Pressure-Relief Discs | McMaster-Carr

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39 Products

Remote-Discharge Threaded Pressure-Relief Discs

Instead of exhausting discharge directly, these discs have a threaded relief port for attaching a drain line to direct discharge away from your work environment. They are for installation in pipelines and tanks. Discs break open at the burst pressure to allow unrestricted flow. All are for one-time use.

316 stainless steel discs are more corrosion resistant than nickel discs.

Operating ratio is the ratio between the normal operating pressure and the burst pressure. Exceeding the operating ratio decreases the service life of the disc. For example, a disc with a burst pressure of 100 psi and an operating ratio of 80% should not be used in a system with an operating pressure greater than 80 psi.

	Inlet		Relief Port
Burst Pressure, psi	Pipe Size	Location	Pipe Size	Location	Operating Ratio	Temperature Range, °F	End-to-End Lg.	Valve Type		Each
NPT Male Inlet and Relief Port
Brass Body—Nickel Disc
100	3/8	Side	1/2	Side	80%	-50° to 500°	2 1/8"	Rupture Disc	00000000	0000000
100	1/2	Side	1/2	Side	80%	-50° to 500°	2 1/4"	Rupture Disc	00000000	000000
125	3/8	Side	1/2	Side	80%	-50° to 500°	2 1/8"	Rupture Disc	00000000	000000
125	1/2	Side	1/2	Side	80%	-50° to 500°	2 1/4"	Rupture Disc	00000000	000000
150	3/8	Side	1/2	Side	80%	-50° to 500°	2 1/8"	Rupture Disc	00000000	000000
150	1/2	Side	1/2	Side	80%	-50° to 500°	2 1/4"	Rupture Disc	00000000	000000
Brass Body—316 Stainless Steel Disc
200	3/8	Side	1/2	Side	80%	-50° to 500°	2 1/8"	Rupture Disc	00000000	000000
200	1/2	Side	1/2	Side	80%	-50° to 500°	2 1/4"	Rupture Disc	00000000	000000
250	3/8	Side	1/2	Side	80%	-50° to 500°	2 1/8"	Rupture Disc	00000000	000000
250	1/2	Side	1/2	Side	80%	-50° to 500°	2 1/4"	Rupture Disc	00000000	000000
500	3/8	Side	1/2	Side	80%	-50° to 500°	2 1/8"	Rupture Disc	00000000	000000
500	1/2	Side	1/2	Side	80%	-50° to 500°	2 1/4"	Rupture Disc	00000000	000000
700	3/8	Side	1/2	Side	80%	-50° to 500°	2 1/8"	Rupture Disc	00000000	000000
700	1/2	Side	1/2	Side	80%	-50° to 500°	2 1/4"	Rupture Disc	00000000	000000

Threaded Pressure-Relief Discs

These valves have a vented relief port to exhaust discharge directly. They are for installation in pipelines and tanks. All break open at the burst pressure to allow unrestricted flow. Discs are for one-time use.

316 stainless steel discs are more corrosion resistant than nickel discs.

	Inlet
Burst Pressure, psi	Pipe Size	Location	Relief Port Location	Operating Ratio	Temperature Range, °F	Overall Ht.	Valve Type		Each
NPT Male Inlet and Relief Vent
Brass Body—Nickel Disc
100	1/4	Bottom	Side	80%	-50° to 500°	1 5/8"	Rupture Disc	00000000	0000000
125	1/4	Bottom	Side	80%	-50° to 500°	1 5/8"	Rupture Disc	00000000	000000
150	1/4	Bottom	Side	80%	-50° to 500°	1 5/8"	Rupture Disc	00000000	000000
Brass Body—316 Stainless Steel Disc
200	1/4	Bottom	Side	80%	-50° to 500°	1 5/8"	Rupture Disc	00000000	000000
250	1/4	Bottom	Side	80%	-50° to 500°	1 5/8"	Rupture Disc	00000000	000000
500	1/4	Bottom	Side	80%	-50° to 500°	1 5/8"	Rupture Disc	00000000	000000
700	1/4	Bottom	Side	80%	-50° to 500°	1 5/8"	Rupture Disc	00000000	000000

Heat-Activated Threaded Pressure-Relief Discs

Also known as fusible plugs, these discs have a metal core that melts at a set temperature to exhaust discharge directly and allow unrestricted flow. Install these one-time-use discs in pipelines and tanks.

Exceeding the maximum operating temperature decreases service life and may cause the disc to open below its melting temperature. These discs should not be used in a system with an operating pressure greater than 500 psi.

Inlet
Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Max. Operating Temperature, °F	Overall Ht.	Disc Material	Valve Type		Each
NPT Male Inlet and Relief Vent
Brass Body—165° F Melting Temperature
1/4	Bottom	Top	500	100°	3/4"	Bismuth, Cadmium, Lead, Tin	Rupture Disc	0000000	000000
3/8	Bottom	Top	500	100°	3/4"	Bismuth, Cadmium, Lead, Tin	Rupture Disc	0000000	00000
1/2	Bottom	Top	500	100°	7/8"	Bismuth, Cadmium, Lead, Tin	Rupture Disc	0000000	00000
Brass Body—212° F Melting Temperature
1/4	Bottom	Top	500	150°	3/4"	Bismuth, Lead, Tin	Rupture Disc	0000000	00000
3/8	Bottom	Top	500	150°	3/4"	Bismuth, Lead, Tin	Rupture Disc	0000000	00000
1/2	Bottom	Top	500	150°	7/8"	Bismuth, Lead, Tin	Rupture Disc	0000000	00000

Flange-Mount Pressure-Relief Discs

Install these discs within the bolt circle of ANSI Class 150 flanges. They break open at the burst pressure to allow unrestricted flow. All are for one-time use. Discs are made of resin-impregnated graphite for resistance to temperature and pressure fluctuations as well as corrosive liquids and gases. They include two gaskets for installation between flanges.

Vacuum-rated discs have supports to resist rupture caused by vacuum.

Discs

Graphite Body—Resin-Impregnated Graphite Disc
Pipe Size	For Flange ANSI Class	OD	Thickness	Operating Ratio	Temperature Range, °F	Gasket Material	Valve Type	Choose a Burst Pressure, psi		Each
1	150	2 1/2"	1 1/8"	80%	-20° to 300°	Neoprene	Rupture Disc	20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 175, 200, 250	00000000	0000000
1 1/2	150	3 1/4"	1 1/8"	80%	-20° to 300°	Neoprene	Rupture Disc	20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 175, 200, 250	00000000	000000
2	150	4"	1 1/8"	80%	-20° to 300°	Neoprene	Rupture Disc	20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 175, 200, 250	00000000	000000
3	150	5 1/4"	1 1/8"	80%	-20° to 300°	Neoprene	Rupture Disc	20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 175, 200, 250	00000000	000000
4	150	6 3/4"	1 1/8"	80%	-20° to 300°	Neoprene	Rupture Disc	20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 175, 200, 250	00000000	000000
6	150	8 5/8"	1 1/8"	80%	-20° to 300°	Neoprene	Rupture Disc	20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 175, 200	00000000	000000

Vacuum Rated Discs

Graphite Body—Resin-Impregnated Graphite Disc
Pipe Size	For Flange ANSI Class	OD	Thickness	Max. Vacuum, in. of Hg	Operating Ratio	Temperature Range, °F	Gasket Material	Valve Type	Choose a Burst Pressure, psi		Each
1	150	2 1/2"	1 1/8"	29.92	80%	-20° to 300°	Neoprene	Rupture Disc	15	00000000	0000000
1 1/2	150	3 1/4"	1 1/8"	29.92	80%	-20° to 300°	Neoprene	Rupture Disc	10, 15	00000000	000000
2	150	4"	1 1/8"	29.92	80%	-20° to 300°	Neoprene	Rupture Disc	5, 10, 15	00000000	000000
3	150	5 1/4"	1 1/8"	29.92	80%	-20° to 300°	Neoprene	Rupture Disc	5, 10, 15	00000000	000000
4	150	6 3/4"	1 1/8"	29.92	80%	-20° to 300°	Neoprene	Rupture Disc	5, 10, 15	00000000	000000
6	150	8 5/8"	1 1/8"	29.92	80%	-20° to 300°	Neoprene	Rupture Disc	5, 10, 15	00000000	000000