C578 Type XIV GPS
Additive grade
GPS = graphite-enhanced EPS (grey/silver bead) at Type XIV density
Pick when the same 276 kPa load capacity is needed with roughly 10–15% lower thermal conductivity.
Values for the GPS condition
Other C578 Type XIV grades and fills
C578 Type XIV is listed in 2 conditions; see the grade overview at C578 Type XIV.
- GEOFOAM
- GPS
Compare all 2 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
EPS39 geofoam block | Pick for lightweight embankment, bridge-abutment backfill and pavement base where 1% and 5% strain limits govern design. | 0.1 | 0.4 | 2 | — |
GPSThis page Graphite-enhanced EPS (grey/silver bead) at Type XIV density | Pick when the same 276 kPa load capacity is needed with roughly 10–15% lower thermal conductivity. | 0.24 | 0.42 | 2.2 | — |
What is C578 Type XIV GPS?
C578 Type XIV GPS is C578 Type XIV in the GPS grade — pick when the same 276 kPa load capacity is needed with roughly 10–15% lower thermal conductivity. C578 Type XIV GPS has a tensile strength of 0.42 MPa (0.0609 ksi), weaker than 91% of polymer grades. The elastic modulus is 0.01 GPa (0.0016 Msi). C578 Type XIV GPS has a density of 0.04 g/cm³ (0.0014 lb/in³), lighter than 91% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Advantages
- Lightweight — 0.04 g/cm³ (0.0014 lb/in³), better than 91% of polymer grades
- Easy to machine — 85/100, better than 88% of polymer grades
- Low embodied carbon — 3.3 kg CO₂/kg, better than 78% of polymer grades
Limitations
- Poor heat conductor — 0.03 W/m·K (0.0173 BTU/hr·ft·°F), worse than 96% of polymer grades
- Degrades in UV without stabilisers — 15/100, worse than 95% of polymer grades
- Low stiffness — 0.01 GPa (0.0016 Msi), worse than 80% of polymer grades
C578 Type XIV GPS properties
Typical room-temperature values for C578 Type XIV GPS; 16 are specific to this condition. Other listed values are C578 Type XIV reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
C578 Type XIV GPS has a density of 0.04 g/cm³ (0.0014 lb/in³), lighter than 91% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical7
C578 Type XIV GPS has a tensile strength of 0.42 MPa (0.0609 ksi), weaker than 91% of polymer grades. The elastic modulus is 0.01 GPa (0.0016 Msi).
Thermal8
C578 Type XIV GPS is rated for continuous service to 75°C (167 °F). It conducts heat at 0.03 W/m·K (0.0173 BTU/hr·ft·°F), worse than 96% of polymer grades. Thermal expansion is 65 µm/m·K (36.1 µin/in·°F).
Electrical4
C578 Type XIV GPS has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of C578 Type XIV GPS takes about 105 MJ of energy and emits 3.3 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 10%.
Manufacturability4
C578 Type XIV GPS's machinability is excellent (85/100, better than 88% of polymer grades); weldability poor (25/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C578 Type XIV GPS
Is C578 Type XIV easy to machine?
Cut with hot wire, hot knife, band saw or CNC router; use vacuum extraction for beads and avoid melting smear by keeping wire temperature just above 200 °C.
Can C578 Type XIV be welded?
Not conventionally welded — join with hot-air/hot-plate fusion of block faces or, more usually, with water-based, cement-based or bitumen-emulsion adhesives and mechanical fasteners.
Can C578 Type XIV be formed, bent or molded?
Produced by pre-expanding EPS beads then steam block-moulding (approx. 0.6–1.0 bar steam) or shape-moulding; age blocks several days before cutting to stabilise dimensions.
What surface finishes work on C578 Type XIV?
No paint with solvent carriers — finish with cement/polymer render, EIFS base coat, water-based coatings, foil or film lamination; always cover to protect from UV and hydrocarbons.
C578 Type XIV 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 |
|---|---|---|
| pentane (residual blowing agent)largely vented during ageing | 0.1 – 1.5 | 0.5 |
| polymeric brominated flame retardantPolyFR; HBCD phased out | 0.3 – 1.2 | 0.7 |
| graphite1–4% only in the GPS/grey-bead variant | ≈ 0 | 0 |
| polystyrene (styrene monomer units)expandable polystyrene bead resin | ≥ 95 (balance) | — |
C578 Type XIV GPS — frequently asked
What is C578 Type XIV GPS used for?
C578 Type XIV GPS is typically used for heavy geofoam fill, bridge approach fill and structural insulation. In short: high-density structural EPS; load-bearing geofoam fill; machinability score 85.
What is the tensile strength of C578 Type XIV GPS?
C578 Type XIV GPS has a typical tensile strength of 0.42 MPa (0.0609 ksi) — weaker than 91% of polymer grades. Strength varies by condition: see the 2 listed tempers.
Is C578 Type XIV GPS easy to machine?
Yes — machinability is rated excellent (85/100, better than 88% of polymer grades). Cut with hot wire, hot knife, band saw or CNC router; use vacuum extraction for beads and avoid melting smear by keeping wire temperature just above 200 °C.
Can C578 Type XIV GPS be welded?
Not readily — weldability is rated poor (25/100). Not conventionally welded — join with hot-air/hot-plate fusion of block faces or, more usually, with water-based, cement-based or bitumen-emulsion adhesives and mechanical fasteners.
What surface finishes work on C578 Type XIV GPS?
No paint with solvent carriers — finish with cement/polymer render, EIFS base coat, water-based coatings, foil or film lamination; always cover to protect from UV and hydrocarbons.
Can C578 Type XIV GPS be formed, bent or molded?
Produced by pre-expanding EPS beads then steam block-moulding (approx. 0.6–1.0 bar steam) or shape-moulding; age blocks several days before cutting to stabilise dimensions.
What is the maximum service temperature of C578 Type XIV GPS?
C578 Type XIV GPS is rated for continuous use to about 75°C (167 °F), and briefly to 85°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM C578 — Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation — ASTM International (2022)
- ASTM D6817 — Standard Specification for Rigid Cellular Polystyrene Geofoam — ASTM International (2021)
- EPS Industry Alliance technical bulletins (physical properties, geofoam design) — EPS Industry Alliance (2023)
- Neopor / graphite EPS insulation board data — BASF (2023)
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.