46 CFR §111.105-32

1. (a)Each vessel that carries bulk liquefied flammable gases or ammonia as a cargo, cargo residue, or vapor must meet the requirements of this section.
2. (b)As used in this section:
   1. (1)The terms “gas-safe” and “gas-dangerous” spaces are used as defined in § 154.7 of this chapter.
   2. (2)The term “gas-dangerous” does not include the weather deck of an ammonia carrier.
3. (c)Each submerged cargo pump motor design must receive concept approval by the Commandant (CG-ENG) and its installation must receive plan approval by the Commanding Officer, Marine Safety Center.
4. (d)Electrical equipment must not be installed in a gas-dangerous space or zone, except:
   1. (1)Intrinsically safe electrical equipment and wiring, and
   2. (2)Other equipment as allowed in this section.
5. (e)A submerged cargo pump motor, if installed in a cargo tank, must meet § 111.105-31(d).
6. (f)Electrical equipment must not be installed in a hold space that has a tank that is not required to have a secondary barrier under § 154.459 of this chapter, except:
   1. (1)Through runs of marine shipboard cable;
   2. (2)Explosionproof lighting fixtures;
   3. (3)Depth sounding devices in gastight enclosures;
   4. (4)Log devices in gastight enclosures;
   5. (5)Impressed current cathodic protection system electrodes in gastight enclosures; and
   6. (6)Armored or MI type cable for a submerged cargo pump motor.
7. (g)Electrical equipment must not be installed in a space that is separated by a gastight steel boundary from a hold space that has a tank that must have a secondary barrier under the requirements of § 154.459 of this chapter, except:
   1. (1)Through runs of marine shipboard cable;
   2. (2)Explosionproof lighting fixtures;
   3. (3)Depth sounding devices in gastight enclosures;
   4. (4)Log devices in gastight enclosures;
   5. (5)Impressed current cathodic protection system electrodes in gastight enclosures;
   6. (6)Explosionproof motors that operate cargo system valves or ballast system valves;
   7. (7)Explosionproof bells for general alarm systems; and
   8. (8)Armored or MI type cable for a submerged cargo pump motor.
8. (h)A cargo-handling room must not have any installed electrical equipment, except explosionproof lighting fixtures.
9. (i)A space for cargo hose storage or a space that has cargo piping must not have any installed electrical equipment, except:
   1. (1)Explosionproof lighting fixtures; and
   2. (2)Through runs of marine shipboard cable.
10. (j)A gas dangerous zone on the open deck must not have any installed electrical equipment, except:
    1. (1)Explosionproof equipment that is necessary for the operation of the vessel; and
    2. (2)Through runs of marine shipboard cable.
11. (k)A space, except those named in paragraphs (f) through (i) of this section, that has a direct opening to gas-dangerous spaces or zones must have no electrical equipment except as allowed in the gas-dangerous space or zone.
12. (l)Each gas-dangerous space that has lighting fixtures must have at least two branch circuits for lighting.
13. (m)Each switch and each overcurrent protective device for any lighting circuit that is in a gas-dangerous space must open all conductors of the circuit simultaneously.
14. (n)Each switch and each overcurrent protective device for lighting in a gas-dangerous space must be in a gas-safe space.