Indiana Administrative Code › Title 355 - STATE CHEMIST OF THE STATE OF INDIANA › Article 3 - AGRICULTURAL AMMONIA › Rule 2 - Basic Rules › Section 2-8 - Pressure relief valves

Current through July 10, 2024
Authority: IC 15-16-1-6; IC 15-16-1-7
Affected: IC 15-16-1-10; IC 15-16-1-11
Sec. 8.
(a) Every
				container used with systems embodied in sections 4 through 7 of this rule shall
				be provided with one (1) or more pressure relief valves of spring-loaded or
				equivalent type. The discharge from pressure relief valves shall be directed
				away from the container upward and unobstructed to the open air. The rate of
				discharge, except as provided in 355 IAC 3-8, shall be in accordance with p
				355 IAC
				3-8-5(a).
(b) Container pressure relief valves shall be
				set to start-to-discharge as follows, with relation to the design pressure of
				the container:
Containers
Minimum
Maximum*
ASME Code-1950, 1952, 1956, 1959, and 1962 editions
95%
100%
ASME Code-1946 and 1949 editions, Par. U-200 and U-201
95%
100%
API-ASME Code-all editions
95%
100%
ASME Code-1949 and earlier editions, Par. U-68 and
							 U-69
110%
125%
DOT
As established by DOT regulations
*Note: A plus tolerance of 10% is permitted.
(c) Pressure relief valves used on
				containers or systems described in sections 4 through 7 of this rule shall be
				constructed to discharge at the rates required in subsection (a). The design of
				these valves must ensure such discharge before the pressure exceeds one hundred
				twenty percent (120%) of the maximum (not including the ten percent (10%)
				referred to in subsection (b) start-to-discharge pressure setting specified in
				subsection (b).
(d) Pressure 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 approved means for sealing the adjustment.
(e) Shutoff valves shall not be installed
				between the pressure relief valves and the container, except that a shutoff
				valve may be used where the arrangement of this valve is such as always to
				afford full required capacity flow through the relief valves. This exception is
				made to cover such cases as a three-way valve installed under two (2) pressure
				relief valves, each of which has the required rate of discharge and is so
				installed as to allow either of the valves to be closed off at the same time.
				Another exception to this may be where two (2) separate relief valves are
				installed with individual shutoff valves. In this case, the two (2) shutoff
				valve stems shall be mechanically interconnected in a manner that allows full
				required flow of one (1) relief valve at all times. Still, another exception is
				a pressure relief valve manifold that allows one (1) valve of two (2), three
				(3), four (4), 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) Pressure relief
				valves shall have direct communication with the vapor space of the
				container.
(g) Each pressure relief
				valve used with systems described in sections 4 through 7 of this rule and this
				section shall be plainly and permanently marked as follows:
(1) With the letters AA or
				NH3. If not so marked, documentation demonstrating
				suitability for ammonia service, traceable to the manufacturer, is
				required.
(2) The pressure in psig
				at which the valve is set to start-to-discharge.
(3) The rate of discharge of the valve at its
				full open position in cubic feet per minute of air at sixty (60) degrees
				Fahrenheit and atmospheric pressure (fourteen and seven-tenths (14.7)
				psia).
(4) The manufacturer's name
				and catalog number.