Blind Flange

Blind Flange manufacturer in USA

Blind Flanges are fabricated by SVR Global out of forged carbon steel, stainless steel, alloy steel, and ductile iron. A Blind Flange is an unpunched and unthreaded solid type of flange which is fabricated to shut-off valves, close up nozzles or ends of pipe runs. It is made according to the following dimensions: ASME B16.5, ASME B16.47 (series A/MSS SP-44 and series B/API 605), ASME B16.48 (spectacle blind flanges), AWWA C207.

What is a Blind Flange?

The Blind Flange is a type of flange which does not have a bore and is used to shut off any pipe or valve. According to ASME B16.5/B16.47 and AWWA C207, the blind flanges will be the same as mating flanges regarding the pattern, size, and pressure class; however, it prevents flow completely.

Function of a Blind Flange:

• Terminates a pipeline or branch connection at a bolted joint

• Isolates a section of piping, a valve, or a vessel nozzle from the rest of the system

• Provides a test point for hydrostatic or pneumatic pressure testing before downstream connections are made

• Allows a future tie-in point without cutting or welding, since the flange can be unbolted and replaced with a flanged fitting

• Blanks off an unused port on a multi port valve, header, or manifold

Facing Types:

• Raised Face (RF) - standard facing with a raised sealing surface, typically 1/16 in. or 1/4 in. height per ASME B16.5

• Flat Face (FF) - full face gasket contact, used against cast iron flanges or low pressure ductile iron fittings

• Ring-Type Joint (RTJ) - grooved facing for metal ring gasket sealing in high pressure and high temperature service

Materials and standards of Blind Flange:

Manufacturing and Testing:

• Forged construction from rolled bar or billet for NPS 24 and below, per ASME B16.5

• Fabricated (welded plate) construction for larger diameters per ASME B16.47 Series A/B

• Face machining, bore facing, and bolt-hole drilling to specified tolerance

• Ultrasonic testing (UT), radiographic testing (RT), and dye penetrant testing (DPT/PT) available on weld seams and forgings

• Positive Material Identification (PMI) verification for alloy and stainless steel grades

• Hydrostatic shell testing where blind flanges are supplied as part of a tested valve or pipe spool assembly

• Mill Test Certificates (MTC) per EN 10204 3.1/3.2 issued with each production lot

Blind Flange Applications:

• Terminating pipeline sections during construction phases before tie-in

• Sealing spare, future use, or decommissioned nozzles on pressure vessels and storage tanks

• Blanking off unused ports on multi port and 3-way valves, headers, and distribution manifolds

• Isolating equipment, strainers, or instrumentation for maintenance and inspection

• Hydrostatic and pneumatic test closures on new pipeline spools

• Closure fittings on water transmission mains, pump station headers, and treatment plant piping

• Isolation points in process piping for chemical, oil and gas, and power generation facilities

• Closure of unused branch connections on skid mounted piping assemblies

Why Specify SVR Global for Blind Flanges?

• Forged and fabricated blind flanges manufactured to ASME B16.5, B16.47, B16.48, and AWWA C207 dimensional standards

• Full pressure class range from Class 150 through Class 2500, and PN 6 through PN 400

• Material traceability with Mill Test Certificates issued per production heat/lot

• Facing options in raised face, flat face, and ring type joint to match mating flange requirements

• Non destructive testing (UT, RT, PT) and PMI verification available on request

• Dimensional compliance verified against mating valve, fitting, and pipe flange drawings before dispatch

• Support for matched sets blind flanges supplied alongside gate, butterfly, check, and plug valves for a single project specification