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EVABarrier 5mm ID x 8mm OD line: 5 mm inner diameter, 8 mm outer diameter double-wall EVA line, double-wall EVA beer / gas tubing, seals on the 8mm OD is what a Duotight 8mm or John Guest 5/16 collet grips. What it fits and the adapters to join it to other keg fittings.

Updated 05 September 2026.

Bench / Fittings / Fitting

EVABarrier 5mm ID x 8mm OD line (5 mm ID / 8 mm OD)

Where 5 mm ID / 8 mm OD is used, its real dimensions, and how to connect it to other keg fittings.

Published dimensions

Designation
5 mm ID / 8 mm OD
Size / thread
5 mm inner diameter, 8 mm outer diameter double-wall EVA line
Fitting form
double-wall EVA beer / gas tubing
Seals on
the 8mm OD is what a Duotight 8mm or John Guest 5/16 collet grips
Rating / role
the common 8mm-system beer line; wider 5mm bore than the 4mm gas line
Tube OD
8 mm

Used on: beer lines on the 8mm Duotight system, where the 5mm bore balances flow and pour resistance.

Same 8mm outer wall as the 4mm line, so it uses the same 8mm push-in fittings, but the wider 5mm bore suits beer runs where the narrow 4mm line would pour too slowly. Pick the bore by duty: 4mm for gas, 5mm for beer, both on the same 8mm fittings.

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

Connect EVABarrier 5mm ID x 8mm OD line to Duotight 8mm push-indirect fitConnect EVABarrier 4mm ID x 8mm OD line to EVABarrier 5mm ID x 8mm OD linenot compatibleConnect Duotight ball-lock liquid QD (8mm) to EVABarrier 5mm ID x 8mm OD linedirect fitEVABarrier 4mm ID x 8mm OD linerelated fitting (4 mm ID / 8 mm OD)EVABarrier 6.3mm ID x 9.5mm OD linerelated fitting (6.3 mm ID / 9.5 mm OD)

Questions and answers

What is the designation of the EVABarrier 5mm ID x 8mm OD line (5 mm ID / 8 mm OD)?

5 mm ID / 8 mm OD

What is the size / thread of the EVABarrier 5mm ID x 8mm OD line (5 mm ID / 8 mm OD)?

5 mm inner diameter, 8 mm outer diameter double-wall EVA line

What is the fitting form of the EVABarrier 5mm ID x 8mm OD line (5 mm ID / 8 mm OD)?

double-wall EVA beer / gas tubing

What is the seals on of the EVABarrier 5mm ID x 8mm OD line (5 mm ID / 8 mm OD)?

the 8mm OD is what a Duotight 8mm or John Guest 5/16 collet grips