(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.
(b)
As used in this section:
(1)
The terms “gas-safe” and “gas-dangerous” spaces are used as defined in § 154.7 of this chapter.
(2)
The term “gas-dangerous” does not include the weather deck of an ammonia carrier.
(c)
Each submerged cargo pump motor design must receive concept approval by the Commandant (CG-521) and its installation must receive plan approval by the Commanding Officer, Marine Safety Center.
(d)
Electrical equipment must not be installed in a gas-dangerous space or zone, except:
(1)
Intrinsically safe electrical equipment and wiring, and
(2)
Other equipment as allowed in this section.
(e)
A submerged cargo pump motor, if installed in a cargo tank, must meet § 111.105-31(d).
(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)
Through runs of marine shipboard cable;
(2)
Explosionproof lighting fixtures;
(3)
Depth sounding devices in gastight enclosures;
(4)
Log devices in gastight enclosures;
(5)
Impressed current cathodic protection system electrodes in gastight enclosures; and
(6)
Armored or MI type cable for a submerged cargo pump motor.
(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)
Through runs of marine shipboard cable;
(2)
Explosionproof lighting fixtures;
(3)
Depth sounding devices in gastight enclosures;
(4)
Log devices in gastight enclosures;
(5)
Impressed current cathodic protection system electrodes in gastight enclosures;
(6)
Explosionproof motors that operate cargo system valves or ballast system valves;
(7)
Explosionproof bells for general alarm systems; and
(8)
Armored or MI type cable for a submerged cargo pump motor.
(h)
A cargo-handling room must not have any installed electrical equipment, except explosionproof lighting fixtures.
(i)
A space for cargo hose storage or a space that has cargo piping must not have any installed electrical equipment, except:
(1)
Explosionproof lighting fixtures; and
(2)
Through runs of marine shipboard cable.
(j)
A gas dangerous zone on the open deck must not have any installed electrical equipment, except:
(1)
Explosionproof equipment that is necessary for the operation of the vessel; and
(2)
Through runs of marine shipboard cable.
(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.
(l)
Each gas-dangerous space that has lighting fixtures must have at least two branch circuits for lighting.
(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.
(n)
Each switch and each overcurrent protective device for lighting in a gas-dangerous space must be in a gas-safe space.
Code of Federal Regulations
[CGD 74-125A, 47 FR 15236, Apr. 8, 1982, as amended by CGD 77-069, 52 FR 31626, Aug. 21, 1987; CGD 94-108, 61 FR 28285, June 4, 1996; 62 FR 23909, May 1, 1997; USCG-2009-0702, 74 FR 49234, Sept. 25, 2009]