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 executive director, through the Board of Boiler Rules, to fix reasonable standards for the safe construction, installation, inspection and repair of boilers and pressure piping. This administrative regulation sets forth requirements for heating boilers which supplement the basic requirements for all vessels set forth in 815 KAR 15:025 and 815 KAR 15:026. Many of the provisions have been in effect for some time under the administrative regulation which preceded this one. This amendment is necessary to codify additional safety measure applicable only to heating boilers; to comply with the requirements of KRS Chapter 13A that the administrative regulation be separated and deal with one (1) topic; and also to allow mechanical couplings to be used where appropriate.

 

      Section 1. New Installations. (1) All hot water supply, hot water and steam heating boilers, except reinstalled boilers and those approved under the "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 incorporated in 815 KAR 15:025, Section 1(1). All boilers and pressure vessels shall comply with other applicable provisions of 815 KAR Chapter 15 of the Kentucky administrative regulations.

      (2) Safety valve requirements for steam boilers.

      (a) 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. 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 maximum allowable working pressure of the boiler. 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. For iron and steel bodied valves exceeding two (2) inch pipe size, the drain hole, or holes, shall be tapped not less than three-eighths (3/8) inch pipe size. For valves two (2) inch pipe size or less, the drain hole shall not be less than one-fourth (1/4) inch in diameter.

      (b) Safety valves for a steam boiler shall not be smaller than one-half (1/2) inch. Safety valves 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 valve, or valves, shall be governed by the capacity-marking on the boiler.

      (d) 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 1000, 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 Table "A." In many cases, a greater relieving capacity of valves will have to be provided than the minimum specified by the Table. In every case, the requirements of paragraph (e) of this subsection shall be met.

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

      1. When a boiler is fired only by a gas having a heat valve not in excess of 200 BTU per cubic foot, the minimum safety valve or safety relief valve relieving capacity may be based on the values given for hand fired boilers.

      2. 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 kilowatt input.

      3. For heating surface determination, see ASME Code for Heating Boilers, paragraph HG403.

      (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 when 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 additional valves are required, they may be installed on the outlet piping, if there is no intervening valve.

      (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 of the boiler.

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

      (c) Safety relief valves officially rated as to capacity shall have pop action when tested by steam.

      (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 up to and including exceeding sixty (60) psi and five (5) percent for those having a maximum allowable working pressure 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) Materials which are likely to fail due to deterioration or vulcanization when subjected to saturated steam temperature corresponding to capacity test pressure shall not be used for any part.

      (f) Safety relief valves shall not be smaller than three-fourths (3/4) inch, nor larger than four and one-half (4 1/2) inches, standard pipe size, except that boilers 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; the inlet opening shall have an inside diameter approximately equal to, or greater than, the seat diameter; and the minimum opening through any part of the valve shall not be less than one-fourth (1/4) inch diameter, or its equivalent area.

      (g) 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 1000, or shall be determined on the basis of pounds of steam generated per hour, per square foot of boiler heating surface, as given in Table A. In many cases a greater relieving capacity of valves will have to be provided than the minimum specified by the Table. In every case, the requirements of paragraph (i) of this subsection shall be met.

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

      (i) Safety relief valve capacity for each boiler with a single safety relief valve shall be such that, with the fuel burning equipment installed and operated at maximum capacity, the pressure cannot rise more than ten (10) percent above the maximum allowable working pressure when more than one (1) safety relief valve is used, 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 Boilers. (1) Design limits. If mechanical pipe couplings are used, the pipe, fittings, couplings and gaskets shall have design ratings by the manufacturer which 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.

      (b) Mechanical pipe couplings tested and listed by a nationally recognized testing laboratory may then be used in lieu of flanged, threaded or welded joints within the complete pressure piping system of boilers in which the operating temperatures shall not exceed 200 degrees Fahrenheit and operating pressures shall not exceed 100 psig.

      (c) All mechanical pipe couplings shall be fabricated and installed with strict adherence to manufacturers written procedures and using only factory approved tooling.

      (d) Mechanical couplings shall not be installed unless the temperature controls on the boiler shall be permanently set to prevent operation in excess of 200 degrees Fahrenheit.

      (3) Tests. The mechanical coupling shall be subjected to the same hydrostatic pressures as are applied to test the strength of the boiler (i.e., 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 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 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 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 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 shall be calculated in accordance with Section IV of the ASME Boiler and Pressure Vessel Code.

      (4) Noncode cast iron boilers.

      (a) The maximum working pressure 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 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 repairs are necessary which affect the working pressure or safety of a boiler, it 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 that is stamped on the boiler with the exception that cast iron steam boilers shall be subjected to a hydrostatic test of not less than forty-five (45) psig.

      (b) In making hydrostatic pressure tests, the pressure shall be controlled to prevent the required test pressure from being be 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, 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 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. 11-6-80; Am. 20 Ky.R. 2735; 2985; eff. 5-18-94; TAm eff. 8-9-2007.)