Current through Register 2024 Notice Reg. No. 38, September 20, 2024
Fuel systems using liquefied natural gas (LNG) installed
before January 1, 2000, and not in compliance with Section
935 above, shall meet the
following requirements in addition to those in Section
936 of this title:
(a) Fuel Supply Container. Each LNG fuel
supply container shall be constructed and inspected in accordance with
49 CFR
178.57 specification 4L for welded insulated
cylinders, including the general requirements contained in
49 CFR
178.35 with the exception of Sections
178.35(e) and 178.35(f). Each LNG container shall meet the following additional
requirements:
(1) The unrelieved fuel
pressure inside the container shall not exceed 100 psi within a total 72-hour
period consisting of 48 hours at 60 degrees F, 12 hours at 70 degrees F, and 12
hours at 90 degrees F ambient temperatures when the container has been filled
with LNG conditioned at one atmosphere.
(2) The container shall be equipped with a
liquid level gauging device and a dip tube to prevent filling beyond 90% by
volume at atmospheric pressure.
(3)
Each completed container, including its supporting structure and valves,
enclosures, and lines normally attached thereto, shall have structural
integrity to withstand damage from deceleration and acceleration forces
resulting from 30 mph front-end and rear-end collision of the type of vehicle
in which the container is installed. A test or other means shall demonstrate
that the container and its openings do not rupture in such
collisions.
(4) Fuel Supply
Container Markings. Each LNG fuel supply container shall have the following
permanent identification markings:
(A) The
letters CHP followed by numbers indicating the service pressure
(B) Serial number
(C) Manufacturer's name, initials, or
trademark as registered with the Department of California Highway
Patrol
(D) Inspector's
mark
(E) Date tested
(F) The words "FOR LNG ONLY" in letters not
less than 1 in. high and visible after installation. (Decals or stencils are
acceptable.)
(G) All inlets and
outlets except relief valves and gauging devices shall be marked to designate
whether they communicate with vapor or liquid
space.
(b)
Valves. Valves shall be certified for LNG use by the manufacturer or certified
for cryogenic service at temperatures down to and including -320 degrees F. All
valves shall be securely mounted and shall be shielded or installed in a
protected location to prevent damage from vibration and unsecured objects.
(1) Safety Relief Valves. Each container
shall be equipped with one or more safety relief valves. The safety relief
valve shall be installed in a line that communicates with the vapor space of
the container. A safety relief valve shall be installed between two shut-off
valves in a supply line to prevent a buildup of pressure between the valves in
the off position. The discharge pressure of safety relief valves shall not
exceed 125% of the service pressure of the container. Relief valves shall have
sufficient capacity to meet the requirements of either the Bureau of Explosives
for approval of safety relief valves or NFPA 59(A) Appendix A and be capable of
preventing explosion of the normally charged cylinder when it is placed in a
fire. Relief valves shall have the following permanent identification markings:
(A) Manufacturer's name, initials, or
trademark
(B) Catalog
number
(C) Discharge pressure (___
psi)
(D) Discharge capacity (___
cfm air at 60 degrees F and 14.7 psia).
(2) Shut-off Valves. One manually operated
shut-off valve shall be secured directly to the tank vapor outlet with no
intervening fitting other than the relief valve and shall be marked with the
words "VAPOR SHUT-OFF VALVE." Another manually operated shut-off valve shall be
secured directly to the tank liquid outlet and shall be marked with the words
"LIQUID SHUT-OFF VALVE." (Decals or stencils are acceptable.) Normally closed
automatic shut-off valves that are held open by electrical current may be used
in lieu of manual shut-off valves at either the tank vapor port or tank liquid
port, or both. An automatic shut-off valve shall be wired so it shuts off when
the ignition switch is in the off and accessory positions and when engine
vacuum is not present.
(3) Control
Valve. A positive shut-off control valve shall be installed in the fuel supply
lines as close to the containers as possible, automatically closing off and
preventing the flow of fuel to the carburetor when the ignition switch is off
or in the accessory position.
(c) Gauges. Gauges used in LNG systems shall
be designed and installed as follows:
(1)
Gauging devices shall be designed for the most severe pressure and temperature
conditions to which the devices may be subjected with a pressure safety factor
of not less than four.
(2) All
gauges shall be securely mounted and shall be shielded or installed in a
protected location to prevent damage from vibration and unsecured
objects.
(3) Gauging devices that
require bleeding of the product shall be bled to the outside of the vehicle
compartment.
(d) Pressure
Reducing Regulators. LNG systems shall be equipped with one- or two-stage
pressure reducing regulators that reduce the pressure to the level certified
and approved by the California Air Resources Board. The regulators shall be
installed so that their weight is not placed on, or supported alone by, the
attaching tubing or flexible lines.
(e) Vents. Every compartment in which an LNG
container is installed shall be vented to the atmosphere unless all piping and
connectors are exterior to the compartment. The vent or vents shall be
installed at the highest practicable point of the compartment and shall have an
open area totaling not less than 3 square inches.
1.
Renumbering of former section
935 to section 935.1, including
amendment of section heading, section and NOTE, filed 12-29-99; operative
12-29-99 pursuant to Government Code section
11343.4(d)
(Register 99, No. 53).
Note: Authority cited: Section
2402.6,
Vehicle Code. Reference: Section
2402.6,
Vehicle Code.
