Pipeline Seal Types

Pipe Caps, Pipe Plugs and Blind Flanges, all of them have the same function that sealing the pipeline.

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Pipe Caps

They are a Pipe Fittings that cover the pipe end to block off the pipeline. They are divided into Butt Weld Cap, Socket Weld Cap, Threaded Cap by connection type.

ASME B16.11 is the standard for Forged Socket Weld Cap and Forged Threaded Cap.

Forged ASME B16.11 Caps are suitable for serving small diameter pipes. They have Beautiful Appearance and Good Mechanical Properties, which belong to the best quality pipe fittings.

Butt Weld Caps are complied with ASME B16.9. They are not forgings but wrought pipe fittings. ASME B16.9 Caps can be divided into seamless pipe cap and welded pipe cap. Welded end cap should be take flaw detection. And service for large diameter pipes.

Socket Weld Cap Dimension

Standard	ASME B16.11
Diameter	1/8inch to 4 inch, DN6-DN100
Pressure	3000#, 6000#, 9000#
Stainless Steel Socket Weld Caps	ASTM A182 F304/304L, F316/316L, F310
Carbon Steel Socket Weld Caps	ASTM A105, A694 F42, F52, F60
Alloy Steel Socket Weld Caps	ASTM A182 F1, F5, F11, F22, F91

Threaded Cap Dimension

Standard	ASME B16.11
Diameter	1/8inch to 4 inch, DN6-DN100
Pressure	2000#, 3000#, 6000#
Threaded Type	FNPT, BSPP, BSPT
Stainless Steel Threaded Caps	ASTM A182 F304/304L, F316/316L, F310
Carbon Steel Threaded Caps	ASTM A105, A694 F42, F52, F60
Alloy Steel Threaded  Caps	ASTM A182 F1, F5, F11, F22, F91

Butt Weld Cap Dimension

Standard	ASME B16.9
Diameter	DN15-DN1200
Type	Seamless and Welded
Schedule	SCH10S, SCH20, SCH40, XS, SCH80, SHC120, SCH160, XXS
Stainless Steel Butt Weld Cap	AMTM A403 WP304, WP316
Carbon Steel Butt Weld Cap	ASTM A234 WPB, WPC, A106B, A 860 WPHY 42, WPHY 46, WPHY 52, WPH 60, WPHY 65.
Alloy Steel Butt Weld Cap	A234 WP1, WP5 WP9, WP11, WP22, WP91

Pipe Plug

Steel Pipe Plug is a pipe fitting that is inserted into the pipe end. It has male threaded type only. And can be divided into Hexagon Head Plug, Round Head Plug and Square Head Plug. Head shape influences its weight.

Threaded plug is ASME B16.11 Forged Fittings. But it is not classified by pressure ratings.

Threaded Plug Dimension

Standard	ASME B16.11
Diameter	1/8inch to 4 inch, DN6-DN100
Pressure	2000#, 3000#, 6000#
Threaded Type	FNPT, BSPP, BSPT
Stainless Steel Threaded Plug	ASTM A182 F304/304L, F316/316L, F310
Carbon Steel Threaded Plug	ASTM A105, A694 F42, F52, F60
Alloy Steel Threaded Plug	ASTM A182 F1, F5, F11, F22, F91

Pipe Plug Weight  

DN	NPS	Approximate Weight/ kg
		Hex head	Round head	Square head
6	1/8	0.01	0.02	0.01
8	1/4	0.02	0.05	0.01
10	3/8	0.04	0.07	0.03
15	1/2	0.06	0.13	0.05
20	3/4	0.12	0.19	0.08
25	1	0.22	0.37	0.17
32	1 1/4	0.43	0.54	0.28
40	1 1/2	0.54	0.68	0.4
50	2	1.09	1.45	0.63
65	2 1/2	1.72	–	1
80	3	2.18	–	1.54
100	4	5.9	–	3.85

Blind Flange

They are covered at the end of the pipe and connected by bolts and gasket. Compare with other forged flanges, it has bolt holes only. But they are all ASME B16.5 Flanges.

Spectacle Blind is one kind of blind flanges with 8 shape. It has a blind plate at one side, and the other side is a throttling ring which does not has throttling effect actually. The throttle end can be used when normal operation is required and to fill the installation clearance.

ASME B16.5 Blind Flanges Dimension

Pressure	150# , 300# , 600#, 900# , 1500#
Diameter	DN 15- DN600, NPS 1/2- NPS24
Stainless Steel Flange	A182 F316/316L, F304/304L, A240 Gr 316, 304, 309, 321, 310
Carbon Steel Flange	A105, A181 LF2, A516 Gr 70
Alloy Steel Flange	A182 F1, F5, F9, F11, F22, F91

Difference between Pipe Cap and Pipe Plug and Blind Flange

1. These Pipe Caps and Threaded Plugs are pipe fittings, blind flange is pipe flange.
2. Standard.
3. Size range and pressure rating. Butt weld cap has the largest size range and Schedule. And then Blind Flange.
4. Connection way.
5. Blind flange is tightly sealed and easy to disassemble. Others have to be cut off when they are removed.

What is ASME Standard?

ASME Standards cover the specifications, tolerances, marking, and testing requirement for pipes fittings and flanges.

For ASME B16.11 that covers forged socket weld and threaded pipe fittings.

While ASME B16.9 is for wrought factory-made butt-welding pipe fittings.

For ASME B16.5, it is forged flange standard.

They are all American standards and approved by American Society of Mechanical Engineering.