Compressed gases nonliquefied

Nonliquefied compressed gases are of no use for pMDIs because liquid is needed for suspension of the dmg and the addition of water makes propulsion of the aerosol in an appropriate manner technically impossible. Hydrocarbons in general have the wrong density for use as propellants in pMDIs. While snitable as propellants for some nonmedicinal honsehold purposes, they are difhcult to use in a situation where dose reprodncibility is essential, and most are of course flammable and thus inappropriate for inhalation. The HCFCs are ozone-damaging and additionally have adverse toxicological effects on the heart and some biochemical hepatic functions. 

Methane may be shipped in any cylinders of the types authorized for nonliquefied compressed gases. Bulk industrial users of methane usually receive it as natural gas by pipeline and purify it if necessary for further processing. Ocean shipment of methane is made in specially designed ships carrying it as a cryogenic liquid. 

Note Forms dense white fumes in moist air Shipped as a nonliquefied compressed gas.]... 

Under DOT regulations, boron trifluoride is also authorized for shipment in any other cylinders specified as appropriate for nonliquefied compressed gas (which includes cylinders meeting DOT specifications 3B, 3E, 4B, 4BA, and 4BW cylinders meeting specifications 3, 3C, 3D, 4, 4A, 4C, 7, 25, 26, 33, and 38 may also be continued in boron trifluoride service, but new construction is not authorized) [4]. Cylinders of the 3A and 3AA type used in boron trifluoride service must be requalified by hydrostatic retest every 5 years under present regulations. All other cylinders authorized for boron trifluoride must similarly be requalified by hydrostatic retest every 5 years, with the following exceptions DOT 4 cylinders require hydrostatic retest every 10 years and types 3C, 3E, 4C, and 7 require no periodic retest. 

Methane is a colorless, odorless, tasteless, flammable gas. It is the first member of the paraffin (aliphatic or saturated) series of hydrocarbons. It is the major constituent of natural gas. Methane is soluble in alcohol or ether, and slightly soluble in water. Methane is shipped as a nonliquefied compressed gas in cylinders at pressures up to 6000 psig at 70°F (41 370 kPa at 21.1 C). Liquefied methane (as natural gas— LNG) is shipped in bulk quantities as a cryogenic liquid on barges and tankers. 

Any cylinders authorized for the shipment of a high-pressure nonliquefied compressed gas may be used in silane service under federal regulations, but cylinders made in accordance with TC/DOT specifications 3A, 3AA, and 3E are probably those most commonly used for silane. See 49 CFR 173.302 [8]. 

Permanent gas A gas that cannot be liquefied at normal ambient temperatures a nonliquefied compressed gas. 

Container capacity For liquefied compressed gas containers, a container s capacity refers to the water capacity at 60° F which when multiplied by the authorized filling density for a particular gas equals the contents capacity for that gas. For example, a container with a water capacity of 277.8 pounds filled to the authorized filling density of 54% with ammonia would contain 150 pounds (68 kg) of ammonia. For nonliquefied compressed gas containers, refer to the authorized service pressures in U.S. Department of Transportation and Transport Canada regulations, and to NBS Technical Note... 

To ensure the proper discharge of compressed gases from cylinders and other containers, the correct regulators and control valves must be used for any nonliquefied or liquefied compressed gas. This section primarily discusses regulators and control valves used for cylinders. 

Use of manifolds and simultaneous loading of a number of cylinders are common practices with nonliquefied gases. Temperature will usually rise as a cylinder is filled, because of the heat of compression of the gas. This rise is... 

Air can be compressed at the point of use for most practical applications. To meet needs for air of special purity or specified composition (as in certain medical, scientific, industrial, fire protection, undersea, and aerospace uses), it is purified or compounded synthetically and shipped in cylinders as a nonliquefied gas at high pressures. 

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