Pipe insulation foam is chosen for two jobs at once: stopping heat gain or loss, and stopping condensation. The second job is the one that causes most field failures, because condensation is a moisture problem rather than a thermal one — and only a closed-cell foam solves it.
Why Pipe Insulation Foam Has to Be Closed-Cell
On a chilled-water or refrigerant line the pipe surface sits below the dew point of the surrounding air. If the insulation can absorb that moisture, the water travels inward, the insulation loses its thermal value and the pipe corrodes. A closed-cell foam has no path for water to travel through it, so the condensation stays on the surface and drains away.
Which Foam for Which Line
| Property | XPE | IXPE | IXPP |
|---|---|---|---|
| Cross-linking | Chemical | Irradiation | Irradiation |
| Expansion ratio | 3–40x | 3–40x | 5–25x |
| Single-layer thickness | 3–15 mm | 0.1–15 mm | 1–6 mm |
| Laminated build | 15–200 mm | 15–200 mm | 6–100 mm |
| Sheet width | 500–2000 mm | 500–2000 mm | 500–1500 mm |
| Thermal conductivity | 0.040–0.095 W/m·K | 0.040–0.095 W/m·K | Lower than PE foam |
| Water absorption (GB/T 1034) | 0.4% or lower | 0.4% or lower | — |
| Maximum service temperature | — | — | 140 °C |
The choice follows the line temperature. Chilled water and refrigerant lines take XPE or IXPE. Hot lines and equipment surfaces that exceed the working range of polyethylene take IXPP, which is rated to 140 °C and resists boiling water.
Choosing the Thickness
Required insulation thickness is set by the line temperature, the ambient temperature and humidity, and the condensation-control standard the installer works to. It is not a single number — the same pipe needs a different wall in a dry plant room than in a humid one.
What we can tell you is the range available. XPE and IXPE are produced in single layers from 3 mm and 0.1 mm respectively, up to 15 mm, and can be laminated into builds from 15 to 200 mm. IXPP runs from 1 mm to 6 mm in a single layer and 6 to 100 mm laminated. Tell us the line temperature and the ambient conditions and we will confirm which build is available for your case.
Foil Facing and Self-Adhesive Backing
- Aluminium foil facing adds a reflective surface and, more importantly, a vapour barrier. On a chilled line this is what keeps humid air away from the cold surface.
- Self-adhesive backing — a solvent-based adhesive under a release liner — lets an installer wrap a pipe in one pass without separate glue, which matters most on long runs and tight radii.
- Embossing and printing are available for branded or textured wraps.
- Flame-retardant grade with a limiting oxygen index of 27 is available where a project specifies it, meeting GB 8410 A0 and UL94 V2.
Where the Foam Goes
Beyond the pipe itself, the same foam insulates air-conditioning ducts, unit casings and panels, and is die-cut into tees and fittings. See the HVAC insulation foam hub for the full range of parts we make.
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Pipe Insulation Foam FAQ
What foam is used for pipe insulation?
Closed-cell polyethylene foam — XPE or IXPE for chilled and ambient-temperature lines, IXPP where the line runs hot. The closed cell structure is what prevents condensation from being absorbed into the insulation.
How thick should pipe insulation foam be?
Thickness follows the line temperature, the ambient humidity and the condensation-control standard being applied, so there is no single figure. We supply XPE and IXPE from 3 mm and 0.1 mm in single layers up to 15 mm, laminated to 200 mm, and IXPP from 1 mm to 6 mm, laminated to 100 mm.
Should pipe insulation foam have a foil facing?
On a chilled line, yes — the foil acts as the vapour barrier that keeps humid air away from the cold surface. On lines that are not at risk of condensation the foil is optional and is chosen for its reflective surface or for mechanical protection.
Related Reading
See also: HVAC & duct insulation foam · Is XPE foam waterproof? · All cross-linked foam materials · Contact Bofeng Foam