D4478 Safety Relief Valve Body Material Bronze Inlet Type MNPT Outlet Type FNPT Inlet Size 1 in Outlet Size 1 1/4 in Factory Set Pressure 25 psi Disc Material B21 Alloy 485 Overall Height 8 1/2 in Application Pressure Reducing Stations etc Steam Boiler and Generators Overall Length 4 in Seat Material EPR Spring Material Stainless Steel Temp Range -60 Degrees to 406 Degrees F Test Lever Yes Standards ASME Section 1 ASTM A-313 TY 631 National Board Certified Steam