Subchapter B. REQUIREMENTS FOR BOILERS AND UNFIRED PRESSURE VESSELS
GENERAL REQUIREMENTS
Sec.
3a.21. Stamping.
3a.22. Other state stamps.
3a.23. Lap seam crack.
3a.24. Boiler controls.
3a.25. Pressure reducing stations.
3a.26. Safety devices.
3a.27. Different working pressures.
3a.28. Blowoff tanks.
3a.29. Discharge outlets.
3a.30. Electric boilers.
3a.31. Forced circulation boilers.
3a.32. Supports.
3a.33. Explosion doors.
3a.34. Ventilation for combustion equipment.
3a.35. Ladders and runways.
3a.36. Clearances.
3a.37. Special design.
3a.38. Commercial beverage dispensing systems.
3a.39. Manufactured parts.
INSTALLATIONS OF POWER BOILERS
3a.51. Compliance with the ASME Code for power boilers.
INSTALLATIONS OF LOW-PRESSURE HEATING BOILERS
3a.61. Compliance with the ASME Code for low-pressure boilers.
3a.62. Registration and installation.
INSTALLATIONS OF UNFIRED PRESSURE VESSELS
3a.71. Compliance with the ASME Code for installations of unfired pressure vessels.
REPAIRS AND ALTERATIONS
3a.81. Major repairs and alterations.
3a.82. Reconstruction and repair.
3a.83. Repairs by welding.
GENERAL REQUIREMENTS
§ 3a.21. Stamping.
(a) A boiler or unfired pressure vessel destined for use in this Commonwealth must be built to the applicable ASME code of construction or meet the requirements of section 7 of the act (35 P. S. § 1331.7).
(b) A boiler or unfired pressure vessel built to the ASME Code must be stamped with the appropriate ASME symbol, the manufacturer’s information in accordance with stamping requirements of the code of construction, and its National Board registration number. The stamping may be applied to a nameplate in accordance with the code of construction.
(c) National Board registration and stamping requirements do not apply to cast iron boilers, which are constructed under ASME Code provisions and do not require final inspection by a National Board inspector.
(d) A new boiler or unfired pressure vessel installed in this Commonwealth must be stamped with an identifying serial number consisting of the keystone symbol and figures, which may not be less than 5/16 inches in height and arranged as follows:
(e) A boiler or unfired pressure vessel that is not built to the ASME Code may be stamped with a Pennsylvania special number if it meets the requirements of section 7(b) of the act.
(f) The Department may accept a boiler or unfired pressure vessel with a registration number from another state for use in this Commonwealth if a National Board inspector inspected and approved the boiler or unfired pressure vessel during construction.
(g) Stamping required under this section must be exposed at all times and may not be concealed by paint or lagging.
Cross References
This section cited in 34 Pa. Code § 3a.162 (relating to portable boilers).
§ 3a.22. Other state stamps.
A boiler or unfired pressure vessel stamped with the ASME symbol and another state stamp may be installed and operated if a National Board inspector witnessed its construction and the shop data report is provided to the Department with a completed Department-provided intent to install form under § 3a.98 (relating to plan approval).
§ 3a.23. Lap seam crack.
The shell or drum of a boiler or unfired pressure vessel containing a lap seam crack along a longitudinal riveted joint shall be immediately taken out of service. Repairs may not be made without Department approval.
§ 3a.24. Boiler controls.
(a) The installation of boiler controls performed after February 4, 2006, must comply with ASME CSD 1 and NFPA 85.
(b) The maintenance and inspection of boilers must comply with ANSI/NB 23.
§ 3a.25. Pressure reducing stations.
(a) The installation of pressure reducing stations must comply with ASME B 31.1.
(b) Hand-controlled bypasses around reducing valves may be used if the bypass has no greater capacity than the reducing valve. Hand controlled bypasses may be used around reducing valves at greater capacity than the reducing valve if the system or unfired pressure vessel has adequate relief or safety valve protection, or meets the requirements of the high pressure system.
(c) A pressure gauge must be installed on the low-pressure side of a reducing station.
§ 3a.26. Safety devices.
(a) A boiler or unfired pressure vessel must be protected by safety relief devices, and indicating and controlling devices sufficient to insure its safe operation which meet all of the following requirements:
(1) The devices must be constructed, located, installed and maintained to prevent the safety devices from becoming inoperative.
(2) The devices must have sufficient relieving capacity to prevent a rise of pressure in the boiler or unfired pressure vessel of more than 10% above the maximum allowable working pressure, taking into account the effect of static head.
(3) The discharge from safety devices must be carried to a safe place away from the boiler or unfired pressure vessel.
(b) Safety valves for other than noxious liquids or toxic vapors must be direct spring-loaded type valves, designed with substantial lifting devices so that the disk can be lifted from its seat by the spindle of at least 1/8 the diameter of the valve if the pressure of the vessel is at 75% of the safety valve setting.
(c) Each safety valve must have clear manufacturer markings that are 1/4-inch or larger. The markings must contain all of the following information stamped on the valve, cast on the valve body, or cast on a plate securely fastened to the valve:
(1) The name or identifying trademark of the manufacturer.
(2) The pipe size, in inches, of the valve inlet.
(3) The pressure, in pounds, at which the valve is set to open.
(4) The blow down, in pounds.
(d) If the valve inlet is not threaded, the initial diameter of the inlet may not be less than the inside diameter of a standard pipe of the same size.
(e) The difference between the opening and closing pressures of a safety valve must be a minimum of 20%.
(f) Existing safety valves bearing ASME stamping different from the requirements in subsection (c) are permitted if the safety valves have equivalent construction and relieving capacity.
(g) Safety valves with a cast iron seat or a disk may not be used.
(h) If more than one safety valve is used, the discharge capacity must be the combined capacity of all safety valves.
(i) A boiler or unfired pressure vessel in which pressure is not generated and is derived from an outside source must have a safety device connected to the vessel or system which it protects in a manner to prevent a rise in pressure beyond the maximum allowable pressure.
(j) A boiler or unfired pressure vessel in which pressure may be generated must have a safety device or devices connected directly to the vessel and comply with all of the following:
(1) When the contents of a vessel may cause interference with the operation of the vessel or safety valve when the safety value is directly attached, the safety valve or valves may be connected in a manner to avoid the interference.
(2) An escape pipe may be used. The pipe must be full sized and fitted with an open drain to prevent liquid from lodging in the upper part of the safety valve. A valve may not be placed on the escape pipe between the safety valve and the atmosphere.
(3) An elbow may be placed on an escape pipe if it is located close to the safety valve outlet or the escape pipe is securely anchored and supported. If two or more safety devices are placed on one connection, the connection must have a cross sectional area at least equal to the combined area of the safety devices’ inlets.
(k) Every safety valve which is exposed to temperatures of 32°F or less must have a drain of at least 3/8 inch in diameter at the lowest point where water can collect.
(l) A spring in a safety or relief valve in service for pressures 250 psi and less may not be reset for a pressure more than 10% above or 19% below the pressure at which the valve is marked. For pressures higher than 250 psi, the spring may not be reset for any pressure more than 5% above or 50% below the pressure at which the safety or relief valve is marked.
(m) Safety valves for compressed air tanks cannot be larger than 3-inch diameter. The valves must be proportioned for the maximum number of cubic feet of free air that may be applied per minute.
(n) A rupture disk may be used as a pressure safety device on boilers or unfired pressure vessels containing nontoxic gases, when it is designed to fail at not more than the design pressure of the vessel.
(o) Safety valves on systems using toxic gases must discharge in accordance with the ASME Code, Section VIII, Division 1, 2 or 3.
(p) A company or organization holding a Department-issued certificate of authorization to reset and reseal safety valves and relief valves or a current VR stamp is required to reset and reseal safety valves and relief valves.
(q) A company or organization holding a current VR stamp is required to repair safety valves and relief valves.
(r) A safety valve or relief valve may not be loaded to maintain a working pressure in excess of the maximum working pressure stated on the boiler or unfired pressure vessel’s certificate of operation.
(s) Additional or supplemental safety or relief valves installed on a boiler or unfired pressure vessel, may exceed maximum working pressure if the valves comply with the applicable code of construction or this chapter.
Cross References
This section cited in 34 Pa. Code § 3a.152 (relating to safety appliances).
§ 3a.27. Different working pressures.
(a) At least one safety valve on each boiler must be set at or below the maximum allowable working pressure. All other valves may be set within a range of 3% above the maximum allowable working pressure. The range of setting of all of the saturated steam valves on the boiler may not exceed 10% of the saturated steam valve set at the highest pressure.
(b) When a boiler system is comprised of boilers with different maximum allowable working pressures having minimum safety valve settings varying more than 6% and connected so that steam flows toward the lower pressure boiler, the boiler system must meet one of the following requirements:
(1) A check valve must be installed in the steam line to protect the lower pressure boilers.
(2) Additional safety valves on the low-pressure side of the boiler system must protect lower pressure boilers and meet the following requirements:
(i) The additional safety valve capacity must be based on the maximum amount of steam that can flow into the low-pressure system.
(ii) Additional safety valves must have at least one valve set at a pressure that is not greater than the lowest maximum allowable pressure.
(iii) Other valves must be set within a range of not more than 3% above the lowest allowable pressure.
§ 3a.28. Blowoff tanks.
(a) Blowoff piping from a power boiler or a miniature boiler may not discharge directly into a sewer. A blowoff tank will be used if conditions do not provide an adequate and safe open discharge.
(b) ASME Section VIII, Division l governs the construction of metal blowoff tanks.
(c) The cross sectional area of the outlet from blowoff tanks must be twice the area of the inlet. The outlet pipe must be located to drain the blowoff tank to within 8 inches of the bottom of the tank.
(d) A vent pipe comprised of at least four times the area of the inlet pipe must lead to the outer atmosphere.
(e) Vents must lead as directly as possible to the outer air and discharge in a safe location. There may be no valve or other obstructions such as water pockets between the tank and the discharge end of the vent pipe.
(f) Pipe connections between the boiler blowoff valves and the tank must be as direct as possible and conform to the ASME Code.
(g) A manhole or an access opening shall be installed for cleaning the tank.
(h) A blowoff tank that is not vented as required in this section must meet one of the following requirements:
(1) Constructed to withstand pressure equal to the pressure allowed on its attached boiler.
(2) Equipped with a safety valve or valves of sufficient capacity to prevent the pressure from exceeding the safe working pressure of the tank.
§ 3a.29. Discharge outlets.
Discharge of safety valves of a boiler generating in excess of 500 pounds of steam per hour must be piped to the outside atmosphere and to a safe point of discharge. Blowoff pipes and other outlets must be located to prevent injury to personnel.
§ 3a.30. Electric boilers.
Appliances required for electric boilers must be attached to the boilers in accordance with the following requirements:
(1) A cable shall be provided for grounding the boiler shell and shall be the same gauge as the incoming power line to the boiler. The cable must be permanently connected and grounded.
(2) A suitable screen or guard shall be placed around high-tension bushings with a sign containing a high voltage warning. The screen or guard shall be located to prevent a person from accidentally coming in contact with the high-tension circuit.
(3) The power circuit to the boiler must be open when safety valves are adjusted.
(4) The power line must be open when the boiler is under steam pressure and the operator is making a necessary adjustment.
(5) Safety or relief valves must have a relieving capacity of 3 1/2 pounds per hour for each kilowatt rating.
(6) Boiler shell grounding connectors shall be installed in accordance with the following:
(i) The NEC, Chapter 4, except that the cable gauge size must comply with paragraph (1).
(ii) A conductor will be permanently attached to the boiler shell by suitable lugs, pressure connectors, clamps, or other Department-approved means. Connectors that depend on solder to maintain connection may not be used.
§ 3a.31. Forced circulation boilers.
Forced circulation boilers and boilers with no fixed steam or waterline must conform to the ASME Code, section 1.
§ 3a.32. Supports.
(a) A boiler or unfired pressure vessel must be supported by masonry or structural supports sufficient to safely support the boiler or vessel and its contents.
(b) An air compressor vessel must be shock mounted.
§ 3a.33. Explosion doors.
Stoker coal fired boilers under positive pressure must be equipped with explosion doors to relieve furnace pressure. The explosion doors must be located in the setting wall within 7 feet of the firing floor or any platform, and must be provided with substantial deflectors to divert the blast away from personnel.
§ 3a.34. Ventilation for combustion equipment.
Adequate air to support combustion shall be provided. The recommendations of the manufacturer of the equipment shall be utilized.
§ 3a.35. Ladders and runways.
(a) Walkways, runways and platforms are required between and on top of boilers, which are more than 8-feet high from the operating floor to afford accessibility for the operation and servicing.
(b) Walkways, runways and platforms must meet the following requirements:
(1) Be constructed of metal.
(2) Be constructed of safety treads, standard grating, or similar material with a minimum clear width of 30 inches.
(3) Be constructed by bolts, welds or rivets.
(4) Be equipped with handrails that are 42-inches high with an intermediate rail and 6-inch toeboard.
(c) A stairway that is a means of access to the walkways, runways or platforms must not exceed an angle of 45°.
(d) A ladder that serves as a means of access to walkways, runways or platforms must be constructed:
(1) Of metal.
(2) So the rungs extend through the side members and are permanently secured to the side rails.
(3) So the front of the rungs have a distance of at least 30 inches from the nearest permanent object on the climbing side of the ladder.
(4) So the back of the rungs have a distance of at least 6 1/2 inches from the nearest permanent object.
(5) So there is a clear width of at least 15 inches from the centerline of the ladder on either side across the front of the ladder.
(e) A welder qualified under Standard Qualification Procedures of the American Welding Society is required for welding a walkway, runway, platform or ladder.
(f) A walkway, runway or platform exceeding 6 feet in length must have at least two means of exit access.
§ 3a.36. Clearances.
(a) The following clearances apply for boilers installed after January 1, 1960:
(1) The minimum clearance around each boiler must be 30 inches with at least 6 feet clearance from the floor to overhead obstructions.
(2) The minimum clearance around each unfired pressure vessel must be 18 inches. The minimum clearance in front of a manhole cover must be 30 inches.
(3) A clearance of at least 12 inches must be provided between the floor and lower head or the underside of the shell of an unfired pressure vessel. The clearance distance must be the measurement from a vessel appendage to the next object.
(b) The following requirements apply to a single installation or assembly of storage water heaters or instantaneous water heaters, which operate as a unit:
(1) The unit may be arranged with a minimum clearance of 6 inches between components if an 18-inch clearance shall be maintained around the assembly. The clearance in front of a manhole opening is a minimum of 30 inches.
(2) An assembly may not exceed 9 million BTU input.
(3) Casings must be readily removable for inspection purposes, if casings are provided.
(c) A new building containing multiple boiler installations must meet the following minimum overhead clearance requirements:
(1) Between the boiler platform and the ceiling: 7 feet.
(2) Between the top of the boiler proper and the ceiling for all installations: 3 1/2 feet.
(3) Between the highest point of any valve or fitting and the ceiling: 6 inches.
(d) Subsections (a) and (b) do not apply to pressure vessels of factory assembled package units that are governed by § 3a.111 (relating to field inspections) if there is adequate clearance for operation and inspection. Subsection (a) applies to the entire factory assembled unit.
(e) The minimum clearance around a wall-hung boiler must be 30 inches except for the wall mount side.
(f) The clearance between modules in a modular system may be reduced to the manufacturer’s recommendations if the entire modular boiler system meets the 30-inch clearance requirement of subsection (a)(1).
(g) This section does not apply to a miniature boiler if the boiler can be safely inspected as installed.
(h) Tripping hazards are not permitted.
Cross References
This section cited in 34 Pa. Code § 3a.98 (relating to plan approval); 34 Pa. Code § 3a.161 (relating to modular boilers); and 34 Pa. Code § 3a.166 (relating to miniature boilers and kitchen equipment).
§ 3a.37. Special design.
(a) The owner or user of a new boiler or unfired pressure vessel having unusual features of special design intended for installation and operation in this Commonwealth shall submit the following to the Department for approval:
(1) One copy of complete specifications.
(2) Drawings that show all details of the proposed construction and the method of computation used in determining the safe working pressure for each new boiler and unfired pressure vessel.
(b) A specially designed boiler or unfired pressure vessel may not be operated until the Department approves its design.
§ 3a.38. Commercial beverage dispensing systems.
(a) An unfired pressure vessel used in a commercial beverage dispensing system must have clearance of 18 inches for at least 50% of the vessel surface. The remaining vessel surface may have its clearance reduced to 1 inch.
(b) The Department will issue one certificate of operation and charge one fee under § 3a.2 (relating to fees) for all vessels used in a commercial dispensing system at a single business location at the same design maximum working pressure.
§ 3a.39. Manufactured parts.
Parts manufactured for boilers or unfired pressure vessels constructed to the ASME Code must be manufactured and stamped in accordance with the applicable section of the ASME Code. Data reports must be furnished in accordance with the applicable section of the ASME Code.
INSTALLATIONS OF POWER BOILERS
§ 3a.51. Compliance with the ASME Code for power boilers.
Installations of power boilers must comply with the provisions of section 1 of the ASME Code, ASME/CSD1 and NFPA 85.
INSTALLATIONS OF LOW-PRESSURE HEATING BOILERS
§ 3a.61. Compliance with the ASME Code for low-pressure boilers.
Installations of low-pressure heating boilers must comply with section IV of the ASME Code and ASME/CSD 1.
§ 3a.62. Registration and installation.
(a) An installer of low-pressure steel heating boilers shall provide a copy of the manufacturer’s data report to the inspector when the boiler is installed.
(b) A cast iron boiler shall be hydrostatically tested when it is installed. The inspector may accept the factory hydrostatic test.
(c) An installer of low-pressure cast iron boilers shall submit a ‘‘Cast Iron Installation Report’’ to the Department on a Department-provided form. The Cast Iron Installation Report contains manufacturer, testing and installation information.
INSTALLATIONS OF UNFIRED PRESSURE VESSELS
§ 3a.71. Compliance with the ASME Code for installations of unfired pressure vessels.
Installations of unfired pressure vessels must comply with sections VIII or X of the ASME Code.
REPAIRS AND ALTERATIONS
§ 3a.81. Major repairs and alterations.
(a) An owner or user of a boiler or unfired pressure vessel shall consult with an inspector on a repair that affects the working pressure or safety of a boiler or unfired pressure vessel.
(b) A repair to a boiler or unfired pressure vessel must comply with the applicable provisions of the ASME Code or ANSI/NB 23. A manufacturer or repair company may not perform welded repairs and tube replacements without holding an ‘‘R’’ Stamp.
(c) An owner or user of a boiler or unfired pressure vessel shall consult with the inspector responsible for completing the report of welded repair before commencement of work or repairs that alter the original design of a boiler or unfired pressure vessel. A manufacturer or repair company holding an ANSI/NB 23 ‘‘R’’ stamp may perform alterations to other vessels.
(d) Welds shall be documented on a Department-issued ‘‘Record of Welded Repair Form’’ or a R-1 form. Hydrostatic testing of welded repairs may be conducted at the inspector’s discretion in accordance with ANSI/NB23.
(e) An owner or user of a boiler or unfired pressure vessel that requires an inspection under this chapter shall immediately notify the Department when a defect affecting the safety of the boiler or unfired pressure vessel is discovered.
§ 3a.82. Reconstruction and repair.
Workmanship, materials, fittings and attachments used in the reconstruction or repair of a boiler or unfired pressure vessel must meet ANSI/NB 23. The boiler or unfired pressure vessel may not become operational until an inspector approves all repairs.
§ 3a.83. Repairs by welding.
(a) Welding repairs must comply with section IX of the ASME Code.
(b) A repair to a boiler or unfired pressure vessel that involves welding may be made if an inspector approves the repair and signs a record of welded repairs.
(c) Repairs by fusion welding must comply with ANSI/NB 23.
(d) Repairs listed as routine in ANSI/NB 23 may be preapproved by an inspector.
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