It appears that it has to be either annealed copper tubing or approved hose. You will need hose in the gimbal area regardless
A-22 MARINE COMPRESSED NATURAL GAS (CNG) SYSTEMS
Based on ABYC's assessment of the state of existing
technology and the problems associated with achieving
the requirements of the standard, ABYC recommends
compliance with this standard by August I, 1994.
These voluntary teclmical practices and engineering
standards are guides for the design, construction and
installation of compressed natural gas (CNG) systems on
These voluntary technical practices and engineering
standards apply to all compressed natural gas (CNG)
systems used for cooking, heating and refrigeration on all
NOTES: 1. Attelltioll is directed to tlte U.S. Coast
Gllard Reglliatiolls wlticlt prohibit tlte lise of
Compressed Natllral Gas (CNG) 011 certaill
vessels alld set dif/erellt stalldards for Small
2. A,wt/,er gaseous flleillsed ill boats is
Liquefied Petrolellm Gas, (LPG). See ABYC
A-I, "Marb,e - Liquefied Petroleum Gas
3. Reqlliremellts for CNG galley stoves
are covered by ABYC A-3, "Galley Stoves".
Accessible - Capable of being reached for inspection,
removal or maintenance without removal of permanent
Attended Appliance ~ An attended appliance is one which
is intended for use when the occupants are in the
accommodation space in which the appliance is installed,
and requires frequent attention by an operator, such as
cooking stoves and ovens and demand type water heaters
with piezo electric ignition.
Compressed Natural Gas - Consists principally of methane
in gaseous form and includes naturally occurring mixtures
of hydrocarbon gases. CNG is a natural gas that is
normally supplied as a fuel by a gas utility and is stored
under pressure in portable cylinders. Certain physical
properties of CNG are listed in the Appendix.
Cylinder - Any vessel or container used to transport or
Locker - An enclosure intended for storage of one or more
Readily Accessible ~ Capable of being reached quickly and
safely for effective use under emergency conditions
without the use of tools.
System - The arrangement of cylinders, safety devices,
regulators, connections, valves, piping, tubing, hose,
fittings, and devices intended to store, supply, monitor or
control the flow of fuel gas up to but not including the
Unattended Appliance - Unattended appliances are those
which are intended to function without frequent attention
by an operator and may cycle on and off automatically,
such as storage type water heaters, refrigerators, or
thermostatically controlled cabin heaters.
22.4 REFERENCED ORGANIZATIONS
ABYC - American Boat & Yacht Council, Inc., 3069
Solomon's Island Road, Edgewater, MD 21037-1416.
AGA - American Gas Association, 1515 Wilson Blvd.,
Arlington, VA 22209. (703)841-8400.
ASME - American Society of Mechanical Engineers, 345
E. 47th Street, New York, NY 10017. (212)705-7722.
ASTM·· American Society for Testing and Materials, 1916
Race Street, Philadelphia, PA 19103. (215)299-5400.
DOT· Department of Transportation, 400 Seventh Street,
Sw., Washington, DC 20590. (202)366-4000.
NFPA National Fire Protection Association,
Batterymarch Park, Quincy, MA 02269 (617)770-3000.
SAE Society of Automotive Engineers, 400
Commonwealth Drive, Warrendale, PA 15096-0001.
UL - Underwriters Laboratories, Inc., 12 Laboratory Drive
PO. Box 13995, Research Triangle Park, NC 27709.
22.5 REQUIREMENTS - IN GENERAL
22.5.1 Comprehensive printed instructions and a
labeled diagram(s) covering details of proper installation,
maintenance, and operation shall be provided with each
CNG system installed in a boat. These instructions shall
include that a test be made every time the cylinder supply
valve is opened for use.
© 1993 American Boat & Yacht Council, Inc.
22.5.2 Components of this system, subject to cylinder
pressure, shall have a working pressure that is at least 133
percent of the maximum fill pressure of the cylinder.
22.5.3 With each CNG system installed on a boat a sign
shall be provided. It shall be located in the immediate
vicinity of the cylinder and shall be plainly visible. The
sign shall withstand the effects of exposure to water, oil,
saIt spray, direct sunlight, heat, cold and wear expected in
normal operation of a boat without loss of legibility, and
shall include the following informational elements:
(1) ~ CAUTION
THIS SYSTEM IS DESIGNED FOR USE WITH
COMPRESSED NATURAL GAS (CNG) ONLY.
DO NOT CONNECT LIQUEFIED PETROLEUM
TO THIS SYSTEM.
(2) Keep cylinder valve(s) and solenoid valve(s)
closed when boat is unattended. Close them immediately
in any emergency. When on board, cylinder valve(s) or
solenoid valve(s) shall be closed when appliances are not
in use. Keep empty cylinders tightly closed.
(3) Close all appliance valves before opening
(4) Test for system leakage each time the cylinder
supply valve is opened for appliance use. Close all
appliance valves. Open solenoid shut-off valve, if
installed. Open, then close cylinder supply valve.
Observe pressure gauge at the regulating device and see
that it remains constant for not less than three minutes
before any appliance is used. If any leakage is evidenced
by a pressure drop check system with a leak detection
fluid or detergent solution, which does not contain
ammonia, and repair before operating system.
(5) NEVER USE FLAME TO CHECK FOR
NOTE: Tltis sign sit all be illstalled ill tlte vicillity of
tlte cylillder alld sltall be plaillly visible.
22.5.4 On boats with a gasoline engine, the sign shall
also contain at least the following:
GASOLINE VAPORS ARE EXPLOSIVE.
OPEN FLAME APPLIANCES CAN IGNITE
GASOLINE VAPOR CAUSING FIRE OR
TURN OFF ALL OPEN FLAME APPLIANCES
© 1993 American Boat & Yacht Council, Inc.
22.5.5 The system and all its components, as installed,
shall be suitable for operation within an ambient
temperature range of _18°C (O°F) to 60°C (140°F).
22.5.6 All devices and appliances using CNG shall be
secured so as to prevent upset or displacement that will
place strain upon fuel distribution system or appliance
22.6 ELECTRlL'AL DEVIL"ES IGNITION
22.6.1 If CNG is provided on a boat, unattended
electrical potential sources of ignition shall be ignition
protected in accordance with UL 1500 "Ignition Protection
Test for Marine Products" or SAE Jl171, "External
Ignition Protection of Marine Electrical Devices", if:
located in compartments containing CNG appliances,
cylinders, fittings, valves, regulators, and the unattended
electrical devices located within one meter of or located
above the level of the cylinder valve.
EXCEPTIONS: 1. Accomlllodatioll spaces.
2. Opell compartmellts:
Itavillg at least 15 square iI/cites of
opell area per cubic foot of
compartmellt voillme exposed to the
opell atmospltere olltside of the craft.
22.7.1 Cylinders used in CNG systems shall meet tile
applicable DOT and AGA Regulations and standards.
22.8 CYLINDER VALVES AND SAFETY
22.8.1 A readily accessible manual or electrically
operated (solenoid) shut-off valve(s) shall be installed in
the low pressure line to each attended appliance(s). The
valve(s) or its control shall be operable from within the
vicinity of the appliance( s) in tile event of a fire at the
appliance(s). If the cylinder valve(s) is readily accessible
from the vicinity of the attended appliance(s), the above
shut-off valve(s) on the supply line is not required.
22.9 PRESSURE REGULATOR
22.9.1 Each CNG system shall be provided with
pressure regulators specifically designed for use with
CNG, made of materials that are compatible with CNG.
22.9.2 The CNG pressure regulator system shall be
adjusted to deliver gas at any or each appliance, under
varying appliance loads, at a pressure not in excess of 16
mbar (six inches water colulJ1J1, approximately 0.22 psig).
22.9.3 The CNG pressure regulators shall be connected
directly to the cylinder shut-off valve, using one CGA
series 350 connection.
22.9.4 Each regulating system shall include a pressure
gauge. The gauge shall read the cylinder pressure side of
the pressure regulatoL
NOTES: Tlte purpose of tit is gauge is hj,ofold:
1. To mo"itor tlte amOllllt of CNG fuel
remai"i"g ill tlte storage cyli"der, a"d
2. to provide a quick a"d easy way to test tlte
systemfor leakage. (ReJ. A-22.13)
22.9.5 The pressure regulation system shall include a
high flow restrictor located on the cylinder pressure side of
the regulator which shalt
18.104.22.168 actuate and control gas flow through the vent
system to the open atmosphere in the event of regulator
22.214.171.124 The vent system shall be designed to contain the
gas flow at the pressure present when the high flow
restrictor is activated.
22.9.6 The high flow restrictor vent system shall be
designed to contain the gas flow at the pressure which
actuates the high flow restrictoL
126.96.36.199 Relief vent outJet(s) shall not discharge to the
interior of the vessel.
22.9.7 The vent discharge system shall be located and
designed to prevent water from entering the regulation
system. The vent hole shall be protected against entry of
other foreign material.
22.10 FUEL SUPPLY LINES
22.10.\ The fuel supply line system and its components,
as installed, shall be designed to be compatible with CNG
and to withstand the stresses and exposure to the marine
22.10.2 Copper tubing, unless internally tinned, is
22.10.3 CNG hose shall meet the applicable
requirements ofNFPA 52.
22.10.4 CNG supply hose shall be equipped with
pennanently attached end fittings such as swaged sleeve or
sleeve and threaded insert or other fittings specifically
designed for use with that hose.
22.10.5 Metal tubing shall be cOimected by means of
flare fittings. Metal to metal compression sleeve type
fittings shall not be used
22.11 LOCATION AND INSTALlATION - FUEL
22.11.1 Fuel supply lines shall be protected from
physical damage and shall be accessible for inspection.
22.11.2 A flexible section shall be used to allow the free
swing of gimbaled stoves.
22.11.3 Fuel supply lines shall be supported by clips,
straps or other suitable means, such as a conduit or tray,
to prevent vibration damage. The clips, straps or otller
means shall be corrosion resistant and shall be designed to
prevent cutting, abrading or damage to the lines and shall
be compatible with fuel supply line material
22.11.4 Fuel supply lines shall be protected by closefitting
grommets, sleeves or sealants of non-abrasive
material wherever they pass through decks and bulkheads.
Fuel supply lines passing through bulkheads that need not
be watertight shall be installed so that the bulkheads will
not cut, abrade or damage the line.
22.11.5 Fuel supply lines shall be continuous lengths of
tubing, piping or hose from the regUlating appliance or to
the flexible section at the appliance. Each appliance shall
be served by a separate supply line.
22.11.6 CNG fuel supply lines shall not be used for an
22.12 LOCATION - CYLINDER AND CONNECTED
22.12.1 CNG systems with cOimected capacity greater
than 100 cubic feet shall provide for storage lockers (see
22.12.2 CNG cylinders and regulation equipment shall
be located in a well ventilated area The area shall
provide protection from water or mechanical damage.
22.12.3 CNG cylinders and regulating equipment shall
be readily accessible and secured (in a vertical or
22.12.4 CNG cylinders shall not be installed in
compartments containing an internal combustion engine.
22.12.5 CNG cylinder storage compartments shall not
have openings which communicate with the engine space
above the level of the pressure regulator.
(\2) 1993 American Boat & Yacht Council, Inc
22.12.6 CNG cylinders shall be located at least one
meter (three feet) from any attended open flame device, in
the same compartment.
22.13 INSTALLATION CYLINDER AND
22.13.1 CNG cylinder location shall be readily
accessible such that the cylinder valve hand wheel can be
conveniently and quickly operated and the system pressure
gauge dial is fully visible.
22 .. 13.2 If CNG cylinders are installed in a space other
than a dedicated locker, the regulators, valves and fittings
shall be protected from the weather and against
mechanical damage ..
22.133 Storage provisions for unconnected reserve
cylinders, filled or empty, shall be the same as the
provisions for the cylinder in use.
22.13.4 Compartments and lockers in which CNG
cylinders are stored shall have a ventilation opening
located above the cylinder.
22.13.5 If the CNG installation includes attached
cylinders of greater than 2.8 cubic meters (100 cubic feet)
combined capacity, the cylinders shall be:
22.13 S I located on the exterior of the boat where
escaping gases can directly escape into the open air, or
188.8.131.52 installed in a locker which shall be:
a vapor tight to the hull interior,
b. vented to the open atmosphere outside the boat,
c. constructed of or lined with corrosion resistant
d.. equipped with a means to discharge incidental
e. equipped with a cover which
i. opens directly to the atmosphere,
ii. latches tightly,
111. is capable of being quickly and conveniently
opened without tools and for operating the cylinder
valves, testing the system for leakage and viewing the
Here are the Canadian standards