Pressure-relief valves.

(a) Each container or system of containers shall have liquid and vapor pressure-relief valves to prevent pressure build-up in any portion of the system. Each pressure-relief valve shall be manufactured for use with anhydrous ammonia and be installed, maintained, and replaced according to the manufacturer's instructions. (b) Each vapor-relief valve shall be set to indicate discharge at a pressure of not less than 95 percent, and not more than 100 percent, of the design pressure of the container to which the vapor-relief valve is attached. Each vapor-relief valve shall be constructed to completely discharge before the pressure exceeds 120 percent of the design pressure of the container to which the vapor-relief valve is attached. (c) Pressure-relief valves shall not exhaust within or beneath any building or other confined area. (d) Each pressure-relief valve discharge opening shall have a suitable rain cap or other device that allows free discharge of the vapor and prevents the entrance of water. (e) Each pressure-relief valve shall be replaced if the valve meets any of the following conditions: (1) Fails to meet applicable requirements; (2) shows evidence of damage, corrosion, or foreign matter; and (3) does not have functional weep holes that permit moisture to escape. (f) The discharge from each pressure-relief valve shall be vented according to one of the following: (1) For vapor-relief valves, upward and away from where people could be located. The discharge shall flow in an unobstructed manner into the open air from a height of at least seven feet above the working area; (2) for liquid-relief valves, downward with the opening positioned between six and 18 inches from the ground; or (3) in any other manner that has been approved by the secretary or an authorized representative of the secretary. (g) (1) Vent pipes or tubing used to channel releases from pressure-relief valves shall not be restricted or smaller in size than the pressure-relief valve outlet connection. (1) Vent pipes may be connected and channeled into a common header if the cross-sectional area of the header is at least equal to the sum of the cross-sectional areas of each of the individual vent pipes. (2) Unless a vent is directed toward the ground and rain will not be able to enter, each pressure-relief valve discharge opening shall have a rain cap. (3) If moisture accumulation could occur in a vent, suitable provision shall be made to drain the moisture from the vent. (Authorized by and implementing K.S.A. 2-1212 ; effective March 12, 2010.)