Internal air emergency valve meets HM183 requirements for an internal self-closing stop valve. Body is constructed of aluminum and incorporates a shear section that satisfies 49CFR178.345-8 tested per TTMA RP 84. The 1/8 NPT air inlet is designed to shear and close the valve in the event of an under-ride accident. A fusible plug is installed to dump air pressure if temperatures exceed 212 F.__ Valve uses Teflon encapsulated seals for compatibility with a wide range of products. Other seal options are also available. Internal air cylinder saves space on exterior of valve providing maximum clearance for piping. Valve is equipped with stainless steel jackscrew that allows for manual operation in the event of an air system failure. The Maximum Operating Pressure is defined as the maximum tank pressure that valve can open against w/ given air line pressure. Maximum Operating Pressure is 18 psi with 80 psi line pressure and 25 psi with 100 psi line pressure. The Valve MAWP is 35 psi [2.4 bar] and the Minimum Bursting Pressure is 140 psi [9.7 bar].