EPA-650/4-74-017
September 1974
Environmental Monitoring Series
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EPA-650/4-74-017
DESIGN OF THE EPA SEMI-TRAILER
MOBILE AIR POLLUTION LABORATORY
by
G. J . Sen
Thermo-Systems Inc.
2500 N. Cleveland Avenue
St. Paul, Minnesota 55113
Contract No. 68-02-0654
ROAP No. 21AKB-28
Program Element No. 1A1008
EPA Project Officer: Jack L. Durham
Chemistry and Physics Laboratory
National Environmental Research Center
Research Triangle Park, North Carolina 27711
Prepared for
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
September 1974
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This report has been reviewed by the Environmental Protection Agency
and approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the Agency,
nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
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PREFACE
Simultaneous field measurements of a number of air pollutants using
sophisticated state-of-the-art instruments can contribute significantly to
the knowledge of air pollution dynamics. Such research measurements are
needed not only at several locations within a specific suburban area, but
at several locations in each of many cities and in several remote, background
areas as well. The cost of state-of-the-art instrument systems and the one-of-
a-kind nature of some instruments for this type of research program prohibits
the use of many fixed field stations as is often done for the routine monitor-
ing of several pollutants with less sophisticated equipment. Thus, the mobile
air pollution research laboratory described below was designed and built.
Many people contributed significantly to the successful design and con-
struction of the mobile laboratory. EPA, principly through Dr. J. L. Durham,
Project Officer, and Dr. VI. E. Wilson, offered many suggestions which improved
the design and layout of the laboratory. Special thanks go to Professor K. T.
Whitby for his many helpful suggestions covering every facet of the design.
Professor B.Y.H. Liu and Mr. J. Agarwal assisted in the design of the aerosol
sampling tubes and the wind shield design. Dr. B. Cantrell assisted in the
layout and electrical design, particularly in the area of the data analysis
center. Many of the design features are similar to, or improvements upon,
the design of the mobile laboratory for the State of California Air Resources
Board contract entitled "Characterization of Aerosols in Three Major Regions
of California". Thermo-Systems Inc. working through prime contractor Rockwell
International Science Center and subcontractor University of Minnesota, designed
and constructed the mobile laboratory for the ARE program. The crew which
operated the ARB laboratory during 1972 offered several suggestions which resulted
in significant improvements. Mr. Robert Odberg and his crew at Fruehauf Division
in St. Paul contributed suggestions, good workmanship, and much patience when
many minor changes were requested. Finally, a special thanks to Marvin Hudalla
who suggested many design improvements, supervised detailed construction of the
facility, and kept a watchful eye on the finished appearance, all resulting in
a significantly neater and more practical mobile laboratory.
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TABLE OF CONTENTS
Page No.
INTRODUCTION 1
DESIGN PHILOSOPHY 1
DESCRIPTION OF THE LABORATORY , 2
Basic Trailer Specifications 2
Exterior Trailer Modifications 4
General Interior Design 7
Air Conditioning Design 7
Interior and Roof Layout 9
Electrical Design 11
Lightning Protection 15
Sampling System 15
SUMMARY 17
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LIST OF ILLUSTRATIONS
Illust.
No.
1 Exterior curbside, rear, front, and roof views
2 Exterior roadside view
3 Interior floor plan for the 1973 programs
4 Interior ceiling layout
5 Interior roadside wall
6 Interior curbside wall
7 Interior front wall and work bench
8 View looking rearward at the aerosol island
9 View looking forward at the aerosol island
10 View looking forward at the data analysis island
11 View looking rearward at the gas island
12 View looking forward at the gas island
13 Interior rear wall
14 Feeder pole and cable-and-plug electrical service entrance
15 Circuit layout of the air conditioning service panel
16 Circuit layout of the instrument systems service panel
17 Outlet receptacle locations of each interior circuit
18 Outlet receptacle locations of each exterior circuit
19 Aerosol sampling and transport system
20 Schematic of gas sampling system
21 Schematic of aerosol sampling system which includes Anderson
samplers
22 Schematic of aerosol sampling system which excludes Anderson
samplers
23 Electrical schematic of isolation-regulation transformers for
computer power
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LIST OF ILLUSTRATIONS (continued)
Illust.
No.
24 Photograph of exterior curbside
25 Photograph of exterior roadside
26 Photograph of interior aerosol island and front wall
27 Photograph of interior looking rearward at the data
analysis island
28 Photograph of aerosol manifolds and flow control panels
29 Closeup photograph of aerosol manifold designed for 4
Anderson samplers
30 Closeup photograph of gas manifold also showing a fused
plug connected to the electrical busway
31 Exterior photograph of both aerosol sampling stacks
showing windshields
32 Photograph of typical electrical feeder pole showing 2 cables
from the laboratory plugged into the feeder pole setup
33 Photograph of a tractor connected to the trailer, nearly
ready for transport
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LIST OF METRIC EQUIVALENT UNITS
Foot = ' = 30.48 cm
Inch = " = 2.54 cm
Pound = Ib = 453.6 gm
Tons = 12,000 BTU/hr = 3',516 watts
°F=f °C+32
BTU/hr = 0.293 watts
Ft /min = CFM = 28.32 liters per min
Gallons = Gal = 3.785 liters
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INTRODUCTION
This report describes the design and construction of the EPA mobile air
pollution research laboratory. Included are the design and specifications of
the basic semi-trailer, the layout and design of the laboratory within the
trailer, the design of exterior laboratory modifications, and the design of
the sampling system. Detailed descriptions of instruments and equipment used
within the laboratory are not included in this document.
DESIGN PHILOSOPHY
Several criteria have played a major role in shaping the design of the
mobile laboratory. Some of these criteria were:
1. The mobile laboratory had to meet the requirements of the experimental
program schedule for St. Louis during the summer and fall of 1973.
The laboratory had to accommodate the instruments, equipment, and
personnel planned for this experiment.
2. The mobile laboratory design must have sufficient flexibility to
allow changes, both during the St. Louis program and during any
subsequent programs. Future air pollution measurement programs
will use new equipment as it becomes available. The laboratory
must be capable of accepting new or different equipment with as
little effort and as little modification of the laboratory as
possible. EPA has suggested a number of instruments which may be
• added at a later date. Although the addition of all of these
instruments simultaneously would result in overcrowding, the
laboratory will accommodate any of the suggested instruments in-
dividually and will accommodate most of them simultaneously with
minor layout changes.
3. The laboratory must be readily moveable to new sampling sites with-
out requiring excessive time and effort. An experienced crew of
3 men must be able to assemble or disassemble the laboratory within
a single working day.
4. Although the laboratory is neat and well organized, functional utility
has priority over appearance. A beautiful laboratory which has been
modified to make it functional is no longer beautiful.
5. Within the limitations imposed by other requirements, the laboratory
is built of standard commercial hardware wherever possible. Not
only is this less expensive now, but it also results in faster repairs
and changes in the future.
6. A similar mobile laboratory was previously designed, constructed, and
operated for the California Air Resources Board. The EPA trailer in-
corporates many significant improvements, but utilizes the same basic
design concept.
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DESCRIPTION OF THE LABORATORY
EPA's choice of a semi-trailer as the basic vehicle satisfies the above
criteria very well. A semi-trailer is the most maneuverable vehicle of its
size, an important feature in programs which frequently require moving to
different locations, sometimes just across town, sometimes across the entire
country. The connection to towing tractors is standardized, simplifying
arrangements for transporting the laboratory. Semi-trailer manufacturers
have spent many years optimizing the design to make the interior as large as
possible, consistent with highway regulations. The rectangular shape and
rugged, but thin, construction simplifies flexible and functional laboratory
design. Semi-trailers are rugged, proven by billions of miles of rough highway
travel. Trailer manufacturers and distributors are familiar with making
modifications to meet customer's needs. Such modifications are thus somewhat
less expensive and can be made more quickly on a semi-trailer than on a mobile
home or converted bus. In addition, the basic cost of a semi-trailer is
generally no higher than other similarly-sized vehicles.
Basic Trailer Specifications
The basic semi-trailer is the Model FB8-W1-40 manufactured by Fruehauf
Corporation. The length and width are the maximum allowable in many eastern -
states. The height of the basic vehicle (without catwalk or ports) is 6 inches
below the maximum legal limit in most states. The trailer meets all other over-
the-highway requirements in nearly every state. The trailer readily connects
to most standard semi-tractors. Other specifications of the basic unmodified
trailer are as follows:
Length Overall 40fl Inside 39' 6 3/16"
Overall 13' Inside 101 3/4"
Overall 96" Inside 92 1/2"
Bulkhead 10 gauge high strength steel front wall bulkhead
30" high wrapping around 10° radius corner.
Swivel mounted glad hands recessed in bulkhead.
Front Wall .050" beaded aluminum panels with high strength
steel hat shaped posts riveted to bulkhead and
panels.
EPA policy is to express all measurements in Agency documents in metric units.
When implementing this practice will result in undue cost or difficulty in
clarity, NERC/RTP is providing conversion factors for the particular non-metric
units used in the document. For this report these factors are located on page vi.
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Upper Coupler &
Pick Up Plate
Roof Assembly
Side Wall
Side Skin
Floor
Brake Lines &
Light Wires
Electrical System
Pick up plate - 1/4" thick with multi-rib box
section reinforcing to front crossmember.
Upper Coupler - waffle design with 1/4" upper
and lower plates. Waffle consisting of 3/8"
plates welded to king pin. Exceeds 1,000,000
cycles of vertical bending at 40,000 Ib. loads.
.040" one-piece aluminum roof bonded to extruded
aluminum roof bows on 24" centers with thickness
controlled heat cured adhesive.
Entire outer roof surface attached to extruded
aluminum upper rail with 3/16" aluminum rivets
on 1 1/2" centers and covered with extruded
aluminum cap.
Upper rail extruded aluminum with marker light
wiring raceway and recessed area for marker
light installation.
Crossmember to lower rail attachment:
Lower rail - 13" high extruded aluminum
Crossmembers - 4" structural steel I-beams
on 15" centers.
Each crossmember attached to lower rail with
(4) 5/16" diameter aluminum squeeze rivets
per side, 2 on either side of I-beam.
.050" pre-painted aluminum panels.
Posts are high strength steel hat shaped posts on
12" centers over coupler and support area and
on 24" centers for the balance of the trailer.
Panels riveted to both sides of hat shaped
post (double row). Rivets on 1 1/2" centers
at panel laps and on 3" centers in other areas.
1 3/8" laminated hardwood attached to I-beam
crossmembers with (3) 5/16" diameter screws per
board per crossmembers. Floor undercoated with
petroleum based preservative.
Run length of trailer over crossmembers incased
in 12 gauge galvanized steel hat section level
with top of floor.
12 volt system with circuit breakers and moisture
proof plugs.
Tractor connection: 6 and 7 way plug.
Upper clearance lights recessed in aluminum rail
for protection from breakage.
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Rear Corner Post One-piece hat rolled, high strength steel corner
post with 1/2" steel bumper bar at lower corner
running completely across the lower crossmember
and up opposite side for door and hardware
protection.
Door Lock Flange on rear corner post completely
locks doors in place when closed.
Hinge pins could be removed and doors would remain
in place.
Side Wall Rating 25,000 Ibs. evenly distributed
Front Wall 40,000 Ibs. evenly distributed
Rear Wall 15,000 Ibs. evenly distributed
Roof 400 Ibs. over a 12" x 12" area
Floor Rating 50,000 Ibs. evenly distributed
30,000 Ibs. distributed in any 10' area
17,000 Ibs. on fork lift axles
Exterior Trailer Modifications
A number of major modifications were made to the exterior of the trailer.
Figures 1 and 2 show details of the modified exterior. Some of the dimensions
may be inaccurate by an inch or two. The modifications include:
- Air ride tandem axles were installed complete with tires, rims,
wheels, air reservoir, and leveling valves. The axles are centered
11 feet ahead of the rear end of the trailer. The air ride sus-
pension cushions nearly any highway bump enough to prevent damage
to most instruments and equipment. Dual axles help reduce the
chances of tipping, particularly when one side drops into a road
depression such as happens when turning too sharply into a drive-
way with a ditch. The forward location distributes most of the
load primarily over the air-suspended axles rather than over the
tractor axles allowing the use of a single axle tractor and cushion-
ing most of the trailer even with a non-air-cushion tractor.
- The two front supports are located at the normal position. Two
additional individually adjustable supports are installed behind
the trailer axles as shown in Figure 1 to stabilize the trailer in
gusty winds. All four supports have standard sand pads to reduce
the chances of the trailer sinking into soft ground. Each of the
four supports is independently adjustable to allow leveling of the
trailer. The adjustments are made by separate manual cranks so that
no external power, either tractor supplied or electrical, is required.
Each crank has 2 gear ratios, one for fast lowering or raising of the
unloaded support, and one for lowering or raising the loaded trailer.
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A steel compartment box is-installed between the front supports
and the tandem axles as shown in Figure 1. The compartment is 96"
wide (external), 29" deep (external), and 13' 4" long (external).
The compartment has two doors, each about 10' long, one on each
side of the trailer. The doors have hinges, locks, and handles.
The compartment door on the curbside is located so that it does not
interfere with the curbside stairs and landing. Although the com-
partment doors have a weather stripping seal to reduce the chance
of water entering the compartment, the compartment is not intended
to be completely water-proof. The compartment is useful for trans-
porting of the stairs and landings, gas cylinders, and other equip-
ment. Vacuum pumps, blowers, voltage regulators, and voltage
isolators are mounted and operated in the compartment, reducing
the noise level and the amount of equipment within the trailer.
The compartment has 2 blowers and vents to cool the pumps and equip-
ment when they must be operated with the compartment locked.
Another steel compartment box is installed behind the tandem axles
as shown in Figure 1. The compartment is 96" wide (exterior), 29"
deep (exterior), and 51 3" long (external). The compartment has
two doors, one nearly the full length on the curbside and one about
3' long on the rear compartment wall. The rear door does not in-
terfere with the stairs and landing. The doors have hinges, locks,
and handles, and have a weather stripping seal to reduce the chance
of water entering the compartment. Most of the rear compartment can
be used for transporting and storing equipment similar to the larger
forward compartment. A separate compartment within the rear com-
partment serves as an electrical service entrance junction box. The
electrical service entrance cables pass through the rear compartment
to the junction box when in operation. The curbside door closes and
locks either with the electrical service entrance cables connected
to the power source or with the cables coiled in storage within the
rear compartment.
A catwalk covers the entire roof, making the roof a working platform.
The catwalk is made of perforated galvanized steel, making the roof
corrosion and skid resistant. The catwalk is attached firmly to the
roof rails and extends 2" above the standard roofline of the trailer.
The perforations in the catwalk simplify the attachment of equipment
to the roof. The trailer structure is sufficiently reinforced to
carry the additional load of the catwalk and equipment. The catwalk
is capable of carrying at least 400 pounds per any square foot and
any 8' x 8* area is capable of bearing at least 2000 pounds.
A personnel door is installed within the original right rear trailer
door. The door opening is about 79 1/2" high and 27 1/2" wide. This
door is used for routine entrance and exit by people. The original
large rear doors of the trailer are used only for loading and unload-
ing large equipment.
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Another personnel door is installed in the curbside wall above the
front supports. The door opening is a minimum of 80" high and 32"
wide. This door is also used for routine entrance and exit of
people. This door meets or surpasses the requirements of the Uniform
Building code, the only door required by the UBC. However, the 2
doors do provide emergency exits near each end of the laboratory.
Stairs, landings, and hand rails are provided for each personnel
door. The landing posts are adjustable to allow setup on sloping
ground. Each of the two stair landings and rail units disassemble
into the following components for storage and transport in an under-
compartment: one stairs, one landing, 2 landing posts, and 4 hand
rail sections. The stair and landing material is skid-resistant
perforated galvanized steel similar to the catwalk material. Each
stair step will bear at least 500 pounds and the landing and stair-
case will bear at least 1000 pounds. The stairs, landing, and
hand rails meet applicable Occupational Safety & Health Act (OSHA)
codes.
Five combination storm-screen windows are installed in the walls.
There are two on each side and one in the rear personnel door.
Approximate locations are shown in Figures 1 and 2. The windows
are nominally 11" high by 18" wide (about 10" x 16" open area).
The storm window or screen can be changed from the inside. The
outside window cranks open from the inside. The windows are large
enough to allow the operators to see the surroundings, but small
enough to prevent unauthorized entry. The windows are also useful
for fresh air ventilation, for inside-outside communications, and
for quick and temporary passage of sampling tubes or electrical
cables.
Seven access ports are installed through the roof. The ports are
10" o.d. aluminum tubes which protrude about 1" above the catwalk
and 2" below the ceiling. The ports have flanges and water-tight
covers on the outside. The exact locations of the access ports
were determined specifically by the layout chosen for the 1973
St. Louis program, but also allow maximum layout flexibility for
future programs. Two access ports are located above the aerosol
island, one above the front bench area near the aerosol island,
one above the gas island, one above each end of the computer area
for electrical signal cables, and another above the rear open ex-
pansion area.
Twin air conditioner units are mounted on the exterior front wall
as shown in Figures 1 and 2. The top of the units are about level
with the original roofline to allow as much tractor clearance as
possible. The vertical angle framework is bolted directly to the
four vertical frame channels of the trailer. The vertical frame
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channels are reinforced with hardwood beams to carry the extra load.
The air conditioner units extend about 57 inches ahead of the front
wall of the trailer and sufficient bracing is installed to carry the
load. The units are mounted flush with the side walls to allow as
much working clearance as possible between the units. Placing the
units outside the trailer allows additional necessary space on the
interior of the laboratory and greatly simplifies the ducting of
supply and return air. Units which mount flat against the front
exterior wall also protrude about 30" into the interior, limiting
the interior layout and complicating the duct layout. Since the
flat-mounted units protrude through the front wall, they are also
more difficult to mount. Any tractor used to tow this trailer
must allow sufficient clearance for the air conditioner units.
Either the tractor must have a low roofline with no protrusions
above its roofline, or the tractor must have a long wheelbase and
enough spacing between the fifth wheel and the rear of the cab.
Neither requirement is very restrictive. Many, perhaps most,
tractors are suitable. However, tractor clearance must be carefully
watched. The specifications of the air conditioning units and the
system design are discussed later in this report.
- All modified exterior surfaces are painted to match the prepainted
aluminum exterior side panels.
General Interior Design
Figures 3-13 show the interior floor layout, ceiling plan, wall plans,
and cross-sections of critical areas. The following discussion covers each
subject individually.
The interior walls are finished with medium-colored 1/4" wood paneling
which is specially treated to meet Underwriters Laboratory (UL) tests for a
flame spread factor of 200 or less as required by the Uniform Building Code
(UBC) for a laboratory of this type. Logistic rails are installed to allow
equipment to be strapped down during transport. The straps, which quick-
fasten into the logistic rails, look and operate like auto seat belts. Vinyl
asbestos floor tiles, 1/8" thick, cover the Fruehauf hardwood floor. The
ceiling is finished with acoustical tile fastened to plywood panels. Wherever
possible, the walls, floor, and ceiling are made so that equipment may be
mounted, holes may be drilled, or other modifications can be made easily.
Air Conditioning Design
The trailer is insulated with 2" of foam on all walls, floor, and ceiling.
The ceiling insulation is installed above the air conditioning duct. Twin air
conditioning units are installed near the roofline on the front exterior of the
trailer. Two units are preferable to a larger single unit for several reasons:
1) while one is being repaired, the other is fully operable, usually allowing
the laboratory to continue operations, 2) during most times of the year, one
unit can be switched off saving wear and power, 3) larger units are not avail-
able in a single-phase model which would make the electrical supply problem
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much more difficult and would greatly limit the possible trailer setup locations,
4) two units are easier to mount than a single larger unit, and 5) each unit can
be switched on separately reducing power line voltage surges.
The supply air is ducted through twin sheet metal ducts, each half-trailer
width, over the full length of the trailer. The ducts are sealed sufficiently
tight to meet the strict California regulations governing commercial coach
construction. Four supply registers, Hart & Cooley Model 24 with No. 22
damper (12" x 12"), are installed in the ceiling on each of the two ducts as
shown in the ceiling layout (Figure 4). Four Hart & Cooley Model 93VOH registers
with adjustable dampers (20" wide x 24" high) with filters are installed as re-
turn air registers in the inside front wall above the work bench as shown in
Figure 7. As shown in Figure 1, two similar registers, about 20" wide x 12"
high, are installed in the exterior front wall as adjustable fresh air supplies.
They have hinged covers which close to protect the registers and ducts from
water, dirt, and insects during transport.
The twin air conditioning units chosen are both Fedders Model CAC060A3
with 15 KW electric heat kits and low ambient kits. Each of the air cooled
units is about 34" high, 46" wide, and 57" long and weighs about 540 pounds.
Each is rated at a nominal 5 tons capacity which is equal to the total output
of each unit at 85 F outside temperature. At 115°F outside temperature, the
total output of each unit is 50,000 BTU/hr. (slightly more than 4 tons each).
The blower in each unit puts out 2,200 CFM at 0.10" of H90 static pressure head
and 2,000 CFM at 0.40" of HO. The electric heaters are installed within the
exhaust ducts of the air conditioners. Each 15 KW unit is made up of three
5 KW elements with staged switching to reduce electric supply line surges. As
required by the National Electrical Code (NEC), the electric duct heaters units
include both an automatic thermal cutout device and a higher-temperature solder-
melt-out thermal interupt. Each air conditioning unit has a separate heating
and cooling thermostat located near the front of the trailer (see Figure 6).
The separately adjustable return air and fresh air registers allow control of
the amount of fresh air entering the system. The individually adjustable supply
registers allow the occupants to distribute the conditioned air to the needed
locations. The low ambient kits reduce the chance of frost buildup on the air
conditioning evaporators when cooling is required with an outdoor temperature
of about 50 F.
The air conditioning system is designed to perform as follows:
1. With an outdoor temperature of 120°F and noon-time sun, the
system will cool the trailer down to below 70°F with no
instrument heat load, but with 6 persons and full lighting.
2. With an outdoor temperature of 120°F and noon-time sun, the
system will cool the trailer down to about 80°F with all
equipment which is planned for immediate installation in
full operation, with 6 people, and with all lights on.
3. With an outdoor temperature of -40°F with a cloudy sky, the
system will heat the trailer up to 70°F with the fresh 'air
inlet closed and with no interior heat gain except all lights.
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4. The thermostats can be set to allow + 2°F control.
A humidifier, the Humid-Aire Vapotron-4000 Infra-Red unit made by Hamilton
Humidity, Inc., is supplied for use during cold outdoor weather. This unit is
large enough to raise inside relative humidity to about 30% at 0°F outdoor temp-
erature. The maximum output is 2.4 gallons per hour. The 45-pound unit can be
installed on a shelf or bench and is 25 1/2" long, 20 1/2" wide, and 10 1/2" high.
A humidistat which controls the unit has a range of 20 - 60% (+ 5%) relative
humidity. The infra-red lamps produce nearly pure water vapor, leaving impurities
such as minerals in the teflon-coated reservoir. In addition to an improvement in
the health of the operators, the humidifier may cause the computer to operate more
reliably. However, the operators will not want to humidify the air unless nec-
essary because water must be carried on board. The 2.4 gallon per hour water
usage rate means over 50 gallons per day may be necessary under extreme conditions.
Since maximum need for the humidifier will occur with the coldest winter weather,
a garden hose or temporary water pipe is not feasible. A dozen 5-gallon plastic
jerry cans are supplied with the trailer for water transport and storage. De-
humidification by the air, conditioner units will reduce inside humidity to about
60% with outside humidity near 100%.
Interior and Roof Layout
The interior floor layout for the equipment installed for the first phase
of operations is shown in Figure 3. This layout is different from most mobile
laboratories, having an aisle down the curbside with work stations (islands) in
the center and on the roadside. The reason for this is to separate the traffic
areas from the work places. Nearly all aerosol instruments are located on one
island arrangement near the front of the trailer. Additional aerosol instru-
ments are located at the front bench. Gas instruments are located on another
island near the rear of the trailer. Instruments on each island face either
forward or backward with some at desk-top height and others on a higher shelf
(see island views in Figures 8, 9, 11, and 12. The rear of each instrument is
easily accessible and no instrument rests on top of another. Repairs and adjust-
ments can thus be made without shutting down everything or interferring with any
other equipment. The operators are not in the aisle making traffic flow much
smoother. Many instruments can be clustered around the sampling ports with short
sampling lines and easy access to all. This is especially important at the aerosol
island where the sampling of large particles requires vertical sampling tubes.
With the clustering of instruments on the island and with some instruments mounted
above other instruments, vertical sampling tubes can be connected to 3, 4, or
sometimes 5 instruments simultaneously. The extra bench space on the aerosol
island and the front bench can be used for loading filter holders, loading
Andersen samplers, writing in the data book, trouble-shooting instruments, or
adding new instruments or test equipment. The aerosol island has 2 roof access
ports and the front bench has one. Two 6-inch diameter sampling systems with
manifolds are supplied for the three aerosol roof access ports. All islands
have knee space and desk-height work surfaces allowing their use as a desk. The
open knee space is located at the aisle end of every island to make easier the
entrance and exit of the computer with its protruding feet and to facilitate the
packing of long items, such as sampling tubes, for transport. The knee space
will also be useful for temporary storage of miscellaneous items. The gas island
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has only one roof access port since vertical sampling is not necessary. However,
the adjustable shelves allows short sampling lines for gases such as ozone. The
space between the 2 halves of the gas island allows zero and span gases to be
piped in from outside. That same space on the aerosol island accommodates plumb-
ing to the pumps and blowers in the undercompartment.
Between the aerosol and gas island is the computer and the data analysis
center. The central location minimizes signal cable lengths and the walking
distance between sensor and data center. There is enough room provided for 4
relay racks of computer or other electronics against the roadside wall. There
is room in front of the computer for a teletype and 2 or 3 chairs. When operat-
ing, programming, or trouble-shooting the computer data system, this amount of
space is necessary. When it becomes necessary to work behind or alongside the
computer system, the unit(s) can be pulled out from the wall and moved around
to a convenient location. If it becomes necessary to completely remove the
computer units, there is room to roll them either out the curbside door or past
the gas island and out the rear door. The two roof access ports, one on either
end of the computer area, accommodate signal cables from roof-mounted equipment.
The operators must have a place to store data, manuals, pencils, and other
necessary paper and equipment near the computer. The data analysis island
provides file cabinets, pencil drawers, a book shelf, and a desk-work table.
Although this island, as all other islands and floor-mounted equipment, can be
easily moved or removed for future expansion and modification, some desk and
work space is a necessity near the computer. The overhang design of the data
analysis island allows a maximum of flexibility during use as well as being
out of the way for the packing of long objects, such as sampling tubes and towers,
for transport. A bookshelf with doors uses excess wall space for needed storage
of manuals, reference books, or even small instruments or equipment. A bulletin
board and blackboard (chalkless type) is attached to the curbside wall opposite
the computer. Every laboratory occupied by humans soon gains a coffee pot with
its rather messy group of accessories. The open shelf next to the bookshelf is
an attempt to move the pot off working surfaces and yet keep it in a central
location convenient to all. The shelf also holds a few accessories such as cups,
spoons, unbrewed coffee, sugar, cream, etc.
There is a small, open floor space at the rear of the trailer under an extra
sampling port. This undesignated open-space could serve as space for an additional
instrument, for a spare teletype, for roof instruments not in use, for boxes of
spare teletype paper, for file cabinets, for a refrigerator, or other equipment.
The space becomes highly valuable when packing the trailer for transport.
EPA will be continually adding or substituting new and different instruments
as they are developed and become available. Therefore, even though we have
designed the floor plan specifically for the instruments to be installed within
the first few months, the islands and computer are readily movable for future
modifications. Each of the Islands is bolted to the floor with 16 easily-remove-
able lag bolts and the adjustable shelf support posts at each island are attached
to the ceiling with about 8 screws. Thus, only about two man-days would be re-
quired to remove all islands and benches, leaving an empty shell. A new interior
10
THERMO-SYSTEMS INC
-------
layout could begin with the empty shell and 7 roof access ports. Six of the ports
are located roughly equidistant along the length of the trailer. The electrical
busway system, described later, allows nearly complete flexibility in the move-
ment of receptacles. We have tried to make the laboratory as flexible as possible,
both in its present island layout and looking ahead to future layouts where the
islands and/or front bench may have to be moved or removed.
The roof layout is also highly flexible. The sampling tubes (described later)
rise to a height of 10 meters above the ground or about 19' above the trailer roof
level. They bolt directly to the flanges on the sampling ports. Guy wires hook
directly to the catwalk. A meteorological tower is mounted on a hinged plate so
that one person may assemble the sensor, mount the sensor to the tower, and raise
the tower into place. Guy wires anchor the tower to the catwalk. The sensor
can easily be aligned north-and-south by matching a mark on the sensor with a
mark on the tower and sighting through diametrically opposing holes in the main
tower support pipe. The tower support pipe can be turned by means of a tube-
within-a-tube arrangement until the operator sees a pre-chosen northerly target
through the sighting holes. All other roof equipment bolts directly to the
catwalk by means of "J"-bolts which loop through the catwalk perforations.
Since the entire roof surface, except ports, is covered with the perforated
catwalk, equipment can be located anywhere on the roof. A heavy-duty, single-
section, aluminum ladder provides human access to the roof wherever needed.
Standard electrical service entrance caps attach to the two ports above the
computer to allow signal cables to feed through the roof to the data system.
This type of feed-through is easy to use, easy to make, and is essentially
waterproof. All port covers, sampling tubes, and the cable feed-through
are interchangable from one port to another. The roof layout is thus perhaps
the most flexible part of the trailer design.
A hoist capable of lifting at least 150 pounds mounts onto a swivel pipe
at the rear curbside corner of the roof. A block-and-tackle allows one or two
men to raise a heavy load. The hoist swings from the area above the rear stair
landing to the area above the roof catwalk.
Packing of the laboratory for transport is a very important consideration.
The large items, such as the computer, and roof-mounted items, such as the hi-
vols, are strapped to the wall using the logistic rails and straps. Small,
delicate instruments are stored in drawers or separate boxes. Most instruments
such as optical particle counters, gas instruments, etc., are strapped in place
on the islands. Long tubes such as the roof-mounted sampling tubes are laid in
the aisle or in the island knee space inside the trailer. Items about 39' in
length can be transported in the knee space area. Papers and data pack into
the file cabinets. Miscellaneous medium-sized boxes and equipment strap to the
lower logistic rails. Stairs, gas bottles, boxes, electrical service supply
cables, and miscellaneous heavy equipment packs into the two undercompartments.
There is room for all the know equipment planned for the trailer during the
first several months of operation.
Electrical Design
Many considerations, some conflicting with others, went into the design of
the electrical system. The primary design criteria were:
11
THERMO-SYSTEMSINC
-------
1. Suitable and sufficient electrical power must be supplied to
every part of the trailer to allow all equipment, present and
future, to operate reliably and continuously.
2. The electrical service connection to the source of line power
must be convenient and must meet all applicable code requirements.
The electrical system meets all applicable National Electrical Code (NEC), State
of California, and State of Minnesota requirements for the classification of
Commercial Coach. The service entrance design also meets State of Colorado and
City of Denver requirements. Nearly all states and cities allow this design
although specific areas within a city or state may have codes prohibiting the
trailer for electrical or other reasons.
All equipment on the trailer, including the air conditioners, uses single-
phase, 115 or 230 volt power, the most commonly available power. Triple-phase
power is not available everywhere and would needlessly limit the choice of sampling
sites.
The trailer uses a cable-and-plug service entrance with twin cables and plugs.
The plugs connect directly to mating receptacles mounted on a feeder pole not
supplied under this contract. The other end of the outdoor-insulated, 4-conductor
cables pass through slots in the bottom of the rear undercompartment (see Figure 1)
and into a junction box located in the upper rear curbside corner of the rear under-
compartment. From there, wires from the separate cables pass through the trailer
floor into separate service panels (circuit breaker boxes). One service panel
serves the air conditioning system including the humidifier. The other service
panel serves the remainder of the trailer electrical system. Thus, the power to
the air conditioning system is connected to the rest of the system only back at
the feeder pole, not within the trailer or service entrance cable.
There are several reasons for using the cable-and-plug service entrance,
as shown in Figure 14, rather than the overhead mast entrance. Both systems
require a separate feeder pole, not attached to the trailer, which has mounted
upon it a power company watt meter and a single switch which disconnects power
to the entire facility. However, the feeder pole for the cable-and-plug system
can be completely wired before the trailer arrives, so that the operators need
only connect the plug(s) and throw the switch to have power. The overhead mast
would require the reassembly of the mast and the restringing of wires on the
roof of the trailer and the stringing of wires from the feeder pole to the
trailer by a licensed electrician. Thus, the cable-and-plug system results in
fewer costly and time consuming delays in getting the laboratory into operation.
The cable-and-plug system has similar advantages at the time of packup. The
overhead mast assembly also requires a hand rail to prevent roof top operators
from accldently contacting live wires. Thus, the overhead mast system would
be bulky, would require excessive operator time to assemble and disassemble for
every site, and would result in excessive delays in getting power connected.
12
THERMO-SYSTEMS INC
-------
There are also several reasons for using 2 cables rather than one. A
single cable large enough for 400 amps - 230 volts is heavy, making it difficult
to handle during packing. Two smaller cables coil up more neatly and easily in-
to the undercompartment. A single large plug is also more difficult to connect
to its receptacle. Another important reason is to separate the air conditioning
load from the rest of the system, reducing the power line fluctuations when the
air conditioners switch on or off.
The layout of circuits within the air conditioning service panel is shown
in Figure 15 and Table 1. Each of the two air conditioning units requires one
60 amp-230 volt circuit for the cooling unit and three 20 amp-230 volt circuits
for the heating unit. In addition, the humidifier requires one 40 amp-230 volt
circuit. The entire panel is protected by a 200 amp main breaker. As with
the entire electrical system, the neutral (white) line is insulated from the
ground (green) line. The conduit runs to the 2 air conditioners pass through
the interior of the trailer along the curbside ceiling. Each air conditioner
circuit has a separate disconnect box mounted on the exterior front wall just
below the air conditioners and fresh air registers. The thermostat controls
are mounted on the curbside wall near the front of the trailer, near the return
air registers. The humidifier has a separate 230 volt outlet near the rear of
the interior. All wire and conduit sizes are at least as large as NEC requires
and usually are somewhat larger. Some extra space is left for the addition of
more circuit breakers in the air conditioner service panel at some time in the
future.
The layout of circuits within the instrument systems service panel is shown
in Figure 16 and Table 2. Again, the entire panel is protected with 200 amp-230
volt main breakers. Each of twin busway systems is fused with 60 amp-230 volt
breakers. Each of the other circuits are fused with breakers as shown in Table 1.
The approximate locations of the outlets for each circuit are shown in Figures
17 and 18. Major electrical components and their model numbers are identified
on the figures. Conduit runs do not interfere with other features described in
this report.
The twin busway system is an excellent way to distribute power throughout
a facility such as this and yet retain the flexibility to change the location of
major power usage later. Each of the two busway systems consists of an insulated
bar, acting as a receptacle, running the length of the trailer. One busway is
located about 14" from the roadside wall and the other about 28" from the curb-
side wall, making both of them convenient to the islands but also making them
useful for future layouts. Separately-fused plugs can be inserted into the bar
at any point of its run. The plugs are attached to a short extension cord with
a standard 115 volt outlet receptacle on the opposite end. Normally, a standard
extension cord of appropriate length and with the necessary number of standard
115 volt receptacles is connected to the short extension cord. Each separately
fused plug-and-cord unit then becomes a separate circuit. If the circuit is no
longer needed at a specific location, it may be unplugged and moved to a needed
13
THERMO SYSTEMS INC
-------
location. Additional fused circuits (either 115 volt or 230 volt) may be added
so long as there is physical room left on the busway and so long as the total
power drawn by all busway circuits does not exceed the rating of the main breaker
on the busway. The trailer was delivered with 25 of the 15 amp-115 volt plug-in
fused circuits and 4 of the 30 amp-230 volt fusible tap boxes.
The lights are 24 incandescent lamps located approximately as shown in
Figure 3. Incandescent lamps produce less electronic noise, which can cause
computer or electronic problems, than fluorescent lights. The fixtures are
rated for 150-watt lamps, but we supplied heavy duty 100-watt lamps. The
fixtures have a heavy duty, shatter-proof diffuser cover which will not break
if hit by a .22 caliber bullet. All fixtures and conduits in the lighting system,
as with nearly all other conduits, are on the outside of the walls and ceiling,
making future changes easier and maintaining the integrity of the walls, ceiling,
and structure of the trailer. The lights are arranged in 4 circuits and are laid
out so that turning on any one circuit turns on every second fixture, on either
the left or right side, from front to rear. Thus, turning only 2 circuits on
lights the entire trailer with half as much intensity. All 4 light circuits have
switches near the rear door and one has 3-way switches at the rear and side doors.
A separate pair of 20 amp-115 volt circuits run to the computer area. They
are isolated for protection from power line voltage spikes and are also regulated
to supply constant voltage with fluctuating power line voltage. The isolator and
regulators are shock-mounted (for noise reduction) in the front undercompartment.
The outlet receptacles are located on the roadside wall about 6.5' above the floor
so that the computer may be tied flat against the wall during transport. The
model numbers and specifications of the regulators and isolator are as follows:
Topaz 8 LRB115SN AC line regulator, 8 KVA, 115 VAC output +3.3%
(2 supplied) with 105-125 VAC input.
General Electric 60 Hz, 120 VAC output with 240 VAC input, 15 KVA,
9T21B9101G3 single-phase isolation transformer.
There are three 20 amp-115 volt circuits on the front exterior of the trailer
and three 20 amp-115 volt circuits on the rear exterior. Each has 4 weather-proof
outlet receptacles pointing downward to prevent rain from entering them while in
use. There are no outlet receptacles on the roof because they cannot be pointed
downward as most codes require. Necessary power for the roof is supplied from
the front, rear, or undercompartment receptacles by means of extension cords and
weather-proof duplex boxes.
The large undercompartment contains four 20 amp-115 volt circuits and four
20 amp-230 volt circuits, each with 4 outlet receptacles. The small undercompart-
ment contains one 20 amp-115 volt and one 20 amp-230 volt circuits, each with 4
outlet receptacles. Vacuum pumps, blowers, and other equipment are powered by
these circuits.
14
THERMO-SYSTEMS INC
-------
Lightning Protection
Since the mobile laboratory will be used in areas where thunder storms often
occur, some degree of lightning protection was provided. The direct hit protection
system consists of 3 copper grounding conductors extending from the base of the 3
sampling towers to 3 separate copper ground rods which extend 6-8 feet into the
ground. A bolt connects the copper wire to the sampling tube and a clamp connects
the copper wire to the ground rod. The 3 ground rods should be separated by 20
feet, if possible, and should make good electrical contact with the earth around
the rod. Keeping the ground around the rods wet helps electrical conduction.
Each of the incoming electrical power lines has a lightning arrester on
the ground line which helps prevent high voltage spikes caused by nearby
lightning strikes from entering the trailer through the ground conductor. This
will not prevent all such damage, but will reduce the frequency and severity
of equipment damage.
The lightning protection problem was Investigated in considerable detail
before finalizing the above design. It appears that full lightning protection
is npt possible and anything approaching it is very expensive and is not practical
for use on a mobile facility. The next step above the existing system in com-
plexity and protection capability is probably a conducting cable which connects
the 3 sampling tubes and extends downward to the ground ahead and behind the
trailer. This system was rejected because of the difficulty of installation
and disassembly at each sampling site. The system provided was recommended by
a consultant and appears to meet the recommendations of the Lightning Protection
Code 1968 of the National Fire Protection Association (NFPA No. 78 ANCI C5.1 1969).
The cone-of-protection concept is important in lightning protection. Lightning
tends to strike the tallest objects in an area. Objects which are located within a
cone defined by a 45 line from the top of the object to the ground will be struck
only rarely, particularly if the tall object is a good conductor. If the meteoro-
logical tower is located within 5 feet of any of the 3 grounded sampling tubes, all
objects provided by this contract are protected by the 45° cone-of-protection. Any
future additions to the roof should consider this aspect carefully.
Summarizing, although the system provided will reduce the frequency and severity
of lightning strike damage, extensive damage may still occur in the case of either a
direct hit or a nearby strike. The mobile laboratory is not a safe place during a
thunderstorm.
Sampling System
The accuracy of the measurements made by the instruments in the laboratory
depends directly on the representativeness of the pollution sample delivered to
the instruments. Since sampling errors is probably the largest single error in
most of the measurements, the design of the sampling system is especially im-
portant. The system is designed to: 1) remove a representative sample from the
air mass above the trailer, and 2) transport that sample into the instrument with
a minimum of change.
15
THERMO SYSTEMS INC
-------
The major particle sampling problems are:
i
1. Losses of large particles by inertial and gravitational forces
acting on the particles, and
2. Losses of very small particles by the diffusion of particles to
sampling system walls.
The design used for this laboratory has strictly vertical sampling tubes leading
to any instrument which samples large particles, essentially eliminating grav-
itational losses. It also has a wind shield at the sampling tube entrance to
reduce the velocity of large wind-blown particles so that they are not impacted
against the inside wall of the tube at the inlet. Diffusion losses are reduced
by using correct flow rates and tube diameters, and by keeping tubing length as
short as possible. All sampling tubes pass through the roof access ports located
above islands as shown in many of the figures. Figure 19 shows the design for
the aerosol sampling and transport system. An access port feed-thru bolts to the
access port flange. A 6" diameter vertical sampling tube bolts to the port feed-
thru above the roof and extends about 10 meters above ground level. A wind shield
attaches to the top of the sampling tube. In addition to reducing wind velocity
at the sampling tube inlet, the wind shield openings are covered with wire mesh
screen to reduce the chance of sampling insects, leaves, twigs, etc. Guy wires
attach to the wind shield and to the catwalk to support the sampling tubes in
high winds. Each sampling tube requires only 2 men to raise or lower it.
Inside the trailer, the access port feed-thru extends several inches below
the ceiling. A sampling manifold clamps onto the feed-thru. The manifold dis-
tributes samples to the various instruments. Instruments which sample large
particles (greater than 1 ym diameter) are arranged directly below the manifold
with vertical sampling tubes protruding into the manifold. Instruments which
sample particles smaller than 1 ym draw their sample from tubes clustered around
the manifold wall. Nuclei counters sample through short tubes from within the
manifold at a point away from the boundary layer of the manifold wall. A separate
outlet near the bottom of the manifold connects to a vacuum blower which maintains
proper air flow through the system with any number of instruments in operation.
All tubes which remove samples for large-particle samplers are sized to maintain
approximately isokinetic sampling from the manifold. A separate tube allows rain
water to drain through the bottom of the manifold to the ground below the trailer.
The entire manifold is easily removable from the feed-thru if it becomes necessary
to move it or if a new one of different design is required. The inside diameter
of the system is maintained constant from the inlet at the wind shield up to and
including the manifold. The gas sampling tube is 2" inside diameter and the
aerosol sampling tubes are 6" inside diameter. Instruments are clustered, in a
3-dimensional layout, on the islands or work benches. The aerosol island has
two sampling systems, the gas island has one, and the front bench accommodates
one of the aerosol manifolds, if it is necessary.
16
THERMO-SYSTEMS INC
-------
The complete gas sampling system is shown schematically in Figure 20. The
two complete aerosol sampling systems are shown schematically in Figures 21 and
22. Vacuum pumps and blowers are mounted in the undercompartments on shock
mounts. Flowmeters and flow control valves for the 3 bypass air systems are
mounted on individual panels on the wall near the islands and convenient to the
operators.
The specific 'instrument arrangement for the 1973 St. Louis program was
as follows. Two Anderson samplers sampled vertically from the front bench aerosol
manifold (Figure 7). A nephelometer, mounted on the front roadside wall, drew a
sample from the same manifold. The 0.5 - 5.0 ym optical counter rested on the
lower bench top of the aerosol island directly below the roadside aerosol manifold.
A Lundgren 8-day sampler and a 47-mm total particle filter rested on the shelf
above the optical counter and also sampled vertically downward from the same
manifold. The large (>5.0 ym) optical particle counter was located on the •
roof to reduce particle losses. A condensation nuclei counter rested on the
upper shelf near the 47-mm filter holder with an electrical aerosol size analyzer
located just below it on the lower bench top. Both drew samples from the road-
side aerosol manifold. A second nephelometer, mounted on the roadside wall near
the first one, drew a sample from the roadside aerosol manifold. A dew point
sensor and a particle mass monitor were located on the other upper shelf of the
aerosol'island and drew samples from the roadside aerosol manifold. Several
other instruments were connected and disconnected from both aerosol manifolds
as required.
Gas sampling instruments were clustered around the manifold above the gas
island. The Beckman 6800 was on the lower bench top facing the data island.
The ozone analyzer was on an upper shelf near the manifold with a short sample
line. Other gas analyzers such as a sulfur analyzer and an NO-NO analyzer
were arranged wherever convenient. Several strip chart recorders connected to
specific instruments operated on the gas island also.
This instrument layout is only one of many possible layouts. As other in-
struments are added or replace present instruments, it will be very easy to re-
arrange the layout to suit the new requirements.
SUMMARY
The mobile laboratory supplied to EPA specifically met the requirements
for the St. Louis program in late 1973. It also has a great deal of flexibility
for adaptation to other programs. Even major layout changes can be done quickly
and without serious problems. The laboratory is capable of efficient operation
for many years to come. Figures 24 - 33 are photographs of the laboratory.
17
THERMO-SYSTEMSINC
-------
Table 1. Circuit breaker layout in the air conditioning systems control panel
No. of
Breaker No. Voltage Amps Receptacles Identification
1 & 5 230 60 - Air conditioner, roadside
9 & 13 230 40 - Heater, 10 KW, roadside
17 & 21 230 20 - Heater, 5 KW, roadside
2 & 6 230 60 - Air conditioner, curbside
10 & 14 230 40 - Heater, 10 KW, curbside
18 & 22 230 20 - Heater, 5 KW, curbside
26 & 30 230 40 1 Humidifier
25 - • - Open
27 - Open
29 - Open
31 - - - Open
33-40 - - - Open
18
THERMO SYSTEMS INC.
-------
Table 2. Circuit breaker layout in the instrument systems control panel
No. of
Breaker No.
1 & 5
2 & 6
9
10
11
12
13
14
15 & 17
16
18
19 & 21
20
22
23 & 25
24
26
27 & 29
28
30
31
32
33
34
35 - 40
Voltage
115/230
115/230
115
115
115
115
115
115
230
115
115
230
115
115
230
115
115
230
• 115
115
115
115
-
115
-
Amps
60
60
20
15
20
15
20
15
20
15
20
20
20
20
20
20
20
20
20
20
20
20
-
30
-
Receptacles
-
-
4
9
4
6
4
6
4
6
4
4
4
4
4
4
4
4
4
4
4
4
-
4
-
Identification
Busway 1
Busway 2
Forward under comp. , pumps & blowers
150W interior lights, 3W switch; under comp. lights
Forward under comp., pumps & blowers
150W interior lights
Forward undercomp. , pumps & blowers, cooling fans
150W interior lights
Forward undercomp. , pumps & blowers
150W interior lights
Weatherproof exterior front, roof & ground equip.
Forward undercomp., pumps & blowers
Weatherproof exterior front, roof & ground equip.
Weatherproof exterior front, roof & ground equip.
Forward undercomp. , pumps & blowers
Weatherproof exterior rear, roof & ground equip.
Weatherproof exterior rear, roof & ground equip.
Rear undercomp. , pumps & blowers
Weatherproof exterior rear, roof & ground equip.
Regulated & isolated, computer.
Rear undercomp., pumps & blowers
Regulated & isolated, computer
Open
Rear interior, special equipment
Open
19
THERMO-SYSTEMS INC.
-------
-37'CC
ACCESS PORTS
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Figure 1. Exterior curbside, rear, front, and roof views
20
-------
O i' £' 5'
SCA.LE
Figure 2: Exterior roadside view
-------
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SCALE
Figure 3: Interior floor plan for the 1973 programs
-------
10
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INCANDESCENT LIGHTS
KCNALLMANUFACTORING CO.
PRtlMATe NO.
AIR CONDITIONING SUPPLY DUCT DIVIDER
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Figure 4: Interior ceiling layout
-------
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Figure 5: Interior roadside wall
-------
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Figure 6: Interior curbside wall
-------
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Figure 7: Interior front wall and work bench
-------
AlR
INCANDESCENT UGHTS •
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I
SCALE
Figure 8: View looking rearward at the aerosol island
-------
v- AEROSOL ACCESS PORTS
•l AEROSOL MANIFOLD
TO BLOWER
ADJUSTABLE SHELF
oo
CABINET HINGED DOOR*
T*JO ADJUSTABLE SHELVE*
<=r.CHAIZ.LE% KITC.MENS
PA.RT IsiO. E- 2^2-4?^ CF —
AIR CONDITIONER
— INCANDESCEMT LIGHTS
CURB-SIDE
SHELF BRACKET
UN l STRUT NO. P-Z4S7
VERTICAL.
ONISTRUT NO.
COUNTER TOP
ST.
NO. E- IS SD
CABINET , -i D«AWE«.
5T.CMARL.es
(.TOP
Figure 9: View looking forward at the aerosol island
-------
- ACCESS PORT
BUS-BAR
r- BUS-BAR
AIR CONDITIONER
ho
vo
ROAD-SIDE
t, ^=^a
A
CABINET, E-DKAvsJER vM/i_OCKS
e>r. CHARLES KITCHENS
INCANDESCENT BIGHTS
CURB-SIDE
COUNTER TOP
FORMIC A" C.5I
SCALE
Figure 10: View looking forward at the data analysis island
-------
- GAS ACCESS PORT
SOS-BAR
AIR CONDITIONER
INCANDESCENT L.IGHTS
SWELF
FORMIC*. *
U>
O
COUNTER. TOP
SUSPENDED
•5T. CHARl-ES KiTCHCNS
p»sl«T MO. E-li SD
CURB-SIDE
G&S MANIFOLD
SHELF
UN I STRUT NO.
uP«iGt-n-
NO. P-S3OO
CABINET 5 3
=>T. CHARLES KlTCMeNS
PA.RT MO. £• Z+Z+yo D-l
(TOP OR*VJe«4 -3PL.IT MORiT..)
CABINET, HINGED DOOR 6-H)
TWO ADJUSTABLE SHELVES
•bT.CHARLES KITCHENS
NO. e- i
SCALE
Figure 11: View looking rearward at the gas island
-------
Bus-
GAS ACCESS PORT
r BUS-BAR
MANIFOLD
SHE.L.F —
FORMICA
ROAD-SIDE
CABINET, 3 DRAWER
"aT. CMABLCS KITCHCNb
PART MO. ff-Z
-------
,- BUS. BAR
3US
rs>
TWO 30' SERVICE CABl_£5-
BUS-BAE JUNCTION SOX
— LOGISTIC
ROAD-SIDE
45*
0 I' 2' 3'
SCALE
Figure 13: Interior rear wall
-------
NEUTRAL
} TO POWER LINE
•MAST
FEEDER POLE PANEL
O -
METER —
METER
CURRENT
TRANSFORMER
RECEPTACLE, I,
CROUSE-MINOS
NO. AREA20426
AIR CONDITIONER
CONTROL PANEL
200AMP SERVICE
INSTRUMENT SYSTEMS
CONTROL PANEL
200 AMP SERVICE
GROUND ROD
RECEPTACLE.2,
C ROUSE-HINDS
NO.AREA20426
INSTRUMENT SYSTEMS CABLE
AIR CONDITIONER CABLE
MOBILE LABORATORY
SEMI TRAILER
•REAR UNOERCOMPAHTMENT
•SERVICE ENTRANCE JUNCTION BOX
INSTRUMENT SYSTEMS PLUG
CROUSE-MINOS
NO.AP2046?
-AIR CONDITIONER PLUG
CBOUSE-MINDS
•30FT. WESTERN INSULATED WIRE
BRONCO 66 CERTIFIED
3 CONDUCTOR 0 90° ZA)6
XL BUTYL
ZOO AMP CAPACITY
Figure 14: Feeder pole and cable-and-plug electrical service entrance
-------
f CWD 4GA B**e C°
ji , cccncotCQu.rr Ci V3 GA TMW B»-AC»
<• 1 FSEOER SERVICE o '
20OAMP IO/Z3OVAC ' i_i V^GA THW WHITE
ft 3/06ATMWRCO*
T«t FULL LlNGT* OP IHSULATlO** OH WIRE PlOTUOlNG
irVTHt DISTRIBUTION PANEL * 1«f «»W\CC JJNCTiQN
eox SHALL ae ?AIN>TTD COLOR specie IED
____. 60A XTN. 1 ,
i !
, i
i
P.LQ to* **>• s
HEATER /W\ I J
IOHW Vfc^/ I '
,-__. 30A ^r^ 17
HEATER /^ | ,
SfcW \Q> |
\ n-U 30* A *'
x-» 25
x-^ 27
s^ ZS
^ S(
x-^ 33
^ 33
x-s 37
X-N 39
IKISUI
PPI
c
•
)--
ATI
•R,
|— '
1
:0h
[ GROUND
\ MAIN CIRCUIT BREAKER
7 2OOAMP
a XTX fcOA ^-,5
! ! 1?
• i >-
& x-K tOA 0_UO __/
IO xp 5OA o-po
1 '' >
14 x^N 5OA 0^ /
IB xjx 3OA ^-^Q
\ 1 ,A-
21 X*N 3OA 0_LTJ /
SWiTO
G,PLAC
26. XTV 4OA
\
>
30
^S HUMIDIFIER
-y C..4KW
Figure 15: Circuit layout of the air conditioning service panel
34
-------
* Z FEEDER SERVICE
2OOAMP
6OH2 SINGLE PHASE
ZGA TO COMPUTER
3/OGA THW BLACK
3/OGA THW WHITE*
* THE HULL LENGTH OF INSUUkTlON ON WIRE PROTRUDING
PA.NEL, a. THE
COLOR
MAIN CIRCUIT BREAKER
REAR UNDERCOMPT
LIGHTS
CENTER
UNOEBCOMPr 20A
(~)4
CE^JTER
UNDER
COMPT
CENTER
UNDER- ( 14
COMPT
REAR
UNDER-
COMPr
REAR UNDERCOMPT
x-x 20A s~^ 33
Figure 16: Circuit layout of the instrument systems service panel
35
-------
u>
MOT€:
S, I I4b (h)
S,i:iZb(h)
FROIS4T
OTHER* l«iE <=,PeClFlED
FROM ©
ALL WIRES ARC
GENERAL --
• DCNOTSS INSTRUMBNT SYSTEMS CONTROL PAMEL
62 DEMOTES AIR CONDITIONING CONTROL. PANEL.
-0- DENOTES CEILING. LAMP HOLDER
O DENOTES <»PCOAI_ PURPOSC OUTLET
s DEMOTES SINGLE POLE SWITCH
SaDENOTES 3-WAX SWITCH
£X* DENOTES CIRCUIT I4O.X. IN A.IR CONO. COMT, PANEL
^Xb DENOTE* CIRCUIT NO.XIN INSTRSYS.COKT.
© DENOTES &KVA LINE VOLTAGE REGULATOR LOCATED
IN CCMTCR
SCHEDULE OF OUTUtT* ft FIXTURES
OmCRlPTlON
. TMSOtOS ZOOAMP 6OHt
SYM QTY
b I
C
d
2
I
DtWRIBUTtOMf«NEL;GE,TM2OZO*ZOO«MP*OMt
%WtRC U«V2BOVAC ^INGLJE PVAASC
BUS WAY > Oe. LW^2<» 3MIRC «iOAMP 210 VAC ,
OUTLET: SOAMP i2s/25ov
STRA\GKT
OUTLET: SOAMP IZVZVOV/ACIMVC
STRAlftHT AUkDC - HU»KLL
LIGHT FlKTUm:Ke
SINGLE POLE SWITCH: \OAMP
VTANOARO
2.
4
OUTLET: BOAMF
TWIV-LOCK
Figure 17: Outlet receptacle locations of each interior circuit
-------
- SIDE
TO COMPUTER CENTER,
(INTERIOR ROAD-«koe WMJL)
VOOA
-0-
REAR
VJNDEfcCOMPARTMENT
ALL WIRE ft ARI I2GA UML»» OTMCRWI«K SPECIFIED
GENERAL 9YMBOLS:
DENOTE* CEILING LAMPHOLDER
_ DENOTE-* DUPLEX OUTLET
X« NUMBER OP RECEPTACLES
* DENOTES WEATHER PROOF DUPLEX OUTLET
X* MUM BE* OF RECEPTACLES
S DENOTES SINGLE POLE SWITCH
O DENOTES SPECJA.L PURPOSE OUTLET
DEMOTES 6KVA LINE VOLTAAE REGULATOR
DENOTES ISOLATION TRANSFORMER
DEMOTES CIRCU\TNO-X IM AIR CONCX CONT. PANEL
IXb DENOTES CIRCUIT V40.X IN INSTR. SYS CO KIT. PANEL
U NOCRCOHPARTMENT
CURS-SIDE SCHEDULE
SYM QTV
-f Z1
OF OUTLETS
Tl
p
r
I
2
DUPLCX: ZOAMP t2ftVACORDCS-MIR*
&BOUKDING STRAIGHT BLAOi
LIGHTING nXTOJte: KENALL MFC. CO*
PRHMAT1 * "ta^O
SINGLE POLE SMITCn: lOAMr I2SVAC
STANDARD GRADE -TOGaLE
DUPLEX: eOAMP ZSOVAC ORDC
GROUNDING STRAIQKT BLADE
LINE VOLTAGE REGULATOR'. AW A
ISOLATION TRANSFORMER'. I
AIR CONDITIONER:
Figure 18. Outlet receptacle locations of each exterior circuit
-------
POLLUTION SAMPLE
WORM-DRIVE CLAMP-
3 PLACES
WIND SHIELD-
ID METERS ABOVE
GROUND LEVEL
POLLUTION SAMPLE
I I »
GASKET
-ACCESS PORT FEED-THRU
(REMOVED 4 REPLACED
BY PLAIN PORT COVER
BOLTS (6
iJn£££ik
tfjffiv
CATWALK
feskiJCAtife°ili
Cf
FALSE CEILING
kNDARO CAM LATCHES
THE SAMPLING MANIF
POINT FOR QUICK RE.I
POLLUTION SAMPLES
TO INSTRUMENTS
SAMPLING MANIFO
BOLTS16)
iS^
$$$$$$$&
OLD >
*OVAL^ f
-•— C
— c
LD-^^
N^X~N.
11 1
2 i
i
i
/ / FOR TRANSPO
(St-"/ / rrn
^3R^sS^s^
I \
E^^- BASKET
^1^
^J
AIR CONDITIONING
SUPPLY DUCT
-ROOF ACCESS PORT
0^~* POLLUTION SAMPLES
U_» TO INSTRUMENTS
TO BLOWER FOR
H-*. MAINTAINING CONTINUOUS
1 ' SAMPLE LINE FLOW
1
1 i i
POLLUTION SAMPLES
TO INSTRUMENTS
Figure 19: Aerosol sampling and transport system
38
-------
SAMPLE
GAS
111
WATER
DRAIN
GAS MAN I FOLD
MEL.OV OZONE
ANALYSER
BEND1K NO-
NOK ANALYSER
MELOY SULFUR
BECKMAN HC
AMALY2ER
OPTIONAL
PRE- FILTER
ADJUST
VALVE
GAS BYPASS PANEL
ADJUST
VALVE
I
CENTER
UNDER-
GO MPARTMENT
1
I FLOW METER
I ROTRON CHE^ I
I BLOWER I
Figure 20: Schematic of gas sampling system
39
-------
AEROSOL
HI
a.
o
i/I
ISOKINETIC
BOTTOM TAPS
CURB-SIDE AERO SOL MAN I FOLD
ESC GIANT PARTICLE
OPTICAL COUNTER
CURB-SIDE
AEROSOL-
BY-PASS RMS EL
J
AOJUSii
VALVE I
JFL6WMETER J
I I
I OPTIONAL i
t DILUTER ,
I !
OPTICAL COUNTER
0,S-5.0 MICRONS
ANDERSEN
IMPACTOR
\
I7i
PANE LI
^h
ADJUST
VALVE
JFLOWMETER
ANDERSEN
IMPACTOR
|A"I
•f
AIPANEL2
I
1
_i
ADJUST)
VALVE j
ANDERSEN
VMPACTOR
5
IFLOWMETER
AI PANEL 3 "^
I
&n
ANDERSEN
IMPACTOR
__^.__J
[A! PANEL4 -j- |
H ^-(5
-------
AEROSOL
t t 1
)
NAL|
TER
_l
ELECT.
TS3
CONDi NUC-
COUNTER
E/l RICH IOO
PART COUNT
NEPMELOMETER 1
MRI ISSO- SPECIAL
NEPHELOMETER 2.
MRI IS50- SPECIAL
AEROSOL
BY- PASS PANEL
/
T\_l ADJUST
\1-/ VALVE
PLOWMETER
CASSETTE SAMPLER
X-RAY FLUORESCENCE
OPTIONAL FILTER PANEL
f~*\ VACUUM
^£' GAGE _,_
1 CENTER
UNDER-
COMPART ^E" NT
i ArV ~t
^Cy^
ROTRON
_ cnea
^ BLOWER
ADJUST
VALVE
w
rTT3^
1 vl/
ROTRON CMEZ
BLOWER
RELIEF
VALVE . ,
I FILTER i_|_L, J-X^V>.J.
7 SAMPLER, [ . ! _ /T-^<->r |
I -4TMM ' L^jrV-l ADJUSTi
I 1 | vy VALVB
i FLOW METER. I
GA5T lOZi
VACUUM
Figure 22: Schematic of aerosol sampling system which excludes
Anderson samplers
41
-------
8KVA
60A
23OVAC
I5KVA
ISOLATION
TRANSFORMER
I HI + +XI ^ |
8KVA
REGULATOR
Figure 23. Electrical schematic of isolation-regulation transformers for
computer power
42
-------
Figure 24. Photograph of exterior curbside
Figure 25. Photograph of exterior roadside
43
THERMO SYSTEMS INC
-------
Figure 26. Photograph of interior aerosol island and front wall
Figure 27. Photograph of interior looking rearward at the data
analysis island
,4sVs
THERMO-SYSTEMS INC
-------
Figure 28. Photograph of aerosol manifolds and flow control panels
Figure 29. Closeup photograph of aerosol manifold designed for 4 Anderson
samplers
45
THERMO-SYSTEMS INC
-------
Figure 30. Closeup photograph of gas manifold also showing a fused plug
connected to the electrical busway
Figure 31. Exterior photograph of both aerosol sampling stacks showing
windshields
46
THERMO-SYSTEMS INC
-------
Figure 32. Photograph of typical electrical feeder pole showing 2 cables
from the laboratory plugged into the feeder pole setup
Figure 33. Photograph of a tractor connected to the trailer, nearly ready
for transport
47
THERMO SYSTEMS INC
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
650/4-74-017
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Design of the EPA Semi-Trailer
Mobile Air Pollution Laboratory
5. REPORT DATE
December 1973
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Gilmore J. Sem
8. PERFORMING ORGANIZATION REPORT NO.
None
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Thermo-Systerns Inc.
2500 North Cleveland Ave.
St. Paul, Minnesota 55113
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-0654
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Protection Agency
National Environmental Research Center
Research Triangle Park, N. C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
17.
mobile air pollution research laboratory described in this report,
has been designed and constructed into a semi-trailer shell. The
laboratory will be used by EPA for making simultaneous measurements of
many air pollutants using state-of-the-art instrumentation. A semi-
trailer with an air suspension system was chosen as the basic vehicle.
Air conditioning was provided for extremes of 115 F and -40 F. Electrical
service of 400 amperes at 230 volts (half for air conditioning) was in-
stalled into the trailer. The 3 work benches for aerosol, gas, and data
instruments, were arranged as islands allowing open aisle space and the
clustering of sampling instruments for reduction of sampling losses.
Sampling systems, carefully designed to reduce sample losses under varying
wind conditions, extend 10 meters above ground level. The roof is covered
with catwalk material which facilitates the fastening of equipment. Under-
compartments contain necessary sampling pumps and blowers and serve as
storage compartments. Two personnel doors with collapsible stairs provide
access to the laboratory near each end. Individually adjustable supports
allow leveling after the tractor leaves. Twin electrical main service
cables connect to an external electrical service pole for 115/230 VAC
power. Outlet receptacles on the exterior and twin busway systems on the
interior offer maximum outlet flexibility.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
48
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