Texas Comptroller of Public Accounts

Texas Comptroller of Public Accounts, Glenn Hegar

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Texas Specification No. 055-20-01
Effective Date:May 29, 1992
Reformatted Date:


1.SCOPE:This specification establishes requirements for the
purchase and after-market installation of fuel conversion
systems to convert vehicular gasoline engines to operate on
compressed natural gas.(See Texas Specification No. 055-20-02
for the conversion of vehicular gasoline engines to liquefied
petroleum gas.)

specifications, standards, test methods, and other documents
shall be to the issues in effect on the date of the Invitation
for Bids.Copies of the referenced documents may be obtained
from the issuing organizations at the addresses shown.In the
event requirements in this specification are in conflict with
rules and/or regulations of the Federal government, the rules
and/or regulations of the Texas Air Control Board, or the
Railroad Commission of Texas, shall take precedence in that
order.The following publications form a part of this
specification to the extent specified herein:

El Monte, CA91731-2900:

2.1.1. Approved LPG and CNG Conversion Systems, February 6,
1992,(or current edition).

Park, Quincy MA 02269-9101:

2.2.1.NFPA 52 -- Compressed Natural Gas (CNG) Vehicular Fuel


Austin, TX78773-0001: Rules, Chapter 23 -- Vehicle Inspection.

2.3.2.Texas Procurement and Support Services (TPASS), P. O. Box 13186,
Austin, TX 78711: Cost Effectiveness of Alternative Fuels Using Life
Cycle Cost Benefit Analysis, 3rd. Printing, December 1, 1992. Specification No. 070-AT-XX--Specification
for Automobiles and Trucks (current edition). Specification No. 070-SB-XX -- Specification for
School Buses (current edition).

2.3.3.RAILROAD COMMISSION OF TEXAS (RRC), 1701 North Congress Avenue,
Austin, TX78711: for Compressed Natural Gas.

2.3.4.TEXAS AIR CONTROL BOARD (TACB), 12124 Park 35 Circle,
Austin, TX78753: of Air Pollution from Motor Vehicles,
Regulation IV., Revised, August 30, 1991.

Motor Vehicles, P. O. Box 2293, Austin, TX78768: Motor Vehicle Code, V.T.C.S. Art. 4413(36).

2.4.FEDERAL DOCUMENTS:Superintendent of Documents,
U.S.Goverment Printing Office, Washington, DC 20402:

2.4.1.Code of Federal Regulations -- CFR, Title 40, Part 85:
Control of Air Pollution from New Motor Vehicles and New Motor
Vehicle Engines, Environmental Protection Agency (EPA).

3.CLASSIFICATION:Gasoline-to-compressed natural gas
conversion systems shall be classified by original equipment
manufacturer and engine size as follows (in cubic inch
displacement unless followed by an "L" suffix indicating
displacement in liters):(Ordering entity must specify whether
the engine is carbureted or electronic fuel injected):


3.1.1. 97-I4

3.1.2. 133-I4

3.1.3. 151-I4

3.1.4. 191-V6

3.1.5. 262-V6

3.1.6. 305-V8

3.1.7. 307-V8

3.1.8. 350-V8

3.1.9. 366-V8

3.1.12.Other 4-cylinder

3.1.13.Other 6-cylinder

3.1.14.Other 8-cylinder


3.2.1. 135-I4

3.2.2. 146-I4

3.2.3. 153-I4

3.2.4. 181-V6

3.2.5. 201-V6

3.2.6. 203-V6

3.2.7. 205-V6

3.2.8. 239-V6

3.2.9. 242-I6

3.2.12.Other 4-cylinder

3.2.13.Other 6-cylinder

3.2.14.Other 8-cylinder


3.3.1. 1.9L-I4

3.3.2. 2.3L-I4

3.3.3. 3.0L-V6

3.3.4. 3.8L-V6

3.3.5. 4.0L-V6

3.3.6. 4.6L-V8

3.3.7. 4.9L-I6

3.3.8. 5.0L-V8

3.3.9. 5.8L-V8

3.3.12.Other 4-cylinder

3.3.13.Other 6-cylinder

3.3.14.Other 8-cylinder


3.4.1. Manufacturer-- Engine Sizes

4.DEFINITIONS:Terminology used in this specification is
intended to be generic in nature and consistent with meanings
that have been defined through general use and/or accepted trade
practices.Where variant meanings may exist, the applicable
interpretation shall be determined by the General Services
Commission (GSC).

4.1.Alternative Fuels:Fuels used to propel vehicular engines
including natural gas, electricity, liquefied petroleum gas,
methanol and others as defined by the Texas Air Control Board.

4.2.ASME:American Society of Mechanical Engineers.

4.3.Bi-Fueled Engine:an engine capable of operating either on
a conventional fuel or an alternative fuel, but not

4.4.CARB:California Air Resources Board.

4.5.CNG:Compressed Natural Gas.

4.6.Commission:Texas Procurement and Support Services (TPASS).

4.7.Conversion Facility:The firm performing the conversion of
an engine to operate on an alternative fuel.

4.8.Dedicated Fueled Engine:An engine, originally designed to
operate on a conventional fuel, which has been converted to use
an alternative fuel only; or an engine designed to operate on an
a single fuel only.

4.9.DOT:United States Department of Transportation.

4.10.Dual-Fueled Engine:An engine capable of simultaneous
operation on a mixture of a conventional fuel and an alternative
fuel.(See Fumigated Engine.)

4.11.Equivalent Gallon:The amount of natural gas at standard
conditions containing the same energy content (114,000 BTUs) as
one gallon of unleaded gasoline (approximately 114 cubic feet).

4.12.Fuel Conversion System:A device or series of components
that, when properly installed and adjusted, will permit an
engine, originally designed to operate on a conventional fuel,
to operate on natural gas, liquefied petroleum gas, or other
alternative fuel, or a mixture of diesel fuel and either CNG,
LPG, or other alternative fuel.
4.13.Fumigated Engine:A diesel engine capable of operation on
a mixture of diesel and either natural gas or liquefied
petroleum gas.

4.14.TPASS:Texas Procurement and Support Services.

4.15.LCCBA:Life Cycle Cost Benefit Analysis.

4.16.LNG:Liquefied Natural Gas.

4.17.LPG:Liquefied Petroleum Gas, also known as "propane".

4.18.Methanol:A non-petroleum, clear liquid fuel, made
primarily from either natural gas, renewable agricultural waste,
organic garbage, wood or coal.

4.19.Natural Gas:A gaseous fuel consisting principally of

4.20.OEM:Original Equipment Manufacturer.

4.21.Pipeline Quality Natural Gas:Natural gas conforming to
the specifications as defined in NFPA 52.

4.22.Propane:A fuel that is composed predominately of
hydrocarbons or mixture of hydrocarbons.

4.23.Standard Conditions:A standard pressure and temperature
at which compressed natural gas is measured which is a pressure
of 14.7 pounds per square inch (psi) and a temperature of 70°F.

4.24.Vendor:The business entity having a contract with the
user to provide and/or install fuel conversion systems or to
provide services for the conversion of engines to alternative
fuels.The vendor may or may not be the conversion facility.

4.25.VIN:Vehicle Identification Number.

5.REQUIREMENTS:Products furnished under this specification
shall meet or exceed the following requirements:

5.1.General Requirements:

5.1.1. All conversion systems and accessories shall be new,
unused, and currently a standard product of an established
manufacturer except for such deviations as may be required by
this specification.These conversion systems shall not be a
rebuilt, repaired, reconditioned, display model, prototype, or a
used model.

5.1.2. The conversion system shall be the latest model in
current production and shall have been tested by a reputable
federal test procedure laboratory.Specific design
configurations and test results fro any acceptable conversion
system must be approved by the CARB After-market Parts Section,
by any other state air quality regulatory authority, sanctioned
by the EPA (for systems applicable to low altitudes), or
recognized, in writing, by the EPA as satisfying applicable
anti-tampering policies included in Memorandum 1A (1974).
Conversion systems and/or components not certified by one of the
above means will not be considered.All conversion systems must
be maintained in their approved configuration without
substitution or modifications.Any system bid must demonstrate
compliance with one of the three procedures listed in the second
sentence of this paragraph.The burden of proof for system
compliance shall rest with the bidder.

5.1.3. All applicable components of the fuel conversion systems
shall meet or exceed applicable rules of the Railroad Commission
of Texas in effect on the date of the Invitation for Bids.In
addition, all dealers and/or vendors, as required, must be
licensed according to the rules of the Railroad Commission of
Texas and the Texas Department of Transportation, Division of
Motor Vehicles.

5.1.4. The conversion system shall be designed to operate on
pipeline quality natural gas which has approximately 1,000 BTUs
per cubic foot and 114,000 BTUs per equivalent gallon of
unleaded gasoline (See Paragraph 4.11.).

5.1.5. Details not specified herein shall be in accordance with
standard commercial practices for products of this type.

5.1.6. The alternative fuel system fuel tank (s) shall be filled
to capacity upon delivery to the ordering agency.

5.1.7. Safety plaques or decals shall be furnished and shall be
affixed at any hazardous area.The plaques or decals shall
include necessary warnings and precautions.Permanent plaques
are preferred to decals.

5.2.Design Requirements:Each conversion system furnished to
this specification shall include, but not be limited to the
following.All other parts or components which are required or
normally included to provide a complete, working fuel conversion
system, shall be furnished.

5.2.1.Fuel Tank (s):Fuel tank (s) shall be manufactured to
ASME or DOT standards and shall have combination of separate
shut-off/relief valves.they shall have a rated capacity of not
less than 3,000 psi.They shall be installed in such a manner
to allow for easy viewing of serial numbers, where accessible.
Exterior surfaces shall be corrosion resistant or shall be
treaded to resist corrosion (primed and painted, etc.). vehicular fuel tank (s) shall be any one
of the following, unless otherwise specified in the Invitation
for Bids: Steel. Aluminum.

NOTE: A stone shield shall be provided on vehicular fuel
tanks furnished with composite material where the tanks are in
direct proximity to the road surface. fuel tanks shall be provided in sufficient
numbers and sizes (capacities) to provide a range (in miles) as
specified in the Invitation for Bids.The range shall be
determined by operation of 100% CNG, not conventional fuels.
The fuel range shall be calculated by multiplying the EPA city
fuel economy rating less 5% of the gasoline equivalent volume of
the CNG tanks.

5.2.2.Fuel Cylinder Cages:Each CNG fuel cylinder installed on
any school bus shall be enclosed by a steel cage similar to
those used on medium duty gasoline bus chassis.These cages
shall be designed to permit removal of the cylinders for testing

NOTE: These cages are not required if the CNG cylinder (s) are
furnished with internal automatic shut-off valves, or if the
tanks are mounted between the frame rails of a full-frame school
bus chassis.

5.2.3.Fuel Filter and Vacuum Fuel Lock:A fuel filter and
vacuum fuel lock (or similar device) shall be provided, as
required, to prevent the flow of fuel to the engine when the
engine is not in operation but the ignition key is on.The
device shall be UL listed and shall be either vacuum operated or
operated electrically.

5.2.4.Pressure Regulator:The pressure regulator shall be
adjusted, adjustable, and tested by the factory.The regulator
shall be water heated and shall be capable of accepting
pressures up to the working pressure of the vehicle's fuel
cylinder (s) and shall deliver CNG at a pressure acceptable for
the mixing devices.The regulator shall be furnished with brass
fittings and coolant shut-off valves for the engine water
coolant inlet and outlet connections.

Pressure regulators shall be designed for each specific engine
so that stoichiometric power settings can be maintained.

For electronic fuel injection systems which have sonic
metering, the functions of fuel filtration, fuel lock-off
pressure regulation, pressure relief and fuel pressure sensing
shall be combined.The regulator, and its components must be
listed by EPA, CARB, or other entities, and approved by the
Railroad Commission of Texas.

5.2.5.Carburetor/Fuel Injection Systems:The existing OEM
carburetor or injection system may be used.However, the fuel
conversion system shall be tested and approved by the CARB and
listed on their Approve LPG and CNG Conversion Systems prior to
the bid opening date, or otherwise approved and/or recognized by
the EPA (See Paragraph 5.1.2.).

5.2.6.Gas/Air Mixer:The gas/air mixer shall be specifically
designed for efficient mixing CNG and air at the correct flow
rate for the engine in which it is installed.

5.2.7.Control Panel:Unless Option 5.7.8. is specified on the
Invitation for Bids, a single pole, 2-position (for fuel
injection systems) or 3-position (for carbureted systems)
electrical fuel selection switch shall be provided on the
instrument panel or in a location convenient to the vehicle
operator.This switch shall allow the operator to select
gasoline operation or CNG operation and shall be so marked.The
operator shall not have to operate any other controls in
switching from one fuel to the other.

5.2.8.Fittings and Plumbing Materials:CNG fuel lines and/or
tubing shall be stainless steel and approved by the Railroad
Commission of Texas.All hoses and tubing shall be rated for
4,000 psi or greater working pressure with burst strength safety
factor of three (3) to five (5) times.Fittings shall be SAE
fittings; NPT pipe fittings are not acceptable.Fuel lines
shall be secured to the body or frame in a manner to avoid
pinching or chafing and shall have fastenings (supports) at not
more than two (2) foot intervals.Fuel lines shall be protected
by placing between the frame rails, if at all possible;
otherwise, these lines shall be placed on closer than eight
inches (8") from any exhaust component and shielded from damage
due to rocks, debris, etc. from the road.The CNG fuel line
shall not be placed adjacent to an exhaust system component
without being shielded.No plumbing or fitting materials shall
be placed in the interior passenger compartment of a school bus.
If this is not possible, the ordering agency shall be advised
and shall provided written acceptance of the location.All fuel
system valves and plumbing located in the cargo area shall be
protected with shields.

5.2.9.Refueling Receptacle:The vehicle refueling receptacle
shall be a quick-disconnect type receptacle requiring no tools
to use in refueling.IT shall be a Sherex SR 1040, Sherex SR
1020 or other Federally approved standard.The receptacle shall
be protected with a dust cap, permanently attached to the
vehicle by means of a metal chain or cable.The vehicle
refueling probe shall be installed in one of the following
locations on the vehicle, unless otherwise specified in the
Invitation for Bids: filler location.(The gasoline filler shall
remain operable.) Grille. compartment.

NOTE: In no case shall the refueling receptacle be mounted in a
vehicle crush area.This area is defined as areas within
eighteen inches (18") of the vehicle bumper surface, front or

5.2.10. Manual Shut-off Valve:A manual, quarter-turn shut-off
valve to isolate the fuel cylinder (s) from the rest of the CNG
system shall be as required by the Railroad Commission of Texas.

5.2.11. Fuel Pressure Gauge:A mechanically operated
non-electric fuel pressure gauge shall be installed under the
hood and at the refueling location except at the gasoline filler
location.A second gauge is not required if the refueling
location is under the hood.The gauge shall be a dial type with
shatter-proof glass providing readings from zero (0) to 4,000
psi maximum.

5.2.12. Fuel Gauge:The OEM analogue fuel gauge shall be
utilized to provide accurate available fuel readings for both
gasoline and CNG selectively with the fuel in use.If the
instrumentation is digital, a separate fuel gauge for CNG shall
be furnished and mounted so that it can be easily observed by
the seated driver.

5.3.Installation and Operation:The installation of the CNG
fuel system and the operation of the vehicle after conversion
shall be in accordance with the following:

5.3.1.Installation:the installed conversion system shall
present a neat, well finished appearance and shall be free of
all imperfections and/or defects which might affect appearance,
normal life, or serviceability.The systems shall be installed
so as not to interfere with normal maintenance tasks such as
tune ups, checking of fluid levels, etc.The installed
conversion system shall not restrict or prevent normal tune-up
activities, such as replacement of spark plugs, distributor caps
and rotors, or drive belts nor render inoperative the functions
of the air filter air connection, or any component of the
emission control system of the vehicle unless approved under EPA
guidelines.Fuel tanks mounted in the cargo area of passenger
vehicles shall be boxed and covered in upholstery that color
coordinates with the vehicle interior.All electrical wiring
shall be insulated and enclosed in a fibrous loom, plastic loom,
or flexible conduit for protection from external damage and
short circuits.Wiring shall be securely fastened at sufficient
intervals to prevent sagging and insure clearance of mechanical
parts.Routing of the wiring through the subframe, body, etc.,
shall be in such a manner so as not to interfere with the normal
operation and use or present a safety hazard.A sealed
splice-free modular wiring harness is acceptable.Rubber
grommets shall be used wherever wires or harness pass through
metal.Workmanship shall be comparable to that of the OEM.the
systems shall be installed in conformance with the system
manufacturer's instructions and recommendations.

5.3.2.Conversion Site:Unless otherwise specified in the
Invitation for Bids, it shall be the responsibility of the
vendor to arrange for pick up and delivery of the vehicle (s)
which are to be converted, at no expense to the ordering state
agency or school district.

5.3.3.Connections:All hose connectors shall be from the same
manufacturer; fittings, etc. from different manufacturers shall
not be used on the same vehicle.Hose connections shall be
tubing fittings.All electrical connections to the vehicle OEM
wiring shall be accomplished with brass or cooper connectors.
Aluminum connectors are not acceptable.

5.3.4.Engine Tune-up:Each conversion system installation
shall be made only after the engine has been tuned to the OEM's
specifications by the vendor.

5.3.5.Pre-conversion Dynamometer Test:When so specified in
the Invitation for Bids (See Paragraph 5.7.6.), the conversion
system installation shall be made only after the vehicle has
been operated on gasoline using a dynamometer to measure the
brake horsepower output at the rear or driving wheels and the
pollution levels checked and recorded.

5.3.6.Post-conversion Dynamometer Test:When so specified in
the Invitation for Bids (See Paragraph 5.7.6.), the conversion
system shall be checked on a dynamometer.the engine, when
operating on CNG, shall be adjusted to provide at least 85% of
the power measured in all speed ranges as specified in Paragraph
5.3.4.The engine shall not lose any power when operated on
gasoline.The installing conversion facility will adjust the
engine for maximum performance on both gasoline and CNG.

5.3.7.Dynamometer Test Reports:Copies of all dynamometer
tests shall be provided to the owner.This test report shall
identify the vehicle (s) by VIN number.If dynamometer testing
is specified on the Invitation for Bids, payment will not be
made until dynamometer testing documentation is provided.

5.3.8.Engine Operating Characteristics:The engine, after
conversion, shall operate on CNG without hesitation, stalling,
power loss of more than 15%, or surging.the OEM's recommended
maximum operating temperature, horsepower, engine speed, etc.
shall not be compromised or surpassed.

5.3.9.Safety and Emissions:The engine, after conversion,
shall meet all Federal and state safety rules and regulations,
all applicable EPA emission standards, Department of Public
Safety Vehicle Inspection Rules, and Texas Air Control Board
Regulation IV when operated on gasoline.The vendor shall
perform a minimum of three (3) emissions tests on each vehicle
using a Four-Gas Analyzer.Data shall be taken at idle and at
2,500 RPM, no load.One test shall be performed prior to
conversion, with the vehicle operating on gasoline.A second
test shall be performed after conversion, with the vehicle
operating on CNG>A third test shall be performed after the
conversion with the vehicle operating on gasoline.The methods
and parameters for all tests shall be identical, with the
exception of fuel used.This test will verify that the
converted vehicle has been converted in compliance with all
applicable emissions requirements.The results of the tests
shall be provided to the school district or ordering state
agency upon completion of each vehicle conversion.Payment
procedure will not be initiated until this documentation is

5.3.10. OEM Engine Speed Governor:Any OEM engine speed
governor shall not be made inoperable during conversion to CNG.
It shall remain operable when the vehicle is operating on CNG as
well as on gasoline.

5.3.11. OEM Fuel Injection System:the fuel injection system of
gasoline engines, if used, shall be made inoperable by means
which will not damage the injectors and associated components,
while the engine is operating on CNG and shall not be damaged by
short or long term use of CNG.

5.3.12. Radio (2-Way) Frequency (RF) Interference:All
electronic conversion components shall be designed to prevent
electromagnetic interference with 2-way radio equipment.

5.3.13. Engine Electronics:all electronics required to
properly interface with the original vehicle electronics, and
necessary in order to meet vehicle performance and emission
objective, shall be included in the conversion.

5.3.14. Installation Time:The installing dealer shall have a
period of time not to exceed five (5) working days in which to
install, adjust, and test each fuel conversion system.


5.4.1.Standard Warranty:All conversion systems shall carry
the manufacturer's standard warranty and shall be guaranteed
against defects in materials, workmanship, and performance for a
minimum of one (1) year.

The warranty shall being on the date of acceptance of the unit
by the school district or state agency.During this warranty
period, the vendor shall repair or replace defective components
and/or units at no cost to the State of Texas or the school

5.4.2.Warranty Responsibility:In case of warranty work on an
engine converted to use CNG, if there is a question of whether
it is the responsibility of the OEM or the vendor, it shall
automatically become the vendor's responsibility.If the
question is not resolved within one (1) week from the date of
notification to the vendor by the owner, the vendor will
arrange, with the permission of the owner, for the vehicle to be
repaired by a duly licensed carburetion technician, at an OEM or
other facility chosen by the owner, at no cost to the owner.
The vendor may then negotiate with the OEM if the repair is
covered by the OEM warranty or pay for the repairs if it is not,
unless it can be determined that the damage to the engine was
due to improper operation such as low oil, low water, etc.A
copy of the conversion equipment manufacturer's warranty and the
vendor's supplemental warranty shall be provided to the state
agency or school district at the time of vehicle delivery.
Payment for the vehicle (s) cannot be processed until these
documents are provided.

When major warranty repairs are required, the state agency or
school district will notify a representative of the vendor's
Texas dealer by telephone as designated by the bidder.Major
repairs are defined as those repairs other than minor
adjustments, replacement of hoses, etc..Major warranty repair
work means major repair to the engine due to operation of the
engine on CNG.All conversion components shall be covered.
Diagnosis of the actual repairs required will be the
responsibility of the vendor.The vehicle (s) will be made
available at the location designated by the owner.The repair
work may be performed by the vendor or his authorized
representative.At the vendor's option, the unit may be taken
by the vendor to a commercial repair facility.The vendor shall
be responsible for the cost of the round trip transportation of
the vehicle (s).

5.4.3.General Engine Warranty:The vendor shall warrant
converted engines for six (6) months or 6,000 miles, whichever
occurs later against damages due to the operation of the engine
on CNG.This warranty shall be equal to or better than the
OEM's original warranty on the engine and shall be limited to
damages caused by the alternative fuel used.

5.4.4.Personal Injury/Property Damage Liability:Proof of
product liability, as required by the Railroad Commission of
Texas, shall be provided with the Invitation for Bids.

5.5.List of References:It is the intent of this specification
to provide for installation of fuel conversion systems by
licensed, skilled and experienced installers only, who are
capable of providing not only safe installations, but conversion
systems that perform as required.Before an award will be
considered, the apparent low bidder shall supply TPASS with a list
of at least five (5) different entities for which the conversion
facility has successfully converted gasoline vehicles to CNG use
within the last three (3) years.In addition, the bidder shall
provide proof of the business for a period of not less than six
(6) months.This list shall include the name of the school
district, state agency, or business, complete address, name and
phone number of a contract person familiar with the
installation, and number of vehicles converted for each
reference.If two (2) or more of the references indicate
unacceptable performance as determinedby the Purchasing
Division, Texas Procurement and Support Services, the bidder will not be
considered for an award.

5.6.Identification of Equipment:The apparent low bidder will
be required to furnish, prior to award, a list of the equipment
being utilized for the conversion, the brand name, and the name
and address of the manufacturer of the equipment.

5.7.Options:When so specified in the Invitation for Bids, one
(1) or more of the following options shall be furnished:

5.7.1. Conversion System Purchase only (including fittings,
lines, etc., but not Vehicular Fuel Tanks and installation).

5.7.2. Conversion System and Vehicular Fuel Tank Purchase only
(including fittings, lines, etc., but not installation).
(Number and kinds of tanks must be specified in the Invitation
for Bids by the ordering entity.)

5.7.3.Bi-Fuel Gauge:A sensor shall be provided in the CNG
fuel system to indicate CNG fuel tank capacity on the OEM fuel
gauge.This gauge shall indicate the fuel capacity of the fuel
in use.(Not applicable for vehicles with digital

5.7.4.CNG Fuel Gauge:A separate fuel gauge shall be provided
to indicate CNG fuel tank capacity.This gauge may be mounted
on, in, or below the instrument panel, or as specified in the
Invitation for Bids.This fuel gauge shall be readily visible
to the seated driver.

5.7.5.CNG Fuel Sensing Detectors:An CNG leak detector shall
be provided.It shall be installed in the passenger compartment
or trunk area, as specified in the Invitation for Bids.These
sensors shall be capable of detecting a concentration of CNG
that is 25% of a lower explosive limit or less.The sensor
shall initiate a warning light visible to the seated driver or
other audible warning device to indicate a leak.

5.7.6.Dynamometer Testing:Pre-conversion and/or
post-conversion dynamometer testing shall be provided, and
reports thereof shall be furnished.

5.7.7.Automatic Fuel Switch-Over Control:An automatic device
to switch from CNG, when depleted, to conventional fuel shall be
provided.The operation of this device shall not subject the
vehicle to hesitation or stalling, and shall not require any
action on the part of the driver (not required with Option
5.7.8., below.).

5.7.8.Primary Fuel Over-ride Device:A device shall be
furnished which will cause the vehicle to start and operate on
CNG exclusively, until such time as the vehiclehas depleted
the supply of CNG.At that time, the vehicle will automatically
switch to the conventional fuel.The operation of this device
shall not subject the vehicle to hesitation or stalling, and
shall not require any action on the part of the driver.

5.7.9.Conventional Fuel Usage Indicator Lamp:A red
dash-mounted light shall be furnished to indicate when the
vehicle is operating on gasoline and shall be so labeled.

5.7.10. Instruction on Safety, Operation and Preventative
The vendor shall provide a minimum of two (2)
hours of instruction by a competent technician licensed by the
Railroad Commission of Texas to install and repair LPG equipment
in the use, operation, safety and preventive maintenance of the
converted vehicle (s).This instruction will be conducted at a
site selected by the owner.

5.7.11. Extended Warranty:The conversion system and related
components shall be warranted against all defects in material
and workmanship for a period of not less than thirty-six (36)
months or 50,000 miles, whichever occurs first, and shall cover
100% parts and labor for the converted unit.If the
manufacturer's standard warranty exceeds thirty-six (36) months
or 50,000 miles, the standard warranty shall be in effect.

5.7.12. Other TxDOT (or ordering entity) Warranty Option:(When
ordering this option, the ordering entity shall specify in
detail, the warranty required on the Invitation for Bids.)

6.TESTING:Testing shall be done by, or at the direction of,
the General Services Commission and/or the receiving school
district or state agency.Tests shall be performed on products
from shipments to ordering agencies.In the event products
tested fail to meet or exceed all conditions and requirements of
this specification, the cost of the samples used and the cost of
testing shall be borne by the supplier.

7.SAMPLES:Unless otherwise specified in the Invitation for
Bids, no prepurchase samples shall be required.Samples tested
shall be obtained from products supplied on regular orders.

8.INSPECTION:Products furnished under this specification
shall be inspected by, or at the direction of the Texas Procurement and Support Services and/or the ordering school district or state
agency (as applicable) either at the destination or place of

9.AVAILABILITY OF SERVICE:Factory-authorized service shall be
available within the State of Texas:

9.1.Service:When so specified in the Invitation for Bids, the
bidder shall submit a current list of companies or individuals,
and their addresses, who can perform service on the products

9.2.Parts:An adequate supply of repair parts shall be carried
in stock within the State of Texas for the expected life of all
products furnished under this specification.

10.INSTRUCTION BOOKS and/or MANUALS:The vendor shall furnish
one (1) copy (unless otherwise specified in the Invitation for
Bids) of any required operating/amintenance/troubleshooting
instructions for each conversion system installed or delivered.
The instructions shall accompany the system when installed or

11.PACKING and/or PACKAGING:Packaging for shipment shall be
in accordance with the manufacturer's standard practice and in a
manner readily accepted by common carriers engaged in interstate
commerce.Within the shipping carton, units shall be packed in
a manner designed to minimize damage during shipment due to
rough or improper handling.


12.1.Marking:Each shipping container shall be clearly marked

12.1.1.Name of contents.


12.1.3.Name and address of the manufacturer.

The container or shipping documents shall include:

12.1.4.Order number or contract number.

12.1.5.Name and address or ordering agency.

12.1.6.Agency requisition number.

12.2.Labeling:Labels shall be installed at appropriate
locations on and in the converted vehicle in conformance with
the rules and regulations of the Railroad Commission of Texas to
indicate the vehicle is equipped for operation on CNG and for
required warnings.

13.BID LITERATURE:All bids shall be accompanied by a complete
and illustrated description of the products being offered.

14.COMPLIANCE:In order for consideration to be given to the
bid on an item under this specification, the bidder must comply
with the following conditions:

14.1.Equipment Identification:The make, model number, name of
manufacturer, brand or trade name, etc., as applicable, of the
item which the vendor proposes to furnish must be stated as part
of the bid.

NOTE: Bids on any equipment not listed on the California Air
Resources Board's latest list (or issued an Executive Order by
CARB) or approved conversion systems or other recognized
entities and not approved by the Railroad Commission of Texas
will not be considered.

14.2.Exceptions:Notwithstanding the above, any exception
taken by the bidder to the requirements and conditions of this
specification must be stated and described in detail as a part
of the bid.If no exceptions or deviations are identified in
this manner, the items must be furnished exactly as described

14.3.Proof:The bidder shall bear the burden of proof of
compliance with this specification.

15.PRODUCT INFORMATION:When considering the selection of
vehicles to convert to an alternative fuel, the school district
or state agency may want to consider the following:

15.1.Selection of Vehicles:As a general rule, newer vehicles
should be considered first for conversion, followed by those
that are somewhat older but still in good condition.Obviously,
those vehicles that are near the end of their useful life and
must soon be replaced, should not be candidates for conversion.
Any vehicle that has several years of useful life that will be
kept in the fleet, might be considered for conversion.School
districts and state agencies may want to use LCCBA to ascertain
if it is cost effective to convert an older vehicle to an
alternative fuel(See guidelines in the GSC's workbook (See

15.2.Selection of Alternative Fuels:All of the Texas Air
Control Board approved alternative fuels shave advantages and
disadvantages.The one selected should be the one that is the
most cost effective meeting the needs of the particular fleet
under consideration.

15.2.1. Safety:The use of CNG and LPG as vehicle fuels has had
an outstanding safety record and these alternative fuels are
probably safer than gasoline.LPG and CNG fuel tanks normally
will not rupture or leak fuel resulting in fires even in
accidents in which the vehicle is totally demolished.When
conversion systems are properly installed, and the vehicle is
operated and maintained as recommended, this should result in a
vehicle that will have a safety record at least as good as a
comparable operated and maintained gasoline vehicle.However,
all recommended safety precautions and suggested operating
procedures should be followed meticulously.

Both CNG and LPG have very narrow limits of flammability and
much higher ignition temperatures than gasoline.
15.2.2. Selection of Vehicular Fuel Tanks:There are basically
four (4) different types of fuel tanks approved for installation
on vehicles using CNG and one (1) for LPG (See Paragraph tanks are much lighter in weight than steel
tanks and the labor in removing and reinstalling aluminum tanks
for testing is much less.Composite aluminum and steel tanks
have a weight advantage over aluminum and steel tanks,
respectively.Steel tanks must be removed from the vehicle and
tested every five (5) years; aluminum and all composite metal
tanks must be removed from the vehicle and tested every three
(3) years.LPG tanks and tanks manufactured to ASME
specifications does not have to be re-tested.

16.ORDERING DATA:When ordering products conforming to this
specification, the requisitioning agency or school district
shall specify the following:

16.1.The number of this specification (055-20-01).

16.2.Engine Type and size (indicate whether carbureted or
electronic fuel injected type, See Paragraph 3.).

16.3.Fuel Tank Material (See Paragraph

16.4.Fuel Tank Size (See Paragraph

16.5.Fuel Gauge type (digital or analogue, See Paragraph

16.6.Refueling Receptacle Location (See Paragraph 5.2.9.).

16.7.Pre-conversion Dynamometer Test, if required (See
Paragraphs 5.3.4. and 5.3.6.).

16.8.Post-conversion dynamometer Test, if required (See
Paragraphs 5.3.5. and 5.3.6.).

16.9.Options (See Paragraph 5.7.).

16.10. Quantity of vehicles to be converted, or, number of
systems ordered of each engine type and size.

specification may be obtained by writing or calling:

Bid Services
Texas Procurement and Support Services
P. O. Box 13186
Austin, TX78711-3047
(512) 463-3416

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