A. All types of pipe and fittings are tested to ensure they meet specific temperature and pressure requirements. Class 150 is one of the ratings given to galvanized malleable iron pipe fittings as determined by the ASME (American Society of Mechanical Engineers). ASME B16.3-2006 is the standard used to test malleable iron threaded fittings to make sure they meet the proper pressure and temperature ratings. A Class 150 rating means these fittings have been tested and approved for a maximum pressure of 300 PSI at 150�F. The black and galvanized fittings we sell are also UL (Underwriters Laboratories) and FM (Factory Mutual Insurance Company) approved. FM has an independent testing facility where products are tested to make sure they meet the highest level of standards for safety and property loss prevention.