CONSTRUCTION OF CYLINDERS

Gas cylinders are made of high-quality steel. High-pressure gases, such as oxygen, hydrogen, nitrogen, and compressed air are stored in cylinders of seamless construction. Only nonshatterable high-pressure gas cylinders may be used by ships or activities operating outside the continental United States. Cylinders for pressure gases, such as acetylene, maybe welded or brazed. All cylinders are carefully tested, either at the factory or a designated processing station, at pressures above the maximum permissible charging pressure. low-

The cylinders for most compressed gases are shaped alike. However, cylinders for acetylene are shorter and of a larger diameter, as shown in figure 5-48.

All gas cylinders have safety devices either in the valve, in the shoulder, in the bottom of the cylinder, or in a combination of these places. A

Figure 5-48.-Cutaway view of compressed gas cylinder: (A) oxygen cylinder; (B) acetylene cylinder. 5-50

threaded valve protection cap screws on the neck ring and protects the valve.

MARKING AND IDENTIFYING GAS CYLINDERS

Gas cylinders are manufactured and maintained in accordance with the regulations of the Interstate Commerce Commission (ICC). The ICC stipulates that each cylinder be indented or stenciled with prescribed identification markings. Cylinders larger than 2 inches in diameter must be indented with serial numbers. Therefore, cylinders exceeding 2 inches in diameter, which are not assigned Navy serial numbers, require manufacturer's serial numbers. No more than 500 cylinders are allowed in each lot manufactured. Requirements for ICC 8 (acetylene) and ICC 9 (aerosol dispenser) cylinders are exceptions to this requirement. ICC 8 cylinders of all sizes require serial numbers and ICC 9 cylinders of all sizes are assigned lot numbers. However, an unlimited number per lot is authorized.

Navy-owned compressed-gas cylinders are indented with figures and letters as shown in table 5-1.

Table 5-1.-Cylinder Markings

Figure 5-49.-Location of color codes on gas cylinders.

In addition to the identifications required by ICC regulations, Navy-owned cylinders for gases in the liquid state with a water capacity in excess of 15 pounds, or gases in the gaseous state with a volume in excess of 658 cubic inches, are identified by an indented Navy serial number. This number is preceded and followed by the letters USN. Acetylene cylinders contain acetylene dissolved in acetone, and are assigned Navy serial numbers on the volume basis. In other words, gases in the liquid state are measured by weight, and those in the gaseous state are measured by volume. Acetylene, though dissolved in a liquid, is measured as a gas by volume.

Since 1 August 1944, Navy serial numbers have had a designated letter placed before the numerals. This letter shows the type of gas carried in the cylinder. The lettering system assigns the following letters to the gases shown below:

A Acetylene

M Ammonia

^D Carbon dioxide

^K Chlorine

E Ethylene oxide

^H Helium

^N Nitrogen

J Nitrous oxide

G Aerosol

x Oxygen

P Liquefied petroleum gas (propane, butane, etc.)

^s Sulfur dioxide

F Freon

^B Carboxide

^Y Hydrogen

R Methyl chloride

^z Compressed Air

^L Ethyl chloride NO Nitrogen dioxide

^V Argon

NOTE: Cylinders without the gas-indicating letters (manufactured prior to 1 August 1944) are still approved for naval service. A list of the identifying serial numbers of these cylinders may be obtained from the Naval Sea Systems Command.

In addition to markings required by the ICC, gas cylinders used by all three services-Navy, Army, and Air Force-have certain standard identifying features. So much injury and damage can be, and has been, caused by mistaking one gas cylinder for another. Therefore, a national program has been established to make it almost impossible to confuse cylinders. The identifying features used by the U.S. Armed Forces in this program consist of using a color code for painting the cylinders, stenciling the name of the gas along two sides of the cylinder, and placing two identifying symbols (decals) on the shoulder _{of each cylinder.} The gas cylinders must be painted as shown in figure 5-49, and the arrangement of colors will appear as shown in table 5-2.

If the color of the cylinders reduces the effectiveness of the ship's camouflage scheme, canvas covers painted with the camouflage colors should be placed over the cylinders. Do not paint the cylinders with camouflage paint.

Shatterproof cylinders are stenciled in two locations with the phrase Non-Shat lengthwise and 900 from the titles. Letters must be either black or white and approximately 1 inch in size.