A nominal 2-inch gate valve is a DN50 valve whose face-to-face length, height, and weight change with pressure class and end connection.
Pipe runs measured for one class rarely accept the other, so the tag matters less than the spec sheet. Four variables drive 2-inch gate valve specs and dimensions: pressure class, end connection, body style, and the standard the casting was built to.
What Does 2-Inch Mean On A Gate Valve?
A 2-inch gate valve is nominal size — DN50 — not an outside diameter or a length you can measure. It describes the pipeline bore the valve matches, so one “2-inch” label covers castings differing by hundreds of pounds.
On a carbon steel flanged Class 150 valve, a typical spec sheet cites ASME B16.5 for the flange pattern, ASME B16.10 for face-to-face length, API 600 for design, and API 598 for testing. The body is usually WCB carbon steel with a flexible wedge, rising stem, handwheel, and metal seating. Change the class or end connection and all of it moves.
A common mistake is ordering by measurement alone. Measure the existing valve’s length and flange pattern, then match those numbers to the pressure class instead of trusting a generic listing.
Spec field list:
- Size: 2 in / DN50 nominal
- Pressure class: 150, 300, 600, 900, 1500, or 2500
- End connection: flanged to ASME B16.5, or threaded
- Face-to-face length: set by ASME B16.10
- Body and trim: WCB carbon steel with a metal seat
- Stem and operation: rising stem, handwheel
2-Inch Gate Valve Dimensions By Pressure Class
| Pressure Class | Face-To-Face (Raised Face) | Approximate Weight |
|---|---|---|
| Class 150 | 7.00 in (178 mm) | 17 kg (37 lb) |
| Class 300 | 8.50 in (216 mm) | 30 kg (66 lb) |
| Class 600 | 11.50 in (292 mm) | 45 kg (99 lb) |
| Class 900 | 14.50 in (368 mm) | 95 kg (209 lb) |
| Class 1500 | 14.50 in (368 mm) | 95 kg (209 lb) |
| Class 2500 | 17.75 in (451 mm) | 135 kg (298 lb) |
Two details catch people out. Class 900 and Class 1500 share the same 14.50-inch length but not the same wall thickness, so length alone never identifies a valve. Weight nearly doubles between Class 150 and Class 600, changing how the line must be supported.
These lengths follow the ASME B16.10 face-to-face convention for raised-face flanged ends, as listed in a gate valve face-to-face dimension chart for 2-inch valves. Other facing styles are dimensioned separately, so match the facing on the existing valve before ordering.
OS&Y vs. NRS: Two Heights For The Same 2-Inch Size
Outside screw and yoke (OS&Y) and non-rising stem (NRS) gate valves in 2-inch nominal size are separate castings with separate heights. A catalog listing shows a Series 6700 OS&Y model 6702 standing 15¾ inches open, while the Series 6800 NRS model 6802 stands 9⅞ inches.
An OS&Y stem rises as the valve opens, so it needs overhead clearance an NRS valve does not. OS&Y valves show stem position at a glance, suiting industrial and fire-protection lines; NRS valves fit where a rising stem has no room, such as buried service reached through a valve box.
Installation follows one rule for both: the valve sits upright in a horizontal line with the handwheel vertically above the valve centerline, per the maker’s manual. Sideways mounting loads the wedge and seat in ways they were not built for.
Pin down four fields before ordering — nominal size, pressure class, end connection, and face-to-face standard — and confirm the flange drilling against ASME B16.5. If comparing makes first would help, this tested roundup of 2-inch gate valves sorts them by class and connection type.
FAQs
Is A 2-Inch Valve The Same As DN50?
Yes. DN50 is the metric name for the same nominal 2-inch bore, and the two labels are interchangeable on spec sheets. Neither is a physical measurement of the valve body — actual outside dimensions come from the pressure class, end connection, and the standard the casting was built to.
Why Is A Class 600 Valve Longer Than A Class 150?
Higher pressure classes need thicker walls and heavier flanges to hold the same bore. ASME B16.10 assigns a face-to-face length for each class reflecting that extra metal, which is why a 2-inch valve grows from 7.00 inches at Class 150 to 11.50 inches at Class 600 and 17.75 inches at Class 2500.
Can A Gate Valve Be Mounted Sideways?
No. Manufacturer guidance calls for the valve upright in a horizontal line, with the handwheel vertically above the valve centerline. Sideways or upside-down mounting loads the wedge and seat differently than designed, can trap debris against the seating surface, and shortens service life.
References & Sources
- Arindo. “Gate Valve Dimensions By Pressure Class” Supports the face-to-face lengths and weights for 2-inch valves from Class 150 through Class 2500.
- Mueller. “Resilient Wedge Gate Valves, 2–3 Inch” Covers AWWA C509 coverage, the 200 psig cold working pressure rating, and the 6702 and 6802 model dimensions.
- DHV Industries. “API 600 Gate Valve Manual” Source for API 600, ASME B16.34, ASME B16.5, and ASME B16.10 references, the nominal size and pressure ranges, and the upright installation guidance.
