Indiana Administrative Code › Title 675 - FIRE PREVENTION AND BUILDING SAFETY COMMISSION › Article 30 - INDIANA BOILER AND PRESSURE VESSEL RULES › Rule 8 - Existing Installations of Power Boilers (prior to July 1, 1953) › Section 8-14 - Safety valves; prohibited types; installation; standards; relieving capacity

Current through July 10, 2024
Authority: IC 22-13-2-8
Affected: IC 22-15-6
Sec. 14.
(a) The use
				of weighted-lever safety valves is prohibited and these valves shall be
				replaced by direct spring loaded pop type valves that conform to the
				requirements in Section I of the ASME B&PVC.
(b) Safety valves having either the seat or
				disc of cast iron shall not be used.
(c) Each boiler shall have at least one (1)
				safety valve. Each boiler having more than five hundred (500) square feet of
				water heating surface shall have two (2) or more safety valves.
(d) The valve or valves shall be connected to
				the boiler, independent of any other steam connection, and attached as close as
				possible to the boiler, without unnecessary intervening pipe or
				fittings.
(e) No valve of any
				description shall be placed between the safety valve and the boiler nor on the
				escape pipe (if used) between the safety valve and the atmosphere. When an
				escape pipe is used, its area shall not be less than the cross-sectional area
				of the valve or drain to prevent water from lodging in the upper part of the
				valve or in the pipe. When an elbow is placed on a safety valve escape pipe, it
				shall be located close to the safety valve outlet, and the escape pipe shall be
				securely supported. All safety valve discharges shall be so located or piped as
				to be carried clear from walkways or platforms used to control the main stop
				valves of boilers or steam headers and discharged to a safe location.
(f) The safety valve capacity of each boiler
				shall be such that the safety valve or valves will discharge all the steam that
				can be generated by the boiler without allowing the pressure to rise more than
				six percent (6%) above the highest pressure to which any valve is set, and in
				no case to more than six percent (6%) above the maximum allowable working
				pressure.
(g) One (1) or more
				safety valves on every boiler shall be set at or below the maximum allowable
				working pressure. The remaining valves may be set not to exceed three percent
				(3%) above the maximum allowable working pressure, but the range of setting of
				all the safety valves on a boiler shall not exceed ten percent (10%) of the
				highest pressure to which any valve is set.
(h) When two (2) or more boilers operating at
				different pressures and safety valve settings are interconnected, the lower
				pressure boilers or interconnected piping shall be equipped with safety valves
				of sufficient capacity to prevent over pressure considering the generating
				capacity of all the boilers.
(i) In
				those cases where the boiler is supplied with feed water directly from pressure
				mains without the use of feeding apparatus (not to include return traps), no
				safety valve shall be set at a pressure greater than ninety-four percent (94%)
				of the lowest pressure obtained in the supply main feeding the
				boiler.
(j) When the required
				relief capacity is unknown, the relieving capacity of the safety valves shall
				be checked by one (1) of the following methods and, if found to be
				insufficient, additional valves shall be provided:
(1) By measuring the maximum amount of fuel
				that can be burned and computing the corresponding evaporative capacity (steam
				generating capacity) upon the basis of heating value of this fuel. These
				computations shall be made as outlined in the Appendix in Section I of the ASME
				B&PVC.
(2) By determining the
				maximum evaporative capacity by measuring the feed water.
When either of these methods are employed, the sum of the
				  safety valve capacities shall be equal to or greater than the maximum
				  evaporative capacity (maximum steam generating capacity) of the boiler.