Ohio Administrative Code › Title 901:5 - Plant Industry › Chapter 901:5-3 - Stationary Ammonia Systems › Section 901:5-3-09 - Safety relief devices

Current through all regulations passed and filed through July 1, 2024
(A) Every container used in systems covered
			 by rules
			 901:5-3-12
			 to
			 901:5-3-14
			 of the Administrative Code shall be provided with one or more safety relief
			 valves of the spring-loaded or equivalent type. The discharge from safety
			 relief valves shall be vented away from the container, upward and unobstructed
			 to the atmosphere. All safety relief valve discharge openings shall have
			 suitable raincaps that will allow free discharge of the vapor and prevent the
			 entrance of water. Provision shall be made for draining condensate which may
			 accumulate. The rate of the discharge shall be in accordance with the
			 provisions of'Appendix A, ANSI K 61.1 -1972;"
(B) Container safety relief valves shall be
			 set to start-to-discharge as follows, with relations to the design pressure of
			 the container:
Click to
				view image
(C)
			 Safety relief devices used in systems covered by rules
			 901:5-3-12
			 to
			 901:5-3-14
			 of the Administrative Code shall be constructed to discharge at not less than
			 the rates required in paragraph (A) before the pressure is in excess of one
			 hundred twenty per cent of the maximum permitted start-to-discharge pressure
			 setting of the device;
(D) Safety
			 relief valves shall be so arranged that the possibility of tampering will be
			 minimized. If the pressure setting adjustment is external, the relief valves
			 shall be provided with means for sealing the adjustment;
(E) Shut-off valves shall not be installed
			 between the safety relief valves and the containers or systems described in
			 rules
			 901:5-3-12
			 to
			 901:5-3-14
			 of the Administrative Code except that a shut-off valve may be used where the
			 arrangement of this valve is such as always to afford required capacity flow
			 through the relief valves.
Note: The above exception is made to cover such cases as a
				threeway valve installed under two safety relief valves, each of which has the
				required rate of discharge and is so installed as to allow either of the safety
				valves to be closed off, but does not allow both safety valves to be closed off
				at the same time. Another exception to this may be where two separate relief
				valves are installed with individual shut-off valves. In this case, the two
				shut-off valve stems shall be mechanically interconnected in a manner which
				will allow full required flow of one safety relief valve at all times. Still
				another exception is a safety relief valve manifold which allows one valve of
				two, three, four or more to be closed off and the remaining valve or valves
				will provide not less than the rate of discharge shown on the manifold
				nameplate.
(F) Safety
			 relief valves shall have unrestricted access to the vapor space of the
			 container;
(G) Each safety relief
			 valve used with systems described in rules
			 901:5-3-12
			 to
			 901:5-3-14
			 of the Administrative Code shall be plainly and permanently marked as follows:
(1) With the letters "AA" or the symbol
			 "NH3";
(2)
			 The pressure in pounds per square inch gage (psig) at which the valve is set to
			 start-to-discharge;
(3) The rate
			 of discharge of the valve in cubic feet per minute of air at sixty degrees
			 Fahrenheit and atmospheric pressure ( 14.7 psia);
(4) The manufacturer's name or trademark and
			 catalog number and date of manufacture shall be required on all newly installed
			 relief valves. For example, a safety relief valve marked "AA-250-4200" (air)
			 means that this valve is suitable for use on an anhydrous ammonia container;
			 that it is set to start-to-discharge at two hundred fifty psig; and that its
			 rate of discharge is four thousand two hundred cubic feet per minute of air;