ASTM A126 Pipe Caps | McMaster-Carr

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41 Products

How to Identify and Measure Fittings

Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.

FM-Approved Low-Pressure Cast Iron Threaded Pipe Fittings

Suitable for use in fire-protection applications, these pipe fittings are made of cast iron, so they are brittle and can be quickly opened with the strike of a sledge hammer. They are also known as Pressure Class 125 fittings. Use in noncorrosive environments.

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

Plugs with Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class: 125
Specifications Met: FM Approved, UL Listed, ASTM A126, ASME B1.20.1, ASME B16.4
Pipe Nipples and Pipe: Use Schedule 40 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material		Each
1	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000
1 1/4	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
1 1/2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
2 1/2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
3	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
4	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000

Plugs with External Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class: 125
Specifications Met: FM Approved, UL Listed, ASTM A126, ASME B1.20.1, ASME B16.4
Pipe Nipples and Pipe: Use Schedule 40 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material		Each
1	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
1 1/4	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	0000
1 1/2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	0000
2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	0000
2 1/2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
3	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
4	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000

Low-Pressure Galvanized Iron and Steel Threaded Pipe Fittings

The galvanized finish on these fittings provides fair corrosion resistance. Fittings are for use in low-pressure applications.

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

Bushing Straight Reducing Adapters with Hex Body

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class: See table
Specifications Met: See table
Pipe Nipples and Pipe: Use Schedule 40 galvanized steel
Flanges: Use Class 150 galvanized steel

Pipe Size
(A)	(B)	Pressure Class	Max. Pressure	Max. Steam Pressure	Material	Specifications Met		Each
NPT Male × NPT Female
1 1/4	3/8	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	00000000	00000
1 1/2	3/8	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	00000000	00000
1 1/2	1/2	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	00000000	0000
2	1/2	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	00000000	00000
2	3/4	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	00000000	00000
2 1/2	1 1/2	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	00000000	00000
3	2	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	00000000	00000
3	2 1/2	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	ASME B1.20.1, ASME B16.14, ASTM A126	0000000	00000

Plugs with External Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class: See table
Specifications Met:
NPT Steel: SAE J531
NPT Iron: ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed
BSPT: ASTM A197, DIN EN 10226
Pipe Nipples and Pipe: Use Schedule 40 steel
Flanges: Use Class 150 galvanized steel

NPT Male
Pipe Size	Plug Construction	Pressure Class	Max. Pressure	Max. Steam Pressure	Material		Each
2 1/2	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	000000
3	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	00000
3 1/2	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	000000
4	Hollow	125	125 psi @ 72° F	125 psi @ 350° F	Galvanized Iron	00000000	000000

Medium-Pressure Iron and Steel Threaded Pipe Fittings

With better strength than our low-pressure iron and steel pipe fittings, these can handle medium-pressure applications. They are for use in noncorrosive environments.

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

Plugs with External Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class : 300
Specifications Met: See Table
Pipe Nipples and Pipe: Use Schedule 80 steel
Flanges: Use Class 300 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material	Specifications Met		Each
1/2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
3/4	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	0000
1	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	0000
1 1/4	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
1 1/2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000
2 1/2	Solid	400 psi @ 72° F	300 psi @ 550° F	Iron	ASME B1.20.1, ASME B16.14, ASTM A126, UL Listed	00000000	00000

FM-Approved Low-Pressure Cast Iron Unthreaded Pipe Flanges

Front

Flat Surface on Back

For Use With: Air, Diesel Fuel, Gasoline, Natural Gas, Oil, Steam, Water
Pressure Class: 125
Specifications Met: ASME B1.20.1, ASME B16.1, ASTM A126, FM Approved
Pipe Nipples and Pipe: Use Schedule 40 steel
Fittings: Use Class 125 or 150 iron and steel

FM-approved for fire protection applications, these flanges are cast iron, so they're brittle and can be quickly opened by hitting them with a sledge hammer. Bolt them together with a gasket (not included) to create an access point within a low-pressure pipe line. All are cap flanges, which are also known as blind flanges. Use them in noncorrosive environments.

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		Each
1	4 1/4"	1/2"	5/8"	4	3 1/8"	200 psi @ 72° F	165 psi @ 300° F	0000000	000000
1 1/2	5"	1/2"	5/8"	4	3 7/8"	200 psi @ 72° F	165 psi @ 300° F	0000000	00000
2	6"	5/8"	3/4"	4	4 3/4"	200 psi @ 72° F	165 psi @ 300° F	0000000	00000
2 1/2	7"	5/8"	3/4"	4	5 1/2"	200 psi @ 72° F	165 psi @ 300° F	0000000	00000
3	7 1/2"	5/8"	3/4"	4	6"	200 psi @ 72° F	165 psi @ 300° F	0000000	00000
3 1/2	8 1/2"	5/8"	3/4"	8	7"	200 psi @ 72° F	165 psi @ 300° F	0000000	000000
4	9"	5/8"	3/4"	8	7 1/2"	200 psi @ 72° F	165 psi @ 300° F	0000000	000000
6	11"	3/4"	7/8"	8	9 1/2"	200 psi @ 72° F	165 psi @ 300° F	0000000	000000