Armaflex Self Seal Class O Insulation 35mm x 9mm

Thin but effective, this Armaflex Self Seal Class O Insulation is pre-slit tube with adhesive already on the seam, sized for 35mm copper with a 9mm wall. That is the slim option, keeping heat in on runs through heated rooms and tight voids where a fatter sleeve will not fit.

What 35mm x 9mm Armaflex self seal insulation is used for

At 35mm you are usually in plant rooms, risers or commercial ceiling voids rather than a house. Closed cells keep moisture out of the foam, so it stays effective on cool pipes as well as hot. If the pipe runs somewhere cold, a thicker wall is the better pick.

• Bore: 35mm, for 35mm copper pipe
• Wall thickness: 9mm
• Overall size: about 53mm fitted
• Length: 2 metres

Bear that 53mm in mind for clip spacing and wall sleeves. Browse our pipe insulation for other bores and walls.

Line the slit up first, then peel the film and press the seam together, working along from one end. Run a hand along the full length to close it tight. On cold pipes, insulated supports stop condensation forming at the clips.

Where to buy 35mm x 9mm pipe lagging in Glasgow

The thin self seal tube for 35mm is sold at Plumb Parts, 555 South Street, Glasgow G14 0QX. Collection Mon-Fri 8am-5pm and Sat-Sun 8am-1pm. The website takes orders as well.

Specification

• Brand: Armaflex
• Range: Class O Self Seal
• Material: Closed cell elastomeric foam
• Connection: Pre-slit tube with self-adhesive seam
• Sizes: 35mm bore, 9mm wall, 2m long
• Standard or approval: Class O, as named
• Suitable for: Heating, hot and cold water pipework
• Pack quantity: One 2m tube

Common Questions

What is pipe insulation used for? It cuts heat loss from hot pipes and stops condensation forming on cold ones. It also helps protect pipes in colder spaces.

What is Armaflex insulation made of? It’s closed cell nitrile rubber. It resists water vapour, doesn’t shed fibres and stays flexible enough to follow gentle bends.

Can I install this insulation myself? Yes. Clean and dry the pipe, open the slit tube over it, peel the backing off the strips and press the seam shut, working from one end. Glue the butt joints between lengths with Armaflex adhesive.

What size insulation do I need for 35mm pipe? Choose a 35mm bore to match the pipe. The 9mm figure is the wall thickness, which is the slim option for heated spaces or tight boxing.

Is it Class O? Yes, it’s Class O to BS 476 Parts 6 and 7, so it suits jobs where the spec asks for that.

How many lengths will I need? Each length is 2m, so halve your run in metres and round up. Add one or two for the waste at bends, tees and valves.

Can I use it on chilled or cold pipes? Yes, the closed cell foam acts as its own vapour barrier. Seal every seam and joint and use insulated supports at the clips.