Brass Breathers | McMaster-Carr

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45 Products

Breather Vents


Style A	Style H

Protect against excess vacuum and pressure in cylinders, gear boxes, enclosures, manifolds, and tanks. You can also use these breather vents to block debris from entering equipment.

Style H—Style H has a Buna-N O-ring for extra protection against leaks.

	Style	Max. Flow Rate @ Pressure	Max. Pressure, psi	Max. Temp., ° F	Ht.	For Use With	Removes Particle Size Down To, μm		Each
NPT Male







		Zinc-Plated Steel Body and Fitting

		A	2	—	1,095 scfm @ 100 psi	150	300	1 5/8"	Air, Inert Gas	90	9833K16	000000




				Nickel-Plated Steel Body and Fitting

				A	1/8	—	2 scfm @ 100 psi	150	300	7/16"	Air, Inert Gas	40	9833K21	0000


				A	1/4	—	3 scfm @ 100 psi	150	300	5/8"	Air, Inert Gas	40	9833K22	0000
				A	3/8	—	7 scfm @ 100 psi	150	300	3/4"	Air, Inert Gas	40	9833K23	0000
				A	1/2	—	17 scfm @ 100 psi	150	300	7/8"	Air, Inert Gas	40	9833K11	0000
				A	3/4	—	20 scfm @ 100 psi	150	300	1"	Air, Inert Gas	40	9833K12	0000
				A	1	—	28 scfm @ 100 psi	150	300	1 5/16"	Air, Inert Gas	40	9833K13	0000
				A	1 1/4	—	50 scfm @ 100 psi	150	300	1 7/16"	Air, Inert Gas	40	9833K14	00000
				A	1 1/2	—	73 scfm @ 100 psi	150	300	1 1/2"	Air, Inert Gas	40	9833K15	00000




						Brass Body and Fitting

						A	1/16	—	13 scfm @ 100 psi	150	300	1/2"	Air, Inert Gas	90	9833K19	0000


						UNF Male







										Brass Body and Fitting

										A	—	10-32	6 scfm @ 100 psi	150	300	3/8"	Air, Inert Gas	90	9833K18	0000


										H	—	10-32	1 scfm @ 100 psi	125	200	7/16"	Air, Inert Gas	40	8556T24	0000


										BSPT Male







														Zinc-Plated Steel Body and Fitting

														A	1/8	—	26 scfm @ 100 psi	150	300	7/16"	Air, Inert Gas	90	9847K11	0000


A														1/4	—	35 scfm @ 100 psi	150	300	11/16"	Air, Inert Gas	90	9847K12	0000
A	3/8													—	87 scfm @ 100 psi	150	300	13/16"	Air, Inert Gas	90	9847K13	0000
A	1/2													—	131 scfm @ 100 psi	150	300	1"	Air, Inert Gas	90	9847K14	0000
A	3/4													—	219 scfm @ 100 psi	150	300	1 1/16"	Air, Inert Gas	90	9847K15	0000


NPSM Female







		Zinc-Plated Steel Body and Fitting

		F	1/8											—	26 scfm @ 100 psi	150	300	5/8"	Air, Inert Gas	90	9833K24	0000


		F	1/4											—	35 scfm @ 100 psi	150	300	3/4"	Air, Inert Gas	90	9833K25	0000
		F	3/8											—	87 scfm @ 100 psi	150	300	15/16"	Air, Inert Gas	90	9833K26	0000
		F	1/2											—	131 scfm @ 100 psi	150	300	1"	Air, Inert Gas	90	9833K27	0000

Self-Draining Breather Vents

Minimize moisture buildup in enclosures. Also known as drain plugs, these breather vents have a small outlet that allows condensation to drain. They have a silicone O-ring above the threads for a tight seal. Install them at the lowest point of the enclosure. Breather vents meet IP66 for protection in washdown environments. Use them to prevent excess vacuum and pressure in cylinders, gear boxes, and tanks and to block debris from entering equipment.

Threaded NPT Male

Image of Product. Bottom orientation. Breather Vents. Self-Draining Breather Vents.

316 Stainless Steel Body and Fitting—316 stainless steel breather vents have excellent corrosion resistance.

Brass Body and Fitting—Brass breather vents have good corrosion resistance.

	Max. Flow Rate @ Pressure	Max. Pressure	Max. Temp., ° F	Ht.	Dia.	For Use With	Environment	Hazardous Location Protection Type	Enclosure Rating	Hazardous Location Rating	O-Ring Material	Certification	Features		Each
316 Stainless Steel Body and Fitting



	1/4	Not Rated	Not Rated	320	1 1/16"	11/16"	Air	Corrosive, Dusty, Outdoor, Washdown, Wet	—	IP66, NEMA 4X	—	Silicone Rubber	—	Drain	8602T31	000000


	1/2	Not Rated	Not Rated	320	1 1/8"	1"	Air	Corrosive, Dusty, Hazardous, Outdoor, Washdown, Wet	Increased Safety, Protection by Enclosure	IP66, NEMA 4X	ATEX I M2 Ex E I Mb; ATEX II 2 GD Ex E IIC Gb Ex Tb IIIC Db; IEC Zone 1 Groups IIC, IIB, IIA; IEC Zone 21 Groups IIIC, IIIB, IIIA; IECEx Ex E I/IIC Mb/Gb; IECEx Ex IIIC Tb Db	Silicone Rubber	CE Marked	Drain	8602T32	00000


	Brass Body and Fitting



			1/4	Not Rated	Not Rated	320	1 1/16"	11/16"	Air	Corrosive, Dusty, Outdoor, Washdown, Wet	—	IP66, NEMA 4X	—	Silicone Rubber	—	Drain	8602T11	00000


			1/2	Not Rated	Not Rated	320	1 1/8"	1"	Air	Corrosive, Dusty, Hazardous, Outdoor, Washdown, Wet	Increased Safety, Protection by Enclosure	IP66, NEMA 4X	ATEX I M2 Ex E I Mb; ATEX II 2 GD Ex E IIC Gb Ex Tb IIIC Db; IEC Zone 1 Groups IIC, IIB, IIA; IEC Zone 21 Groups IIIC, IIIB, IIIA; IECEx Ex E I/IIC Mb/Gb; IECEx Ex IIIC Tb Db	Silicone Rubber	CE Marked	Drain	8602T12	00000

Submersible Threaded Breather Vents

Use these vents to maintain consistent pressure as temperatures fluctuate by allowing air to flow through sealed enclosures. All have a hydrophobic and oleophobic filter membrane that blocks moisture and contamination from particle buildup.

Metric

Nickel-Plated

Brass

Nickel-Plated Brass—Nickel-plated brass vents stand up to corrosive environments better than nylon and polycarbonate vents. They’re also durable, which means you won’t have to replace them as often.

Head Dia.	Environment	Enclosure Rating	Features		Each







Nickel-Plated Brass

M12	1.5	1/2"	3/4"	Dusty, Submersible, Washdown, Wet	IP66, IP68	Gasket	4375N11	000000


M16	1.5	5/8"	3/4"	Dusty, Submersible, Washdown, Wet	IP66, IP68	Gasket	4375N12	00000
M20	1.5	13/16"	15/16"	Dusty, Submersible, Washdown, Wet	IP66, IP68	Gasket	4375N13	00000

Air-Release Valves for Water and Coolant

These valves are often used to remove air pockets in cooling and heating systems to maintain consistent flow and prevent water surges that can damage equipment. All have a vented relief port to exhaust discharge directly.

NPT Female Inlet and Relief Vent

Image of Product. Front orientation. Air Vent Valves. Air-Release Valves for Water and Coolant, Female Inlet.

	Inlet
	Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Temp. Range, ° F	Overall Ht.		Each
Brass Body—Vertical Mount



		1/8	Bottom	Top	75	33 to 240	4 3/8"	4928K1	000000


		1/4	Bottom	Top	150	33 to 240	4 3/8"	4928K3	00000

NPT Female Inlet, NPT Female Outlet and Relief Vent

Image of Product. Front orientation. Air Vent Valves. Air-Release Valves for Water and Coolant, Female Outlet, Female Inlet.

	Inlet		Outlet
	Pipe Size	Location	Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Temp. Range, ° F	Overall Ht.		Each
Brass Body—Vertical Mount



		1/8	Bottom	1/8	Side	Top	75	33 to 240	4 3/8"	4928K2	000000

NPT Female/Male Inlet and Relief Vent

Valves with female/male inlets have an inlet with both male and female threads, so they can be connected to both male and female adapters and equipment ports.

	Inlet
	Female Pipe Size	Male Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Temp. Range, ° F	Overall Ht.		Each
Brass Body—Vertical Mount



		1/2	3/4	Bottom	Top	150	33 to 240	4 3/4"	4928K4	000000

NPT Male Inlet and Relief Vent

Image of Product. Top orientation. Air Vent Valves. Air-Release Valves for Water and Coolant, Male Inlet.

	Inlet
	Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Temp. Range, ° F	Overall Ht.		Each
Brass Body—Vertical Mount



		1/8	Bottom	Top	50	33 to 240	2 5/8"	4928K11	000000


		1/8	Bottom	Top	50	33 to 240	3 3/4"	4928K12	00000
		1/8	Bottom	Top	75	33 to 240	4 3/8"	4928K8	00000
		1/4	Bottom	Top	50	33 to 240	4"	4928K13	00000
		1/4	Bottom	Top	150	33 to 240	4 3/4"	4928K9	00000
		1/2	Bottom	Top	150	33 to 240	3 3/8"	4928K16	00000
		3/4	Bottom	Top	150	33 to 240	3 3/8"	4928K17	00000
		1	Bottom	Top	150	33 to 240	3 1/2"	4928K18	00000

Air-Release Valves for Steam

Our only air-release valves for steam, these seal shut when steam enters the valve to prevent system contents from escaping through the relief port. They are commonly used to eliminate air pockets in steam mains and risers. They exhaust discharge directly through the vented relief port.

		Inlet
	Max. Steam Pressure, psi	Pipe Size	Location	Relief Port Location	Max. Temp., ° F	Overall Ht.		Each
NPT Male Relief Vent







				Brass Body

				15	3/4	Bottom	Top	250	3 1/2"	4926K52	000000

Inline Air-Release Valves for Water

Eliminate air pockets without stopping flow—these valves have an internal wire brush that traps air bubbles and discharges them through the top relief port while allowing inline flow from the inlet to the outlet. They are often used to increase efficiency in heating and cooling systems. The vented relief port exhausts discharge directly. Valves have a durable bronze body for a long service life.

	Inlet		Outlet
	Pipe Size	Location	Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Temp. Range, ° F	Overall Ht.	End-to-End Lg.		Each
NPT Female Inlet, NPT Female Outlet and Relief Vent







				Bronze Body—Vertical Mount

				3/4	Side	3/4	Side	Top	125	40 to 240	6 15/16"	2 11/16"	4742T11	0000000


				1	Side	1	Side	Top	125	40 to 240	6 1/2"	3 1/8"	4742T12	000000

Key-Operated Air-Release Valves for Water

Turn the key to manually release air from radiators, heaters, and other hot water equipment. These valves have a vented relief port that exhausts discharge directly. Body is nickel-plated brass for good corrosion resistance.

	Valves								Replacement Keys
	Inlet
	Pipe Size	Location	Relief Port Location	Max. Pressure, psi	Temp. Range, ° F	Overall Ht.		Each		Each
NPT Male Inlet and Relief Vent







				Nickel-Plated Brass Body—Any-Angle Mount

				1/8	Bottom	Side	150	33 to 200	13/16"	1813K31	000000	1813K21	00000