Section 680IAC2-5-8. Blow-off tanks; outlets and discharges

   (a) Blow-off piping from a power boiler or a miniature boiler shall not discharge directly into a sewer.

  (b) A blow-off tank shall be used where conditions do not provide an adequate and safe open discharge. Blow-off tanks and piping shall meet one (1) of the following requirements:

(1) The outlet from the blow-off tank shall be twice the area of the inlet pipe and made to extend internally within eight (8) inches from the bottom of the tank. A vent pipe at least four (4) times the cross-sectional area of the inlet pipe shall lead to the outer atmosphere. Vents shall be as direct as possible to the outside and discharge at a safe location. There shall be no valve or other possible obstructions, such as water pockets, between the tank and the discharge end of the vent pipe. All pipe connections between the tanks and the boiler shall be as direct as possible and shall conform to the ASME code. For convenience in cleaning the tank, a manhole or an access opening shall be provided. Where a blow-off tank is not vented as specified in this subdivision, it shall be constructed for a pressure equal to that allowed on the boiler to which it is attached or shall be equipped with a safety valve or valves of sufficient capacity to prevent the pressure from exceeding the safe working pressure of the tank.

(2) Boiler blow-off equipment which cannot be designed in accordance with subdivision (1) shall be referred to the board for consideration.

(Boiler and Pressure Vessel Rules Board; 680 IAC 2-5-8; filed Jan 5, 1996, 10:15 a.m.: 19 IR 1125; 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)