Air Products and Chemicals, Allentown, Pa.
Pages: 18 Published: Jan 1983
A number of known or assumed hazard mechanisms for oil films in oxygen systems are itemized. Each mechanism is discussed for understanding in terms of its hazard and pertinent data available from the literature and laboratory tests at Air Products and Chemicals, Inc. The methods of collection, values, and shortcomings of these available data are reviewed to place the various hazards in perspective. Areas not fully understood and in need of further work or that require specific evaluation procedures are itemized.
The principal oil film hazard in oxygen systems is flammability. However, an indirect hazard is migration of nonflammable films and accumulation to flammable levels. Generally, flammability of oil films has not been reported below roughly 0.108 to 1.08 g/m2 (10 to 100 mg/ft2) film concentrations. In comparison, migration of films of thickness above roughly 0.215 to 0.431 g/m2 (20 to 40 mg/ft2) can be substantial, while films of thickness below this range migrate more slowly. Migration along a surface can be greatly inhibited by choice of surface finish. Vapor phase migration is complex. Traditional cleaning methods provide systems of cleanliness well below flammable thresholds. However, migration of oil films can eventually produce hazardous regions, and, in combination with the rate of introduction of new contaminants, dictates required cleaning intervals.
oxygen, oil film, migration, fire, flammability, cleanliness, contamination, hazards, oxygen compatibility
Paper ID: STP35210S