WORK INSTRUCTION NO: - Q80/WI/50P2//01

CONTROLS OF KNPC 50P2Following are some of the controls / additional requirements of KNPC 50 P2 SPECIFICATIONS for valves.

SCOPEThis specification provides additional requirements for valves in addition to the applicable international codes/ standards.

SUBSTITUTION 1) Forged material is acceptable in place of specified cast material but not vice/versa. 2) In place of C-0.5Mo, 1.125Cr-0.5Mo is acceptable. 3) In place of SS 304, SS 316 material is acceptable. 4) In place of SS 321, SS347 material is acceptable. Above substitutions do not require written approval from KNPC but should be clearly indicated in the quotation.

MATERIALSFor austenitic stainless steel like 304,316,321 and 347 minimum carbon content shall be 0.04%.For austenitic stainless steel forging material ASTM A 182 F 347 no cold and hot working is allowed after solution annealing for optimum resistance to stress corrosion cracking.

HARDNESS CONTROL1) For sour service valve shall comply the all requirements except hardness as per NACE MR 0175 and the same should be certified by the manufacturer.For sour service hardness limit should be as below for 50 P2 and not as per NACE MR 0175.

1) For P 1 group (WCB, WCC, LCB, LCC,) hardness is limited to 200 BHN as against 237 BHN of NACE MR 0175.

2) For alloy steel of group P 3, P 4 and P 5 material hardness is limited to 215 BHN.3) For ASTM A 182 F5a material hardness is limited to 217 BHN and higher values of ASTM

A 182 are not acceptable as per this specification. 4) For all austenitic stainless steel of group P 8 material hardness is limited to 237 BHN. 5) For non NACE valves hardness values should be as per ASTM standard.

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WORK INSTRUCTION NO: - Q80/WI/50P2//01

TRIM1) Trim no.8 is acceptable in place of trim no.1.2) Stellite used shall be ST-6.3) Minimum 50 BHN differential hardness should maintain between disc and seat and between

stem and backseat. If 50 BHN differential hardness is not possible due to metallurgy one of the mating seats should be stellited to provide differential hardness so as to prevent galling.

4) Ductile iron valves with API trim 9 shall have solid Monel seat rings, wedges or Discs.

DESIGN1) All valves shall comply with the reference standard /codes, standard and specific requirements of this standard and purchase order requirements.2) The design of valves for special materials like inconel alloys, Hastalloy shall be approved from KNPC.3) For all ring joint flanges flat bottom groove and for all ring joint octagonal ring gasket shall provide.4) Flange face finish shall be provided as per P.O. specifications but maximum up to 500 AARH.5)Wedge/disc and seat ring valves 1.1/2 “ size and below shall be solid material of the trim specified e.g SS 410 for 13%cr and SS 316 for trim 10,12,16 etc.6) All valve packing shall be non-asbestos.7) Auxiliary connections shall be provide as per the purchase order specifications and locations as per ASME B16.34.But when auxiliary connections specified with welded nipples then only schedule 160 or XX- strong pipe shall be used and shall be socket welded to the body.8) Soft seated ball /Plug valves shall be fire type tested as per API 607 and shall provide with secondary metal seat as back up to primary soft seat. 9) Soft seated ball valves and plug valves with socket weld and butt weld end shall provided with 6” long pipe when specified. Pipe material and schedule shall be as per P.O specifications. 10) All gear operators shall have dust tight and weatherproof gear housings with O- rings. The gear lubricant shall be suitable for a metal temperature 180 degF (82 deg.C) of direct solar radiation.11) Flanged and Butt weld end bolted bonnet Globe and Check valves in carbon and alloy steel are identified as API 600 Modify. These valves shall conform to API 600 for wall thickness, bonnet construction, bolting, inspection, testing and other applicable standards.12) The Stainless steel valves in high temperature service are specified to conform API 600; wall thickness should as per API 600 and balance as per ASME B 16.34. 13) For Hydrogen rich service back seat shall be stellited for valve size 2” and above.14) Cast steel valves are not acceptable in place of ductile iron valves.16)Globe/Check valves 1.1/2”and below are specified as API 602 Modify and these valves shall comply API 602 for wall thickness, bonnet design, stem diameter ,bolting ,inspection and testing. 17) When 11/2” and below size heavy duty valves specified in P.O specifications then wall thickness should be excess of API 602 and shall be equal to minimum wall thickness of double extra pipe as below

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WORK INSTRUCTION NO: - Q80/WI/50P2//01

18) For heavy duty valves, 800 class valves may be provided in place of 600 class but with wall thickness equal to double extra strong pipe.19) Pressure sealed bonnet valves 2” and larger in carbon steel, alloy steel and high temperature stainless steel are identified as API 600 in P.O. specifications. Wall thickness for these valves should be as per API 600 and balance valve features should be as per ASME B 16.34.Pressure sealed valves 2” and larger in stainless steel shall conform to ASME B 16.34 when specified in P.O specification.Following are the minimum requirements of pressure sealed valves.a) Seats, wedge/discs and back seat shall be stellited.b) Corrosion resistance overlay on gasket seating area in the body of equal to or better than

valve trim specified.c) Impact or hammer blow hand wheels with ball bearings and grease fittings for size 4” and

above. 20)Pressured sealed bonnet valves 1.1/2” and smaller are identified as heavy duty valves and wall thickness of these valves shall be equal to wall thickness of double extra strong pipe and basic design to ASME B 16.34.Following are the minimum trim requirementsa) Seats, wedge/discs and back seat shall be stellited.b) Stellite ST-6 shall be deposited on gasket seating area in the body.c) Bonnet gasket shall be soft and as per manufacturer’s standard but without chrome plated

and with better corrosion resistance than body. Alternate to pressure sealed valves welded bonnet valves can be quoted subjected to KNPC approval.

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Size Min. wall thickness ½” 0.294” (7.47 mm) ¾” 0.308” (7.82 mm) 1” 0.358” (9.09 mm) 1.1/2” 0.400” (10.16 mm)

WORK INSTRUCTION NO: - Q80/WI/50P2//01

INSPECTION AND TESTING

1) Valves shall be tested as per API 598. 2) Valves specified as block and bleed shall be of Zero leakage. 3) Water used for carbon and alloy steel shall have chlorine content less than 3000 ppm and deminerlised water less than 50 ppm shall be used for stainless steel valves. 4) Water testing report shall be also submitted along with the valve certification documents.

NON DESTRUCTIVE TESTING

All valves shall be radiograhically examined and Magnetic particle/Liquid penetrent tested as per table I & II attached.

All butt welded nipples to valve shall be 100% radigraphically tested.All socket welded pipes to the valves shall be MPT/LPT examined.Acceptance criteria for all NDE are as per ASME B 16.34.

WELDING

No repair welding shall be carried out without KNPC approval.Cast iron and duct iron valves are not permitted for repair welding.

PAINTING

Unless otherwise specified carbon and alloy steel valves shall painted as per manufacturer’s standard procedure.

IDENTIFICATION / TAGGING

Valves for special services like Hydrogen rich/ NACE MR 0175 shall be identified with suitable tags in addition to valve name plate.For Butt weld ends valves internal bore diameters shall be indicated on the tag plate.

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