Stainless Steel Pipe Fittings

Blind Flanges (BL Flanges) By

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Blind Flanges (BL Flanges) By

The Blind Flanges (BL Flanges) are used to close ends of piping systems. It is a kind of round plate with no center hold but with all the proper bolt holes. These Blind Flanges (BL Flanges) are available in various sizes and materials and is used to provide positive closer on the ends of pipes, valves or equipment nozzles. These flanges help in easy access to a line once it has been sealed. The blind flange is sometimes custom made or machined to accept a nominal sized pipe to which reduction is being made. This reduction can be a threaded reduction or welded reduction.

Blind flange draws :

Size: 1/2” to 60”, DN 12mm to DN 1500mm
Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
Facing: RF / RTJ

Cabon steel: A105, A350 LF2
Stainless steel: A182 F304/F304L/F316/F316L/F321
Alloy steel: F11, F12
Packing: plywood case and plywood pallet

  • ASME/ANSI B16.5 Class 150 BL
  • ASME/ANSI B16.5 Class 300 BL
  • ASME/ANSI B16.5 Class 600 BL
  • ASME/ANSI B16.5 Class 900 BL
  • ASME/ANSI B16.5 Class 1500 BL
  • ASME/ANSI B16.5 Class 2500 BL
  • ASME B16.47 Series A/MSS SP-44 Class 150 BL
  • ASME B16.47 Series A/MSS SP-44 Class 300 BL
  • ASME B16.47 Series A/MSS SP-44 Class 600 BL
  • ASME B16.47 Series A/MSS SP-44 Class 900 BL
  • ASME B16.47 Series B/API 605 Class 75 BL
  • ASME B16.47 Series B/API 605 Class 150 BL
  • ASME B16.47 Series B/API 605 Class 300 BL
  • ASME B16.47 Series B/API 605 Class 600 BL
  • ASME B16.47 Series B/API 605 Class 900 BL
  • DIN 2527 PN10
  • DIN 2527 PN16

Blind Flanges (BL Flanges) are pipe flanges used to seal the end of a piping system or pressure vessel openings to prevent flow.

Blind Flanges (BL Flanges) are commonly used for pressure testing the flow of liquid or gas through a pipe or vessel. Blind pipe flanges also allow easy access to the pipe in the event that work must be done inside the line. Slip on Pipe flanges with a hub have published specifications that range from 1/2″ thru 96″. Coastal Flange provides Blind pipe flanges in all material grades, specifications and sizes.

Blind Flanges (BL Flanges) are typically provided with a raised face, flat face, or RTJ facing. When a raised face is necessary for blind pipe flanges, the standard height is 1/16″ for blind pipe flanges under 400#. For blind pipe flanges of 400# and up, the standard blind pipe flange raised face height is 1/4″.

SS Blind Flange CS Blind Flange Alloy Steel Blind Flange F5 Blind Flange
F11 Blind Flange F22 Blind Flange F12 Blind Flange F91 Blind Flange
SS 304 Blind Flange SS 304L Blind Flange SS 316 Blind Flange SS 316L Blind Flange
SS 317 Blind Flange SS 317L Blind Flange SS 321 Blind Flange SS 347H Blind Flange
SS 904L Blind Flange Duplex Blind Flange Super Duplex Blind Flange S31803 Blind Flange
S32205 Blind Flange Monel 400 Blind Flange Monel K500 Blind Flange Inconel Blind Flange
S32750 Blind Flange S32760 Blind Flange F51 Blind Flange F53 Blind Flange
A694 F42 Blind Flange A694 F46 Blind Flange A694 F52 Blind Flange A694 F56 Blind Flange
A694 F60 Blind Flange A694 F65 Blind Flange A694 F70 Blind Flange A350 LF2 Blind Flange
A350 LF3 Blind Flange A707 L1 Blind Flange A707 L2 Blind Flange A707 L3 Blind Flange
A105 Blind Flange F904L Blind Flange Inconel 625 Blind Flange Inconel 800 Blind Flange
Inconel 800H Blind Flange Inconel 800HT Blind Flange Hastelloy Blind Flange Hastelloy B2 Blind Flange
Hastelloy B3 Blind Flange Hastelloy C22 Blind Flange Hastelloy C276 Blind Flange KOC approved Blind Flange
KNPC approved Blind Flange Aaramco approved Blind Flange SS BLRF Flange CS BLRF Flange
Alloy Steel BLRF Flange F5 BLRF Flange F11 BLRF Flange F22 BLRF Flange
F12 BLRF Flange F91 BLRF Flange SS 304 BLRF Flange SS 304L BLRF Flange
SS 316 BLRF Flange SS 316LBLRF Flange SS 317 BLRF Flange SS 317L BLRF Flange
SS 321 BLRF Flange SS 347H BLRF Flange SS 904L BLRF Flange Duplex BLRF Flange
Super Duplex BLRG Flange S31803 BLRF Flange S32205 BLRF Flange Monel 400 BLRF Flange
Monel K500 BLRF Flange Inconel BLRF Flange S32750 BLRF Flange S32760 BLRF Flange
F51 BLRF Flange F53 BLRF Flange A694 F42 BLRF Flange A694 F46 BLRF Flange
A694 F52 BLRF Flange A694 F56 BLRF Flange A694 F60 BLRF Flange A694 F65 BLRF Flange
A694 F70 BLRF Flange A350 LF2 BLRF Flange A350 LF3 BLRF Flange A707 L1 BLRF Flange
A707 L2 BLRF Flange A707 L3 BLRF Flange A105 BLRF Flange F904L BLRF Flange
Inconel 625 BLRF Flange Inconel 800 BLRF Flange Inconel 800H BLRF Flange Inconel 800HT BLRF Flange
Hastelloy BLRF Flange Hastelloy B2 BLRF Flange Hastelloy B3 BLRF Flange Hastelloy C22 BLRF Flange
Hastelloy C276 BLRF Flange KOC approved BLRF Flange KNPC approved BLRF Flange Aaramco approved BLRF Flange
SS BLFF Flange CS BLFF Flange Alloy Steel BLFF Flange F5 BLFF Flange
F11 BLFF Flange F22 BLFF Flange F12 BLFF Flange F91 BLFF Flange
SS 304 BLFF Flange SS 304L BLFF Flange SS 316 BLFF Flange SS 316LBLFF Flange
SS 317 BLFF Flange SS 317L BLFF Flange SS 321 BLFF Flange SS 347H BLFF Flange
SS 904L BLFF Flange Duplex BLFF Flange Super Duplex BLFF Flange S31803 BLFF Flange
S32205 BLFF Flange Monel 400 BLFF Flange Monel K500 BLFF Flange Inconel BLFF Flange
S32750 BLFF Flange S32760 BLFF Flange F51 BLFF Flange F53 BLFF Flange
A694 F42 BLFF Flange A694 F46 BLFF Flange A694 F52 BLFF Flange A694 F56 BLFF Flange
A694 F60 BLFF Flange A694 F65 BLFF Flange A694 F70 BLFF Flange A350 LF2 BLFF Flange
A350 LF3 BLFF Flange A707 L1 BLFF Flange A707 L2 BLFF Flange A707 L3 BLFF Flange
A105 BLFF Flange F904L BLFF Flange Inconel 625 BLFF Flange Inconel 800 BLFF Flange
Inconel 800H BLFF Flange Inconel 800HT BLFF Flange Hastelloy BLFF Flange Hastelloy B2 BLFF Flange
Hastelloy B3 BLFF Flange Hastelloy C22 BLFF Flange Hastelloy C276 BLFF Flange KOC approved BLFF Flange
KNPC approved BLFF Flange Aaramco approved BLFF Flange Hastelloy C276 BLFF Flange KOC approved BLFF Flange
KNPC approved BLFF Flange Aaramco approved BLFF Flange    

Features of blind flanges:

Some important features of blind flanges are as follows:

  • Blind flanges are sometimes supplied with NPT fittings which allow pressure test connections to be fitted.
  • They are used to blank off the ends of pipe.
  • They are also used to blank off the ends of valves and pressure vessel opening.
  • Considering factors like internal pressure and bolt loading, blind flanges, especially in the larger sizes, are the most highly stressed of all types of flanges.
  • Since the maximum stresses in a blind flange are bending stresses at the center, they can safely be allowed to be higher than in other types of flanges.
  • Blind flanges are made to fit standard pipes in all sizes.

Source: Zhejiang Yaang Pipe Industry Co., Limited (

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