W21.8 CO2 cylinder valve (W21.8-14 (DIN 477 / BS 341 No.8))
Where W21.8-14 (DIN 477 / BS 341 No.8) is used, its real dimensions, and how to connect it to other keg fittings.
Published dimensions
- Designation
- W21.8-14 (DIN 477 / BS 341 No.8)
- Size / thread
- W21.8 x 1/14" (22 mm, 14 TPI)
- Fitting form
- cylinder valve outlet nut, external
- Seals on
- captive O-ring or washer in the nut against the valve outlet
- Rating / role
- the European, UK, Oceania and Asian CO2 cylinder connection
Used on: the outlet of refillable CO2 cylinders across Europe, the UK and Australia; also called DIN 477, BS 341 No.8 and Type 30.
W21.8 does the same job as CGA-320 but is the rest-of-world standard. The two are not interchangeable, so a US regulator brought to Europe needs a CGA-320 to W21.8 adapter. Confirm your cylinder outlet before buying a regulator on the wrong side of the split.
Flare fittings seal on the 45 degree flare face and must never be taped. Push-in fittings seal on an O-ring against the tube wall and need the tube cut square. Barbs seal under a worm clamp. Getting the sealing method right matters more than the thread label, because most homebrew leaks are a taped flare or an unclamped barb.
Connect this fitting
Sources: CO2Art guide to cylinder connections (CGA320, W21.8, DIN477, BS341, G5/8, TR21-4)