Texas Administrative Code › Title 16 - ECONOMIC REGULATION › Part 4 - TEXAS DEPARTMENT OF LICENSING AND REGULATION › Chapter 65 - BOILERS › Subchapter R - TECHNICAL REQUIREMENTS › Section 65.607 - Power Boilers, Excluding Unfired Steam Boilers and Process Steam Generators

Current through Reg. 49, No. 28; July 12, 2024
(a) Safety
				  valves and pressure relief valves.
(1) The
				  use of weighted-lever safety valves, or safety valves having either the seat or
				  disk of cast iron, is prohibited.
(2) Each boiler shall have at least one
				  safety valve and, if it has more than 500 square feet (47 square meters) of
				  bare tube water heating surface or has electric power input more than 1,100
				  kilowatts, it shall have two or more safety valves. These valves shall be "V"
				  stamped per ASME Code.
(3) Safety
				  valves or pressure relief valves shall be connected so as to stand in the
				  upright position, with spindle vertical. The opening or connection between the
				  boiler and the safety valve or pressure relief valve shall have at least the
				  area of the valve inlet.
(4) The
				  valve or valves shall be connected to the boiler, independent of any other
				  steam connection, and attached as close as practicable to the boiler without
				  unnecessary intervening pipe or fittings.
(5) Except for changeover valves as defined
				  in §65.2(14), other valve(s) shall not be placed:
(A) between the required safety valve or
				  pressure relief valve or valves and the boiler; or
(B) in the discharge pipe between the safety
				  valve or pressure relief valve or valves and the
				  atmosphere.
(6) When a
				  discharge pipe is used, it shall be:
(A) at
				  least full size of the safety valve discharge; and
(B) fitted with an open drain to prevent
				  water lodging in the upper part of the safety valve or discharge
				  pipe.
(7) When an elbow
				  is placed on a safety valve discharge pipe:
(A) it shall be located close to the safety
				  valve outlet; and
(B) the discharge
				  pipe shall be securely anchored and supported.
(8) In the event multiple safety valves
				  discharge into a common pipe, the discharge pipe shall be sized in accordance
				  with ASME Code, Section I, PG-71.
(9) All safety valve or pressure relief valve
				  discharges shall be located or piped to a safe point of discharge, clear from
				  walkways or platforms.
(10) If a
				  muffler is used on a pressure relief valve, it shall have sufficient area to
				  prevent back pressure from interfering with the proper operation and discharge
				  capacity of the valve. Mufflers shall not be used on High-Temperature Water
				  Boilers.
(11) The safety valve
				  capacity of each boiler must allow the safety valve or valves to discharge all
				  the steam that can be generated by the boiler without allowing the pressure to
				  rise more than 6.0% above the highest pressure to which any valve is set, and
				  to no more than 6.0% above the MAWP. For forced-flow steam generators with no
				  fixed steam and waterline, power-actuated relieving valves may be used in
				  accordance with ASME Code, Section I, PG-67.
(12) One or more safety valves on every drum
				  type boiler shall be set at or below the MAWP. The remaining valve (s) may be
				  set within a range of 3.0% above the MAWP, but the range of setting of all the
				  drum mounted pressure relief valves on a boiler shall not exceed 10% of the
				  highest pressure to which any valve is set.
(13) 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 overpressure, considering the maximum
				  generating capacity of all boilers.
(14) In those cases where the boiler is
				  supplied with feedwater directly from water mains without the use of feeding
				  apparatus (not to include return traps), no safety valve shall be set at a
				  pressure higher than 94% of the lowest pressure obtained in the supply main
				  feeding the boilers.