XPS Foam Core C578-X
Grade
ASTM C578 · GB GB/T 10801.2
C578-X = aSTM C578 Type X
Cheapest, lightest XPS for pure insulation or very lightly loaded sandwich skins.
Values for the C578-X condition
Other XPS Foam Core grades and fills
XPS Foam Core is listed in 8 conditions; see the grade overview at XPS Foam Core.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
C578-XThis page ASTM C578 Type X | Cheapest, lightest XPS for pure insulation or very lightly loaded sandwich skins. | 0.25 | 0.28 | 2.5 | — |
Flame-retardant grade | Mandatory grade for building envelopes and cold-store panels in China; polymeric brominated FR replaces HBCD. | 0.34 | 0.38 | 2.5 | — |
CO₂ / co-blown grade | Pick where HFC blowing agents are banned; slightly higher lambda than HFC/HFO boards. | 0.34 | 0.38 | 2.5 | — |
C578-IVDefault ASTM C578 Type IV | Default construction/sandwich grade — best balance of price, strength and lambda. | 0.36 | 0.4 | 3 | — |
HFO-blown high-R grade | Lowest thermal conductivity XPS with low-GWP blowing agent; premium price. | 0.36 | 0.4 | 3 | — |
ASTM C578 Type VI | Choose for floor slabs, plaza decks and sandwich panels with moderate face pressure. | 0.45 | 0.5 | 3 | — |
ASTM C578 Type VII | For loaded floors, cold-store bases and cores that must carry higher crush loads. | 0.54 | 0.6 | 3 | — |
ASTM C578 Type V | Highest-density XPS for runways, heavy-load floors and structural sandwich cores. | 0.76 | 0.85 | 3.5 | — |
What is XPS Foam Core C578-X?
XPS Foam Core C578-X is XPS Foam Core in the C578-X grade — cheapest, lightest XPS for pure insulation or very lightly loaded sandwich skins. XPS Foam Core C578-X has a yield strength of 0.25 MPa (0.0363 ksi) and a tensile strength of 0.28 MPa (0.0406 ksi) — weaker than 100% of composite grades. Elongation at break is 2.5% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi). XPS Foam Core C578-X has a density of 0.02 g/cm³ (7.59×10⁻⁴ lb/in³), lighter than 100% of composite grades. Its glass-transition temperature is 100°C (212 °F). C578-IV is the default condition FabDigit quotes; C578-X is available on request or by drawing note.
Advantages
- Lightweight — 0.02 g/cm³ (7.59×10⁻⁴ lb/in³), better than 100% of composite grades
- Easy to machine — 90/100, better than 94% of composite grades
- Low embodied carbon — 4.2 kg CO₂/kg, better than 88% of composite grades
- Good corrosion resistance — 90/100, better than 85% of composite grades
- Low moisture uptake — 0.1%, better than 85% of composite grades
Limitations
- Low strength — 0.25 MPa (0.0363 ksi), worse than 100% of composite grades
- Low stiffness — 0.01 GPa (8.7×10⁻⁴ Msi), worse than 98% of composite grades
- Limited service temperature — 70°C (158 °F), worse than 98% of composite grades
- Poor heat conductor — 0.03 W/m·K (0.0173 BTU/hr·ft·°F), worse than 98% of composite grades
- Degrades in UV without stabilisers — 20/100, worse than 94% of composite grades
XPS Foam Core C578-X properties
Typical room-temperature values for XPS Foam Core C578-X; 17 are specific to this condition. Other listed values are XPS Foam Core reference data and may not represent this condition. Bars are the position among composite grades.
Physical4
XPS Foam Core C578-X has a density of 0.02 g/cm³ (7.59×10⁻⁴ lb/in³), lighter than 100% of composite grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical11
XPS Foam Core C578-X has a yield strength of 0.25 MPa (0.0363 ksi) and a tensile strength of 0.28 MPa (0.0406 ksi) — weaker than 100% of composite grades. Elongation at break is 2.5% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi).
Thermal8
XPS Foam Core C578-X is rated for continuous service to 70°C (158 °F). It conducts heat at 0.03 W/m·K (0.0173 BTU/hr·ft·°F), worse than 98% of composite grades. Thermal expansion is 70 µm/m·K (38.9 µin/in·°F).
Electrical3
XPS Foam Core C578-X has an electrical resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 85% of composite grades. UV resistance is poor.
Sustainability3
Producing a kilogram of XPS Foam Core C578-X takes about 100 MJ of energy and emits 4.2 kg of CO₂ — less than 67% of composite grades. Typical recycled content is 10%.
Manufacturability1
XPS Foam Core C578-X's machinability is excellent (90/100, better than 94% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with XPS Foam Core C578-X
Is XPS Foam Core easy to machine?
Cuts cleanly with hot wire, knife, band saw or CNC router; use sharp tools, low feed pressure and vacuum extraction — static-charged dust sticks to everything.
Can XPS Foam Core be welded?
Not weldable in the metal sense; panels are joined by shiplap/tongue-and-groove joints and PS-compatible adhesives (water-based, PU or epoxy) — never solvent-based or polyester resin.
Can XPS Foam Core be formed, bent or molded?
Supplied as extruded board only; thermoforming is impractical — shape by cutting, grooving or CNC contouring, and add scrim/skin coats before laminating.
What surface finishes work on XPS Foam Core?
Bond FRP, cement board or metal facings with epoxy/PU; skin the surface or cover within a few weeks since UV rapidly chalks and embrittles the outer cells.
XPS Foam Core 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 (CO2 / HFC-134a / HFO-1234residual cell gas | 1.5 – 6 | 3 |
| flame retardant (polymeric brominated, eB1/E84 grades only | 0.5 – 3 | 1.5 |
| talc / nucleating agentcell-size control | 0.2 – 1.5 | 0.6 |
| pigment & processing aids | 0.1 – 1 | 0.3 |
| polystyrene (GPPS/recycled PS)matrix resin | ≥ 92 (balance) | — |
XPS Foam Core C578-X — frequently asked
What is XPS Foam Core C578-X used for?
XPS Foam Core C578-X is typically used for insulated roofing/wall sandwich panels, cold-chain panels and DIY composite core stock. In short: stronger and drier than EPS; board stock only; low-cost insulating core.
What is the yield strength of XPS Foam Core C578-X?
XPS Foam Core C578-X has a typical yield strength of 0.25 MPa (0.0363 ksi) and a tensile strength of 0.28 MPa (0.0406 ksi) — weaker than 100% of composite grades. Strength varies by condition: see the 8 listed tempers.
Is XPS Foam Core C578-X easy to machine?
Yes — machinability is rated excellent (90/100, better than 94% of composite grades). Cuts cleanly with hot wire, knife, band saw or CNC router; use sharp tools, low feed pressure and vacuum extraction — static-charged dust sticks to everything.
Can XPS Foam Core C578-X be welded?
Not weldable in the metal sense; panels are joined by shiplap/tongue-and-groove joints and PS-compatible adhesives (water-based, PU or epoxy) — never solvent-based or polyester resin.
What surface finishes work on XPS Foam Core C578-X?
Bond FRP, cement board or metal facings with epoxy/PU; skin the surface or cover within a few weeks since UV rapidly chalks and embrittles the outer cells.
Can XPS Foam Core C578-X be formed, bent or molded?
Supplied as extruded board only; thermoforming is impractical — shape by cutting, grooving or CNC contouring, and add scrim/skin coats before laminating.
What is the maximum service temperature of XPS Foam Core C578-X?
XPS Foam Core C578-X is rated for continuous use to about 70°C (158 °F), and briefly to 85°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between XPS Foam Core C578-IV and XPS Foam Core C578-V?
C578-IV is the default condition — default construction/sandwich grade — best balance of price, strength and lambda. C578-V: highest-density XPS for runways, heavy-load floors and structural sandwich cores. Yield strength is 0.36 MPa in C578-IV versus 0.76 MPa in C578-V.
Sources
- ASTM C578 Standard Specification for Rigid Cellular Polystyrene Thermal Insulation — ASTM International (2022)
- FOAMULAR XPS insulation product data — Owens Corning (2023)
- STYROFOAM Brand XPS technical data — Dow / DuPont Performance Building Solutions (2022)
- Rigid polystyrene foam property records — CES EduPack / Granta (2021)
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.