Armaflex, Kaiflex and other elastomeric foams
The black, closed-cell rubber foam that makes cooling and HVAC pipes vapour-tight without an extra vapour barrier — the trade's number one for cold installations indoors.
Key figures
λ-value (thermal conductivity)
** ≤ 0.033 W/m·K at 0 °C for AF/Armaflex and Kaiflex KKplus s2 (tubes). Sheets and lower classes typically sit at 0.036–0.040 W/m·K at 0 °C [Cellegummi slanger.pdf p.3] [armacell.com] [kaimann.com].
Temperature range
** −50 °C to +110 °C for "ordinary" elastomeric foam (NBR-based) [Cellegummi slanger.pdf p.4] [armacell.com]. HT variants (EPDM-based) handle −50 °C to +150 °C [kaimann.com Kaiflex EPDMplus] [armacell.com HT/Armaflex]. Special types such as K-Flex ST go all the way down to −200 °C [kflex.com].
Fire class
** Standard elastomeric foam B/BL-s3,d0 per EN 13501-1 (corresponds to the old B1) [Cellegummi plader.pdf p.31] [armacell.com]. Low-burning variants (AF/Armaflex Evo) achieve B(L)-s2,d0; ArmaFlex Ultima achieves BL-s1,d0 [armacell.com].
µ-value (water-vapour diffusion resistance)
** ≥ 10,000 for AF/Armaflex and Kaiflex KKplus s2 — among the highest on the market. Standard Kaiflex EPDM ≥ 4,500 [Cellegummi slanger.pdf p.3] [kaimann.com].
sd-value (equivalent air-layer thickness)
** At 13 mm thickness and µ = 10,000 this gives sd ≈ 130 m. That is why elastomeric foam acts as a built-in vapour barrier.
Available thicknesses
** Tubes typically 6, 9, 13, 19, 25, 32 and 50 mm. Sheets/rolls 3, 6, 10, 13, 19, 25, 32, 40, 50 mm.
Tube dimensions
** Internal diameters from approx. 6 mm up to 89 mm. Above 89 mm, sheets are used [Cellegummi plader.pdf p.3, p.11, p.31].
Weight (density)
** approx. 40–80 kg/m³ depending on variant.
UV resistance
** Poor in the standard variant; must be painted or clad within 7 days for outdoor use [Cellegummi plader.pdf p.4].
Typical brands
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