Connecticut Administrative Code › Title 29 - Public Safety and State Police › 232 - Boiler Design, Construction, Installation, Repair, Use and Operation › Existing Installations - Low Pressure Heating Boilers › Section 29-232-91 - Safety relief valve requirements for hot water boilers

Current through July 10, 2024
(a) Each hot water heating boiler shall have
				at least one ASME/National Board certified safety relief valve set to relieve
				at or below the maximum allowable working pressure of the boiler. Each hot
				water supply boiler shall have at least one ASME/National Board certified
				safety relief valve of the automatic reseating type set to relieve at or below
				maximum allowable working pressure of the boiler. Safety relief valves
				ASME/National Board certified as to capacity shall have pop action when tested
				by steam. When more than one safety relief valve is used on either hot water
				heating or hot water supply boilers, the additional valve or valves shall be
				ASME rated and may be set within a range not to exceed 6 psig above the maximum
				allowable working pressure of the boiler up to and including 60 psig and 10
				percent for those having a maximum allowable working pressure exceeding 60 psi.
				Safety relief valves shall be spring loaded. Safety relief valves shall be so
				arranged that they cannot be reset at a higher pressure than the maximum
				permitted by this paragraph.
(b) No
				materials liable to fail due to deterioration or vulcanization when subject to
				saturated steam temperature corresponding to capacity test pressure shall be
				used for any part.
(c) No safety
				relief valve shall be smaller than 3/4 in. nor larger than 4-1/2 in. standard
				pipe size, except that boilers having a heat input not greater than 15,000 BTU
				per hour may be equipped with a safety relief valve of 1/2 in. standard pipe
				size. The inlet opening shall have an inside diameter approximately equal to,
				or greater than, the seat diameter. In no case shall the minimum opening
				through any part of the valve be less than 1/2 in. in diameter or its
				equivalent area.
(d) The required
				steam relieving capacity, in pounds per hour, of the pressure relieving device
				or devices on a boiler shall be the greater of that determined by dividing the
				maximum output in BTU at the boiler nozzle obtained by the firing of any fuel
				for which the unit is installed by 1,000 or shall be determined on the basis of
				pounds of steam generated per hour per square foot of boiler heating surfaces
				as given in Table 2. In many cases a greater relieving capacity of valves will
				have to be provided than the minimum specified by these rules. In every case,
				the requirements of (f) shall be met.
(e) When operating conditions are changed, or
				additional boiler heating surface is installed, the valve capacity shall be
				increased, if necessary, to meet the new conditions and shall be in accordance
				with (f). The additional valves required, on account of changed conditions, may
				be installed on the outlet piping provided there is no intervening
				valve.
(f) Safety relief valve
				capacity for each boiler shall be such that, with the fuel burning equipment
				installed and operated at maximum capacity, the pressure cannot rise more than
				6 psi above the maximum allowable working pressure for pressure up to and
				including 60 psi and 10 percent of maximum allowable working pressures over 60
				psi.
(g) If there is any doubt as
				to the capacity of the safety relief valve, an accumulation test shall be run.
				(See ASME Code, Section VI, Recommended Rules for Care and Operation of Heating
				Boilers.)
(h) No valve of any
				description shall be placed between the safety relief valve and the boiler, nor
				on the discharge pipe between the safety relief valve and the atmosphere. The
				discharge pipe shall be at least full size and fitted with an open drain to
				prevent water lodging in the upper part of the safety relief valve or in the
				discharge pipe. When an elbow is placed on the safety relief valve discharge
				pipe, it shall be located close to the safety relief valve outlet or the
				discharge pipe shall be securely anchored and supported. All safety relief
				valve discharges shall be so located or piped as not to endanger persons
				working in the area.