Section 680IAC2-10-12. Safety valves for low pressure steam heating boilers; dimensions and capacity

   (a) Each low pressure steam heating boiler shall have one (1) or more safety valves of the spring-pop type adjusted and sealed to discharge at a pressure not to exceed fifteen (15) psig.

  (b) Each safety valve for a low pressure steam heating boiler shall, if three-fourths (¾) inch or larger, have a substantial device which will positively lift the disk from its seat at least one-sixteenth (1/16) inch when there is no pressure on the boiler. The seats and disks shall be of suitable material to resist corrosion.

  (c) No safety valve for a low pressure steam heating boiler shall be smaller than three-fourths (¾) inch and shall have a substantial device which will positively lift the disk from its seat at least one-sixteenth (1/16) inch when there is no pressure on the boiler. The seats and disks shall be of suitable material to resist corrosion.

  (d) The minimum capacity of the valve or valves shall be governed by the capacity marking on the boiler called for in Section IV of the ASME code.

  (e) The minimum valve capacity in pounds per hour shall be determined by dividing the maximum Btu output at the boiler nozzle obtained by the firing of any fuel for which the unit is designed by one thousand (1,000). In every case the requirements of subsection (f) shall be met.

  (f) The steam safety valve capacity for each low pressure steam heating boiler shall be such that with the fuel-burning equipment installed, and fires at a maximum rate, the pressure of the low pressure steam heating boiler shall not exceed fifteen (15) psig with all safety valves open.

  (g) When operating conditions are changed or additional boiler heating surface is installed, the valve capacity shall be checked and increased if necessary to meet the new conditions and be in accord with subsection (f). The additional valves required may be installed on the outlet pipe providing there is no intervening valve nor any other branching pipes between additional valves and the boiler.

  (h) When there is any doubt as to the total capacity of the safety valve or valves, an accumulation test shall be run. (Boiler and Pressure Vessel Rules Board; 680 IAC 2-10-12; filed Jan 5, 1996, 10:15 a.m.: 19 IR 1135; readopted filed Jul 9, 2001, 1:33 p.m.: 24 IR 3822; readopted filed Sep 21, 2007, 9:16 a.m.: 20071010-IR-680070389RFA; readopted filed Oct 19, 2007, 1:08 p.m.: 20071114-IR-680070389RFA; readopted filed Sep 5, 2013, 10:09 a.m.: 20131009-IR-680130182RFA)