Texas CNG Test. Driver Study Guide. 2026 QUESTIONS
AND ANSWERS WITH COMPLETE SOLUTION
What is a cascade storage system-answer-
Storage in multiple cylinders.
What does a CNG system include-answer-
Safety devices, cylinders, piping, fittings, valves, compressors, regulators, gauges,
relief devices, vents, installation fixtures, and other CNG equipment.
How can fuel supply installation minimize collision damage (9)-answer-
Fuel supply cylinders must not be installed so as to adversely affect the driving
characteristics of the vehicle.
How can fuel supply installation minimize collision damage (10)-answer-
Containers must be secured to a school bus, mass transit, or special transit vehicle
frame (not the floor) by container fastenings or mounting brackets described in
subsection (f) of this section. The fastenings or brackets must be secured to the
frame or securely mounted to a supporting structure so as not to compromise the
strength of that structure (i.e., backing plates or other acceptable means may be
used to accomplish this purpose). Containers which are currently installed on
school buses or mass transit vehicles by means of strap mounting brackets may
continue to be used.
How can fuel supply installation minimize collision damage (11)-answer-
The motor fuel containers installed on a school bus or mass transit vehicle must
be installed on the underside of the vehicle.
How can fuel supply installation minimize collision damage (12)-answer-
,If necessary, a plumbing chamber door must be provided in the sidewall of the
school bus, mass transit, or special transit vehicle to allow easy access for filling or
securing the service valve in the event of an emergency. The plumbing chamber
door must be hinged and latched, but not locked.
Should a manual or electronic cylinder service valve be installed on a fuel
cylinder-answer-
Yes. A manual or electronic cylinder service valve must be installed on each fuel
cylinder.
How are CNG fuel systems labeled-answer-
Any vehicle equipped with a CNG fuel system must have a durable label, readily
visible, located at the fueling connection receptacle. The label must include the
system working pressure, name of company or entity and license number, the
cylinder retest dates where applicable, and the total cylinder water volume in
cubic inches.
What are two critical aspects of system testing of CNG systems-answer-
1. After installation, every connection must be checked with a non-ammonia soap
solution or a leak-detection instrument after the equipment is connected and
pressurized to its working pressure. 2. If a completed CNG fuel system assembly is
leak-tested with natural gas, the testing must be done under adequately
ventilated conditions.
How do you vent CNG systems to the Atmosphere-answer-
All venting of CNG must be done outdoors only, under conditions that will result
in rapid dispersion of the product being released. When venting CNG to the
atmosphere, consideration must be given for the use of a vent pipe or stack so
that a flammable mixture will not reach a point of ignition.
Test question: Compression, storage or dispensing installations, excluding
automatic dispensers and residential fueling facilities, must be protected from
tampering by a chain link type fence a minimum of ________ feet in height.
6 feet
What does it mean for CNG system to be suitably packaged-answer-
, All equipment related to a residential fueling facility must be suitably packaged
and located to be protected from physical damage and vandalism.
What instructions must be followed for a CNG residential fueling facility-
answer-
All residential fueling facility equipment must be installed in accordance with the
equipment manufacturer's instructions.
What must appear on a residential fueling facility nameplate-answer-
The residential fueling facility must have a nameplate marked with minimum and
maximum gas inlet pressure and flow rate, gas outlet maximum pressure, and
electrical requirements.
What must pressure relief valves do at a residential facility-answer-
The discharge vent line on a residential fueling facility must be able to withstand
the pressure from the relief vapor discharge when the relief valve is in full open
position and must permit sufficient pressure relief relieving capacity.
Are Pressure Gauges required for testing at residential facilities-answer-
No. For measurement and test purposes, pressure gauges may be installed, but
are not required.
What is the maximum length of fueling Piping and Hoses at a residential fueling
facility-answer-
The maximum length of a fueling hose on a residential fueling facility is limited
to 12 feet.
What are two key components of Emergency Shutdown Equipment at a
residential fueling facility-answer-
1. A residential fueling facility must be equipped with emergency manual
shutdown of the gas supply power and electrical power. 2. Break-away
protection must be provided in a manner such that, in the event of a pull-away,
natural gas will cease to flow at any separation.
AND ANSWERS WITH COMPLETE SOLUTION
What is a cascade storage system-answer-
Storage in multiple cylinders.
What does a CNG system include-answer-
Safety devices, cylinders, piping, fittings, valves, compressors, regulators, gauges,
relief devices, vents, installation fixtures, and other CNG equipment.
How can fuel supply installation minimize collision damage (9)-answer-
Fuel supply cylinders must not be installed so as to adversely affect the driving
characteristics of the vehicle.
How can fuel supply installation minimize collision damage (10)-answer-
Containers must be secured to a school bus, mass transit, or special transit vehicle
frame (not the floor) by container fastenings or mounting brackets described in
subsection (f) of this section. The fastenings or brackets must be secured to the
frame or securely mounted to a supporting structure so as not to compromise the
strength of that structure (i.e., backing plates or other acceptable means may be
used to accomplish this purpose). Containers which are currently installed on
school buses or mass transit vehicles by means of strap mounting brackets may
continue to be used.
How can fuel supply installation minimize collision damage (11)-answer-
The motor fuel containers installed on a school bus or mass transit vehicle must
be installed on the underside of the vehicle.
How can fuel supply installation minimize collision damage (12)-answer-
,If necessary, a plumbing chamber door must be provided in the sidewall of the
school bus, mass transit, or special transit vehicle to allow easy access for filling or
securing the service valve in the event of an emergency. The plumbing chamber
door must be hinged and latched, but not locked.
Should a manual or electronic cylinder service valve be installed on a fuel
cylinder-answer-
Yes. A manual or electronic cylinder service valve must be installed on each fuel
cylinder.
How are CNG fuel systems labeled-answer-
Any vehicle equipped with a CNG fuel system must have a durable label, readily
visible, located at the fueling connection receptacle. The label must include the
system working pressure, name of company or entity and license number, the
cylinder retest dates where applicable, and the total cylinder water volume in
cubic inches.
What are two critical aspects of system testing of CNG systems-answer-
1. After installation, every connection must be checked with a non-ammonia soap
solution or a leak-detection instrument after the equipment is connected and
pressurized to its working pressure. 2. If a completed CNG fuel system assembly is
leak-tested with natural gas, the testing must be done under adequately
ventilated conditions.
How do you vent CNG systems to the Atmosphere-answer-
All venting of CNG must be done outdoors only, under conditions that will result
in rapid dispersion of the product being released. When venting CNG to the
atmosphere, consideration must be given for the use of a vent pipe or stack so
that a flammable mixture will not reach a point of ignition.
Test question: Compression, storage or dispensing installations, excluding
automatic dispensers and residential fueling facilities, must be protected from
tampering by a chain link type fence a minimum of ________ feet in height.
6 feet
What does it mean for CNG system to be suitably packaged-answer-
, All equipment related to a residential fueling facility must be suitably packaged
and located to be protected from physical damage and vandalism.
What instructions must be followed for a CNG residential fueling facility-
answer-
All residential fueling facility equipment must be installed in accordance with the
equipment manufacturer's instructions.
What must appear on a residential fueling facility nameplate-answer-
The residential fueling facility must have a nameplate marked with minimum and
maximum gas inlet pressure and flow rate, gas outlet maximum pressure, and
electrical requirements.
What must pressure relief valves do at a residential facility-answer-
The discharge vent line on a residential fueling facility must be able to withstand
the pressure from the relief vapor discharge when the relief valve is in full open
position and must permit sufficient pressure relief relieving capacity.
Are Pressure Gauges required for testing at residential facilities-answer-
No. For measurement and test purposes, pressure gauges may be installed, but
are not required.
What is the maximum length of fueling Piping and Hoses at a residential fueling
facility-answer-
The maximum length of a fueling hose on a residential fueling facility is limited
to 12 feet.
What are two key components of Emergency Shutdown Equipment at a
residential fueling facility-answer-
1. A residential fueling facility must be equipped with emergency manual
shutdown of the gas supply power and electrical power. 2. Break-away
protection must be provided in a manner such that, in the event of a pull-away,
natural gas will cease to flow at any separation.
