Valve Protection

36 AFMAN 24-204(I)/TM 38-250/NAVSUP PUB 505/MCO P4030.19H/ DLAI 4145.3 11 DECEMBER 2001 A3.3.2.2. Valve Protection. Protect all valves of containers charged with compressed gas by one of the following methods: - By a securely attached metal cap of sufficient strength to protect the valve from injury during transit. - By boxing or crating the cylinder or sphere to give proper protection to the valve. - By recessed valve or otherwise protected valve so that it cannot be subjected to a blow when the container is dropped on a flat surface. - By valves strong enough to avoid injury during transit for cylinders or spheres containing nonliquefied gas under pressure not over 2068.5 kPa (300 psig) at 21 degrees C (70 degrees F). A3.3.2.3. Cylinders Containing Poisonous Material. Overpack cylinders containing a poisonous material, which have a wall thickness at any point of less than 2.03 mm (0.080 inch) and do not have fitted value protection, in a 4C1, 4D, 4F, 4G, 4H1, or 4H2 box. The box must meet the requirements of A3.1. Ensure box and valve protection is of sufficient strength to protect all parts of the cylinder and valve (if it has a valve) from deformation and breakage resulting from a drop of 2.0 m (7 ft) or more onto a concrete floor, impacting at an orientation most likely to cause damage. If the cylinder is not overpacked, equip the cylinder with a protective cap or other means of valve protection sufficient to protect the valve from deformation and breakage resulting from a drop of 2.0 m (7 ft) or more onto a concrete floor, impacting at an orientation most likely to cause damage. A3.3.2.4. Cylinders Requiring an Outside Container. Ship DOT 2P, 2Q, 3E, 3HT, 4BA spherical type, 4D, 4DA, 4DS, 9, 39, 40, and 41 cylinders in strong outside containers. Ensure the package is capable of protecting the cylinder and all its parts from deformation or breakage resulting from a 1.2 m (4 foot) drop on a solid concrete floor. Do not pack cylinders, spheres, or containers under pressure in metal drums or airtight outside packages. DOT 4BA spherical cylinders may be securely mounted on pallets to provide protection for the spheres and any attachments. A3.3.2.5. Pressure and Filling Requirements. - Ensure the pressure in the container at 21 degrees C (70 degrees F) is not more than the service pressure for which the container is marked or designated, except as provided below. - When cylinders with a marked pressure limit are prescribed, other cylinders made under the same specification, but with a higher marked service pressure limit are authorized. For example, a cylinder marked DOT 4B500 may be used where DOT 4B300 is specified. - The pressure in the cylinder or sphere at 54 degrees C (130 degrees F) must not exceed 1 1/4 times the service pressure except cylinders of acetylene, liquefied nitrous oxide, and liquefied carbon dioxide which must not exceed the allowable charging pressure of the cylinder. - The pressure of a cylinder containing a poisonous material must not exceed the service pressure of the cylinder at 55 degrees C (131 degrees F). Provide sufficient outage to ensure the cylinder is not liquid full at 55 degrees C (131 degrees F). - Use the service pressure identified for a current specification for containers made before the effective date of specifications. - Except for carbon dioxide, nitrous oxide, and vinyl fluoride, stabilized, the liquid portion of the gas (if any) must not completely fill the cylinder at 54 degrees C (130 degrees F). The liquid portion of vinyl fluoride, stabilized, may completely fill the cylinder provided the pressure is not over 1 1/4 times the service pressure (see definition for filling density). - Use the service pressure identified in figure A3.1 for authorized cylinders not marked with a service pressure. - DOT 3A, 3AX, 3AA, 3AAX, and 3T cylinders may be charged with compressed gases other than liquefied, dissolved, poisonous, or flammable gases to a pressure of 10 percent over their marked service pressure, provided the following conditions are met: - Equip each cylinder with frangible disc safety devices (without fusible metal backing) having a bursting pressure not over the minimum prescribed test pressure. - Determine the elastic expansion at the time of the last test or retest by the water-jacket method. - Do not exceed either the average wall stress or the maximum wall stress limitations in figure A3.2. - Use figure A3.3 for filling density requirements of Liquified Petroleum Gases. Any filling density prescribed in figure A3.3 may be increased by 2 percent for liquefied petroleum gas in DOT 26 or DOT 3 cylinders (or in DOT 3A cylinders marked for 1,800 pounds or higher service pressure, subject to the bullet above). - Use figure A3.4 for filling density requirements when shipping cryogenic liquids of argon, helium, neon, nitrogen, and oxygen. Ship hydrogen (minimum 95 percent parahydrogen) according to figure A3.5.