The flash point of a liquid is the lowest temperature at which the vapors in sufficient concentration will ignite in the air if exposer to a source of ignition. All materials that are used in liquid penetrant testing are accompanied by a material safety data sheet from the manufacturer.The material safety data sheet contains data regarding the chemical makeup and characteristics of that material including the flash point. A low flash point number means the material can easily catch on fire.
Portable penetrant kits with aerosol cans can be very dangerous. Some of the materials included can have a flash point as low as 5ºC (40 ºF).
When these materials are used, they are sprayed in a fine mist, which increases the flammability hazard. In addition, if these materials are used in a small confined area, the danger of a fire is increased. Therefore, inspectors must know the materials they are working with and ensure that all the necessary steps are taken to prevent a flammability hazard.
Vapors from penetrant in open tanks can concentrate in the tank above the liquid penetrant surface. Occupational Safety and Health Administration (OSHA) regulations have established the minimum flash point as 93ºC (200ºF) for liquids in open tanks without special ventilation. Know the flash point of the penetrant and observe the necessary safety requirements.
Emulsifiers peresent many of the same hazards as penetrants. Inspectors should check the material safety data sheet and know the precautions when using and storing emulsifiers.
Dryers on stationary penetrant lines are designed for drying parts. personnel should not use combustible materials in dryers.Nonaqueous solvent developers can have liquid vehicles with very low flash points. Extreme care is need when spraying with these product. Do not spray around surfaces of flame such as welding and grinding operations.
Cloths and papers sed for precleaning, postcleaning and the removal of the penetrant should be disposed of in a metal container.
When fluorescent penetrant tests are performed in or near areas where flammable fumes are present, open aircraft fuels cells for example, only approved ultraviolet lights should used.
All penetrant materials should be stored in areas away from sources of flame an heat. Storage areas should be well ventilated or approved flammable materials storage lockers.