would be downtime of the incinerator, with a roughly
50% loss in recovery efficiency. The weighted average
recovery loss is thus 75%.
D. Aspirator Units
These units are deemed highly reliable by Dick Smith
of the S. D. APCD and Mike Manos, of Scott Environmental
Technology. Accordingly, a nominal 2% failure rate (a
failure being a misadjustment of the aspirator flow
sufficient to affect vapor-return-line vacuum) was assumed,
with a marginal (10%) effect on vapor recovery.
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E. Canister System
Though the canister system portion—'of an onboard
control system will presumably be designed to be maintenance-
free, it seemed resonable to assume that at least some nominal
amount of vehicles (2%) would exhibit some loss in processing
efficiency due to deterioration of some system component
(e.g. crack in a hose, reduced working capacity of carbon
adsorption bed). The average loss was assigned the midrange
value of 50%.
F. Fillpipe Seal
In the onboard case where a tight seal is achieved
through use of a conventional nozzle and a modified fillpipe,
the fillpipe sealing apparatus will presumably be designed
to function optimally, without maintenance, for the life of
the vehicle. It is expected, however, that actual field
performance would fall somewhat below optimum. Potential
recovery-affecting deficiencies include wear of the seals as
a result of nozzle insertions, and deterioration of the sealing
material itself as the result, for example, of exposure to
5/ The "canister system" includes all components installed
between the vehicle fuel tank and carburetor for the
purpose of adsorbing and purging vapors trapped in
the vehicle as a result of the tight seal at the
nozzle/fillpipe interface.
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gasoline vapors. Presently, the only experimental data
regarding fillpipe seal durability is that generated for API
by ARCO. These data show excellent seal durability. It was
desired, however, to make a more conservative projection of
seal durability than that suggested by the ARCO data. The
assumption that on average, 10% of the in-use vehicle
fleet will experience problems with fillpipe seals with an
average 50% reduction in efficiency strikes a mid-range
course between the optimistic scenario suggested by the
ARCO data and more pessimistic scenarios which could
be imagined.
Tampering
A,B. Nozzles/Nozzles,Hoses (Stage II)
Balance System - Observations by Bill Bepsher of MSED and
a study performed for Union Oil Company by the Weitzman
Research Co. of Los Angeles tend to indicate that a
significant number of motorists find balance-system type
nozzles difficult and onerous to use—' . MSED's survey
of stations in the District of Columbia indicates that
dealers and attendants likewise find the nozzles onerous— .
6/ See Appendix F for discussion of these observations and
study. The principal reason for the distaste for the
balance-system type of nozzle appears to be the No
Seal-No Flow feature which requires the nozzle to be
pressed against the fillpipe with a fair amount of
force in order to obtain product flow.
7/ See Appendix F.
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Stage II nozzles require several hundreds of dollars a
year (at a typical station) to maintain and refurbish.
Stage II systems which have been grossly misinstalled
will, as has been noted, render dispensing of product
difficult. (See discussion of "Misinstallation"). All
three of these factors—inconvenience of system use,
costs of system maintenance, and misinstallations—are
assumed capable of prompting a certain amount of system
tampering. This tampering would assume the form of
dismantling nozzle bellows or disconnection of vapor re-turn
hoses, or a failure to use vapor recovery-type nozzles—_
each tampering mode having a 100% effect on vapor recovery
efficiency.
In conducting their survey of service stations in the
District of Columbia, MSED personnel looked for certain
forms of tampering. At the service stations which utilized
Emco-Wheaton Type 3003 (No Seal/No Flow) nozzles, there
should have been a total of 218 A-3003 nozzles in place and
functioning. The survey showed, however, that three of the
required nozzles had no bellows whatsoever, and that, in 20
instances, a conventional nozzle had been substituted for
the required vapor recovery nozzle. (The District currently
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allows the use of one conventional nozzle per product per
8/
service mode—7. Any such "legal" conventional nozzles were
excluded from the count).
At the stations utilizing OPW-7VA nozzles, there should
have been a total of 244 vapor recovery nozzles in place and
functioning. The survey showed, however, that 12 nozzles
had no bellows and that 11 conventional nozzles were being
used illegally. Combining the figures for the Emco-Wheaton
3003 and OPW-7VA stations, the overall tampering rate was
determined to be:
Overall
Tampering = 23 + 23 = 10%.
Rate 218 + 244
(D.C. Survey)
At the surveyed stations, a total of 63 conventional
nozzles were being legally used. Assuming that these
conventional nozzles would have been employed regardless
of legal authority, the overall tampering rate would have
been 20%. (46 + 63). This establishes an outer bound to
(462+ 63)
the rate of tampering that might be expected to occur in a
voluntary compliance situation. As a conservative projection,
a midrange figure of 15% was assumed to represent the
actual rate of tampering which would occur.
8/ Provided that there is at least one vapor recovery
nozzle per product per service mode. (The two
service modes referred to are attendant-serve and
self-serve).
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As already noted under "Misinstallations", 33% (i.e. 5%
of 15%) of this tampering would be attributable, in the case
of balance systems, to gross systems misinstallations. As
likewise already noted, this 5% would be reduced, in the
case of aspirator and vacuum-assist systems, to 3% and 2%,
respectively. It is assumed that the remaining 67% of the
tampering (10% of 15%) would be divided equally among
economic and convenience motivations. Since the differences
in the costs of maintaining balance systems and assist-
system nozzles are not extreme, a 5% tampering rate attr-ibutable
to economic considerations was assigned to assisted systems.
As the survey of nozzle use shows—' , however, assisted
systems nozzles do not appear as onerous to use as the
heavier balance system nozzles (also made more onerous by
the necessity of a no-seal no-flow feature) and thus will
not share in the 5% of tampering attributable to the user-
convenience motivation.
A. Nozzles — Onboard
Nozzle-modification—As the nozzle employed in this
type of system has essentially the same features as a
balance system nozzle, the balance system tampering rate
(excluding misinstallation-motivated) was assumed applicable.
£/ See Appendix F.
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Fillpipe-modification—The only nozzle tampering
applicable to this form of control would occur when an
unleaded nozzle was used to fuel a vehicle designed for
leaded fuel, and therefore containing an oversized (compared
to the fillpipe seal on an unleaded car) fillpipe seal.
The current estimate of the rate of use of unleaded
nozzles on leaded product dispensers is 3 to 4%—' , and
the current estimate of the percentage of new cars designed
to run on leaded fuel is 5%—•' . Accordingly,. the amount
of this form of tampering is deemed to be negligible.
In addition, the effect on recovery efficiency of this .'
form of tampering is deemed to be minimal. This is because
the fillpipe seals are designed substantially undersized
compared to the convential nozzles with which they are
intended to be compatible. The API report on onboard
controls, for instance, shows the inside diameter of
what is taken to be the seal for an unleaded vehicle to be
about .7 inches. If the seal for a leaded car were sized
in the same proportion to a leaded nozzle as the seals for
unleaded cars are sized in proportion to unleaded nozzles,
10/ Source: MSED Fuels Section Statistics.
ll/ Source: MSED Fuels Section estimate.
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their inside diameter would be about .78 inches. Thus, even
if a designed-for-leaded-fuel vehicle were fueled with an
unleaded nozzle, the nozzle would still be larger (by
six-hundredths of an inch) than the seal. Accordingly, a
nominal (10%) loss in recovery efficiency was attributed to
this failure mode.
C. Processing Unit
Stage II - This "failure mode" consists of a user's deliberately
turning off the vacuum-assist secondary unit with resultant
100% loss of vapor recovery efficiency. As discussed
under the sub-section "Tampering: Nozzles", 15% is the
estimated rate at which balance system-type nozzles would
be tampered with in a voluntary compliance situation, for
the purpose of obviating difficulties associated with the
use of such nozzles and for economic reasons. Overall,
the incentive for shutting off a vacuum assist secondary
unit would appear to be equally as great. To begin with,
there is the fact that the unit consumes about $50 worth
of electricity (annually) at a typical station where such
127
a system would be installed—'. More significantly,
12/ Because of the relatively high capital cost involved,
it is assumed that vacuum assist systems will be '
installed only at higher throughput stations. The
$50 figure is EPA's estimate for a nine-dispenser,
60,000 gal. per month station.
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typical annual maintenance costs of the unit are estimated
at $330 per year—. Particularly at outlets where
maintenance costs run higher than average, this level of
expense will tend to induce cost-saving system shutdowns.
Given the economic incentives and the 15% level of pro-
jected nozzle tampering in the case of balance systems and
onboards (modified-nozzle case), it is not believed that a
15% shutdown rate is unrealistic for a voluntary compliance
scenario.
D. Canister System
The rate of tampering with current evaporative canister
147
systems is 2.6%— . As the most typical form of tampering
consists in a disconnected hose— , as a worst-case
scenario it was assumed that the average effect on recovery
efficiency for this failure mode is 100%.
E. Fillpipe Seal
The MSED Draft Tampering Survey shows a 3.4% rate of
fillneck tampering. It is assumed that the addition of a
seal to the fillneck will neither deter nor increase this
tampering. The effect on vapor recovery efficiency is
assumed to be total—i.e., 100%.
13/ This is the estimate used in EPA's cost-effectiveness
study.
14/ Source: MSED Draft Tampering Survey.
15/ Source: MSED Technical Support Branch.
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Table 20
In order to determine the actual efficiency of the
Stage II programs, it was necessary to assume the proportion
of regulated throughput which would be covered by each
type of Stage II system. It was assumed that the cheapest,
although most difficult to use system-i.e., the balance
system-would be installed at all non-retail outlets and, in
addition, would be used on all attendant-serve retail
throughput. These assumptions result in balance systems
covering 55% of regulated throughput—' . The remaining -.-
45% was split between the assisted systems on a 35%,
10% basis on the assumption that the aspirator assist
system would capture the lion's share of the self-serve
retail market, with the relatively expensive vacuum assist
system being installed only at very high-throughput stations.
16/ The 55% figure is based on the outlet coverage
pattern of Option V. According to the November, 1976
Arthur Little Report, non-retail stations with greater
than 10,000 gallons per month throughput pump 53% of
the non-retail throughput which throughput, according
to the July, 1978 Arthur Little Economic Impact Study,
is 23% of the national total. Accordingly, greater-than-
10,000-gallons-per-month non-retail outlets pump 12% of
national throughput.
According to the May 5, 1978 Lundberg Letter, 46% of
service-station throughput is currently attendant-served,
Thus, given Arthur Little's 1978 estimate that retail
throughput is 77% of the national total, attendant-
serve retail throughput constitutes 35.4% of the
national total. Accordingly, the percentage of
regulated throughput covered by balance systems
would be 55%. (12% + 35.4%) = (47.4%)
( 77% + 12% ) (89% ) .
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Table 21
The estimates of total non-compliance were obtained
by using existing rates of non-compliance with Stage I vapor
recovery regulations as a baseline. Region II estimates a
current total non-compliance rate at service stations of
12%, despite the fact that the Region has been active
in enforcing Stage I, and despite the fact that the regulations
have been in effect for 2 1/2 years. Stationary Source
Enforcement indicates that the rate of total non-compliance
with Stage I regulations at small bulk plants is quite
large—probably well in excess of 40%. With'these two
guideposts, the 40%f 30%, 20% estimates of total non-
compliance appear conservative, if anything:
1. Stage II regulations are substantially more
onerous, both economically and as a burden
on service station operations, than Stage I
regulations. (Stage I costs only about $900 per
station and requires little, if any, operating
and maintenance costs; Stage II costs $7,000 at
a typical station for the cheapest system, and
costs several hundred dollars a year to maintain).
The economic impact of Stage II at a service
station is perhaps more comparable to the economic
impact of Stage I at bulk plants (10 to 11 thousand
dollar investment) and, accordingly, the rates of
Stage II non-compliance should be akin to those
for Stage I at bulk plants.
2. The Stage I compliance figures reflect a situation
where at least 1 in 10 stations per year are
being checked for compliance, whereas Table 21
assumes a voluntary compliance scenario.
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3. There are not known to presently be any equipment-
availability problems associated with Stage I
implementation. It must be assumed that there
will be some delays due to equipment shortages
if Stage II is implemented on a large scale—
particularly, if implemented on a nationwide
basis—7.
TABLE 25
As was indicated on page 8 of §VII, the optimum form
of any Stage II regulation would be an emission limitation
standard, supplemented by minimum equipment and maintenance
standards, and the optimum strategy for enforcing such a
regulation would consist primarily of visual inspections
of vapor recovery equipment at service stations. (See
Appendix E for rationale.) As was also indicated on page-
8, the optimum form of an onboard control (modified-nozzle)
regulation would be a dual performance standard, with the
optimum strategy for enforcement consisting of monitoring
compliance with the standard for the onboard portion of the
apparatus through the certification and in-use testing
programs, and monitoring of compliance with the standard for
the nozzle portion of the apparatus through in-use pressure
testing of nozzle sealing ability. (See Appendix E). Table
25 sets out, for the various program options, the rates at
17/ In 1976, for example, Arthur Little estimated that'18
to 24 months lead time would be needed to produce the
requisite number of nozzles if Stage II were required
in only 11 AQCR's. Arthur D. Little, Inc., Economic
Impact of Stage II Vapor Recovery Regulations, November,
1976, at 204.
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which gasoline-dispensing outlets could be inspected, using
40 man-years' resources in the optimum enforcement strategy,
with the regulation written in its optimum form. These
rates of inspections were determined from the total inspections
figures calculated in Appendix E as follows:
1. Stage II-Nationwide (Option V) —
Rate of = Number of Inspections
Inspection Number of Regulated Outlets
= 19,750 = 1 in 9
176,000
Onboard - Modified Nozzle Case
Rate of = Number of Inspections
Inspection Number of Regulated Outlets
= 26,000,n=7 1 in 7
176,000—'
2. Stage II - Nonattainment Areas —
See Discussion of Table 23 following.
18/ Assumes enforcement efforts respecting non-retail
outlets would concentrate on those with 10,000 gallons
per month and greater throughput. Other non-retail
outlets account for only a small fraction of national
throughput. Arthur D. Little 1976 Report.
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-25-
TABLE 23
A. Nonattainment Area Program
Tables 23 and 24 set forth the assessed effects on
non-compliance rates of the inspections performable under
the optimum enforcement strategy. Basically, the non-
attainment area columns in Table 23 show 50% reductions
over the non-compliance rates appearing in Table 18. This
50% rate of reduction was arrived at by the following
reasoning:
1. §113(a)(1), under which a non-attainment area
program would be enforced, requires, after the initial
determination of violation, a 30-day grace period and
redetermination of violation before any legal action can
be taken. It was optimistically assumed that, at a minimum,
any station initially determined to be in violation which
could be re inspected would be brought into compliance.
2. The percentage of violators which would initially
be determined to be in violation and which could be
reinspected was determined to be 40% by the following
reasoning:
2 x #of Stations Inspected + 1 x #of Stations Inspected
Twice Once =
Total Inspections Performable
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This formula can be expressed as:
2 x Total ftof Stations Inspected x % of Stations +
Total # of Stations Reinspected
Total IStations Inspected x (100%-% of Stations =
Total # of Stations Reinspected)
Total Inspections Performable
Total t of Stations
The total number of Stage II inspections performable with 40
man-years' resources (see Appendix F) is 19,750. The total
number of stations covered in a non-attainment area program
is 34,175. The percentage of stations reinspected
197
is estimated at 50%—. Accordingly,
2 x Total tStns. Inspected x 50% + Total ftStns. Inspected .
Total # of Stns. Total # Stations
x 50% = 12,750 = 1_
34,175 1.73
And, therefore,
Total #Stns Inspected X (2x50% + 50%) = 1
Total f Stns. 1.73
19/ This is the weighted average, by throughput, of the
reinspection rates for balance, aspirator and vacuum-
assist systems. The individual rates are 67%, 30%
and 50%, respectively, based on the proportion of
overlap deemed to exist among the failure modes set
out in Table 16 and the degrees of frequency of the
failure modes set out in Table 18.
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Thus,
Total ftStns. Inspected = 1 x 1
Total * Stns. -. 1.73 150%
= i IP/
T76~ = 40%
This figure represents the proportion of stations
which will be visited at least once if 50% of the stations
are being reinspected. This figure accordingly represents
the percentage of violators who will be caught and rein-
spected.
3. It was assumed that, in addition to the 40%
reduction in non-compliance attributable to inspection and
reinspection of outlets, there would be a modest (estimated
at 10%) spillover impact on non-compliance produced by the
relatively high (1 in 2.6) overall frequency of inspection,
even though §113(a)(l)'s preclusion of taking legal action
based on an initial determination of violation strictly
speaking militates against creating any deterrent effect.
B. Nationwide Stage II
The non-compliance rates shown in in the Nationwide
Stage II columns of Table 23 generally show 33% reductions
20/ This ratio of the stations initially inspected to total
stations constitutes the overall inspection frequency
for non-attainment area programs appearing in Table 10.
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over the rates appearing in Table 18. One-third of this
reduction is attributable to forced compliance at inspected
217
stations—' . The other two-thirds is the estimated result
22/
of the deterrent effect achievable under §113(a)(3)—'
with a 1 in 9 inspection rate.
C. Onboard-Control/Modified Nozzle
The nozzle tampering and nozzle maintenance non-
compliance rates for the onboard-control, modified-nozzle
option show approximately 40% reductions over the rates.
appearing in Table 18. About one-third of the 40% reduction
is attributable to forced compliance at inspected outlets—
the inspection rate in the onboard case being 1 outlet in
237
1—'. The remaining two-thirds, as in the case of
2I/ The percentage of violators brought into compliance as
a result of being caught in an inspection is expressed
by the rate of inspection—in this case, 1 of 9, or
11%.
22/ §113(a)(3), which governs enforcement of NESHAPS
(§112) regulations, permits legal action to be taken
upon the initial determination of violation.
23/ The percentage of reductions in non-compliance
attributable to forced compliance is expressed as in
the case of Nationwide Stage II, by the rate of
inspection—in this case, 1 in 7, 14%.
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Nationwide Stage II, is attributable to the estimated
deterrent effect achievable under §113(a)(3), with the 1
outlet in 7 inspection rate.
Categories of failure modes for which the reduction
in non-compliance rate was estimated to be other than 50%
(for a non-attainment area Stage II program), 33% (for a
nationwide Stage II program), and 40% (nationwide onboard,
modified-nozzle case) include: Aspirator unit (improper
maintenance), Vacuum-Assist Processing Unit (Imp. Maint),
Canister system (imp. maint.), Canister system (tampering)
and Misinstallation (onboard/modified-nozzle). These noji-
compliance rates were not changed as the system defects
involved would not be subject to detection and/or cure using
the enforcement strategies selected as optimum.
TABLE 24
The rates of total non-compliance set out in Table
24 show year-by-year incremental reductions over the rates
set out in Table 21—down to a believed maximum level of
installation (95%). The rate by which non-compliance is
reduced each year is 50% for the non-attainment area
program and 33% for the nationwide program—the rates
deemed generally applicable to reductions in non-compliance
for other failure modes. See preceeding discussion of Table
23 figures.
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APPENDIX E
Selection of Optimum Enforcement Strategy for Each
Program Option; Calculation of the Numbers of Enforcement
Inspections Achievable Thereby for Each Program Opt'i'on; .
Costs of Administering Optimum Enforcement Strategy -for
Each Program Option; Administrative Considerations
Respecting Various Enforcement Options
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I. OPTIMUM ENFORCEMENT STRATEGY FOR EACH PROGRAM OPTION
In order to assess the impact on compliance rates of
the commitment of 40 man-years of resources to enforcement
of Stage II and onboard (modified nozzle) programs, it is
necessary to determine how those resources would be used.
In order to make this determination, it is in turn
necessary to assess the optimum strategy for enforcement
of the various programs. The success of any enforcement
strategy can be measured by the percentage of non-complying
outlets brought into compliance in a given year. The
percentage of non-compliance "cured", in turn, depends on
two factors: the percentage of violators who are "caught"
and legally forced into compliance, and the percentage of
violators who, though not caught themselves, are deterred
into compliance as a result of seeing other violators caught
and dealt with under the law. Both of these factors obviously
thus depend on the percentage of violators who get caught in
a given year which, in turn, depends upon the number of
regulated outlets which can be tested for compliance within
that year.
A. Stage II Programs
So far as Stage II is concerned, the compliance test
relied upon at the time of the Nov. 1, 1976 proposal
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was the Short Test then under development by the Office of
Enforcement. The short test was designed to measure the
mass emission rate (grams per gallon dispensed) of Stage
II systems, and it was proposed to couch EPA's Stage II
standard as a mass emission limitation measurable by the
Short Test. The enforcement strategy deemed optimum
consisted of field testing regulated outlets using
that test.
While developmental work on the Short Test is not yet
quite completed, much is known about the manpower and time
requirements associated with this test (and with the Refueling
Emissions Simulation Test [REST] enforcement procedure, also
currently under development). That which is known, when
considered in conjunction with statutory limitations on the
treatment of violators, indicates there is little prospect
of forcing or deterring meaningful percentages of violators
into compliance with either the nationwide or nonattainment
area Stage II programs currently being considered by EPA—
if either the Short Test (or REST) constituted the exclusive
compliance test mechanism.
The percentage of outlets which can be compliance-tested
in a given year is the ratio of the number of outlets which
can be compliance-tested in that year to the total number
of outlets. To determine this ratio for the nationwide and
nonattainment area Stage II programs being considered by
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EPA, assuming 40 man-years' resources were devoted to
enforcement, the starting point is the number of compliance
tests which can be performed with 40 man-years' resources
for each type of enforcement mechanism.
The Short Test measures vapor recovery system emissions
occurring during actual vehicle refuelings. Vapors emitted
at the nozzle-fillpipe interface are captured by a
flexible sleeve and fed into recording instrumentation.
According to MSED and NEIC personnel, the Short Test
requires two people—one to conduct the vehicle refueling
process and one to handle the instrumentation. As presently-
conceived, the test requires that emissions from 100 cars
be measured in order to establish a violation. Experience
to date with use of the short test indicates that about 75
cars can be measured at high throughput stations in an
average eight hour workday— . An average regional
S&A inspector spends about 50% of his time in the
I/ Source: Interim Report on the Stage II Vapor Recovery
Short Test, December 30, 1976, Table I; March, 1977
Updated Report, Addition to Table I; Records of Bill
Rutledge, who was involved in the testing.
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field—' . Thus, even under the most optimistic of
assumptions, the number of complete short tests which
could be performed by a team of two inspectors in a year
would be roughtly 100— , or 50 per man-year.
2/ A fifty-fifty field-to-office time split was estimated
by both Jules Cohen (NEIC) and Keith Silva (a former -
fuels inspector now working in MSED). In addition,
a fifty-fifty split is consistent with information
supplied by Mark Siegler about the unleaded inspection
program. Mark indicates that roughly one hour was
alloted per inspection and that inspectors averaged
about 1,000 inspections per year. At eight inspections
per day, 1,000 inspections would require about 125"
days in the field.
_3/ 130 days x 3/4 test/day = 98. There is no reason to
assume the figure will be any higher. Indeed, as
noted, the 75 car per day figure was achieved at
relatively high throughput stations. At lower
throughput stations, attainment of even the 75 car
per day figure will be impossible. For example,
assuming 25 days' a month operating time, a 15,000
gallon per month facility will dispense about 600
gallons of gas in an average day. As automobile
owners (on average) take about 10.5 gallons per trip
to the station, a 15,000 gallon-per-month facility
services only about 57 cars a day. Thus, even if all
cars were utilized, a short test at this size facility
would consume the better part of two days. (In
practice, of course, cars tend to arrive at the
station in "bunches"—particularly during the morning
and evening peak periods—and not nearly all the cars
can be utilized).
No increases in the ratio of field time to office
time appear likely, as data reduction for the short
test takes about two hours. Lastly, it may be necessary
to obtain warrants to inspect for vapor recovery
violations as a dealer who realized his station was in
violation could gain valuable time for performing
needed maintenance by turning a warrantless inspector
away.
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Based on past experience, 40 man-years of federal
enforcement resources would be allocated as follows:
50% - field inspectors
25% - legal support
25% - administrative, clerical support
The annual number of compliance tests performable with the
Short Test using 40 man-years' resources can thus be
expressed as:
Short Tests = 20 man-years x 50 tests =1000
Performable man-year
EPA estimtes that the total number of outlets covered
by Option V (Stage II nationwide, with exemptions) would" be
176,000 and that the total number of outlets covered under
Option II (Stage II, nonattainment areas) would be 34,175.
The percentage of outlets which could be compliance-tested
in a given year under these programs, using 40 man-years
resources and the Short Test, would thus be 1 in 176 and 1
4/
in 50—' , respectively. The percentage of violators who
can be forced into compliance with such inspection rates are
roughly half-of-one percent and three percent respectively.
It is not believed that such rates of detection of violators
4/ The percentage of total outlets inspectable in a given
year in a non-attainment area program, where (see p, 8
below) violators must be inspected twice, was calculated
using the method set out in Appendix D, at pp. 25-27.
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would deter any substantial numbers of violators into
compliance.
The alternative compliance test to the Short Test,
known as the REST procedure, would not measure emissions
during actual vehicle refuelings. Rather, emissions would
be determined by measuring the vapors escaping when gasoline
was dispensed into two portable fuel tanks equipped with a
number of interchangeable fillnecks designed to be represent-
ative of the on-the-road vehicle population. As in the case
of the Short Test, two persons are required to perform the
procedure. By eliminating the need for actual vehicle
refuelings, however, the REST procedure achieves a time
advantage over the Short Test. Mike Manos, the lead engineer
for the REST project contractor, estimates that about three
hours will be required to perform the test at each station.
In addition, a daily calibration of the equipment requiring
about 45 minutes will be necessary. Adding in travel time
to and from stations, the most reasonable estimate at this
point is that, using REST, two service stations could be
tested per day by each team of two inspectors. This means
that one team could inspect about 260 stations per year.
(130 field inspection days x 2 tests per day). Accordingly,
130 tests can be performed per man-year.
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Using the percentage allocation of enforcement resources
assumed above, the number of REST test procedures performable
in a year with a 40 man-year resource effort comes to 2600.
(20 man-years x 130 tests per man-year). Accordingly, the
percentage of outlets which could be compliance-tested in a
nationwide Stage II program, using 40 man-years of resources
and the REST procedure, would be 1 in 67. Like the inspection
rates for the Short Test, this rate is deemed inadequate to
bring about any significant amounts of forced or deterred
compliance.
For a nonattainment area program, the percentage of" -
outlets which could be inspected in a given year using the
REST procedure would be 1 in 20— . This inspection rate
produces only 5% forced compliance. Moreover, given the
statutory procedural limitations on enforcement of a non-
attainment area program, an inspection rate of this magnitude
will produce virtually no deterrence. The problem is that
nonattainment area regulations would have to be promulgated
under authority of §110 of the Act—i.e., as remedies for
5/ The percentage of total outlets inspectable in a given
year in a non-attainment area program, where (see p. 8
below) violators must be inspected twice, is calculated
using the method set out in Appendix D, at pp. 25-27.
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deficiencies in state implementation plans. Under the scheme
of the Act, §113(a)(l) would govern enforcement of such
regulations. §113(a)(l) requires, before any enforcement
proceeding can be initiated against a violator-
1. determination of a violation
2. submission to the violator of a notice of such
violation
3. a 30 day waiting period (during which such
violation may be remedied)
4. redetermination of the violation subsequent
to the conclusion of the 30 day period
These procedural requirements pose an almost insuperable
barrier to creation of an effective enforcment deterrent" in the
context of a non-attainment area Stage II program—at least
where enforcement depends on a test procedure which can be used
on a regulated outlet only once every twenty years on average.
Under §113(a)(1), the violator has every incentive to wait to
be caught before performing needed system maintenance. He can
avoid civil penalties merely by performing the maintenance
during the grace period. Meanwhile, during the 19 years (on
average) between enforcement inspections, the violator can save
substantial amounts of money by neglecting system maintenance.
The inability of the Short Test and REST procedures to
produce substantial amounts of forced or deterred compliance at
outlets subject to either national or non-attainment area Stage II
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-9-
regulations—even with the application of 40 man-years of
resources—serves notice that the in-use emissions testing
enforcement strategy envisioned in the November 1, 1976
Stage II regulatory proposal needs to be altered. The
problem, in summary, is that the time needed to perform any
emissions test, coupled with limitations on enforcement
resources, will prevent enforcement efforts from achieving
substantial amounts of forced or deterred compliance.
It should be noted, however, that many of the failure
modes which will occur with Stage II systems (e.g. nozzle
rips and tears, hose defects, nozzle or hose tampering,
shutting off of vacuum assist systems) are matters readily-
visible to the eye. This suggests that more non-compliance
could be cured if a Stage II emission standard could be
supplemented by a standard specifying minimum maintenance
and operational requirements for the various types of vapor
recovery systems.
There appears to be legal authority for imposing such a
standard. In the case of a nationwide Stage II program,
§112(e)(l) provides that:
11 [I] f, in the judgement of the Administrator, it is not
feasible to prescribe or enforce an emission standard
for control of a hazardous air pollutant... he may
instead promulgate a design, equipment, work practice
or operational standard, or combination thereof whicl)
in his judgment is adequate to protect the public
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health from such pollutant... with an ample margin of
safety. In the event the the Administrator promulgates
a design or equipment standard... he shall include as
part of such standard such requirements as will assure
the proper operation and maintenance of any such element
of design or equipment."
According to §112(e)(2), the phrase "not feasible to prescribe
or enforce an emission standard" covers an enforcement
situation of the Stage II type as it includes "any situation
in which the Administrator determines that... the application
of measurement methodology to a particular class of sources ••
is not practicable due to technological or ecomonic limitations."
In the case of a nonattainment area program, §110(a)(2)
(b) specifies that State Implementation Plans contain
"emission limitations... and such other measures as may be
necessary to insure attainment and maintenance of [air
quality standards.]..." The emphasized languange is believed
broad enough to cover equipment/maintenance standards made
necessary by technological and economic limitations associated
with currently available emissions testing procedures.—
6/There is precedent for EPA's setting equipment standards in
the SIP context. See, e.g., Stage I regulations requiring
submerged fill pipes and no-connect no-flow features in
addition .to setting a performance standard. See 40 C.F.R.
§52.1598 for sample Stage I regulation.
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-li-
lt is estimated that as many as ten stations a day
could be visually inspected for compliance with an equipment
(with minimum maintenance requirements) and operational
tand d —/ Eac^ inspection would require only one inspector.
The Short Test and REST, by contrast, both require two men
to perform and the numbers of each test which can be performed
in a day are three-quarters and two, respectively. Accordingly,
substantial advantages in enforcing Stage II programs would
be achieved if the emissions limitation standard were
supplemented (on the rationale of enforcement necessity) by
an equipment (with required maintenance) and operational
standard enforceable by visual inspections.8/
—' See discussion below.
8/
—The emissions limitation standard and emissions testing
could not be eliminated entirely. Misinstallations which
are not so severe as to result in gross system tampering
would not be subject to visual detection; accordingly, the
threat of emissions tests must be preserved in order to
promote proper system installations. In addition, some
amount of emissions testing will be necessary to deter the
installation of system types which, even though properly
maintained and otherwise in conformity with a general
equipment/maintenance and operational standard, do not
achieve sufficient emissions reductions. Testing results
would also provide, in the early years of any Stage II
program, information upon which dealers could make purchase
decisions regarding systems and, in later program years,
information upon which updating or revision of equipment/
maintenance and operational regs could be based.
It is believed that about 250 emissions tests a year
would be adequate for these purposes. This means that,about
25% of field inspection time would need to be allocated to
emissions testing. (This assumes use of the Short Test.
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Footnote Continued
The number of emissions tests performable can be expressed
as:
tTests = % of Inspector x Total # of x # of
Performable Time Allocated Man-Days per Inspector
In one year to Emissions Inspector Man-Years
Tests Man-Year
x Test Performable
Per Inspector
Man-Day
Thus, the % of Inspector Time allocated to emissions testing
can be expressed as:
% Inspector
Time Allocated = 250 tests x 1
to Emissions year 130 Man-Days x 20 Man-Years
Tests Per Man-Year
x 3/8 Test Per
Man -Day
=25% ).
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B. Onboard Programs
Modified Fillpipe .Case — This program option, could be
9 /
enforced, at probably modest incremental cost,—' by
including the onboard vapor recovery function among those
monitored within the established certification and in-use
testing programs. The standard would be a performance
standard couched in the form most compatible with measure-
ment techniques employable in conjunction with the Federal
Test Procedure evaporative emissions tests.
Modified Nozzle Case — This program option would add a
tight-sealing nozzle function to the enforcement workload
for an onboard control program. Fortunately, there appears
to be a mechanism available for effectively dealing with this
problem. At a July, 1976 briefing of EPA officials, API's
task force on onboard controls demonstrated a pressure test
of nozzle sealing ability. This procedure was simple,
involving just the insertion of the nozzle into a standard-
ized fillpipe capable of being pressurized by means of an
electric pump. Under this procedure the flow of air out of
a leak (if any) is read from a flowmeter inserted into the
pressurized system. Nozzle sealing ability can then be
determined from the pressure gauge and flowmeter readings.
9/See subsection III below.
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-14-
This test can be performed very quickly, and the
equipment needed for it is inexpensive.—' This suggests
that, in the case of an onboard-control/modified-nozzle
program, the performance standard for the onboard portion of
the apparatus be supplemented by a performance standard for
nozzle sealing ability, enforced by use of the described
nozzle pressure-testing procedure.
II. Numbers of Inspections of Fuel-Dispensing Outlets
Performable With 40 Man-Years' Resources;
Stage II and Onboard-Control/Modified-Nozzle Options
A. Stage II (Enforcement Mechanism; Visual Inspections"plus
Short Test)- - .
As previously noted, it is anticipated that 75% of
field inspection time would be allocated to visual inspection
of service station vapor recovery equipment; 25% to systems
emission testing. As likewise already noted, a field
inspector typically spends about 50% of his time, or 130
man-days in the field. As noted, three-fourths of a short
test can be completed in one day by two people; accordingly,
the rate of emission testing with the Short Test, per man
day, equals 3/8. It is estimated that visual inspections of
a service station will consume roughly half an hour so
that, adding in fifteen minutes travel time between stations,
about 10 stations can be inspected in a typical eight hour
_10/The entire apparatus—-standarized fillpipe, electric pump,
pressure gauge and flowmeter—is believed to cost $300 at'
most. MSED Stage II Vapor Recovery Project estimate.
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workday. Accordingly, the total number of visual inspections
and emissions tests performable with 40 man-years' resources
can be expressed as follows:
Total
Inspections/ = 75% x 130 man-days x 20 inspectors
Tests Performable (Inspection per inspector man-years x
Alloction) man-year
10 inspections per + 25% x 130 man-days
inspector man- (Test per inspector
day Allocation) man-year
20 inspector
man-years
x 3/8 test per
inspector man-day
= 19,500 + 250 = 19,750
B. Onboard (Modified-Nozzle Case)—
Under this option, 100% of field inspector time would
be allocated to nozzle pressure-testing. It is estimated
that pressure-testing of the nozzles at a station would
require roughly half an hour on average and thus,
factoring in travel time, 10 stations could be inspected in
an average 8-hour workday. These inspections would require
only one man to perform and, accordingly, the total number
of inspections which could be performed with 20 man-years'
resources allocated to field inspections can be expressed as
follows:
Total
Pressure Tests
Performable
130 man-days x 10 tests
per inspector per inspector x
man-year
20 inspector
man-years
= 26,000
man-day
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III. Costs of Implementing Optimum Enforcement Strategies
Stage II - 40 Man-Years' Resources
As noted, 40 man-years of resources would be allocated
to the enforcement -of Stage II programs as follows: 50% for
field inspection, 25% for legal support, and 25% for adminis-
trative/clerical support. Past experience indicates that the
cost per man-year of such an allocation, when travel costs
are included, comes to about $30,000. To this must be added
the cost of test equipment figured as follows (Short Test
assumed the operative test) :
Cost of Test Apparatus Per Unit - $1 ,QQQ=j
Cost of Transport Van - $10,000—
Annualized = (7,000 + $10,000) x .263—' x 10 teams
Cost of Test
Equipment
= $40,000 per year
Accordingly, the annual costs of enforcing either Stage II
option with 40 man-years' resources comes to $1,240,000.
(40 man-years x $30,000 per man-year + 40,000).
_ll/Sources: Jules Cohen (NEIC), Mike Manos (Scott Environmental
Technology).
12/Includes $2,500 to modify the van. At least a 3/4 ton van
Ts required.
].3_/Capital Recovery Factor for assumed 5 year useful life.
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Onboard
Modified Fillpipe Case
As already noted, the onboard-control, modified-fillpipe
option can be enforced through the established certification
and in-use testing programs. It appears that the amount of
personnel and equipment needed to effectively enforce this
type of onboard control would be much less than that required
for enforcing service station controls. Marty Reinemann, of
MSAPC, has indicated that testing the onboard control system
would add only about 1/2 man-year to the MSAPC certification
14/ • i
program—, and would require only about $50,000 in
equipment costs.— According to Mort Cohen—' and Roy
Reichlen,— monitoring onboard controls would probably not
require any additional personnel in the Recall or Technology
and Testing Sections of MSED. Additionally, according to
Roy, the increase in the testing budget necessary to accommo-
14/This estimate is based on the assumption that only several
hundred tests of onboard-equipped vehicles (about one-half the
number of tests currently used for certifying the evaporative
emissions control system) will be necessary to certify-onboard
vehicles.
1^5/This would be the cost to equip 2 or 3 SHED's with the
capacity for measuring the onboard vapor control function.
l_6/Acting Chief, Recall Section.
_17_/Chief (at time of communication), Technology and Testing
Section.
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-18-
date the monitoring of onboard controls would be modest,
running at most 10% of the FY 79 budget of $1.5 million.
Accordingly, the annualized cost of enforcing this type of
18/
onboard control program would be about $178, 500.—'
Modified Nozzle Case - -
The costs of enforcing this option would consist of
the cost of enforcing the performance standard for the
onboard portion of the apparatus and the cost of enforcing
the performace standard for the special nozzles. The
former cost is the same as the cost of enforcing the modified
fillpipe option. The latter cost, assuming a 40 man years
years' resource effort, would be the same as enforcing the Stage ]
options, with the exception that the annualized cost of the
equipment needed to pressure-test the special nozzles would be
IJj/Total annual cost =
10% of $1.5 Million — $150,000
1/2 Man year — 15,000
Equipment costs — $50,000 x .263 (C.R.F. for
5 yr.useful life)
= $150,000 + $15,000 + $13,500
= $178,500
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i u eimn 19/ Accordingly, the total annualized cost
only about $1600.—
of enforcing the modified-nozzle option amounts to:
Total Annualized = $178,500 + $1,200,000 + $1200 = 1,379,700.
Cost
It should be noted that the foregoing costs represent
federal enforcement outlays only. As noted in footnote
13 of Section VII, it was assumed for purposes of the analysis
therein that the enforement resources deployed were federal
enforcement resources operating under federal enforcement
authority.
IV. Administrative Considerations
From an administrative viewpoint, the onboard-control
modified-fillpipe option presents the least expense and
the least difficulty. With this form of control, enforcement
could be accomplished through a centralized mechanism using,
for the most part, existing personnel and a relatively
limited amount of testing. (Vehicles would be tested as
classes, not on an individual basis, with the maximum number
of tests needed for any one class being the number deemed
statistically sufficient to justify a recall action.)
lj)/The unit cost of each test apparatus—consisting of
fillpipe, electric pump, pressure gauge and flowmeter—would
probably be $300 at most. Assuming a 5-year useful life,
the total annualized cost of 20 sets of apparatus would be
$1600. (20 sets x $300 per set x .263 Capital Recovery
Factor).
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With service station controls or with onboard controls,
modified-nozzles, enforcment would be decentralized throughout
the regional offices; the upkeep of the equipment installed
at service stations would have to be monitored and compliance
would be on an individual, case-by-case basis. Substantial
additions to and training of, inspection personnel would
thus be required, as well as a substantial amount of coordin-
ation and review of inspection personnel efforts.
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Public Use of Nozzles
On July 15, 1978, Bill Repsher of MSED visited three
service stations in the San Diego, Cal. area—one station
where each type of vapor recovery system was in use—and
observed use of the nozzles by self-serve customers. The
results were as follows:
- At the station with aspirator-assisted controls,
of thirteen customers observed, twelve—' used the
nozzle correctly without assistance - i.e. inserted
the nozzle spout sufficiently far that the bellows
made contact with the fillpipe or surrounding sheet
metal. One customer at an unleaded pump started out
using the nozzle incorrectly - it was not inserted
far enough to open the "trap door" in the restrictor
area. The customer recognized immediately that some-
thing was wrong, however, as gas poured back out of-
the fillpipe, and looked around for help. Upon being
instructed as to what the proper technique was, she,
proceeded to use the nozzle correctly.
- At the Hasselman system station, each of the 11
customers—' observed used the nozzle correctly -
i.e. inserted the nozzle far enough into the fillpipe
to cause the bellows to come into close proximity
to the fillpipe or surrounding sheet metal.
- At the station employing balance system controls,
the nozzle in use was an Emco-Wheaton 3003» the type
of nozzle conditionally certified by GARB— . The
no-seal, no-flow feature was tested by simultaneously
I/ Includes 4 females, 8 males.
2/ Includes 5 females, 6 males.
3/ Before finally certifying the EMCO-Wheaton nozzle,
GARB is requiring an increase in spout length and some
improvement in the sensitivty of the back pressure-
shut off valve. Neither of these modifications should
affect the no-seal no-flow or sealing features of the
nozzle, however.
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compressing the bellows and cocking the nozzle at an
angle to the fillpipe. It was determined that gas
would flow even though the faceplate portion of the
nozzle boot was not in contact with the entire circum-
ference of the outer fillpipe surface—to the point
where escaping vapors could be seen and smelled.
4/
Of the 14 customers observed—', however, none
inserted the nozzle at a perceptible angle to the
fillpipe, all appeared to make a good faith effort to
shove the nozzle straight in. Despite this fact, 4 of
the 14 refuelings observed resulted in substantial 5/
dripping of fuel from the nozzle/fillpipe interface— .
Public Reaction to Nozzles
At the three service stations surveyed, the customers
were asked to state their feelings about the vapor recovery
system in use at the station they were patronizing. At the
aspirator-assist station, 9 customers expressed neutral
feelings,— 2 expressed positive feelings— and 1
8 /
expressed negative feelings.— At the vacuum assist
4/ Included 1 female, 13 males.
5/ Substantial dripping means sufficient to create a
visible pool of gasoline on the ground. This phenomenon
was not observed with either of the assisted recovery
systems.
6/ E.g, "It's O.K." or "I don't mind using it".
7/ "It's a good idea"; "I'd rather use it than breathe
the fumes."
8/ "It squirts gas and the gas doesn't come out fast
enough."
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9/
station, 6 were neutral, 3 were positive,—' and one was
negative.—'At the balance system station, by contrast,
only four were neutral, one was positive,—' and five were
12/
negative.—'in the only formal survey performed to date of
consumer reaction to vapor recovery nozzles, Weitzman
Research Co. found a "statistically significant" preference
for the Hasselman nozzle over an OPW no latch/no flow
balance system nozzle.—'
The conclusion that may be drawn from this data is that
public reaction to vapor recovery will depend upon the type
of system in use, with reaction to assisted'systems being
essentially neutral and reaction to balance systems being
substantially negative.
9/ E.g., "I don't get fumes; that's why I gas up here";
"It's better for me. I don't get spills."
10/ "I don't like it; it dumps gas out."
ll/ "It's harder to fill the tank, but I like it".
12/ "The nozzles are too heavy"; "I hate them (the nozzles).
They're awkward to use"; "They (the nozzles) are
ridiculous". "I hate the nozzles. My wife can't use
them—they splash gas and are hard to press".
13/ Report; Consumer Reaction to the OPW No Latch/No
Flow Nozzle and the Hasselman Nozzle, Prepared for
Union Oil Co. of Calif. Weitzman Research Co., December,
1977.
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-4-
Attendant Attitudes
During the October, 1978, field survey of vapor recovery
147
systems in the District of Columbia—' , many station
attendants voiced their opinions regarding the systems. By
an overwhelming margin, station attendants were dissatisfied
with Stage II. Positive comments were virtually non-
existent—/.
Negative comments related to three general areas:
inconvenience of use, high costs, and fuel spillage and
recirculation. The heavier Stage II nozzles (all systems
in the District are balance systems), with the additionaJL
vapor recovery hoses, were cited as difficult to use,
especially for self-serve customers—. A number of
dealers noted that the nozzles are more difficult to use on
certain vehicles, owing to particular sheet metal configur-
ations, and it was pointed out that some vehicles were
difficult to fuel because the end-of-bellows to end-of-spout
distance was not long enough.
14/ See discussion in Appendix D, pp. 4 and following.
15/ One attendant, whose attitude was otherwise negative,
did concede that he expreienced fewer headaches since
Stage II was put into effect at his station.
16/ One dealer claimed that his business had fallen off
5% since the advent of the District's vapor recovery
program, owing to self-serve customers switching to
uncontrolled stations outside the District.
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The nozzle bellows were claimed not to be very durable,
ripping rather easily on sharp vehicle sheet metal edges.
Nozzle replacement parts were said to be difficult or
impossible to obtain. One dealer, assured that the MSED
inspector was not on an enforcement mission, confided that
he had removed some nozzle bellows—partly to avoid maintenance
costs and partly to avoid the inconvenience associated with
use of the nozzles. Attendants pointed out that instances
of fuel recirculation occurred with existing Stage II
equipment. In addition, many attendants, citing instances
of spills, spitbacks and leaking nozzles, questioned the
environmental benefits of Stage II.
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APPENDIX G
CUMULATIVE COST ESTIMATES
1982-1995
The cumulative cost figures shown in Table 10 represent estimates
of the cash flow expenditures for the period 1982 through 1995. Cash
flow was choosen as the appropriate cost indicator because this is the
least complicated (in terms of calculations) indicator of a total
expenditure pattern which is very complex because of the various phase-
in patterns assumed for each regulatory option. The algorithm used in
these calculations is set out below in three subcategories:
(1) Onboard (Option III)
This calculation was the least complex of the six options.
(a) No nozzle modifications:
With no O&M expenditures this cost estimate equals the
assumed retail price ($16.80 per vehicle) times the number of
vehicles sold C233.1 million) over the period 1982-1995.
(b) With nozzle modification:
This cost estimate adds vehicle costs ($14.40 x 233.1 million
vehicles) and nozzle costs. Nozzle costs include the purchase of
new nozzles every eight years (.in 1982 and 1990) with annual
maintenance costs and a rebuilding costs every second year.
Some adjustment was made for an increase in the number of nozzles
beyond 1.9 mi 11 ton.
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(2) Stage II (Options II, V, VI)
Stage II cost estimates were generated as follows:
(a) Investment cash flow:
Using the appropriate number of stations (see exemptions
explained for each option), the cost figures of Appendix C
and the number of nozzles per station shown in Table 9A, ^he
total investment cost fs simply the sum of the products of the
investment costs of each station and the number of stations in
each stze category. This figure is adjusted for the number of
new stations (using new station incremental costs) which will
replace existing stations over the period 1992-1995.
(b) O&M cash flow: _
Using the appropriate ttme phasing estimate this figure is
generated by summing the products of the annual O&M cost
estimates of Appendix C and the number of stations in each size
category.
(c) Adjustments:
The investment and O&M costs are adjusted to reflect some
growth in the number of nozzles at service stations. This growth
rises, but not proportionally, with the growth in the motor
vehicle fleet.
Total investment costs are adjusted for "adverse grade"
as explained in Appendix C.
Total costs are reduced by the size of the energy credit
derived from the energy saved by Stage II systems. See
*
Appendix B for a derivation of the cost saved per 1000 gallon
throughput.
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(3) Onboard and Stage II (Options IV and VII)
These simply sum the costs of Options II and III and Options
III and VI as appropriate.
Equilibrium Costs (any 15 year period after 1995)
The procedures followed in calculating equilibrium costs are
nearly identical to those used for the period 1982-1995. The only
differences relate to the use of a 15 year period and to the fact that
phase-in schedules have no impact on O&M costs and the size of the
energy credit.
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