Phenolic Foam
GB GB/T 20974
Phenolic Foam is a rigid, closed-cell phenol-formaldehyde thermoset insulation covered by GB/T 20974, offering 0.023 W/m·K thermal conductivity at 45 kg/m³ (0.045 g/cm³) with low smoke and toxicity on combustion.
Reference datasheet — Phenolic Foam is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the PF-045 condition
Phenolic Foam grades and fills
Phenolic Foam is supplied in 6 conditions, soft to hard. PF-045 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Low density board, ~30–40 kg/m³ | Pick for roof and sandwich-core fill boards where lowest cost and lowest conductivity of 0.022 W/m·K govern; strength and resistance to dusting are the weakest of the range. | 0.09 | 1.5 | ||
PF-045Default Standard building board, ~40–50 kg/m³ | Use as the mainstream GB/T 20974 external wall and roof board density, giving the best balance of 0.023 W/m·K conductivity and 0.15 MPa tensile strength. | 0.15 | 2 | ||
Medium density, ~55–65 kg/m³ | Choose for facades, floors or composite air-duct panels needing higher compressive and wind-load capacity, accepting 0.025 W/m·K conductivity at 55–65 kg/m³. | 0.22 | 2 | ||
Toughened / modified phenolic foam | Use where dusting and brittleness must be cut for thin-render wall systems; polyether/polyurethane or nano-filler toughening gives 4% elongation but limits service to 140 °C. | 0.25 | 4 | ||
Glass-fibre reinforced phenolic foam | Choose for air-duct panels and large board areas needing higher bending strength, dimensional stability and crack resistance; 3–8% chopped glass fibre lowers machinability to 75. | 0.28 | 1.5 | ||
High density, ~70–90 kg/m³ | Pick for pipe insulation shells, equipment lagging and load-bearing positions where 0.32 MPa strength is required and conductivity rising to 0.028 W/m·K is acceptable. | 0.32 | 2.5 |
Supply forms, finishes and certifications
Ways Phenolic Foam is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOIL | Aluminium-foil / glass-scrim faced composite board | Supply form |
What is Phenolic Foam?
Phenolic Foam is a rigid, closed-cell phenol-formaldehyde thermoset insulation covered by GB/T 20974, offering 0.023 W/m·K thermal conductivity at 45 kg/m³ (0.045 g/cm³) with low smoke and toxicity on combustion. It is used as board, pipe section and sandwich-panel core where fire performance and dimensional stability govern, in plain, modified, glass-reinforced and foil-faced conditions. Strength is low (0.15 MPa tensile, 0.012 GPa modulus), the foam is friable and residually acidic, and service temperature is limited to 150 °C. PIR board is the usual alternative where friability or acid attack on metals is a concern. Phenolic Foam has a density of 0.05 g/cm³ (0.0016 lb/in³), lighter than 90% of polymer grades. Phenolic Foam has a tensile strength of 0.15 MPa (0.0218 ksi), weaker than 97% of polymer grades. Elongation at break is 2% and the elastic modulus is 0.01 GPa (0.0017 Msi).
What is Phenolic Foam used for?
- Building wall/roof insulation
- HVAC duct and pipe insulation
- Fire-rated sandwich panel cores
- Cold-chain/cryogenic insulation
Advantages
- Easy to machine — 90/100, better than 95% of polymer grades
- Lightweight — 0.05 g/cm³ (0.0016 lb/in³), better than 90% of polymer grades
- High service temperature — 150°C (302 °F), better than 79% 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 — 3%, worse than 99% of polymer grades
- Difficult to weld — 1/100, worse than 96% of polymer grades
- Limited ductility — 2%, worse than 95% of polymer grades
- Needs corrosion protection — 60/100, worse than 89% of polymer grades
Phenolic Foam properties
Typical room-temperature values for Phenolic Foam-PF-045; bars are the position among polymer grades.
Physical3
Phenolic Foam has a density of 0.05 g/cm³ (0.0016 lb/in³), lighter than 90% of polymer grades.
Mechanical9
Phenolic Foam has a tensile strength of 0.15 MPa (0.0218 ksi), weaker than 97% of polymer grades. Elongation at break is 2% and the elastic modulus is 0.01 GPa (0.0017 Msi).
Thermal8
Phenolic Foam is rated for continuous service to 150°C (302 °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 25 µm/m·K (13.9 µin/in·°F).
Electrical2
Phenolic Foam has an electrical resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 89% of polymer grades. UV resistance is poor.
Sustainability3
Producing a kilogram of Phenolic Foam takes about 95 MJ of energy and emits 4.5 kg of CO₂ — less than 70% of polymer grades. Typical recycled content is 0%.
Manufacturability3
Phenolic Foam's machinability is excellent (90/100, better than 95% of polymer grades); weldability not recommended (1/100); formability not recommended (10/100).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. Phenolic Foam is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Phenolic Foam
Is Phenolic Foam easy to machine?
Cuts easily with band saw, hot wire or CNC foam tooling (machinability score 90), but the material is brittle and sheds powder, so dust extraction and PPE are required. It cannot be tapped and will not carry fastener clamping loads.
Can Phenolic Foam be welded?
A thermoset, so heat welding is not possible. Seal and lap board joints with fire-rated adhesive, polyurethane adhesive or aluminium foil tape.
Can Phenolic Foam be formed, bent or molded?
Produced by continuous board-line pouring and foaming with oven cure at roughly 50–80 °C, or by cavity casting for pipe shells and profiled parts. Once cured it cannot be reformed.
Phenolic Foam 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 |
|---|---|---|
| blowing agent (pentane / HFO-1233zd / HFphysical blowing agent, sets initial thermal conductivity | 3 – 8 | 5 |
| acid curing catalyst (p-toluenesulfonic residual acidity is a source of metal corrosion | 5 – 12 | 8 |
| surfactant (silicone / castor-oil ethoxycontrols cell size and closed-cell content | 1 – 4 | 2 |
| toughener / plasticizerin MOD grades, reduces brittleness and dusting | 0 – 8 | 2 |
| glass fiberGF-reinforced grades | 0 – 8 | 0 |
| aluminium hydroxide / mineral fillerimproves fire performance and smoke suppression | 0 – 10 | 0 |
| phenol-formaldehyde resole resinmatrix resin, phenol/formaldehyde molar ratio about 1:1.5–1:2.2 | ≥ 70 (balance) |
What surface finishes work on Phenolic Foam?
Surfaces must be treated with a dedicated interface primer plus crack-resistant mortar and mesh, or faced with aluminium foil or glass cloth. Add a moisture barrier wherever the foam contacts carbon steel, copper or aluminium to avoid corrosion from residual acid.
Equivalent designations
Standards and trade names that resolve to Phenolic Foam in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- GB (China)
- GB/T 20974
How much does Phenolic Foam cost?
Phenolic Foam is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Phenolic Foam — frequently asked
What is Phenolic Foam used for?
Phenolic Foam is typically used for building wall/roof insulation, HVAC duct and pipe insulation, fire-rated sandwich panel cores and cold-chain/cryogenic insulation. In short: lowest-conductivity rigid foam board; low smoke and toxicity; brittle, non-load-bearing.
What is the tensile strength of Phenolic Foam?
Phenolic Foam has a typical tensile strength of 0.15 MPa (0.0218 ksi) — weaker than 97% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is Phenolic Foam easy to machine?
Yes — machinability is rated excellent (90/100, better than 95% of polymer grades). Cuts easily with band saw, hot wire or CNC foam tooling (machinability score 90), but the material is brittle and sheds powder, so dust extraction and PPE are required. It cannot be tapped and will not carry fastener clamping loads.
Can Phenolic Foam be welded?
Not readily — weldability is rated not recommended (1/100). A thermoset, so heat welding is not possible. Seal and lap board joints with fire-rated adhesive, polyurethane adhesive or aluminium foil tape.
What surface finishes work on Phenolic Foam?
Surfaces must be treated with a dedicated interface primer plus crack-resistant mortar and mesh, or faced with aluminium foil or glass cloth. Add a moisture barrier wherever the foam contacts carbon steel, copper or aluminium to avoid corrosion from residual acid.
Can Phenolic Foam be formed, bent or molded?
Produced by continuous board-line pouring and foaming with oven cure at roughly 50–80 °C, or by cavity casting for pipe shells and profiled parts. Once cured it cannot be reformed.
What is the maximum service temperature of Phenolic Foam?
Phenolic Foam is rated for continuous use to about 150°C (302 °F), and briefly to 200°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Phenolic Foam cost?
Phenolic Foam is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM C1126 Standard Specification for Faced or Unfaced Rigid Cellular Phenolic Thermal Insulation — ASTM (2018)
- EN 13166 Thermal insulation products for buildings — Factory made phenolic foam (PF) products — CEN (2012)
- Phenolic insulation board technical data (Kooltherm-type rigid PF board) — Kingspan / (2023)
- Handbook of Polymeric Foams and Foam Technology — phenolic foams chapter — Hanser (2004)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.