Every year people are killed by breathing “air” that contains too little oxygen. Because 78 percent of the air we breathe is nitrogen gas, many people assume that nitrogen is not harmful. However, nitrogen is safe to breathe only when mixed with the appropriate amount of oxygen. These two gases cannot be detected by the sense of smell. A nitrogenenriched environment, which depletes oxygen, can be detected only with special instruments. If the concentration of nitrogen is too high (and oxygen too low), the body becomes oxygen deprived and asphyxiation occurs.
USE OF NITROGEN
One of the most important commercial uses of nitrogen is as an inerting agent to improve safety. Nitrogen is inert under most conditions (i.e., it does not react with or affect other material). It is often used to keep material free of contaminants, including oxygen—which can corrode equipment or present a fire and explosion hazard when in contact with flammable liquids or combustible solids. In such cases, a flow of nitrogen is maintained in a vessel to keep oxygen out.
Nitrogen is also used to purge air from equipment prior to introducing material, or to purge flammable or toxic material prior to opening equipment for maintenance.
In industrial and commercial settings where a nitrogen-enriched environment may present a hazard, such as when using supplied air or working in or around spaces that are confined, precautions must be taken to ensure that sufficient oxygen is provided to personnel.
Failure to detect an oxygen deficient (nitrogen-enriched) atmosphere was a significant factor in several incidents. Below is the effect of oxygen deficiency on the huma body ;
Good Practices for Safe Handling of Nitrogen
- Implement Warning Systems and Continuous Atmospheric Monitoring of Enclosures during any job which involved nitrogen (under inert job)
- Ensure Ventilation With Fresh Air after purging with nitrogen completed esspecially in confined space area
- Implement System for Safe Rescue of Workers
- Ensure Uninterrupted Flow and Integrity of Breathing Air
- Develop and Implement Comprehensive Nitrogen handling Training Programs
Source : Safety Buletin (U.S. Chemical Safety and Hazard Investigation Board), June 2003