PIR/PUR pipe sections

Lambda value (declared, aged at 10 °C)

** 0.025-0.030 W/(m·K) for pipe sections; as low as 0.022 W/(m·K) for the best PIR products [dan-iso.dk, kingspan.com]

Lambda in pre-insulated district heating pipes (PUR blown with cyclopentane, λ50)

** 0.026 W/(m·K) [provak.no, logstor.com]

Initial λ (fresh, unaged)

** as low as 0.021-0.025 W/(m·K) [kingspan.com]

Temperature limit

** PUR approx. 90-100 °C (PUR foam begins to degrade at ~200 °C); PIR approx. 120 °C continuous, up to 140-150 °C short-term (PIR does not degrade until ~300 °C) [products.pcc.eu, logstor.com]

Reaction-to-fire class

** PUR typically class E (ignitable); PIR with flame retardant can achieve B-s1,d0 [bygningsfysik.dk, scandisupply.dk]

Closed-cell foam

** ~95-98 % closed cells — almost vapour-tight

Density (bulk weight)

** Soft pipe sections 30-40 kg/m³; rigid PIR sections 40-80 kg/m³; district heating PUR approx. 60-80 kg/m³ [logstor.com]

Diffusion resistance μ

** typically 30-100 (closed-cell → high resistance to water vapour)

Available thicknesses

** Pipe sections 20-100 mm; district heating pre-insulated pipes in 3 series (Series 1, 2, 3) with increasing insulation thickness [logstor.com]

Expected service life

** 50+ years for district heating; aged λ is declared after 25 years (EN ISO 8497 / EN 253) [kingspan.com, logstor.com]