BS21 Flanges | McMaster-Carr

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	Pipe Size Pipe Size

	Thread Type Thread Type

BSPT

	Material Material

Bronze

	Type Type


Flange	Adapter

	Connection Style Connection Style

Flanged

Threaded

	For Use With For Use With

	Flanged Connection Surface Flanged Connection Surface

	Flat

	Flange OD Flange OD

	Specifications Met Specifications Met	Show

BS21

	Specifications Met Specifications Met	Hide

Warning: Products have one, but not necessarily all, of the selected characteristics.

3-A Sanitary Certified

International Fuel Gas
Code

Uniform Mechanical Code

UPC

USP

	Pressure Class Pressure Class

150

	Shape Shape

	Straight

	Connection Type Connection Type

	Pipe

	For Pipe Material For Pipe Material

Brass

	Maximum Pressure Maximum Pressure

200 psi @ 72 ° F

	Gender Gender

Female

	Maximum Steam Pressure Maximum Steam Pressure

125 psi @ 400° F

	Bolt Hole Diameter Bolt Hole Diameter

5/8"

3/4"

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

	For Bolt Diameter For Bolt Diameter

1/2"

5/8"

	For Pipe Schedule For Pipe Schedule

	40

	Bolt Circle Diameter Bolt Circle Diameter

	Number of Bolt Holes Number of Bolt Holes

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Front

Flat Surface on Back

For Use With: Air, Drinking Water, Natural Gas, Oil, Steam, Water
Pressure Class: 150
Specifications Met:
NPT: ASME B1.20.1, ASME B16.24, ASTM B584, NSF/ANSI 61
BSPT: ASTM B584, BS21
Pipe Nipples and Pipe: Use Schedule 40 brass
Fittings:
NPT: Use Class 125 brass
BSPT: Use Class 125 bronze

Also known as Pressure Class 150 flanges, these are designed for low-pressure applications. Bolt two same-size flanges together with a gasket (sold separately) to create an access point within a line. Flanges have good corrosion resistance. To adhere to safety standards for drinking water systems, use flanges that meet NSF/ANSI 61.

For technical drawings and 3-D models, click on a part number.

			Bolt Hole
Pipe Size	Flange OD	For Bolt Dia.	Dia.	No. of	Bolt Circle Dia.	Max. Pressure	Max. Steam Pressure	Material		Each
BSPT
1/2	3 1/2"	1/2"	5/8"	4	2 3/8"	200 psi @ 72° F	125 psi @ 400° F	Bronze	00000000	000000
3/4	3 7/8"	1/2"	5/8"	4	2 3/4"	200 psi @ 72° F	125 psi @ 400° F	Bronze	00000000	000000
1	4 1/4"	1/2"	5/8"	4	3 1/8"	200 psi @ 72° F	125 psi @ 400° F	Bronze	00000000	000000
1 1/4	4 5/8"	1/2"	5/8"	4	3 1/2"	200 psi @ 72° F	125 psi @ 400° F	Bronze	00000000	000000
1 1/2	5"	1/2"	5/8"	4	3 7/8"	200 psi @ 72° F	125 psi @ 400° F	Bronze	00000000	000000
2	6"	5/8"	3/4"	4	4 3/4"	200 psi @ 72° F	125 psi @ 400° F	Bronze	00000000	000000

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How to Identify and Measure Fittings

Low-Pressure Brass and Bronze Threaded Pipe Flanges