815 KAR 15:051. Heating boiler supplemental requirements - steam heating, hot water heating, and hot water supply boilers.

 

      RELATES TO: KRS 236.030

      STATUTORY AUTHORITY: KRS 236.030

      NECESSITY, FUNCTION, AND CONFORMITY: KRS 236.030 authorizes the commissioner, through the Board of Boiler and Pressure Vessel Rules, to fix reasonable standards for the safe construction, installation, inspection, and repair of boilers and pressure piping. This administrative regulation establishes requirements for heating boilers which supplement the basic requirements for all vessels set forth in 815 KAR 15:025 and 815 KAR 15:026..

 

      Section 1. New Installations. (1) All hot water supply, hot water, and steam heating boilers, except reinstalled boilers and those approved under the "state special design" provisions of 815 KAR 15:025, Section 5, shall be constructed, stamped, inspected, and installed in conformity with the ASME Boiler and Pressure Vessel Code Section IV, as established by KRS 236.040(2). A boiler or pressure vessel shall comply with all other applicable provisions of 815 KAR Chapter 15.

      (2) Safety valve requirements for steam boilers.

      (a)1. Each steam boiler shall have one (1) or more officially rated safety valve of the spring-pop type adjusted and sealed to discharge at a pressure not to exceed fifteen (15) psi.

      2. A seal shall be attached in a manner to prevent the valve from being taken apart without breaking the seal.

      3. A safety valve shall be arranged so that the valve cannot be reset to relieve at a higher pressure than the maximum allowable working pressure (MAWP) of the boiler.

      4. A body drain connection below seat level shall be provided by the manufacturer, and this drain shall not be plugged during or after field installation.

      5. For an iron or steel bodied valve exceeding two (2) inch pipe size, the drain hole, or holes, shall be tapped not less than three-eighths (3/8) inch pipe size.

      6. For a valve two (2) inch pipe size or less, the drain hole shall not be less than one-fourth (1/4) inch in diameter.

      (b) A safety valve for a steam boiler shall not be smaller than one-half (1/2) inch. A safety valve shall not be larger than four and one-half (4 1/2) inches. The inlet opening shall have an inside diameter equal to, or greater than, the seat diameter.

      (c) The minimum relieving capacity of a valve, or valves, shall be governed by the capacity-marking on the boiler.

      (d)1. The minimum valve capacity in pounds per hour shall be the greater value as determined by the methods established in this paragraph.

      a. The maximum BTU output obtained at the boiler nozzle shall be divided by 1,000.

      b. The pounds of steam generated per hour per square foot of boiler heating surface shall be calculated in accordance with Table A.

TABLE A

MINIMUM POUNDS OF STEAM PER HOUR PER

SQUARE FOOT OF HEATING SURFACE

 

Fire Tube

Boilers

Water Tube

Boilers

Boiler Heating Surface

 

Hand fired

5

6

Stoker fired

7

8

Oil, gas or pulverized fuel fired

8

10

Waterwall Heating Surfaces

 

Hand fired

8

8

Stoker fired

10

12

Oil, gas or pulverized fuel fired

14

16

      2. If a boiler is fired only by a gas having a heat value not exceeding 200 BTU per cubic foot, the minimum safety valve or safety relief valve relieving capacity shall be based on the values given for hand fired boilers.

      3. The minimum safety valve or safety relief valve relieving capacity for electric boilers shall be three and one-half (3 1/2) pounds per hour per kilowatt input.

      4. Heating surface determination shall be calculated in accordance with ASME Code for Heating Boilers, paragraph HG-403.

      (e) The safety valve capacity for each steam boiler shall be sufficient to prevent the pressure from rising more than five (5) psi above the maximum allowable working pressure (MAWP) if the fuel-burning equipment is installed and operated at maximum capacity.

      (f) If 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 be in accordance with paragraph (e) of this subsection. If an additional valve is required, the valve may be installed on the outlet piping if there is no intervening valve.

      (g) In all cases, the pressure relieving capacity of the safety valve or safety relief valve shall equal or exceed the maximum possible output capacity of the boiler.

      (h) Materials that are likely to fail due to deterioration or vulcanization if subjected to saturated steam temperature corresponding to capacity test pressure shall not be used.

      (3) Safety relief valve requirements for hot water heating boilers and hot water supply boilers.

      (a) Each hot water heating boiler shall have at least one (1) officially rated pressure relief valve set to relieve at or below the maximum allowable working pressure (MAWP) of the boiler.

      (b) Each hot water supply boiler shall have at least one (1) officially rated pressure and temperature safety relief valve of the automatic-reseating type, set to relieve at or below the maximum allowable pressure of the boiler.

      (c) A safety relief valve officially rated as to capacity shall have pop opening action.

      (d) If more than one (1) safety relief valve is used on either hot water heating or hot water supply boilers, the additional valve or valves shall be officially rated and may be set within a range not to exceed six (6) psi above the maximum allowable working pressure (MAWP) up to and including exceeding sixty (60) psi and five (5) percent for those having a maximum allowable working pressure (MAWP) exceeding sixty (60) psi, shall be spring loaded and shall be arranged to prevent resetting at a higher pressure than the maximum permitted in this subsection.

      (e)1. Except as provided in subparagraph 2. of this paragraph, a safety relief valve shall not be smaller than three-fourths (3/4) inch, nor larger than four and one-half (4 1/2) inches, standard pipe size.

      2. A boiler having a heat input not greater than 15,000 BTU per hour may be equipped with a rated safety relief valve of one-half (1/2) inch, standard pipe size, if:

      a. The inlet opening shall have an inside diameter approximately equal to, or greater than, the seat diameter; and

      b. The minimum opening through any part of the valve shall not be less than one-fourth (1/4) inch diameter, or its equivalent area.

      (f) The minimum relieving capacity of the safety relief valve shall be equal to or exceed the maximum BTU output of the boiler.

      (g) If 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 paragraph (h) of this subsection. The additional valves required may be installed on the outlet piping if there is no intervening valve.

      (h) Safety relief valve capacity for each boiler with a single safety relief valve shall be sufficient to ensure that, with the fuel burning equipment installed and operated at maximum capacity, the pressure shall not rise more than ten (10) percent above the maximum allowable working pressure (MAWP) if more than one (1) safety relief valve is used, and the over pressure shall be limited to ten (10) percent above the set pressure of the highest set valve allowed by subsection (2) of this section.

 

      Section 2. Mechanical Couplings for Heating and Hot Water Supply Boilers. (1) Design limits. If mechanical pipe couplings are used, the pipe, fittings, couplings, and gaskets shall have design ratings by the manufacturer that meet or exceed the operating control settings of the boiler itself and shall comply with this section.

      (2) Materials used and location.

      (a) Piping materials listed in the ASME Code, Section IV, shall be used up to the first stop valve on supply and return piping. Mechanical pipe couplings shall not be used prior to the first stop valve.

      (b) Mechanical pipe couplings tested and listed by a nationally recognized testing laboratory shall be permitted in lieu of flanged, threaded, or welded joints within the complete pressure piping system of boilers in which the operating temperature and operating pressure shall not exceed the manufacturer’s designed pressure/temperature rating.

      (c) All mechanical pipe couplings shall be fabricated and installed in accordance with the manufacturer’s written procedures and using only factory approved tooling.

      (d) A mechanical coupling shall not be installed unless the temperature controls on the boiler are permanently set to prevent operation in excess of the manufacturer’s designed temperature rating.

      (3) Tests. The mechanical coupling shall be subjected to the same hydrostatic pressures as are applied to test the strength of the boiler (for example, up to one and one-half (1 1/2) times the maximum allowable pressure of the boiler).

      (4) Certification by the contractor. The contractor shall document to the boiler inspector, special inspector, or owner’s piping inspector that the mechanical joints conform to the design and were installed to comply with the manufacturer procedures, utilizing the materials and equipment specified and that the temperature and pressure ranges comply with subsection (2)(b) of this section.

 

      Section 3. Existing Installations, Heating Boilers. (1) ASME Code boilers. The maximum allowable working pressure of a boiler built in accordance with the ASME Code shall not exceed the pressure indicated by the manufacturer's identification stamped or cast upon the boiler or upon a plate secured to it.

      (2) Noncode riveted boilers. The maximum allowable working pressure (MAWP) on the shell of a noncode riveted heating boiler shall be determined in accordance with 815 KAR 15:040, Section 2 (power boiler installations) except that the maximum allowable working pressure (MAWP) of a steam boiler shall not exceed fifteen (15) psi or a hot water boiler shall not exceed 160 psi at a temperature not to exceed 250 degrees Fahrenheit.

      (3) Noncode welded boilers. The maximum allowable working pressure (MAWP) of a noncode steel or wrought iron heating boiler of welded construction shall not exceed fifteen (15) psi. For other than steam service, the maximum allowable working pressure (MAWP) shall be calculated in accordance with Section IV of the ASME Boiler and Pressure Vessel Code, as established by KRS 236.040(2).

      (4) Noncode cast iron boilers.

      (a) The maximum allowable working pressure (MAWP) of a noncode boiler, composed principally of cast iron, shall not exceed fifteen (15) psi for steam service or thirty (30) psi for hot water service.

      (b) The maximum allowable working pressure (MAWP) of a noncode boiler having cast iron shell or heads and steel or wrought iron tubes shall not exceed fifteen (15) psi for steam service or thirty (30) psi for water service.

      (5) Hydrostatic tests.

      (a) If a repair is necessary that affects the working pressure or safety of a boiler, the boiler repair shall be subjected to a hydrostatic test of the greater of sixty (60) psig or one and one-half (1 1/2) times the maximum allowable working pressure (MAWP) that is stamped on the boiler.

      (b) In making a hydrostatic pressure test, the pressure shall be controlled to prevent the required test pressure from being exceeded by more than ten (10) psig.

      (c) Hydrostatic test water shall be at no less than ambient room temperature, but in no case less than seventy (70) degrees Fahrenheit for boilers and thirty (30) degrees Fahrenheit above the minimum design metal temperature for pressure vessels, nor high enough to allow the metal temperature to exceed 120 degrees Fahrenheit.

      (d) The safety valve or safety relief valve shall be removed or each valve disc shall be held to its seat by means of a testing clamp.

      (e) To test for tightness, the test pressure shall be equal to the relieving pressure of the safety valve having the lowest relief setting.

      (6) General. If the boiler inspector or special inspector finds that a steam heating boiler is unsafe for operation at the pressure previously approved, the pressure shall be reduced, proper repair made, or the boiler retired from service. (7 Ky.R. 386; eff. 11-6-1980; Am. 20 Ky.R. 2735; 2985; eff. 5-18-1994; TAm eff. 8-9-2007; 42 Ky.R. 1636; 2121; eff. 2-5-2016.)