Texas Administrative Code › Title 16 - ECONOMIC REGULATION › Part 4 - TEXAS DEPARTMENT OF LICENSING AND REGULATION › Chapter 65 - BOILERS › Subchapter R - TECHNICAL REQUIREMENTS › Section 65.611 - Heating Boilers

Current through Reg. 49, No. 28; July 12, 2024
(a) Steam Heating
				  Boilers.
(1) Safety valves.
(A) Each steam boiler shall have one or more
				  safety valves, that are identified with applicable designator with the ASME
				  Certification Mark of the spring pop type, adjusted and sealed to discharge at
				  a pressure not to exceed 15 psig (103 kilopascals). Seals shall be attached in
				  a manner to prevent the valve from being taken apart without breaking the seal.
				  The safety valves shall be arranged so that they cannot be reset to relieve at
				  a higher pressure than the MAWP of the boiler. A body drain connection below
				  seat level shall be provided. For valves exceeding 2 1/2 inch nominal pipe size
				  (65 mm), the drain hole or holes shall be tapped not less than 3/8 inch nominal
				  pipe size (10 mm). For valves 2 1/2 inch nominal pipe size (65 mm) or less, the
				  drain hole shall not be less than 1/4 inch (6 mm) in diameter.
(B) Each safety valve 3/4 inch nominal pipe
				  size (20 mm) or over, used on a steam boiler, shall have a substantial lifting
				  device, which will positively lift the disk from its seat at least 1/16 inch
				  (1.6 mm), when there is no pressure on the boiler. The seats and disks shall be
				  of suitable material to resist corrosion.
(C) No safety valve for a steam boiler shall
				  be smaller than 1/2 inch nominal pipe size (15 mm). No safety valve shall be
				  larger than 4 1/2 inches nominal pipe size (15 mm). The inlet opening shall
				  have an inside diameter approximately equal to, or greater than, the seat
				  diameter.
(D) The minimum relieving
				  capacity of valve or valves shall be governed by the capacity marking on the
				  boiler.
(E) The minimum valve
				  capacity in pounds per hour shall be the greater of that determined by dividing
				  the maximum Btu output 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 the pounds of steam generated per hour, per square foot of boiler heating
				  surface as given in §
												RSA
				  65.615, Exhibit 7. For cast iron boilers, the
				  minimum valve capacity shall be determined by the maximum output method. In
				  every case, the safety valve capacity for each steam boiler shall be such that
				  with the fuel burning equipment installed, and operated at maximum capacity,
				  the pressure cannot rise more than 5psig (35 kilopascals) above the
				  MAWP.
(F) Safety valve piping. No
				  valve shall be placed between the safety valve and the boiler or on the
				  discharge pipe between the safety valve and the atmosphere. When a discharge
				  pipe is used, it shall be full size and fitted with an open drain to prevent
				  water from lodging in the upper part of the safety valve or pressure relief
				  valve or in the discharge pipe. When an elbow is placed on the safety valve
				  discharge pipe, it shall be located close to the valve outlet. The discharge
				  pipe shall be securely anchored and supported, independent of the valve. 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.
(G) Safety
				  valves and pressure relief valves shall be installed on the boiler with
				  spindles positioned vertically. The opening or connection between the boiler
				  and any safety valve or pressure relief valve shall have at least the area of
				  the valve inlet.