1. (1) The flanges of all valves and pipe fittings of cast iron or steel shall conform to the American National Standards accepted by ASME.

   Note:

   Flange bolts or bolt studs shall conform to a standard accepted by ASME and the bolts or bolt studs shall extend completely through the nut. (Where the word “fittings” is used, it is understood that pipe fittings are meant and it does not include, other types.)

2. (2) All valves and fittings shall be marked as required by ASME.
3. (3) Rolled or forged flanges may be in accordance with the requirements of ASME.
4. (4) Valves and other boiler appurtenances, such as water columns, may have fusion-welded joints provided the welding procedure and welding operator are qualified under the requirements of ASME except that no stress-relieving, radiographic examination, or inspection of the joint is required. The manufacturer shall furnish, if requested, a statement certifying that these requirements have been met.

5. (b) The minimum pressure and temperature rating for all valves and fittings in steam, feedwater, blowoff, and miscellaneous piping shall be equal to the pressure and temperature specified by ASME for the connected piping on the side that has the higher pressure, except that in no case shall the pressure be less than 100 psi, and for pressures not exceeding 100 psi in feedwater and blowoff service, the valves and fittings shall be equal at least to the requirements of the American National Standards for class 125 cast iron or class 150 steel accepted by ASME.

   1. (1) All valves and fittings on all feedwater piping from the boiler up to and including the first stop valve and the check valve shall be equal at least to the requirements of any Standard accepted by ASME for a pressure exceeding the maximum allowable working pressure of the boiler by either 25 percent or 225 psi, whichever is the lesser.
   2. (2) All valves and fittings for feedwater piping between the required check valve and the globe or regulating valve, when required by ASME and including any by-pass piping up to and including the shutoff valves in the by pass, shall be equal at least to the requirements of any Standard accepted by ASME for a pressure rating equal to the expected operating pressure required to feed the boiler.

   3. (3) Valves and fittings made of any material permitted by this Part for pressure ratings of 125 pounds or more and marked as required may be used for feed line and blowoff service up to 80 percent of the rated pressure, except where certain materials are specified, and in no case shall they be used for temperatures exceeding that permitted by ASME.

      (d)

   4. (1) In all cases the scheduled working pressure (primary service pressure rating) for American National Standard steel fittings or valves accepted by ASME may be used for maximum saturated steam pressures (and for feed and blowoff services at pressures not to exceed the adjusted maximum allowable working pressure) as given in Table P-15, provided that all pressure retaining parts of the valves are suitable for the pressure at which they are to be used.
   5. (2) Valves and fittings of steel construction otherwise complying with the requirements of ASME, but having butt welding ends, may be rated at the pressure stated in Table P-15, provided also that all parts of the valves are suitable for the pressure at which they are used.
   6. (3) When the service requirements exceed the permissible values given in Table P-15, the requirement of the Code will be met if the bolting material, flange, and/or body thicknesses are increased so that the deflection limits are no greater and the factor of safety is at least that of the nearest pressure rating class in Table P-15.

   (c)

6. (e) Screwed fittings of cast iron or malleable iron conforming to the requirements of the Standards for 125, 150, 250, and 300 pounds pressure accepted by ASME may be used except where otherwise specifically prohibited. They shall not be used for temperatures over 450° Fahrenheit.
7. (f) Cast- or forged-steel screwed fittings or valves that are at least equal to the strength requirements of ASME which would otherwise be required may be used in all cases except where flanged fittings are specifically required.

8. (g) Brass or bronze screwed or flanged-type fittings or valves may be used provided they are least equal to the strength requirements of ASME for cast-iron fittings which would otherwise be required. The materials shall comply with ASME specifications SB-61 and SB-62 with maximum temperatures allowed of 550° Fahrenheit for SB-61 and 406° Fahrenheit for SB-62. Brass or bronze shall not be used where steel or other material is specifically required. Screwed type fittings shall not be used where flange types are specified.

   Table P-15

   MAXIMUM ALLOWABLE WORKING PRESSURE (MAWP) FOR THE USE OF ANSI B16.5-1981 STEEL PIPE FLANGES AND FLANGED FITTINGS AND ANSI B16.34-1981 STEEL VALVES, FLANGED AND BUTT WELDING END (STANDARD CLASS)

   Maximum Allowable Working Pressure (MAWP), psiq, Except as Noted
   Steam Service at Saturation Boiler Feed and Blowoff Line
   ANSI B16.5-1981 and	Temperature	Service
   B16.34-1981
   150	205	170
   300	605	490
   400	785	640
   600	1135	935
   900	1635	1430
   1500	2675	2455
   2500	3206 psi	3206 psi

   Notes:

9. (1) Adjusted pressure ratings for Steel Pipe Flanges and Flanged Fitting, for steam service at saturation temperature corresponding to the pressure, derived from Tables 1A and 2, using material group 1.1 of ANSI B16.5-1981. Adjusted pressure ratings for Steel Valves (Standard Class) for steam service at saturation temperature corresponding to the pressure, derived from Tables 1 and 2-1.1A, using material group 1.1 of ANSI B16.34-1981. For other materials or design temperatures exceeding saturation temperature, see ANSI B16.5-1981 and ANSI B16.34-1981 for pressure-temperature limitations. The pressure listed is rounded to the nearest 5 psi.
10. (2) Pressures shown include the factor for boiler feed and blowoff line service, corrected for line design temperature, as required by ANSI/ASME B31.1. The pressure listed is rounded to the nearest 5 psi.
11. (3) Rating exceeds critical pressure of water.
12. (4) The pressure-temperature ratings provided herein apply to the flange and do not necessarily reflect the rating of the assembled flange joint. The pressure-temperature ratings provided apply to the gasketed and bolted flange joint only when the gasket and studs conform to the recommendations of ANSI B16.5-1981.

(a)