PUR/PIR Board PIR-35
Grade
ASTM C591 · EN 13165 · JIS A9511 · GB GB/T 21558
PIR-35 = polyisocyanurate board, ~32–40 kg/m³
Pick when higher temperature capability, better char formation and lower smoke/fire spread than plain PUR are required.
Values for the PIR-35 condition
Other PUR/PIR Board grades and fills
PUR/PIR Board is listed in 7 conditions; see the grade overview at PUR/PIR Board.
Compare all 7 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
PUR-30Default Unfaced rigid polyurethane board, ~30–35 kg/m³ | Default generic boardstock for building walls/roofs and equipment insulation where ≤100 °C and standard 0.15 MPa compressive class suffice. | — | 0.28 | 8 | — |
PIR-35This page Polyisocyanurate board, ~32–40 kg/m³ | Pick when higher temperature capability, better char formation and lower smoke/fire spread than plain PUR are required. | — | 0.32 | — | — |
Flame-retardant grade to GB 8624 B1 / EN 13501 Class D-E | Use where building fire regulations demand B1(B)/B-s1,d0 class external wall or duct insulation. | — | 0.32 | 6 | — |
cryogenic-service PIR, LNG/LIN lines to −196 °C | Choose for LNG, ethylene and liquid-nitrogen pipework/tanks needing low-temperature dimensional stability and low thermal contraction cracking. | — | 0.4 | 5 | — |
High-density board ~48 kg/m³ | Pick for trafficked roofs, tank bases and pipe insulation where higher compressive strength and creep resistance are needed. | — | 0.5 | 7 | — |
Glass-fibre reinforced PIR boardstock | Use where reduced thermal contraction/cracking and higher flexural stiffness are needed on large-diameter cold pipe or roof decks. | — | 0.5 | 4 | — |
Load-bearing / pipe-support block, 80–160 kg/m³ | Use for cryogenic pipe shoes, tank supports and structural inserts where compressive load, not lambda, governs. | — | 1 | 6 | — |
What is PUR/PIR Board PIR-35?
PUR/PIR Board PIR-35 is PUR/PIR Board in the PIR-35 grade — pick when higher temperature capability, better char formation and lower smoke/fire spread than plain PUR are required. PUR/PIR Board PIR-35 has a tensile strength of 0.32 MPa (0.0464 ksi), weaker than 93% of polymer grades. Elongation at break is 8% and the elastic modulus is 0.01 GPa (7.25×10⁻⁴ Msi). PUR/PIR Board PIR-35 has a density of 0.04 g/cm³ (0.0013 lb/in³), lighter than 92% of polymer grades. Its glass-transition temperature is 180°C (356 °F). PUR-30 is the default condition FabDigit quotes; PIR-35 is available on request or by drawing note.
Advantages
- Easy to machine — 95/100, better than 100% of polymer grades
- Lightweight — 0.04 g/cm³ (0.0013 lb/in³), better than 92% of polymer grades
Limitations
- Poor heat conductor — 0.02 W/m·K (0.0133 BTU/hr·ft·°F), worse than 100% of polymer grades
- Absorbs moisture — dry before molding — 2%, worse than 97% of polymer grades
- Low stiffness — 0.01 GPa (7.25×10⁻⁴ Msi), worse than 89% of polymer grades
- Difficult to weld — 5/100, worse than 89% of polymer grades
- Degrades in UV without stabilisers — 20/100, worse than 88% of polymer grades
PUR/PIR Board PIR-35 properties
Typical room-temperature values for PUR/PIR Board PIR-35; 11 are specific to this condition. Other listed values are PUR/PIR Board reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
PUR/PIR Board PIR-35 has a density of 0.04 g/cm³ (0.0013 lb/in³), lighter than 92% of polymer grades. Its glass-transition temperature is 180°C (356 °F).
Mechanical11
PUR/PIR Board PIR-35 has a tensile strength of 0.32 MPa (0.0464 ksi), weaker than 93% of polymer grades. Elongation at break is 8% and the elastic modulus is 0.01 GPa (7.25×10⁻⁴ Msi).
Thermal8
PUR/PIR Board PIR-35 is rated for continuous service to 120°C (248 °F). It conducts heat at 0.02 W/m·K (0.0133 BTU/hr·ft·°F), worse than 100% of polymer grades. Thermal expansion is 60 µm/m·K (33.3 µin/in·°F).
Electrical3
PUR/PIR Board PIR-35 has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 52% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PUR/PIR Board PIR-35 takes about 105 MJ of energy and emits 5 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 5%.
Manufacturability3
PUR/PIR Board PIR-35's machinability is excellent (95/100, better than 100% of polymer grades); weldability not recommended (5/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PUR/PIR Board PIR-35
Is PUR/PIR Board easy to machine?
Cuts cleanly with hot wire, band saw, router or knife; use dust extraction and avoid overheating (isocyanate/amine fumes), and deburr crumbly cell faces before bonding.
Can PUR/PIR Board be welded?
Thermoset — cannot be welded; join with PU/epoxy adhesives, tapes, or foamed-in-place gap fill.
Can PUR/PIR Board be formed, bent or molded?
Made continuously on a double-belt laminator (or discontinuously in block moulds) then cut to thickness; no post-forming, but thin boards can be thermally curved slightly for pipe segments.
What surface finishes work on PUR/PIR Board?
Requires protective facing — foil, glass-mat, bitumen, metal skin, render or mastic/vapour barrier — for UV, fire and mechanical protection; surfaces accept water-based coatings after light abrasion.
PUR/PIR Board chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| polymeric MDI (isocyanate)PIR uses higher isocyanate index (>250) than PUR (~110) | 45 – 60 | 52 |
| flame retardant (TCPP/phosphate) | 2 – 10 | 5 |
| blowing agent (n-/iso-pentane or HFO-123 | 3 – 8 | 5 |
| silicone surfactant + catalysts (K-octoa | 1 – 3 | 2 |
| water (co-blowing) | 0.1 – 1 | 0.4 |
| polyester/polyether polyolaromatic polyester polyol typical for PIR boardstock | ≥ 30 (balance) | — |
PUR/PIR Board PIR-35 — frequently asked
What is PUR/PIR Board PIR-35 used for?
PUR/PIR Board PIR-35 is typically used for roof and wall insulation boards, cold-chain and refrigeration panels, sandwich panel cores and duct and pipe insulation. In short: lowest-conductivity board insulation; PIR improves fire behaviour; thermoset, no post-forming.
What is the tensile strength of PUR/PIR Board PIR-35?
PUR/PIR Board PIR-35 has a typical tensile strength of 0.32 MPa (0.0464 ksi) — weaker than 93% of polymer grades. Strength varies by condition: see the 7 listed tempers.
Is PUR/PIR Board PIR-35 easy to machine?
Yes — machinability is rated excellent (95/100, better than 100% of polymer grades). Cuts cleanly with hot wire, band saw, router or knife; use dust extraction and avoid overheating (isocyanate/amine fumes), and deburr crumbly cell faces before bonding.
Can PUR/PIR Board PIR-35 be welded?
Not readily — weldability is rated not recommended (5/100). Thermoset — cannot be welded; join with PU/epoxy adhesives, tapes, or foamed-in-place gap fill.
What surface finishes work on PUR/PIR Board PIR-35?
Requires protective facing — foil, glass-mat, bitumen, metal skin, render or mastic/vapour barrier — for UV, fire and mechanical protection; surfaces accept water-based coatings after light abrasion.
Can PUR/PIR Board PIR-35 be formed, bent or molded?
Made continuously on a double-belt laminator (or discontinuously in block moulds) then cut to thickness; no post-forming, but thin boards can be thermally curved slightly for pipe segments.
What is the maximum service temperature of PUR/PIR Board PIR-35?
PUR/PIR Board PIR-35 is rated for continuous use to about 120°C (248 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 13165 — Thermal insulation products for buildings: factory made rigid polyurethane foam (PU) products — CEN (2016)
- ASTM C591 — Unfaced Preformed Rigid Cellular Polyisocyanurate Thermal Insulation — ASTM International (2022)
- ASTM C1289 — Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board — ASTM International (2022)
- Handbook of Polymeric Foams and Foam Technology — Hanser (2004)
- Rigid PIR boardstock and pipe insulation datasheets — Kingspan / Recticel / Dyplast / Huntsman (2023)
- Rigid polyurethane foam LCA and embodied-energy ranges — ICE / CES-type material data (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.