46 CFR §38.01-2

1. (a)DOT cylinders, DOT Specification portable tanks or other approved portable tanks containing liquefied flammable gases may be transported under deck, provided the following requirements are met:
   1. (1)The cargo space shall be provided with efficient means of ventilation, be protected from artificial heat, and be readily accessible from hatches.
   2. (2)Containers shall be stored in such a position that the safety relief device is in communication with the vapor space of the container. They shall be properly stowed, dunnaged, and secured to prevent movement in any direction.
   3. (3)Unless a method acceptable to the Commandant is used, the containers shall not be overstowed in the same dry cargo space with other liquefied flammable gas containers, nor with other cargo.
   4. (4)The containers shall be suitably protected against physical damage from other cargo, ship's stores, or equipment in such spaces.
   5. (5)Cylinders shall have their valves protected at all times by one of the following methods:
      1. (i)By metal caps securely attached to the cylinders and of sufficient strength to protect the valves from injury.
      2. (ii)By having the valves recessed into the cylinders or otherwise protected so that they will not be subject to a blow if the cylinder is dropped on a flat surface.
   6. (6)Portable tanks shall have their valves protected at all times by a housing in accordance with the requirements under which they were manufactured.
   7. (7)Electrical circuits in the cargo spaces must meet the hazardous area requirements in subchapter J (Electrical Engineering Regulations) of this chapter. If an electrical circuit does not meet those requirements, it must be deenergized by a positive means and not reenergized until the cargo has been removed and the space has been tested and found free of flammable vapor.
   8. (8)During the stowage of portable cylinders or portable tanks in a hold or compartment that is not fitted with electrical fixtures meeting the hazardous area requirements of subchapter J (Electrical Engineering Regulations) of this chapter, portable lights must not be used within the space unless the portable lights are explosion-proof. Electrical connections for portable lights must be made from outlets on the weather deck. Hand flashlights used in the stowage area must be explosion-proof.
   9. (9)The following dangerous cargoes shall not be stowed in the same hold or compartment with liquefied flammable gas containers:
      1. (i)Division 1.1, 1.2, 1.3, or 1.4 (explosive) materials, as defined in 49 CFR 173.50.
      2. (ii)Flammable solids.
      3. (iii)Oxidizing materials.
      4. (iv)Corrosive liquids.
      5. (v)Poisonous articles.
      6. (vi)Cotton and similar fibrous materials.