: A hazard detection and suppression apparatus comprising: (a) a single-action discharge valve (1.20, 2.20, 3.20) for discharging the contents of a vessel, (b) an electrical power source; (c) control means interposed between said single-action discharge valve (1.20, 2.20, 3.20) and said electrical power source for selective connection of said electrical power source to single-action discharge valve (1.20, 2.20, 3.20); and (d) a hazard detector for detecting a hazard, said hazard detector being operably connected to said control means; said control means being responsive to detection of said hazard by said hazard detector by connecting said electrical power source to said single-action discharge valve (1.20, 2.20, 3.20); wherein said single-action discharge valve (1.20, 2.20, 3.20) comprises i. a valve body (1.22, 2.22, 3.22) having a passage (1.26,2.26,3.26) therethrough through which said contents are discharged, said passage (1.26, 2.26, 3.26) having a perimeter thereabout and having a substantially constant cross-section area, and said passage (1.26, 2.26, 3.26) having a center; ii. a frangible seal (1.28, 2.28, 3.28) held within said valve body (1.22, 2.22, 3.22) and sealing said passage (1.26, 2.26, 3.26) while said seal (1.28, 2.28, 3.28) is intact; iii. a solenoid (1.30, 2.30, 3.30) for selective connection to the power source for selective actuation thereby, said solenoid (1.30, 2.30, 3.30) including an armature (1.34, 2.34, 3.34) movable from a first position to a second position; and iv. impacting means (1.36, 2.36, 3.36) for breaking said frangible seal (1.28, 2.28, 3.28) said impacting means(1.36, 2.36, 3.36) being moved by said armature(1.34, 2.34, 3.34) to break said seal (1.28, 2.28, 3.28) as said armature (1.34, 2.34, 3.34) moves into said second position; characterised in that the armature (1.34, 2.34, 3.34) is substantially exterior of said passage (1.26, 2.26, 3.26), with substantially all of said passage (1.26, 2.26, 3.26) passing axially through said armature (1.34, 2.34, 3.34); the passage (1.26, 2.26, 3.26) has a substantially constant cross-section area from said frangible seal (1.28, 2.28, 3.28) through said substantially all of said passage (1.26, 2.26, 3.26) passing axially through said armature (1.34, 2.34, 3.34); the impacting means (1.36, 2.36, 3.36) impact said frangible seal (1.28, 2.28, 3.28) remote from said center of said passage (1.26, 2.26, 3.26) and proximate said perimeter of said passage (1.26, 2.26, 3.26); and the impacting means (1.36, 2.36, 3.36) breaks said frangible seal (1.28, 2.28, 3.28) into at least two pieces. (a) a single-action discharge valve (1.20, 2.20, 3.20) for discharging the contents of a vessel, (b) an electrical power source; (c) control means interposed between said single-action discharge valve (1.20, 2.20, 3.20) and said electrical power source for selective connection of said electrical power source to single-action discharge valve (1.20, 2.20, 3.20); and (d) a hazard detector for detecting a hazard, said hazard detector being operably connected to said control means; said control means being responsive to detection of said hazard by said hazard detector by connecting said electrical power source to said single-action discharge valve (1.20, 2.20, 3.20); wherein said single-action discharge valve (1.20, 2.20, 3.20) comprises i. a valve body (1.22, 2.22, 3.22) having a passage (1.26,2.26,3.26) therethrough through which said contents are discharged, said passage (1.26, 2.26, 3.26) having a perimeter thereabout and having a substantially constant cross-section area, and said passage (1.26, 2.26, 3.26) having a center; ii. a frangible seal (1.28, 2.28, 3.28) held within said valve body (1.22, 2.22, 3.22) and sealing said passage (1.26, 2.26, 3.26) while said seal (1.28, 2.28, 3.28) is intact; iii. a solenoid (1.30, 2.30, 3.30) for selective connection to the power source for selective actuation thereby, said solenoid (1.30, 2.30, 3.30) including an armature (1.34, 2.34, 3.34) movable from a first position to a second position; and iv. impacting means (1.36, 2.36, 3.36) for breaking said frangible seal (1.28, 2.28, 3.28) said impacting means(1.36, 2.36, 3.36) being moved by said armature(1.34, 2.34, 3.34) to break said seal (1.28, 2.28, 3.28) as said armature (1.34, 2.34, 3.34) moves into said second position; i. a valve body (1.22, 2.22, 3.22) having a passage (1.26,2.26,3.26) therethrough through which said contents are discharged, said passage (1.26, 2.26, 3.26) having a perimeter thereabout and having a substantially constant cross-section area, and said passage (1.26, 2.26, 3.26) having a center; ii. a frangible seal (1.28, 2.28, 3.28) held within said valve body (1.22, 2.22, 3.22) and sealing said passage (1.26, 2.26, 3.26) while said seal (1.28, 2.28, 3.28) is intact; iii. a solenoid (1.30, 2.30, 3.30) for selective connection to the power source for selective actuation thereby, said solenoid (1.30, 2.30, 3.30) including an armature (1.34, 2.34, 3.34) movable from a first position to a second position; and iv. impacting means (1.36, 2.36, 3.36) for breaking said frangible seal (1.28, 2.28, 3.28) said impacting means(1.36, 2.36, 3.36) being moved by said armature(1.34, 2.34, 3.34) to break said seal (1.28, 2.28, 3.28) as said armature (1.34, 2.34, 3.34) moves into said second position;