300PSI Butterfly Valve with Gearbox/Lever - Wafer End WD-371G/WD-371L

Q: Which internal materials are used in the WD-371 wafer butterfly valve stem and disc to ensure corrosion resistance?

The WD-371 series utilizes dual 416 Stainless Steel shafts paired with WCB sealing nuts. The disc features a Ductile Iron core fully encapsulated with EPDM rubber, while the stem is supported by PTFE / C95400 bushings.

Date Updated: July 29, 2026
Prepared by: Fire Gate Valve Technical Department

Categories:

Butterfly Valve

Compliance Credentials: Strictly certified to UL 260 and FM standards for high-hazard critical infrastructure

Butterfly Valve with Gearbox/Lever

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300PSI Butterfly Valve with Gearbox/Lever - Wafer End WD-371G/WD-371L

▏Product Description

The 300PSI Butterfly Valve with Gearbox/Lever - Wafer End WD-371G/WD-371L engineered by Ningjin APC Industries is a high-performance fire protection valve designed for demanding indoor and outdoor fire-fighting applications. Built with a heavy-duty ductile iron body and an EPDM fully encapsulated disc, this wafer-type butterfly valve ensures flawless bubble-tight sealing and exceptional resistance to tuberculation and corrosion. Featuring dual 416 stainless steel upper and lower shafts supported by PTFE / C95400 stem bushings, the WD-371 series provides long-term operational reliability with ultra-low operating torque.

Engineered to meet stringent international standards, this model delivers a maximum working pressure of 300 PSI and a test pressure of 600 PSI. It serves as a reliable solution for high-rise fire standpipe systems, commercial fire inflow water lines, and industrial factory fire safety infrastructure where pressure conforms to UL 1091 & ULC / ORD-C1091 & FM 1112 standards. Compatible with ANSI 125/150 and DIN2501 PN10/16 flange connections, it features a standardized ISO 5211 top flange for effortless actuator installation and gear/lever interchangeability, with optional lead-free NSF/ANSI 61 and NSF/ANSI 372 compliance upon request.

▏Technical Features

Connection Standard	ANSI125/150, DIN2501 PN10/16
Sizes	2", 2½", 3", 4", 5", 6", 8", 10", 12"
Maximum Working Pressure	300 PSI
Maximum Testing Pressure	600 PSI
Pressures Conformance	Pressures conforms to UL1091 & ULC / ORD-C1091 & FM 1112
Maximum Working Temperature	80°C / 176°F
Coating Details	Epoxy coated or coating upon request
Disc Construction	Ductile iron disc– EPDM Encapsulated
Top Flange Standard	ISO 5211
Lead-Free Certification Option	Certified lead-free by NSF / ANSI 61 & NSF / ANSI 372 is available
Application Range	Indoor & Outdoor Use, Fire inflow water, drain pipe, high-rising building fire fighting system, industrial factory building fire protection system

▏Valve Material List

NO.	Description	Material
1	Upper Shaft Sealing Nut	WCB
2	Shaft Seal	EPDM
3	Body	Ductile Iron
4	Upper Shaft	416 Stainless Steel
5	Disc+Rubber Seat	Ductile Iron+EPDM
6	Lower Shaft	416 Stainless Steel
7	Lower Shaft Sealing Nut	WCB
8	End Face Seal	EPDM
9	Stem Bushing	PTFE / C95400
10	O-Ring	EPDM
11	Lever
12	Gearbox

▏Dimensions

Size	A	B	C	D	H1	H2	K1	K2	J	P	M	N	d	L
2"	110	85	32	100	32	65	267	151	152	90	70	9	10	42
2½"	125	95	32	112	32	65	267	151	152	90	70	9	10	44.2
3"	140	100	32	120	32	65	267	151	152	90	70	9	11	45.3
4"	160	100	32	161	32	65	267	151	152	90	70	9	14	52
5"	170	125	32	182	32	65	267	151	152	90	70	9	14	54.4
6"	190	140	32	216	32	65	267	146	200	90	70	9	16	55.8
8"	230	175	37(lever) 32(gear)	260	37	77	353	233	290	125	102	12	19	60.5
10"	260	200	45	320	/	77	/	233	290	125	102	12	24	66.5
12"	300	240	45	375	/	118	/	244	350	150	125	14	26	76.9

▏FAQ

Q1: What pressure standards and testing levels does the WD-371 series fire butterfly valve comply with?

The WD-371G/WD-371L butterfly valve is engineered for high-pressure safety systems with a Maximum Working Pressure of 300 PSI and a shell/seat test pressure of 600 PSI. Its pressure design fully conforms to UL 1091, ULC / ORD-C1091, and FM 1112 requirements. It is suitable for high-rise fire standpipe lines, drain pipes, and industrial fire protection systems.

Q2: Which internal materials are used in the WD-371 wafer butterfly valve stem and disc to ensure corrosion resistance?

The WD-371 series utilizes dual 416 Stainless Steel shafts (Upper Shaft NO. 4 & Lower Shaft NO. 6) paired with WCB upper and lower shaft sealing nuts. The disc features a Ductile Iron core fully encapsulated with EPDM rubber (NO. 5), while the stem is supported by low-friction PTFE / C95400 bushings and EPDM O-rings, ensuring zero leakages and superior torque stability.

Q3: How does the ISO 5211 top flange facilitate lever, gear operator, or actuator conversion?

Equipped with a standard ISO 5211 mounting pad, the WD-371 series supports direct installation of gearboxes (WD-371G) or lever handles (WD-371L) as well as electric/pneumatic actuators. For 8" models, shaft drive details feature C dimensions of 37mm for lever and 32mm for gear, enabling seamless field retrofit and automated monitoring integrations. For more details on custom configurations, visit our high pressure wafer butterfly valve series.

Q4: Are WD-371 butterfly valves suitable for dual fire protection and potable water service?

Yes. Beyond standard epoxy-coated fire protection water lines, the WD-371 wafer butterfly valve offers optional NSF/ANSI 61 & NSF/ANSI 372 lead-free certifications. This allows fire protection contractors to specify the valve for dual-purpose systems carrying both fire inflow water and potable drinking water without compromising health or safety regulations.

Q5: What flange specifications and face-to-face dimensions are supported across the 2" to 12" size range?

The WD-371 series is dual-flange compatible with ANSI 125/150 and DIN2501 PN10/16 standards. Face-to-face dimension (L) ranges from 42mm (2") up to 76.9mm (12"), with exact laying lengths such as 52mm for 4" and 55.8mm for 6", providing standard drop-in replacements for global EPC fire sprinkler and standpipe installations.

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