Nitrogen Safety Part 4

Within every workplace that uses nitrogen, there are certain areas or spaces that are particularly hazardous. Confined and enclosed spaces pose the greatest risk, including: reactor vessels, venting points within the plant, tank interiors, small rooms or enclosed buildings. These areas allow nitrogen to accumulate, creating potential for an oxygen deficient atmosphere.

In some cases, lack of oxygen or nitrogen rich atmospheres may be detected with a personal (i.e., 4 head) monitor. It is important to note that in atmospheres that have been “inerted” using nitrogen, a standard “personal” monitor may not work.

Most importantly, the LEL (Lower Explosive Limit) sensor, in particular, will not function in an oxygen deficient atmosphere. The monitor may give you a false reading because the sensors require a certain percentage of oxygen to function. This is something extremely important we must watch for in the vessel prior to assigning task to worker in the affected area. Be sure to contact your local safety personnel or occupational hygienist for specialized equipment which may be required for testing in “inert” atmospheres.

In order to safely transport nitrogen, it is transported in a compressed form in cylinders (1 ft of liquid nitrogen will expand and create 696ft of gaseous nitrogen). The cylinders must be handled with care. Cylinders can “rupture” if not handled with care and become projectiles.

Please note that contact with liquid nitrogen can readily cause frostbite. Use extreme caution when handling. You must have face, eye, hand and skin protection.