United States
Environmental Protection
Agency
Industrial Environmental
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-84-047 May 1984
Project Summary
Long-Term  Continuous  Monitor
Demonstration  Program:
Columbus  and Southern  Ohio
Electric  Company,  Conesville
Unite
Edward F. Peduto, Jr.
  A continuous emission monitoring
(CEM) demonstration program was
conducted at the Columbus and South-
ern Ohio Electric Co.'s Conesville
Generating Station. The primary pur-
pose of this program was to demonstrate
the feasibility of the monitoring require-
ments specified in 40 CFR,  Part 60,
Subpart Da. A secondary objective was
to adhere to the draft quality assurance
requirements scheduled for promulga-
tion as Appendix F.
  An assessment of system availability
as a percentage of hourly unit uptime
indicated  an average of 78 and 75
percent availabilities for the SO2 outlet
emissions and control system removal
efficiency reporting parameters, respec-
tively. Availability  for the NOx system
averaged  65  percent.  Subpart Da
availabilities (number of valid 30-day
rolling averages) were 67, 59, and 62
percent for the SOz emissions, efficiency
and NOx emissions reporting param-
eters, respectively.
  Evaluation of labor requirements
indicates that the total average weekly
level of effort was 27 hours. Of the
total, 64 percent are attributable to
dairy operations, 23 percent to nonrou-
tine maintenance, and the remaining 13
percent to preventive maintenance.
  The system consistently complied
with the performance specifications
criteria.  Relative accuracy results
were well within the 20 percent limit
except on one occasion when the NOx
result slightly exceeded this level.
  This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title  (see Project Report ordering
information at back).

Introduction
  On June 11,1979, the U.S. EPA promul-
gated new source performance standards
(NSPS) for new utility steam generators
for which construction commenced after
September 18,  1978.  To  demonstrate
compliance,  EPA  also promulgated a
reference method (Method 19) that
supplies a protocol for determining  the
control device, sulfur input rate by either
fuel sampling and analysis or continuous
monitors, and the final sulfur emissions
to the atmosphere by continuous flue gas
analysis. In addition, the sulfur removal
efficiency for the control device is
calculated using these measurements.
This method was used to collect data for
developing the current set of performance
standards.
  EPA's Office of  Air  Quality Planning
and Standards, assisted by the Technical
Support Office of EPA's Industrial Envi-
ronmental Research Laboratory at  Re-
search Triangle Park (IERL-RTP), initiated
a program to demonstrate the feasibility

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of the requirements for monitoring and
control of SOa emissions. This program
focused on sources subject to the NSPS
specified in 40 CFR 60, Subpart Da.
  GCA/Technology Division was con-
tracted  to  conduct  the  portion  of the
program associated  with  measuring
gaseous emissions. The primary objective
of the program was to demonstrate the
feasibility of the monitoring requirements
specified in Subpart Da. Of secondary
importance was  the development of
background and support data for quality
assurance regulations. The study involved
a planning and procurement stage, a 1-
year field demonstration phase, and final
evaluation of the data. Approximately 12
months of data were collected during the
field portion of the program.

General Program Approach
  The  approach  simulated activities
involved in preparing for and complying
with the Subpart Da requirements. To
fulfill these requirements: the utility must
prepare a monitoring system specification;
procure, install, and certify the system;
and (finally) operate the system. Subse-
quently, the data are reported according
to the Subpart Da specifications.  In this
program, a number of prospective utility
sites  were surveyed as possible test
locations. Since no sources subject to
Subpart Da were operational,  newer
operational facilities subject to Subpart D
specifications were considered. The test
site selection criteria were:
   • Coal-fired steam generator, 100
     MWE minimum, less than 10 years
     old.
   • Coal sulfur  content,  2-5 percent;
     and medium  to high ash content.
   • Flue  gas desulfurization  (FGD)
     system designed for a  minimum of
     80  percent  SO2 removal on 100
     percent of the flue gas.
   • FGD system which employs multiple
     scrubber modules which are parallel.
   Installation of the monitoring system
was followed by a start-up  and trouble-
shooting phase, during which the system
was operated  and debugged. Shortly
thereafter, the system was certified
according to proposed Appendix B "Per-
formance Specifications  Tests 2 and 3,"
specified  in  the October 10,  1979,
Federal Register.  After certification, the
1 -year field demonstration involved:
   • Routine  operation according to
     Method 19  and Proposed  Quality
     Assurance Requirements.
   • Reporting consistent with Subpart
     Da.
   • Data Collection and Quality  Assur-
     ance  activities for assessing moni-
     toring economics and system per-
     formance.
 Routine activities were conducted daily
 by an onsite technician. Additional data
 were collected during quarterly quality
 assurance and stratification tests.
  After the test  phase,  all data  were
 evaluated, including an assessment  of
 continuous emission monitor (CEM)
 availability and data capture, the costs of
 procurement and operation, and monitor-
 ing system performance. System perform-
 ance is discussed in reference to 40 CFR
 60,  Appendix  B,  and proposed quality
 assurance protocols.

 Test Facility Description
  The  Conesville  Generating Station's
 Unit 6 was  selected as  the site for the
 CEM demonstration program. In Unit 6,
 the  flue gas  exiting the  boiler passes
 through two, parallel, air preheaters and
 into two, parallel, electrostatic precipitator
 modules.  The  gas from the precipitators
 passes into two,  double-inlet/single-
 outlet,  ID fans, which move the gas
 through the two scrubber modules. The
 modules  are  spray types designed  to
 operate with free floating balls; however,
 the balls were removed to reduce module
 pressure drop and increase flow capacity.
 Each module  can  handle  50 percent of
 the  flue gas at full load conditions. Gas
 exiting  the  scrubber  modules and the
' bypass duct are combined into a single
 common duct  before entering the 244 m
 (800 ft) tall stack.
  At full  generating capacity, total flue
 gas flow rate through the system is about
 1.3  x 106 acfm (36.8 x 103 mVmin) at
 300°F (149°C). About 30 percent of the
 total flue  gas flow is bypassed for reheat
 purposes  around the scrubber modules
 during full load conditions.
   During  the  initial  period of the  Field
 Demonstration Phase, Unit 6 was oper-
 ated year-round as a baseload unit. Unit 6
 normally  operated at full-load capacity
 during daytime  peak power demand
 periods;  at  night,  the unit operated at
 half-load  with only one scrubber module
 in service. During the later stages of the
 demonstration period, Unit 6 operated
 intermittently  as a baseload unit and was
 frequently  taken offline for varying
 lengths of time as a result of  the low
 power demands during spring and early
 summer  of 1982. The  unit was  never
 operated  in  a  swing load configuration.

 Continuous Emission
 Monitoring System (CEMS)
 Description
  The overall  design objectives for the
 CEMS were to meet Subpart Da monitor-
ing and  reporting requirements while
minimizing manpower requirements. To
meet these requirements, the following
CEM capabilities were required:
  • Dual inlet FGD emissions monitor-
    ing for S02.
  • Outlet FGD emissions monitoring
    for S02 and NOX.
  • Daily emissions and removal effi-
    ciency average calculations.
  • 30-Day rolling averaged emissions
    and removal efficiency calculations.
These  requirements  were met  with a
system approach  entailing  automatic
CEMS  operation.
  Monitoring points were at each scrub-
ber module  inlet  and at the  combined
outlet  breaching prior  to entering the
stack.  At the inlet  to  each  scrubber
module,  a single sample  probe was
downstream  of  the  ID fans and just
upstream of a guillotine bypass damper
door. A single outlet sampling point was
in the  common breaching, downstream
from both the scrubber module and
bypass duct outlets.
  The  multilocation  extractive system
was specified by GCA and designed and
constructed by KVB, Inc., of Irvine, CA. The
system consisted  of two sets of gas
sensors and the conditioning  hardware
and data acquisition equipment listed in
Table 1. One set of instruments measured
inlet SOz and 02 on a time-shared cycling
basis, and a second set measured outlet
concentrations of SO2, 02,  and NO*.
Samples were conditioned  by filtering
particles  using an  in-stack filter and a
high-surface area, glass fiber filter, both
at the extraction  point. A  dual-pass
condensation unit in the instrumentation
shelter removed  moisture.  The KVB
system operated automatically, including
multipoint calibration, zero/span checks,
automatic data  acquisition, and  onsite
data reporting.

Routine Operation
  During the field demonstration period,
a CEMS operator was onsite most of the
time Unit 6 was  online. The operator
performed  dialy  diagnostic checks,
maintenance, and logistical support
services for the CEMS. In keeping with
the approach of minimal operator atten-
tion, the CEMS operator left the site and
checked the CEMS status remotely using
the modem  link during Unit 6 outages.
The modem link was  also used when an
operator  was not  onsite when Unit 6
was operating.
  Daily, weekly,  and monthly operator
routines  involved CEMS  diagnostic
checks, checking  analyzer calibrations,
generating  daily  reports, performing

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Table 1.    Major KVB System Components
INLET MEASUREMENTS
 • SO2 — DuPont Model 400; 0-5000 ppm
   Oz — Thermox WDG III, 0-25 percent
OUTLET MEASUREMENTS
 • SO2 — DuPont Model 400; 0-1000 ppm (Normal Range 100O-5OOO ppm (Auto range)
   /VOx — Thermo Electron Model 10A; 0- 1OOO ppm
   Oz — Thermox WDG III; 0-25 percent
COMPUTER SYSTEM
 • Cromemco System Three
 • Dual 8 in. floppy disc drive
 • CRT Terminal
 • Report Format Printer
EXTRACTION SYSTEM
 • Paniculate Removal—Filtration
 • Moisture Removal—Dual Pass Condensation
routine and  nonroutine maintenance,
computer operations, and general admin-
istrative  duties, including project docu-
mentation and logistical support.
  The CEMS diagnostic checks were
performed twice daily, including visual
checks  of various CEMS operating
parameters such as sample flow rates,
vacuum and pressure levels, and temper-
atures, to ensure that all were within
specified operating limits.
  Calibration checks  were controlled
automatically by the computer at midnight,
and the  results were evaluated by the
operator each morning. If  calibration
results indicated  excessive drift, the
operator terminated CEMS operations
and manually recalibrated the  affected
analyzer.
  The CEMS operator reviewed the
process and  emissions data, and noted
any process upsets  (e.g., scrubber
malfunctions) and  any emissions  data
invalidations (e.g., periods when an
analyzer was offline for  repair or an
analyzer  was malfunctioning). The  time
and nature of process upsets  or  data
invalidations were recorded in the CEMS
uptime log.

Discussion of  Results
  The KVB  system was operated and
performance  tested over a period of 16
months in which Unit 6 was operational
for approximately 12 months. During this
period, various external quality assurance
tests were conducted  in addition to the
routine monitoring activities. In total,
program activities provided the necessary
data for assessing system  performance,
system  availability,  and  monitoring
economics. The following subsections
summarize each area.
Assessment of Monitoring
System Performance
  The continuous monitoring system was
operated and  maintained according to 40
CFR 60, proposed Appendix B. In addition,
other tests  were conducted to further
evaluate  system performance, including
initial and final performance specifica-
tions tests, stratification testing, relative
accuracy audits, and  calculation  of
precision estimates.

Stratification Tests
  Before initiating the Operational Test
Period and the routine monitoring phase,
stratification tests were conducted at the
monitoring locations, to ensure that the
probes were placed to provide represent-
ative  flue gas samples. The procedure
consisted of measuring the SOz and Oa
concentrations  at each  designated tra-
verse point.  Between each pair of ports
(three traverse points per port), the
monitoring system was switched from
the traverse point to a reference  point.
Data from the reference point were used
to correct for temporal process variations
during the test. Temporally corrected
traverse  data were used to define the
spatial variability of the flue gas stream.
  One stratification test was conducted
at one of the two inlets. Additional tests
were not conducted because the probabil-
ity  of stratification is low  at  scrubber
inlets.
  During the program, eight stratification
tests were conducted at the outlet: four at
full  load with both modules online, and
the remaining four  with the  boiler
operating at half  load and one module
online. Two  such  tests were conducted
for each module.


Performance Specifications
Tests
  Monitoring system  performance was
assessed using the Performance Specifi-
cations Tests outlined in the October 10,
1979, Federal Register. These tests
provide a basis for determining adherence
to minimum  compliance monitoring
system  performance levels. Tests were
conducted  to  quantify both  short- and
long-term drift, calibration error (preci-
sion), response t i me, a nd system accu racy
relative to the reference methods.
  These tests were conducted during the
latter part of May and the first week of
June 1981. An  abbreviated version  of
these tests was conducted during the last
month of the program (August  1982).
During this last test session, the relative
accuracy and calibration error tests were
repeated.
  The entire monitor system conformed
to all performance criteria, except that the
outlet SOa monitor exceeded the 24-hour
drift  and mid-scale calibration error
criteria. As a result of the drift exceedance,
the  monitor  was  equipped  with an
automatic zero function which rezeroed
the analyzer every 15 minutes. The mid-
scale calibration error result exceeded
the specification during the first tests,
but was within  limits during the  final
tests.
  The relative accuracy tests conducted
at the beginning and the conclusion of the
demonstration phase  indicate  perform-
ance consistent with regulatory require-
ments. During the  initial tests, the inlet
and outlet SOz system relative accuracies
(emission  rate) were 6.5  and 15.6
percent, respectively.  Results  for the
concluding test were comparable  with
inlet and outlet relative accuracies of 9.8
and  4.8 percent, respectively. Emission
rate  relative  accuracies  for the  NOX
monitoring system  were not appreciably
different when comparing the two tests.
Initially, the relative accuracy was  15.2
percent; the concluding result was  14.8
percent.
Accuracy and Precision
  As an extension of current monitoring
methodologies, EPA's Quality Assurance
Division  is formulating  and evaluating
quality assurance measures applicable to
power plant monitoring. These procedures
include protocols for demonstrating the
accuracy of data relative to a reference
method, as well as a simple daily routine
to determine the necessary  data for
assessing the precision of the measure-
ment equipment on a monthly basis.
  To demonstrate the utility  of these
methods,  GCA conducted the  accuracy
and precision estimating methods. Various
draft  versions  of  Appendix F were
prepared  during the 1980-1982 time
frame. The  precision  and  accuracy
checks were conducted according to the
November 19, 1981, version.

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Accuracy
  Proposed Appendix F provides two
options for assessing system accuracy:
one involves standard gases in which the
standard gas is analyzed and processed
as  a  flue  gas sample;  and the other
involves side-by-side comparisons of
CEMS outputs using applicable reference
methods. For this program, the reference
method was chosen.
  Results of the relative accuracy audits
are shown in Table 2, which includes
results  of the  initial and final relative
accuracy tests.  Each relative accuracy
audit  consisted of  at least six valid test
replicates; whereas, the initial and final
relative accuracy tests consisted  of nine
replicates.
  The inlet and outlet S02/O2 moaitoring
system  exhibited relative accuracies in
the range of 4.8 to 16.9 percent on an
emission  rate  basis. When reviewing
these results,  note that the monitoring
system and  reference methods  each
contributed an imprecision and  bias
component to the  relative accuracy
result.
  N0« results were in the range of 9.7 to
23.2 percent on an emission rate basis.
During the July 1982 audit, the relative
accuracy exceeded the allowable  20.0
percent criterion. This result indicates a
comparable bias to  other test periods;
however, the confidence interval (preci-
sion component) was much larger  than
before.

Precision
  Data from the daily calibration checks
were used  to  estimate the  upper and
lower probability limits for each analyzer.
These estimates were determined using
the protocol  in  the  proposed Draft
Appendix F Quality Assurance procedures,
dated November 19,  1981.
  Daily, the zero  and high  span gases
were input through the entire  system
(including all extraction equipment) and
analyzed as a  sample gas. The resulting
voltages were substituted in the appropri-
ate calibration equation to determine the
corresponding concentration in units of
ppm S02, ppm IMOx, or percent 02. Using
these data as inputs, the upper and lower
probability estimates for the zero and
high  span  levels  were calculated  by
determining the relative percent differ-
ences between the measured span (zero)
gas concentration  and the accepted
concentration.

CEMS Availability
  For this discussion,  two definitions
of  availability are presented. Total
Table 2.    Summary of Relative A ccuracy A udits
Date
June 1981
July 1981
June 1982
July 1982
August 1982

S02
4.3
11.6
6.5
7.4
9.8
Met
Oi
0.46
0.55
0.68
1.53
0.53
Outlet"
System
6.5
15.0
7.8
9.4
9.8
SO2
10.9
16.0
13.3
12.9
3.9
02
0.28
0.40
0.19
0.24
0.43
System
15.6
16.9
12.8
14.2
4.8
Outlet"
NO*
12.8
6.7
17.2
23.7*
12.7
System
15.2
9.7
17.7
23.2"
14.8
"SOa /VO,, and system are in terms of % relative accuracy; O2 is in terms of % Oz concentration.
"Exceeded the allowable criterion of <2O%.
availabilities refer to a simple proportion
of CEMS uptime to boiler uptime on an
hourly basis. This proportion is  also
modified  to  conform to Subpart Da
requirements, which involve definitions
of valid periods of data that are required
for reporting purposes. A valid data  hour
must consist  of at least two quarters of
data; and a  valid  daily average must
contain at least 18 hours of data for a 24-
hour, midnight to midnight, boiler operat-
ing day. A valid 30-day rolling average
must contain  at least 22 valid days of
data.
  Figure 1 shows valid monitoring data
availability based  on the  number  of
boiler operating hours in each calendar
month. The primary Subpart Da reporting
parameters are  outlet  SO2  and  NOX
emission  rates (ng/J) and  the control
unit S02  removal  efficiency.  Emission
rates  are calculated using  the  data
generated by  the pollutant and diluent
monitor combination.  Similarly, the SOz
removal  efficiency is calculated  using
concurrent data generated by the inlet
  WOf
SO2/O2 and outlet SO2/02 monitor
pairs.
  The hourly availability rates shown in
Figure 1 range from 38 to 90 percent for
the outlet S(?2 emission rate,  18 to 90
percent for the NOX emission rate, and 35
to 88 percent for removal efficiency.
Overall, the outlet SO2  emission  rate
availability averaged 78 percent; the NOX
emission rate, 65 percent;  and removal
efficiency, 75 percent.
  Table 3 summarizes the overall availa-
bility, indicates  the adherence to the
Subpart Da data capture requirement on
a  daily basis,  and shows the  data
availability for  reporting  the 30-day
rolling averaged data. In total, there were
277 "boiler operating days (as defined in
Subpart Da)" during the demonstration
phase. For these boiler operating days,
the daily data capture rate for outlet S02
emission rate was met  72 percent of the
time;  the  removal efficiency availability
requirement was slightly less (69 percent).
The daily NOX reporting requirement was
met 59 percent of the time. About half of
          i    I    I     I    l    I     I    I    I     I    i     r
        Jun  Jul Aug Sep  Oct  Nov Dec  Jan  Feb  Mar  Apr May Jun  Jul  Aug
       m	1981	9*"^	1982	*•
Figure  1.  Monitoring data availability by calendar month for outlet SO2 and NO „ emission rates
          and S02 removal efficiency (percentage of CEMS uptime relative to total boiler
          uptime).

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Table3.   Availability Summary for Required Subpart Da Reporting Requirements
    Parameter units
  Outlet
  SO2
Emissions
  Outlet
   NO,
Emissions
Removal
Efficiency
Total availability
  % total Unit 6 uptime
24 hour availability*
  % valid 18-24 hour days
Subpart Da availability
  % of valid 30-day rolling averages
   78
   72
   67
   65
   59
   62
   75
   69
   59
"Based on 277 total boiler operating days.

the NOx data unavailability was due to
NOx vacuum pump failure.
  Subpart Da 30-day rolling average
availabilities were 67 and 59 percent for
the SOz outlet emissions and removal
efficiency,  respectively.  The availability
for the NOX reporting requirement was 62
percent. For rolling averages that do not
fulfill the minimum data capture require-
ments, the upper and lower confidence
intervals for each parameter are calcula-
ted. The upper limit is used for reporting
outlet emission rates, and the ratio of the
upper outlet emission limit and the lower
inlet interval  limit are used to report the
efficiency parameter.

Assessment of Economic
Requirements
  The economic  impact of  continuous
monitoring regulations is also an area of
concern. The cost data  presented  are
based solely  on  actual costs associated
with the Conesvilie program. The applica-
bility of  these costs to other  utilities
installations provides a basis for projec-
tions. Proper use of the experience gained
in this program should significantly
reduce certain  costs;  however, site-
specific variables must be considered if
meaningful projections are to be obtained.
  The utility  operator experiences two
cost categories in fulfilling the Subpart
Da reporting requirements. Initially,
major capital expenditures are made in
purchasing, installing,  and certifying a
monitoring system. Subsequently, ongo-
ing costs  result  from routine operation
and data reporting.
  The  total $269,030 "premonitoring"
costs for the Conesville CEMS include: (1)
the system purchase price, $181,000; (2)
the cost to build a temperature controlled
monitor room and to route electrical
wiring and sample line, $31,030; (3) final
installation,  start-up,  and checkout,
nearly $36,000; and (4) the certification
tests, $21,000.
  Operating  costs at Conesville are
shown in Table 4. The 1,438 labor hours
include 915 (68  hr/mo)  for daily opera-
tions, 327 (24 hr/mo)  for  nonroutine
  maintenance, and  196 (16 hr/mo) for
  preventive maintenance. Nonroutine
  material  costs  were  $2,769, routine
  expendable material costs were $2,869,
  and calibration gas costs were $8,607.
  (Note that the nonroutine material costs
  are  biased  low because many of the
  replacement parts were  supplied under
  warranty, free of charge.)
   A comparison of the CEMS  operating
  costs with  the  total quality assurance
  activities  is given  in the  full report. The
  quality  assurance costs  were $90,000
  and covered an initial and final perform-
  ance specifications test series, three
  abbreviated relative accuracy audits, four
  stratification test series, and the calcula-
  tion of monthly precision estimates. The
  utility operator is required to conduct the
  initial performance specifications test
  series and a location representativeness
  (stratification) test. Future  regulations
  may include the reporting of  precision
  estimates and the conduct of a periodic
  relative accuracy audit and/or a cylinder
  gas audit.

  Conclusions
   While program results do  not fully
  answer all questions concerning contin-
  uous monitoring, several conclusions
  and/or judgements can be made. State-
  ments concerning this program should be
  prefaced by several qualifiers.  First and
  foremost  is that  the  experience and
  results may be specific to the Conesville
  monitoring  situation. Second, several
  economic constraints precluded imple-
  mentation of system modifications which
  would have most likely  improved system
  uptime.

  Design  and Software
  Deficiencies
   Several design deficiencies noted with
  the CEMS severely hampered availability
  and the subsequent fulfillment of moni-
  toring requirements. The primary prob-
  lems were  not  hardware related, but
  more "action  and  reaction" related;
  specifically, system  reactions  to  alarm
  conditions. KVB configured this system to
be totally automated: all operation and
control functions  are  "slaved" to  the
computer. As a result,  normal data
acquisition ceased whenever computer
operations terminated. Provisions should
be made for the system to be operated
manually during computer outage.
  Other  problems were related to  the
conditioning  and switching system.
Responsible for most of the hardware-
related downtime was the valve switching
system, which primarily used solenoid
valves which are prone to sticking. These
could  be replaced with multiport ball
valves.
  The  NOx converter and vacuum system
were responsible for most of the NOX
downtime. When exposed to high-sulfur
and  -chloride laden gases, the stainless
steel converters show a high corrosion
rate. Bypassing the converter would
eliminate this problem. The NOx vacuum
pump  was failure prone  for unknown
reasons: it appears that the best approach
for maintaining uptime is to keep a spare
pump on hand.
  The  computer disc system was very
failure prone. Repeated read/write errors
resulted in significant data loss. Much of
the problem can be attributed to dust.
  Aside from the read/write problems,
the durability of the floppy disc system for
field applications is questioned. During
the 16 month demonstration phase, the
disc system  was replaced once and
underwent significant  component  re-
placement on  another occasion.  For
future  applications, a sealed Winchester
or electronic disc storage  device is
recommended.

Availability
  Overall availability for future systems
of this  sort can be improved significantly
by implementing several generic design
changes. Based on the results of this
study, future systems should be configured
in two basic subsystems: the condition-
ing/monitoring  subsystem and the data
storage/reduction system. In addition,
these two systems should be separable;
i.e.,  if  the data system is removed, the
monitoring subsystem should continue to
collect  and store data on a secondary
system such as a secondary buffer or strip
chart recorder. Data availability should be
significantly higher since the monitoring
process  is not terminated upon the
termination of computer control.
  Other considerations should be given
to the servicing of  alarm conditions.
Often,  the computer  system terminates
system operation for what may be a very
minor problem. The power plant environ-

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Table 4.    OEMS Operation Manhour Requirement Summary

                                      OEMS Maintenance Summary

Total
Hours
% Total
Weekly
Average
Hours
Conditioning
System
NR" R"
242 62
17% 4%
4.5 1
Analyzers Computer
NR
60
4%
1
R NR
118 25
8% 2%
2.2 0.5
ft
re
1%
0.3
Total
NR
327
23%
6
R
196
14%
4
Daily
Operations
915
63%
17
Total
Manhour
Requirements
1438
27
*NR = Nonroutine Maintenance.
b/? = Routine Maintenance.
ment is well geared to the  use of
enunciator panels to report alarm condi-
tions. After acknowledging these types of
alarms, the appropriate action is taken by
operators or technicians.
  Automatic routines such as calibrations
should be scheduled during time periods
when more  personnel are  on duty.
Considerable downtime was encountered
during the Conesville program when an
automatic function occurred at midnight,
activating an alarm. The alarm would not
be discovered until  morning  because
personnel were unavailable to correct the
problem.


Projected Utility Costs
  The operational  experience gained
during  the  program can be used to
determine projected  costs to  the utility
industry. Yearly operations comprise the
largest cost element associated with the
monitoring. An estimated 900 manhours
per year will be expended to operate the
system, verify the data being stored, and
acquire the proper process and monitor
documentation for preparing the quarterly
Subpart Da and Appendix F reports.
  Quarterly  relative accuracy audits
constitute the next major labor require-
ment. Approximately 140 manhours per
audit will  be expended  if conducted by
inhouse personnel. An outside contractor
would charge approximately $10,000 per
audit including travel.
  Routine maintenance labor constitutes
about 8 percent of  the yearly level of
effort, or 210 manhours. This level may
be elevated slightly as the maintenance
schedules are refined.  The  nonroutine
maintenance level should be reduced
with a slight  increase in  preventive
maintenance.
  Nonroutine maintenance  has been
estimated at slightly over 310 manhours
per year. This is higher than expected, but
should decrease with time as the preven-
tive maintenance program is refined.
  Quarterly Subpart Da and Appendix F
(Draft) reports are projected at a combined
yearly total of 220 manhours, based on
using  an automated data reduction
system.
  Calibration gas cost is the single largest
quarterly expendable material expense
and most predictable utilizing  automatic
analyzer calibration systems in which the
gas  is  injected at the probes.  The
estimated yearly  cost (based  on the
Conesville  system) is  $13,940 using
Protocol  I certified span gases. Other
types of systems which use gas diluters
for blending  the  various span  gas
concentrations will require  about 30
percent of the gases required for Cones-
ville.
  The  spare parts  inventory  cost  is a
somewhat  significant  addition to the
original purchase cost of a CEMS. Usage
rate  and quarterly  replacement cost are
difficult  to predict.  A good  warranty
maintenance agreement with the CEMS
vendor can drastically reduce this cost for
the first  years  of  CEMS  operation. An
adequate spare  parts inventory for the
Conesville system would approach $11,600,
or 6.4 percent of the system cost.
i
   Edward F. Peduto, Jr.. Timothy J. Porter, and David P. Midgley are with GCA/
     Technology Division. Bedford. MA 01730.
   D. Bruce Harris is the EPA Project Officer (see below).
   The complete report,  entitled "Long-Term Continuous Monitor Demonstration
     Program: Columbus and Southern Ohio Electric Company, Conesville Unit 6,"
     (Order No.  PB 84-178 649; Cost: $13.00, subject to change) will be available
     only from:
          National Technical Information Service
          5285 Port Royal Road
          Springfield. VA 22161
           Telephone: 703-487-4650
   The EPA Project Officer can be contacted at:
          Industrial Environmental Research Laboratory
          U.S. Environmental Protection Agency
          Research Triangle Park, NC 27711

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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
                                                                                          * U.S. GOVERNMENT PRINTING OFFICE: 1964-759-102/950

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