Elastomeric foam (elastomeric foam) is the preferred material for cold pipes and refrigeration systems, because the closed-cell structure itself acts as a vapour barrier. We go through its properties, temperature limits, gluing and the practical working rules from the basic course.
Introduction
Elastomeric foam is a flexible, elastomeric closed-cell foam. It is precisely the closed-cell structure that makes the material a strong vapour retarder, so it is well suited to cold pipes and refrigeration systems, where condensation would otherwise collect. The material is supplied as tubes and as sheets/rolls and is glued together at the joints.
Properties and limits
- 01Elastomeric foam (FEF) according to EN 14304.
- 02Thermal conductivity at 0 °C for AF/Armaflex: at most 0.033 W/(m·K) for tubes AF-1 to AF-4 and sheets 3-32 mm, at most 0.036 for tubes AF-5/AF-6 and 50 mm sheets. It increases with temperature, so always look it up at the mean temperature.
- 03Medium temperature up to +110 °C for AF/Armaflex (+85 °C if sheet or tape is glued over the whole surface) and down to −50 °C — check the data sheet for your product. Not a high-temperature material.
- 04Best for cold pipes and refrigeration; the closed cell acts as a built-in vapour barrier.
- 05Not for outdoor use without protection — UV and weather degrade the surface.
Why the μ-value matters
The μ-value (water vapour diffusion resistance factor) tells how hard it is for water vapour to pass through the material, compared with air. The higher the μ, the better a vapour retarder the material is in itself. On a cold pipe, the water vapour in the air will move towards the cold surface. With a high μ-value, the vapour does not get there, and no condensation forms inside the insulation. AF/Armaflex has μ ≥ 10,000 for tubes AF-1 to AF-4 and sheets up to 32 mm, and μ ≥ 7,000 for AF-5/AF-6 and 50 mm sheets. But the μ-value only helps if all joints are glued tight.
Members only
The rest of the article is locked
Create a free user account to unlock all articles, calculators, templates and range — and get access to quizzes and classes. It takes less than a minute: name, email and a password. No payment card.
Want to try something first? See what you can use without an account — the junior zone, the encyclopedia, the videos and more.