Connecticut Administrative Code › Title 29 - Public Safety and State Police › 232 - Boiler Design, Construction, Installation, Repair, Use and Operation › Existing Installations - Power Boilers › Section 29-232-58 - Safety valves

Current through July 10, 2024
The use of weighted-lever safety valves is prohibited. Safety
				  valves having either the seat or disc of cast iron, shall not be used. Each
				  boiler shall have at least one safety valve and if it has more than five
				  hundred sq. ft. of water heating surface, or if an electric boiler has a power
				  input more than 500kw, it shall have two or more safety valves. 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. 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,
				  it shall be full size and fitted with an open drain to prevent water lodging in
				  the upper part of the safety valve or escape pipe. When an elbow is placed on a
				  safety valve escape pipe, it shall be located close to the safety valve outlet
				  or the escape pipe shall be securely anchored and 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. 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 above the highest pressure
				  to which any valve is set and in no case to more than six percent above the
				  maximum allowable working pressure. One or more safety valves on every boiler
				  shall be set at or below the maximum allowable working pressure. The remaining
				  valves may be set within a range of three percent above the maximum allowable
				  working pressure, but the range of setting of all the safety valves on a boiler
				  shall not exceed ten percent of the highest pressure to which any valve is
				  set.
When two 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
				  boilers. 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 of the lowest pressure obtained in the supply main feeding the boiler.
				  The relieving capacity of the safety valves on any boiler may be checked by one
				  of the three following methods and, if found to be insufficient, additional
				  valves shall be provided.
(a) By
				making the accumulation test, which consists of shutting off all other
				steam-discharge outlets from the boiler and forcing the fires to the maximum.
				The safety valve capacity shall be sufficient to prevent a pressure in excess
				of six percent above the maximum allowable working pressure.
(b) By measuring the maximum amount of fuel
				that can be burned and computing the corresponding evaporative capacity (steam
				generating capacity) upon the basis of the heating value of this fuel. These
				computations shall be made as outlined in the appendix of the A.S.M.E. Boiler
				Construction Code for Power Boilers, section I.
(c) By determining the maximum evaporative
				capacity by measuring the feed water.
When either of the methods outlined in (b) or (c) is
				  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.