Plastic Relief Valves | McMaster-Carr

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	Body Material Body Material

	Inlet Pipe Size Inlet Pipe Size

	For Use With For Use With

	Valve Function Valve Function

Pressure Relief

Pressure Regulation

Back-Pressure Regulation

Exhaust Flow

Flow Adjustment

Vacuum Regulation

	Inlet Thread Type Inlet Thread Type

NPT

UNF

	Shape Shape

	90° Elbow
	Straight
	Tee

	For Outlet Tube OD For Outlet Tube OD

	Inlet Connection Type Inlet Connection Type


Pipe	Tube

	Maximum Inlet Pressure Maximum Inlet Pressure

Less than 500 psi

Not Rated

	Inlet Connection Style Inlet Connection Style

Threaded

Push to Connect

Compression

	For Inlet Tube OD For Inlet Tube OD

	Outlet Connection Style Outlet Connection Style

Compression

Push to Connect

Threaded

	Outlet Connection Type Outlet Connection Type


Pipe	Tube

	Valve Type Valve Type

Relief

Pressure Regulator

Back-Pressure Regulator

Exhaust

Needle

Vacuum Regulator

	Activation Activation

Pressure Driven

Vacuum Driven

	Outlet Pipe Size Outlet Pipe Size

	Set Pressure Set Pressure

	Flow Coefficient (Cv) Flow Coefficient (Cv)

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant with
Exemptions

RoHS Compliant

	Overall Height Overall Height

	Inlet Location Inlet Location

Bottom

Side

	Seal Material Seal Material

Rubber

Plastic

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

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About Pressure-Relief Valves

Matching Flow Diagrams to Replace an Air Directional Control Valve

Choosing an Air Directional Control Valve

About Flow Control Valves

Also known as cylinder speed controls, flow control valves let you control the extension or retraction speed of your air cylinder. They regulate airflow as it passes from the valve's inlet to its outlet. Air flows freely in the opposite direction.

Compact Pressure-Relief Valves

Due to their small size, these valves are often installed on tanks in low-clearance areas. They begin opening at the set pressure. Nylon valves fully open at about 10% over the set pressure and steel valves fully open at about 50% over the set pressure. Valves begin closing as pressure drops and fully close when the system pressure is restored below the set pressure. All have a vent outlet to exhaust discharge directly. Set pressure is not adjustable.

Nylon valves have better corrosion resistance than steel valves. They are color coded based on the set pressure for easy identification.

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

Nylon Body—For Air

For Use With: Air
Temperature Range: 26° to 255° F

Inlet
Pipe Size	Location	Maximum Pressure	Relief Port Location	Overall Ht.	Seal Material	Choose a Set Pressure, psi		Each
NPT Male Inlet and Relief Vent
1/8	Bottom	Not Rated	Top	5/8"	Buna-N	0.5 (Red), 1 (Blue), 1.5 (Light Green), 3 (Light Blue), 6 (Natural), 10 (Yellow)	0000000	000000
1/4	Bottom	Not Rated	Top	11/16"	Buna-N	0.5 (Red), 1 (Blue), 1.5 (Light Green), 3 (Light Blue), 6 (Natural), 10 (Yellow)	0000000	00000

Pressure-Relief Valves with Push-to-Connect Fittings for Air

For Use With: Air
Temperature Range: 26° to 255° F

For a low-pressure seal around plastic and soft metal tubing, these valves have push-to-connect fittings. They allow inline flow from the inlet to the outlet during normal conditions and divert flow to the relief port in overpressure conditions. The relief port begins opening at the set pressure and fully opens at about 10% over the set pressure. It begins closing as pressure drops and fully closes when the system pressure is restored below the set pressure. The vented relief port exhausts discharge directly. Set pressure is not adjustable. Valves are color coded based on the set pressure for easy identification.

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

Inlet			Outlet
For Tube OD	Location	Maximum Pressure	For Tube OD	Location	Relief Port Location	Overall Ht.	Choose a Set Pressure, psi		Each
Push-to-Connect Female Inlet, Outlet and Relief Vent
Nylon Body—Buna-N Seal
1/4"	Side	Not Rated	1/4"	Side	Top	1 1/4"	0.5 (Red), 1 (Blue), 1.5 (Light Green), 3 (Light Blue), 6 (Natural), 10 (Yellow)	0000000	000000
5/16"	Side	Not Rated	5/16"	Side	Top	1 5/16"	0.5 (Red), 1 (Blue), 1.5 (Light Green), 3 (Light Blue), 6 (Natural), 10 (Yellow)	0000000	00000
3/8"	Side	Not Rated	3/8"	Side	Top	1 1/2"	0.5 (Red), 1 (Blue), 1.5 (Light Green), 3 (Light Blue), 6 (Natural), 10 (Yellow)	0000000	00000
1/2"	Side	Not Rated	1/2"	Side	Top	1 3/4"	0.5 (Red), 1 (Blue), 1.5 (Light Green), 3 (Light Blue), 6 (Natural), 10 (Yellow)	0000000	00000

Adjustable Inline Pressure-Relief Valves for Chemicals

For Use With: Potassium Sulfate, Sodium Hypochlorite
Temperature Range: 0° to 140° F

With a three-port design, these valves allow inline flow from the inlet to the outlet during normal conditions and divert flow through the relief port in overpressure conditions. Often used with feed pumps for fertilizers and bleach, they have a PVC body and a PTFE seal for excellent chemical resistance. The relief port begins opening at the set pressure and fully opens at about 10% over the set pressure. It begins closing as pressure drops and fully closes when the system pressure is restored below the set pressure, resuming inline flow from the inlet to the outlet. Adjust the set pressure within the range.

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

Inlet			Outlet		Relief Port		Set Pressure
Pipe Size	Location	Maximum Pressure, psi	Pipe Size	Location	Pipe Size	Location	Range, psi	Adjustment Method	Overall Ht.		Each
NPT Female Inlet, Outlet, and Relief Port
Dark Gray PVC Body—PTFE Seal
1/4	Side	350	1/4	Side	1/4	Bottom	10 to 150	External Adjustment Screw	3 17/32"	00000000	0000000
1/2	Side	350	1/2	Side	1/2	Bottom	10 to 250	External Adjustment Screw	5 9/16"	00000000	000000
1	Side	350	1	Side	1	Bottom	10 to 250	External Adjustment Screw	5 7/8"	00000000	000000

Adjustable Pressure-Relief Valves for Chemicals

For Use With: Aluminum Chloride, Boric Acid
Temperature Range: 40° to 140° F

Often used with catalysts, pH buffers, and electroplating solutions, these valves have a PVC body and an EPDM seal for excellent chemical resistance. They begin opening at the set pressure and fully open at about 10% over the set pressure. Valves begin closing as pressure drops and fully close when the system pressure is restored below the set pressure. Adjust the set pressure within the range. Valves have a port for attaching a pressure gauge.

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

Inlet			Relief Port		Set Pressure
Pipe Size	Location	Maximum Pressure, psi	Pipe Size	Location	Range, psi	Adjustment Method	Overall Ht.	Gauge Port Pipe Size		Each
NPT Female Inlet and Relief Port
Dark Gray PVC Body—EPDM Seal
1/2	Bottom	150	1/2	Side	5 to 75	External Adjustment Screw	6 3/4"	1/4	0000000	0000000
3/4	Bottom	150	3/4	Side	5 to 75	External Adjustment Screw	6 7/8"	1/4	0000000	000000
1	Bottom	150	1	Side	5 to 75	External Adjustment Screw	8 3/4"	1/4	0000000	000000
1 1/2	Bottom	150	1 1/2	Side	5 to 75	External Adjustment Screw	13 1/4"	1/4	0000000	00000000
2	Bottom	150	2	Side	5 to 75	External Adjustment Screw	15 1/2"	1/4	0000000	00000000

Plastic Panel-Mount Pressure-Regulating Valves for Air

For Use With: Air
Temperature Range: 40° to 150° F

Regulate pressure in air and inert gas systems from your instrument panel—these valves have threads below the adjustment knob and come with a panel-mount nut. All automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range. Body is polysulfone, which is lightweight and corrosion resistant.

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

Inlet				Outlet
Pipe Size	Thread Size	Location	Max. Pressure, psi	Pipe Size	Thread Size	Location	End-to-End Lg.	Panel Cutout Dia.	Choose an Outlet Pressure Range, psi		Each
NPT Female
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal
1/8	__	Side	150	1/8	__	Side	1 9/16"	9/16"	0.5 to 3.5, 0.5 to 10, 0.5 to 30, 0.5 to 90	00000000	000000
UNF Female
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal
__	10-32	Side	150	__	10-32	Side	1 1/8"	9/16"	0.5 to 3.5, 0.5 to 30, 0.5 to 60, 0.5 to 90	00000000	00000

Plastic Panel-Mount Pressure-Regulating Valves for Water

For Use With: Water
Temperature Range: 40° to 150° F

For easy panel mounting in your water system, these valves have threads below the adjustment knob and come with a panel-mount nut. They automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range. Body is polysulfone, which is lightweight and corrosion resistant.

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

Inlet				Outlet
Pipe Size	Thread Size	Location	Max. Pressure, psi	Pipe Size	Thread Size	Location	End-to-End Lg.	Panel Cutout Dia.	Choose an Outlet Pressure Range, psi		Each
NPT Female
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal
1/8	__	Side	150	1/8	__	Side	1 9/16"	9/16"	0.5 to 10, 0.5 to 60	00000000	000000
UNF Female
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal
__	10-32	Side	150	__	10-32	Side	1 1/8"	9/16"	0.5 to 3.5, 0.5 to 10, 0.5 to 30, 0.5 to 90	00000000	00000

Pressure-Regulating Valves with Push-to-Connect Fittings for Food and Beverage

For Use With: Food and Beverage
Temperature Range: 35° to 125° F

Insert plastic or soft metal tubing into the push-to-connect fittings on these valves for a low-pressure seal in food and beverage lines. They automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range. They have two gauge ports.

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

Inlet				Outlet
Tube Connection Type	For Tube OD	Location	Max. Pressure, psi	For Tube OD	Location	Pressure Adjustment Method	End-to-End Length	Specifications Met	Choose an Outlet Pressure Range, psi		Each
Push-to-Connect Female
Noryl PPO Body—Buna-N Diaphragm and Seal
Push to Connect	1/4"	Side	300	1/4"	Side	Screw	2 13/16"	NSF/ANSI 61	0 to 25, 0 to 60, 0 to 125	0000000	0000000

Pressure-Regulating Valves with Compression Fittings for Food and Beverage

For Use With: Food and Beverage
Temperature Range: 35° to 125° F

Compression fittings bite down on hard metal and plastic tubing for a tighter seal than push-to-connect fittings. These valves automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range. The Buna-N/stainless steel diaphragm and EPDM seal are FDA compliant 21 CFR 177.2600.

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

Inlet			Outlet
For Tube OD	Location	Max. Pressure, psi	For Tube OD	Location	Pressure Adjustment Method	End-to-End Lg.	Specifications Met	Choose an Outlet Pressure Range, psi		Each
Compression Female
Acetal Body—Buna-N/Stainless Steel Diaphragm and EPDM Seal
1/4"	Side	250	1/4"	Side	Knob	2"	FDA Compliant 21 CFR 177.2600	1 to 10, 2 to 50, 5 to 100	0000000	0000000

Threaded Pressure-Regulating Valves for Food and Beverage

With Knob

With Screw

For Use With: Food and Beverage
Temperature Range: 35° to 125° F

These valves are often used to regulate pressure in food and beverage lines. They automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range. Valves have two gauge ports and come with plugs to close the unused ports.

Valves with knob have a Buna-N/Nylon diaphragm which is FDA Compliant 21 CFR 177.2600.

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

Inlet			Outlet
Pipe Size	Location	Max. Pressure, psi	Pipe Size	Location	Pressure Adjustment Method	End-to-End Lg.	Specifications Met	Choose an Outlet Pressure Range, psi		Each
NPT Female
Acetal Body—Buna-N/Nylon Diaphragm and EPDM Seal with Knob
1/4	Side	150	1/4	Side	Knob	1 5/8"	FDA Compliant 21 CFR 177.2600, NSF/ANSI 61	5 to 50, 5 to 125	0000000	000000
Noryl PPO Body—Buna-N Diaphragm and Seal with Screw
1/4	Side	300	1/4	Side	Screw	1 9/16"	NSF/ANSI 61	0 to 25, 0 to 60, 0 to 125	0000000	000000

Pressure-Regulating Valves for Chemicals

For Use With: Chemicals
Temperature Range:
Polypropylene Body: 35° to 180° F
PVC Body: 40° to 140° F

A plastic body and fluoroelastomer seal stand up to harsh chemicals. These valves automatically reduce a high, variable inlet pressure to a lower, stable outlet pressure. Adjust the outlet pressure within the range.

Polypropylene valves withstand higher temperatures than PVC valves.

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

Inlet			Outlet
Pipe Size	Location	Max. Pressure, psi	Pipe Size	Location	Pressure Range, psi	End-to-End Lg.		Each
NPT Female
Polypropylene Body—Fluoroelastomer Seal
1/2	Side	125	1/2	Side	10 to 80	3"	00000000	0000000
3/4	Side	125	3/4	Side	10 to 80	3 15/16"	00000000	000000
1	Side	125	1	Side	10 to 80	3 15/16"	00000000	000000
PVC Body—Fluoroelastomer Seal
1/2	Side	125	1/2	Side	10 to 80	3"	00000000	000000
3/4	Side	125	3/4	Side	10 to 80	3 15/16"	00000000	000000
1	Side	125	1	Side	10 to 80	3 15/16"	00000000	000000
1 1/2	Side	125	1 1/2	Side	10 to 80	6 1/8"	00000000	00000000
2	Side	125	2	Side	10 to 80	6"	00000000	00000000

Panel-Mount Back-Pressure-Regulating Valves for Air and Inert Gas

For Use With: Air, Inert Gas
Temperature Range: 40° to 150° F

Threads below the adjustment knob and an included panel-mount nut allow you to add these valves to your instrument panel. Often used in systems running on air compressors, they're installed after pressure-sensitive equipment to obstruct flow and maintain a consistent operating pressure. If the system pressure exceeds the set pressure, they exhaust through the outlet. Adjust the set pressure within the range.

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

Inlet				Outlet
Pipe Size	Thread Size	Location	Max. Pressure, psi	Pipe Size	Thread Size	Location	End-to-End Lg.	Panel Cutout Dia.	Choose an Outlet Pressure Range, psi		Each
NPT Female
Polysulfone Body—Buna-N Diaphragm and Silicone Seal
1/8	__	Side	100	1/8	__	Side	1 1/8"	9/16"	0.5 to 3.5, 0.5 to 10, 0.5 to 30, 0.5 to 60, 0.5 to 90	00000000	000000
UNF Female
Polysulfone Body—Buna-N Diaphragm and Silicone Seal
__	10-32	Side	100	__	10-32	Side	1 1/8"	9/16"	0.5 to 3.5, 0.5 to 10, 0.5 to 30, 0.5 to 60, 0.5 to 90	00000000	00000

Plastic Panel-Mount Vacuum-Regulating Valves for Air and Inert Gas

For Use With: Air, Inert Gas
Temperature Range: 40° to 150° F

A lighter and more corrosion-resistant alternative to metal valves. All valves throttle a high vacuum source to maintain a lower vacuum level in your system. Adjust the outlet vacuum level within the range. Threads below the adjustment knob and an included panel-mount nut let you add these valves to your instrument panel. All are constant-bleed style, so they continually release small amounts of process gas to improve accuracy and repeatability.

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

Inlet			Outlet
Pipe Size	Thread Size	Location	Pipe Size	Thread Size	Location	Vacuum Range, in. of Hg	Vacuum Adjustment Method	End-to-End Lg.	Panel Cutout Dia.		Each
NPT Female
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal
1/8	__	Side	1/8	__	Side	0 to 30	Knob	1 9/16"	9/16"	00000000	000000
UNF Female
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal
__	10-32	Side	__	10-32	Side	0 to 30	Knob	1 1/8"	9/16"	00000000	00000

Elbow Air-Exhaust Control Valves with Flow Control

Control the flow of exhaust air while also regulating the exhaust air speed. These valves dump exhaust air to the atmosphere without routing it back through a directional control valve. They control flow in one direction as air flows from the inlet to the outlet, and adjust the volume of exhaust air exiting an air cylinder (meter out) to control its speed. Air flows freely in the opposite direction. They have a 90° elbow shape that allows you to install them in tight spaces. The push-to-connect outlet ports are for use with plastic or soft metal tubing; insert tubing into the ports. A muffler reduces exhaust noise. Also known as quick exhaust valves.

Flow coefficient (Cv) is a measurement that indicates how much airflow can pass through a valve. When selecting between valves with the same port size, choose the valve with the higher flow coefficient to ensure it provides enough airflow to operate your system.

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

							Overall
No. of Flow Ports	Inlet Size	For Outlet Tube OD	Max. Flow Rate, scfm @ 100 psi	Flow Coefficient (Cv)	Pressure Range, psi	Body Material	Lg.	Wd.	Ht.		Each
Threaded Male Inlet × Push-to-Connect Female Outlet
3	1/8 NPT	1/4"	14.05	0.44	14-145	PBT Plastic	2 7/8"	11/16"	1 1/16"	00000000	000000
3	1/8 NPT	5/16"	24.91	0.78	14-145	PBT Plastic	2 7/8"	15/16"	1 3/16"	00000000	00000
3	1/8 NPT	3/8"	24.91	0.78	14-145	PBT Plastic	3 3/8"	15/16"	1 5/16"	00000000	00000
3	1/4 NPT	1/4"	14.05	0.44	14-145	PBT Plastic	2 7/8"	11/16"	1 1/8"	00000000	00000
3	1/4 NPT	5/16"	24.91	0.78	14-145	PBT Plastic	3 1/4"	15/16"	1 3/8"	00000000	00000
3	1/4 NPT	3/8"	24.91	0.78	14-145	PBT Plastic	3 3/8"	15/16"	1 5/8"	00000000	00000
3	1/4 NPT	3/8"	47.89	1.5	14-145	PBT Plastic	3 9/16"	15/16"	1 5/8"	00000000	00000
3	3/8 NPT	5/16"	24.91	0.78	14-145	PBT Plastic	3 1/4"	15/16"	1 1/8"	00000000	00000
3	3/8 NPT	3/8"	24.91	0.78	14-145	PBT Plastic	3 3/8"	15/16"	1 5/16"	00000000	00000
3	3/8 NPT	3/8"	51.09	1.6	14-145	PBT Plastic	3 9/16"	1 3/16"	1 3/4"	00000000	00000
3	1/2 NPT	3/8"	51.09	1.6	14-145	PBT Plastic	3 9/16"	1 3/16"	1 5/8"	00000000	00000

Quiet Air-Exhaust Control Valves

A muffler on these valves reduces exhaust noise. They allow airflow into your equipment and then quickly vent exhaust air to the atmosphere without routing it back through a directional control valve to speed up the movement of equipment. Also known as quick exhaust valves.

							Overall
No. of Flow Ports	For Inlet Tube OD	For Outlet Tube OD	Maximum Flow Rate	Flow Coefficient (Cv)	Pressure Range, psi	Body Material	Lg.	Wd.	Ht.		Each
Push-to-Connect Female Inlet × Push-to-Connect Female Outlet
3	1/4"	1/4"	11.36 scfm @ 100 psi	0.8	14-145	PBT Plastic	2"	1/2"	3/4"	0000000	000000
3	1/4"	1/4"	6.82 scfm @ 100 psi	0.54	14-145	PBT Plastic	1 5/8"	1/2"	5/8"	0000000	00000
3	4mm	4mm	4.47 scfm @ 100 psi	0.14	14-145	PBT Plastic	39.7mm	10mm	14.3mm	0000000	00000
3	6mm	6mm	11.36 scfm @ 100 psi	0.8	14-145	PBT Plastic	44.5mm	11.6mm	19mm	0000000	00000
3	6mm	6mm	4.79 scfm @ 100 psi	0.15	14-145	PBT Plastic	41.3mm	11.6mm	15.9mm	0000000	00000