Pressure-Relief Discs | McMaster-Carr

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39 Products

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-filled graphite for resistance to temperature and pressure fluctuations as well as corrosive liquids and gases. They include two gaskets for installation between flanges.

Pressure-Relief Discs

Operating Ratio—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.

	For Flange ANSI Class	OD	Thk.	Operating Ratio	Temp. Range, ° F	Gasket Material	Valve Type	Choose a Burst Pressure, psi		Each
Graphite Body—Resin-Filled Graphite Disc



	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 Pressure-Relief Discs

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

	For Flange ANSI Class	OD	Thk.	Max. Vacuum, in. Hg	Operating Ratio	Temp. Range, ° F	Gasket Material	Valve Type	Choose a Burst Pressure, psi		Each
Graphite Body—Resin-Filled Graphite Disc



	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

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

		Inlet
	Burst Pressure, psi	Pipe Size	Location	Relief Port Location	Operating Ratio	Temp. Range, ° F	Overall Ht.	Valve Type		Each
NPT Male Inlet and Vent Relief Port







				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

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

		Inlet		Relief Port
	Burst Pressure, psi	Pipe Size	Location	Pipe Size	Location	Operating Ratio	Temp. Range, ° F	End-to-End Lg.	Valve Type		Each
NPT Male Inlet and Pipe 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

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.

500 psi Maximum Pressure—These discs should not be used in a system with an operating pressure greater than 500 psi.

Maximum Operating Temperature—Exceeding the maximum operating temperature decreases service life and may cause the disc to open below its melting temperature.

	Inlet
	Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Max. Operating Temp., ° F	Overall Ht.	Disc Material	Valve Type		Each
NPT Male Inlet and Vent Relief Port







				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