| The best single investment in safety is trained personnel. Some workers will need detailed training in a particular type of equipment, cryogen, or repair operation. Others will require broader training in safe handling practices for a variety of cryogenic liquids. The following subjects should be familiar to everyone involved in using, handling, storing, or transferring cryogens:
- Nature and properties of the cryogen in both its liquid and gaseous states.
- Operation of the equipment.
- Approved, compatible materials.
- Use and care of protective equipment and clothing.
- First-aid and self-aid techniques to employ when medical treatment is not immediately available.
- Good housekeeping practices.
Good housekeeping is essential to safety. Few cryogens are spontaneously hazardous, but each liquefied gas poses another hazard.
Liquid oxygen may form mixtures that are shock sensitive with fuels, oils, or grease. Porous solids, such as asphalt or wood, can become saturated with oxygen and also become shock sensitive. Ignition is more likely with weaker sparks and lower temperatures than would be required in air.
Flammable gases such as hydrogen and methane are lighter than air. At normal temperatures, they will rise, but at the first temperatures that exist just after evaporation from the liquid state, the saturated vapor is heavier than air and tends to fall. Wind or forced ventilation will affect the direction of the released gases and must be considered during disposal of any leaking fluid.
The location and maintenance of safety and firefighting equipment are important. Outside personnel also should be informed of all necessary safeguards before entering a potentially hazardous area. In general, maintaining good housekeeping rules and demanding a high level of worker conduct everywhere in the plant will minimize negligence. |
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