Brass Pop-Safety Valves | McMaster-Carr

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	Inlet Pipe Size Inlet Pipe Size

1/8

1/4

	For Use With For Use With

Liquid Carbon Dioxide

Liquid Helium

Liquid Hydrogen

Liquid Methane

	Test Mechanism Test Mechanism

Ring

Lever

None

	Seal Material Seal Material

Brass

Rubber

Plastic

	Set Pressure Configuration Set Pressure Configuration

Nonadjustable

Adjustable

	Shape Shape


90° Elbow	Straight

	Maximum Temperature Maximum Temperature

	Minimum Temperature Minimum Temperature

	Overall Height Overall Height

	Relief Port Connection Type Relief Port Connection Type

Vent

Pipe

	Relief Port Location Relief Port Location

Side

Top

	Maximum Inlet Pressure Maximum Inlet Pressure

	Set Pressure Set Pressure

	Set Pressure Accuracy Set Pressure Accuracy

	Airflow Capacity Airflow Capacity

	Relief Port Pipe Size Relief Port Pipe Size

1/4

3/4

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42 Products

About Pressure-Relief Valves

Valve
With
Test Ring

Valve With Test Lever

For Use With: Air, Inert Gas
Temperature Range: See table

To protect against damage in air lines, air receivers, compressor tanks, and other air-powered equipment, these valves spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. All meet ASME Code Section VIII for use with air and inert gas pressure vessels. They have a vented relief port to exhaust discharge directly.

Valves with a nickel-plated brass body are more corrosion resistant than valves with a plain brass body.

Silicone seals provide better leak protection than brass seals.

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

Inlet
Pipe Size	Location	Relief Port Location	Temperature Range, ° F	Overall Ht.	Test Mechanism	Valve Type	Specifications Met	Choose a Set Pressure, psi		Each
NPT Male Inlet and Relief Vent
Nickel-Plated Brass Body—Silicone Seal
1/8	Bottom	Side	-15° to 250°	2"	Ring	Pop Safety	ASME BPVC.VIII	50, 75, 100, 125, 150, 175, 200, 225, 250	0000000	000000
1/4	Bottom	Side	-15° to 250°	2"	Ring	Pop Safety	ASME BPVC.VIII	50, 75, 100, 125, 150, 175, 200, 225, 250	0000000	00000
3/8	Bottom	Side	-15° to 250°	2"	Ring	Pop Safety	ASME BPVC.VIII	50, 75, 100, 125, 150, 175, 200, 225, 250	0000000	00000
Brass Body—Brass Seal
1/8	Bottom	Side	-40° to 400°	2 1/8"	Ring	Pop Safety	ASME BPVC.VIII	50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250	0000000	0000
1/4	Bottom	Side	-40° to 400°	3 1/8"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	00000
1/4	Bottom	Side	-40° to 400°	3 3/16"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	00000
1/4	Bottom	Side	-20° to 300°	3 3/16"	Ring	Pop Safety	ASME BPVC.VIII	60, 100, 250, 300, 400, 500, 750, 1,000, 1,500, 2,000, 2,500, 3,000, 3,500, 4,000	0000000	000000
1/4	Bottom	Top	-40° to 400°	3 1/8"	Lever	Pop Safety	ASME BPVC.VIII	15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 110, 125, 130, 140, 150, 175, 200	0000000	00000
3/8	Bottom	Side	-40° to 400°	3 1/8"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	00000
3/8	Bottom	Side	-40° to 400°	3 9/16"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	00000
3/8	Bottom	Top	-40° to 400°	3 1/8"	Lever	Pop Safety	ASME BPVC.VIII	15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 110, 125, 130, 140, 150, 175, 200	0000000	00000
1/2	Bottom	Side	-40° to 400°	3 3/4"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	00000
1/2	Bottom	Side	-40° to 400°	3 13/16"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	00000
1/2	Bottom	Top	-40° to 400°	3 1/8"	Lever	Pop Safety	ASME BPVC.VIII	15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 110, 125, 130, 140, 150, 175, 200	0000000	00000
3/4	Bottom	Side	-40° to 400°	5 7/16"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	000000
1	Bottom	Side	-40° to 400°	5 3/4"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	0000000	000000
Brass Body—Silicone Seal
1/8	Bottom	Side	-15° to 250°	2"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	00000000	0000
1/4	Bottom	Side	-15° to 250°	2"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	00000000	0000
3/8	Bottom	Side	-15° to 250°	2"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	00000000	0000
1/2	Bottom	Side	-15° to 250°	3 3/8"	Ring	Pop Safety	ASME BPVC.VIII	50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250	00000000	00000
1/2	Bottom	Side	-15° to 250°	3 13/16"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	00000000	00000
3/4	Bottom	Side	-15° to 250°	3 13/16"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	00000000	00000
1	Bottom	Side	-15° to 250°	4 7/8"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	00000000	00000
1 1/4	Bottom	Side	-15° to 250°	4 7/8"	Ring	Pop Safety	ASME BPVC.VIII	25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 175, 200, 225, 250, 275, 300	00000000	00000

Fast-Acting Pressure-Relief Valves for Air and Inert Gas

Valve

Valve With Test Lever

Valve
With
Test Ring

For Use With: Air, Inert Gas
Temperature Range: -30° to 400° F

These valves spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. They have a vented relief port to exhaust discharge directly.

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

Inlet
Pipe Size	Location	Maximum Pressure, psi	Relief Port Location	Overall Ht.	Test Mechanism	Valve Type	Choose a Set Pressure, psi		Each
NPT Male Inlet and Relief Vent
Brass Body and Seal
1/8	Bottom	100	Side	1 3/4"	__	Pop Safety	5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100	000000	00000
1/4	Bottom	200	Top	3 1/8"	Lever	Pop Safety	5, 10	0000000	00000
1/4	Bottom	300	Side	2 1/2"	__	Pop Safety	5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100	000000	00000
1/4	Bottom	300	Side	3 1/8"	Ring	Pop Safety	10, 15, 20	0000000	00000
3/8	Bottom	200	Top	3 1/8"	Lever	Pop Safety	5, 10	0000000	00000
3/8	Bottom	300	Side	2 1/2"	__	Pop Safety	5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100	000000	00000
3/8	Bottom	300	Side	3 1/8"	Ring	Pop Safety	10, 15, 20	0000000	00000
1/2	Bottom	200	Top	3 1/8"	Lever	Pop Safety	5, 10	0000000	00000
1/2	Bottom	300	Side	3 1/8"	__	Pop Safety	5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100	000000	00000
1/2	Bottom	300	Side	3 3/4"	Ring	Pop Safety	10, 15, 20	0000000	00000
3/4	Bottom	300	Side	5 7/16"	Ring	Pop Safety	10, 15, 20	0000000	000000
1	Bottom	300	Side	5 3/4"	Ring	Pop Safety	10, 15, 20	0000000	000000

Adjustable Fast-Acting Pressure-Relief
Valves for Air and Inert Gas

For Use With: Air, Inert Gas
Temperature Range: -15° to 250° F

Change set pressure to suit your application—this valve includes four interchangeable color-coded springs with different set pressure ranges. Remove the adjustment screw to change springs; turn the screw to alter the set pressure within the range. The valve springs fully open at the set pressure and remains open until the system pressure is restored below the set pressure. It has a vented relief port to exhaust discharge directly.

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

Inlet				Set Pressure
Pipe Size	Location	Maximum Pressure, psi	Relief Port Location	Range, psi	Adjustment Method	Overall Ht.	Valve Type	Includes		Each
NPT Male Inlet and Relief Vent
Brass Body—Silicone Seal
1/4	Bottom	200	Side	25 to 200	External Adjustment Screw	1 5/8"	Pop Safety	Yellow Spring (25-50 psi), Red Spring (51-100 psi), Silver Spring (101-150 psi), Blue Spring (151-200 psi)	00000000	00000

Fast-Acting Pressure-Relief Valves for Air with Gauge Port

With Air-Fill Valve

With Switch Port

For Use With: Air
Temperature Range: -15° to 250° F

Attach a pressure gauge to the 1/4 NPT female port on these valves. They spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. All have a vented relief port to exhaust discharge directly.

Valves with an air-fill (Schrader) valve let you quickly fill and empty compressed air tanks.

Valves with a switch port allow you to install a pressure switch for activating alarms and other equipment when pressure exceeds the set point.

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

	Inlet		Relief Port			Switch Port		Gauge Port
Features	Pipe Size	Location	Pipe Size	Location	Overall Ht.	Pipe Size	Connection	Pipe Size	Connection	Test Mechanism	Valve Type	Choose a Set Pressure, psi		Each
NPT Male Inlet and NPT Female Relief Port
Brass Body—Silicone Seal
Air-Fill (Schrader) Valve	1/2	Bottom	1/4	Side	1 7/8"	__	__	1/4	NPT Female	Ring	Pop Safety	125, 135, 150	0000000	000000
Switch Port	1/2	Bottom	1/4	Side	2 1/2"	1/4	NPT Male	1/4	NPT Female	Ring	Pop Safety	100, 125, 135, 150	0000000	00000

Fast-Acting Pressure-Relief Valves for Cryogenic Liquids

For Use With: Liquid Argon, Liquid Nitrogen, Liquid Oxygen
Temperature Range: -250° to 350° F

Cleaned and bagged for oxygen service and other high-purity applications, these valves can withstand the extreme cold of liquid argon, liquid nitrogen, and liquid oxygen. They spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. All have a vented relief port to exhaust discharge directly.

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

Inlet
Pipe Size	Location	Maximum Pressure, psi	Relief Port Location	Overall Ht.	Valve Type	Choose a Set Pressure, psi		Each
NPT Male Inlet and Relief Vent
Brass Body—PTFE Seal
1/4	Bottom	400	Side	2 5/16"	Pop Safety	5, 10, 15, 20, 25, 30, 40, 50, 88, 100, 110, 125, 150, 200, 220, 250, 300, 325, 350, 400	0000000	000000

ASME-Code Fast-Acting Pressure-Relief
Valves for Cryogenic Liquids

For Use With: Liquid Argon, Liquid Carbon Dioxide, Liquid Helium, Liquid Hydrogen, Liquid Methane, Liquid Nitrogen, Liquid Oxygen
Specifications Met: ASME BPVC.VIII
Temperature Range: -320° to 150° F

These valves meet ASME Code Section VIII for use with cryogenic pressure vessels. Rated for use with liquid argon, liquid carbon dioxide, liquid helium, liquid methane, liquid nitrogen, and liquid oxygen, they are cleaned and bagged for oxygen service and other high-purity applications. All spring fully open at the set pressure and remain open until the system pressure is restored below the set pressure. Attach a drain line to the threaded relief port for remote discharge.

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

Inlet			Relief Port
Pipe Size	Location	Maximum Pressure, psi	Pipe Size	Location	Overall Ht.	Valve Type	Choose a Set Pressure, psi		Each
NPT Male Inlet and NPT Female Relief Port
Brass Body and Seal
1/2	Bottom	600	3/4	Side	6 9/16"	Pop Safety	20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300	0000000	0000000
3/4	Bottom	600	1	Side	6 9/16"	Pop Safety	20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300	0000000	000000

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About Pressure-Relief Valves

ASME-Code Fast-Acting Pressure-ReliefValves for Air and Inert Gas

Fast-Acting Pressure-Relief Valves for Air and Inert Gas

Adjustable Fast-Acting Pressure-ReliefValves for Air and Inert Gas

Fast-Acting Pressure-Relief Valves for Air with Gauge Port

Fast-Acting Pressure-Relief Valves for Cryogenic Liquids

ASME-Code Fast-Acting Pressure-ReliefValves for Cryogenic Liquids

ASME-Code Fast-Acting Pressure-Relief
Valves for Air and Inert Gas

Adjustable Fast-Acting Pressure-Relief
Valves for Air and Inert Gas

ASME-Code Fast-Acting Pressure-Relief
Valves for Cryogenic Liquids