46 CFR §184.240

1. (a)The design, installation and testing of each LPG system must meet ABYC A-1, “Marine Liquefied Petroleum Gas (LPG) Systems,” Chapter 6 of NFPA 302, or other standard specified by the Commandant.
2. (b)The design, installation and testing of each CNG system must meet ABYC A-22, “Marine Compressed Natural Gas (CNG) Systems,” Chapter 6 of NFPA 302, or other standard specified by the Commandant.
3. (c)Cooking systems using Chapter 6 of NFPA 302 as the standard must meet the following additional requirements:
   1. (1)The storage or use of CNG containers within the accommodation area, machinery spaces, bilges, or other enclosed spaces is prohibited;
   2. (2)LPG or CNG must be odorized in accordance with ABYC A-1 appendix 4 or A-22 appendix 4, respectively;
   3. (3)The marking and mounting of LPG cylinders must be in accordance with ABYC A-1 appendix 7; and
   4. (4)LPG cylinders must be of the vapor withdrawal type as specified in ABYC A-1 section 1.7.
4. (d)Continuous pilot lights or automatic glow plugs are prohibited for an LGP or CNG installation using ABYC A-1 or A-22 as the standard.
5. (e)CNG installation using ABYC A-22 as the standard must meet the following additional requirements:
   1. (1)The storage or use of CNG containers within the accommodation area, machinery spaces, bilges, or other enclosed spaces is prohibited;
   2. (2)CNG cylinders, regulating equipment, and safety equipment must meet the installation, stowage, and testing requirements of paragraph 6-5.12 of NFPA 302.
   3. (3)The use or stowage of stoves with attached CNG cylinders is prohibited as specified in paragraph 6-5.1 of NFPA 302.
6. (f)If the fuel supply line of an LPG or CNG system enters an enclosed space on the vessel, a remote shutoff valve must be installed that can be operated from a position adjacent to the appliance. The valve must be located between the fuel tank and the point where the fuel supply line enters the enclosed portion of the vessel. A power operated valve installed to meet this requirement must be of a type that will fail closed.
7. (g)The following variances from ABYC A-1 section 1.12 are allowed for CNG:
   1. (1)The storage locker or housing access opening need not be in the top.
   2. (2)The locker or housing need not be above the waterline.
8. (h)The following variances from NFPA 302 are allowed:
   1. (1)The storage locker or housing for CNG tank installations need not be above the waterline as required by paragraph 6-5.12.1.1(a);
   2. (2)Ignition protection need not be provided as required by paragraph 6-5.4.