Pliable corrugated (stainless steel) tube is a semi rigid gas pipe that has the ability to bend and mould to curvature required. It is suitable for use in domestic, commercial and industrial applications.

The system is Kitemarked approved to BS7838:1996 – Specification for corrugated stainless steel semi-rigid pipe and associated fittings for low-pressure gas pipework of up to DN 50 and BS EN 15266:2007 – Stainless steel pliable corrugated tubing kits in buildings for gas with an operating pressure up to 0,5 bar.

Pliable corrugated (stainless steel) tube is typically available in DN sizes:

DN10/12 DN15 DN20/22 DN25/28 DN32 DN40 DN50

Pliable corrugated (stainless steel) tubing can form to either a metal to metal seal or use elastomeric seals. No special tools are required: a wheeled tube cutter with a stainless steel wheel, a utility knife and correctly sized spanners. The use of jointing compounds between the metal to metal sealing face is prohibited.

After the gas tightness test – care must be taken after pressure test to ensure that no stainless steel pipe is visible. Any portions of exposed stainless steel behind the fitting nut shall be wrapped with self-amalgamating silicone tape.

General installation requirements:

  • Pliable corrugated (stainless steel) tubing still needs to be sleeved where it passes through walls or solid floors.
  • Support intervals are similar to rigid pipe materials and the manufacturer will stipulate the maximum intervals within their installation instructions.
  • Pliable corrugated (stainless steel) tubing for direct burial must have a minimum 0.5mm outer cover that has a maximum chloride content of 50ppm.
  • Fittings need to remain accessible and should not be buried or conceals within the fabric of the building.

Special restrictions apply when passing pliable corrugated (stainless steel) tubing through a protected shaft containing a stair and/or lift or other protected fire escape route. BS6891:2015 states any pipe carrying gas installed in, or passing through, a protected area shall be:

  • steel pipework with screwed joints
  • steel pipework with welded joints
  • continuous length of copper (no joints)
  • continuous length of pliable corrugated (stainless steel) tubing manufactured to withstand Fire Test A of BS EN 1775:2007, Annex A

Note: Pliable corrugated (stainless steel) tubing manufactured to BS7838 meets Fire Test A. For pliable corrugated tubing manufactured to BS EN 15266 the manufacturer should be consulted.

Where pliable corrugates (stainless steel) tube passes through an unventilated void:

  • the void should be ventilated in accordance with the appropriate standard
  • the pliable corrugated (stainless steel) tube should be routed within a secondary containment for horizontal runs only (it is not possible to adequately support the internal pipe on vertical runs when installed with a secondary containment)
  • the void can be ventilated to a ‘normally occupied space’ providing continuous lengths of pliable corrugated (stainless steel) tube meeting BS 7838 and/or BS EN 1775 Annex A Fire Test A are used
  • double sleeved product can be used in both horizontal and vertical unventilated voids

The advantages of pliable corrugated (stainless steel) tubing – installs faster, easier and safer!

Always seek professional advice.

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