SPF SR (Stress relieved)
Heat-treated state
ASTM C1029 · EN 14315 · JIS A9526 · GB GB/T 26689
Pick where movement, vibration or acoustic damping matters (duct wrap, gap filling around moving joints, packaging).
Values for the SR condition
Other SPF grades and fills
SPF is listed in 9 conditions; see the grade overview at SPF.
Compare all 9 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Open-cell light-density spray foam | Pick for low-cost interior cavity fill, air sealing and sound damping where no vapor control or strength is needed. | — | 0.03 | 12 | — |
SRThis page Stress relieved | Pick where movement, vibration or acoustic damping matters (duct wrap, gap filling around moving joints, packaging). | 0.04 | 0.12 | 60 | 15 Shore A |
Single-component moisture-cure gun/canister foam | Pick for small-volume gap filling, window/door perimeters and penetration sealing where a spray rig is impractical. | — | 0.1 | 10 | — |
Flame-retardant formulation | Pick when code requires low flame spread/smoke or B1 rating on exposed insulation; higher TCPP/TEP load slightly raises density and cost. | — | 0.28 | 6 | — |
ccSPF-2.0Default Closed-cell medium-density spray foam | Default construction grade: insulation + air barrier + vapor retarder + racking stiffness in one pass. | — | 0.3 | 8 | — |
Low-GWP HFO-blown closed-cell system | Pick for current environmental/code compliance (HFC phase-down); same or slightly better aged R-value than HFC-245fa foam. | — | 0.3 | 8 | — |
Cryogenic spray/pour insulation grade | Pick for −165 °C LNG tanks, cold boxes and cryogenic piping; glass- or milled-fiber reinforced to control thermal contraction cracking. | — | 0.42 | 5 | — |
Closed-cell roofing grade | Pick for foot-traffic roof decks and tank/pipe exteriors under elastomeric coating, where compressive strength and moisture resistance dominate. | — | 0.45 | 7 | — |
high-density structural / geotechnical foam (64–160 kg/m³) | Pick for slab lifting/void filling, load-bearing insulation blocks and marine flotation where compressive load, not R-value, governs. | — | 0.75 | 6 | — |
What is SPF SR?
SPF SR is SPF heat treated to SR — pick where movement, vibration or acoustic damping matters (duct wrap, gap filling around moving joints, packaging). SPF SR has a tensile strength of 0.12 MPa (0.0174 ksi), weaker than 99% of polymer grades. Elongation at break is 60% and the elastic modulus is 0 GPa (1.74×10⁻⁴ Msi). SPF SR has a density of 0.04 g/cm³ (0.0013 lb/in³), lighter than 92% of polymer grades. Its glass-transition temperature is 110°C (230 °F). ccSPF-2.0 is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Lightweight — 0.04 g/cm³ (0.0013 lb/in³), better than 92% of polymer grades
- Forms and bends easily — 85/100, better than 81% of polymer grades
Limitations
- Hard to polish — 5/100, worse than 99% of polymer grades
- Low stiffness — 0 GPa (1.74×10⁻⁴ Msi), worse than 97% of polymer grades
- Poor heat conductor — 0.03 W/m·K (0.0191 BTU/hr·ft·°F), worse than 95% of polymer grades
- Degrades in UV without stabilisers — 15/100, worse than 95% of polymer grades
- Absorbs moisture — dry before molding — 1.5%, worse than 91% of polymer grades
SPF SR properties
Typical room-temperature values for SPF SR; 19 are specific to this condition. Other listed values are SPF reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
SPF SR has a density of 0.04 g/cm³ (0.0013 lb/in³), lighter than 92% of polymer grades. Its glass-transition temperature is 110°C (230 °F).
Mechanical9
SPF SR has a tensile strength of 0.12 MPa (0.0174 ksi), weaker than 99% of polymer grades. Elongation at break is 60% and the elastic modulus is 0 GPa (1.74×10⁻⁴ Msi).
Thermal8
SPF SR is rated for continuous service to 80°C (176 °F). It conducts heat at 0.03 W/m·K (0.0191 BTU/hr·ft·°F), worse than 95% of polymer grades. Thermal expansion is 70 µm/m·K (38.9 µin/in·°F).
Electrical3
SPF SR has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 89% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of SPF SR takes about 105 MJ of energy and emits 5 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 5%.
Manufacturability5
SPF SR's machinability is fair (45/100, worse than 78% of polymer grades); weldability not recommended (5/100); formability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SPF SR
Is SPF easy to machine?
Trim excess with a serrated knife, hot wire or reciprocating rasp within a few days of application; sanding creates fine dust—use HEPA extraction and respirators.
Can SPF be welded?
Not weldable; join by adhering fresh foam to a clean, dry (<20% MC), primed substrate or bond skins with PU/epoxy adhesive.
Can SPF be formed, bent or molded?
Plural-component 1:1 by volume spray at 1000–1500 psi with A/B and hose at 40–50 °C; apply in ≤50 mm lifts on a 10–50 °C substrate and respect re-spray cooling times to avoid core scorch and off-ratio (sticky/friable) foam.
What surface finishes work on SPF?
Always cover exposed foam: elastomeric acrylic/silicone/polyurea coating outdoors for UV, and an approved thermal/ignition barrier (12.7 mm gypsum or intumescent coating) indoors.
SPF 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, A-side)diphenylmethane diisocyanate oligomer, NCO ≈ 31% | 42 – 55 | 50 |
| flame retardant (TCPP / TEP)higher end for Class A / B1 formulations | 3 – 12 | 7 |
| blowing agent (HFO-1233zd, HFC-245fa or water-blown for open-cell grades | 1 – 8 | 5 |
| amine / metal catalystscontrols cream, gel and tack-free times | 0.5 – 3 | 2 |
| silicone surfactantcell nucleation and cell-size control | 0.5 – 2 | 1.2 |
| polyether/polyester polyol blendaromatic polyester or sucrose/amine-initiated polyether, B-side backbone | ≥ 28 (balance) | — |
SPF SR — frequently asked
What is SPF SR used for?
SPF SR is typically used for building envelope thermal/air sealing, roofing insulation, cold storage and tank insulation and void filling and structural reinforcement. In short: seamless field-applied air seal; highest R per inch on site; needs ignition barrier indoors.
What is the tensile strength of SPF SR?
SPF SR has a typical tensile strength of 0.12 MPa (0.0174 ksi) — weaker than 99% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is SPF SR easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 78% of polymer grades). Trim excess with a serrated knife, hot wire or reciprocating rasp within a few days of application; sanding creates fine dust—use HEPA extraction and respirators.
Can SPF SR be welded?
Not readily — weldability is rated not recommended (5/100). Not weldable; join by adhering fresh foam to a clean, dry (<20% MC), primed substrate or bond skins with PU/epoxy adhesive.
What surface finishes work on SPF SR?
Always cover exposed foam: elastomeric acrylic/silicone/polyurea coating outdoors for UV, and an approved thermal/ignition barrier (12.7 mm gypsum or intumescent coating) indoors.
Can SPF SR be formed, bent or molded?
Plural-component 1:1 by volume spray at 1000–1500 psi with A/B and hose at 40–50 °C; apply in ≤50 mm lifts on a 10–50 °C substrate and respect re-spray cooling times to avoid core scorch and off-ratio (sticky/friable) foam.
What is the maximum service temperature of SPF SR?
SPF SR is rated for continuous use to about 80°C (176 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SPF ccSPF-2.0 and SPF SR?
ccSPF-2.0 is the default condition — default construction grade: insulation + air barrier + vapor retarder + racking stiffness in one pass. SR: pick where movement, vibration or acoustic damping matters (duct wrap, gap filling around moving joints, packaging).
Sources
- ASTM C1029 — Spray-Applied Rigid Cellular Polyurethane Thermal Insulation — ASTM International (2023)
- ASTM D1621 / D1623 / D2842 / D2126 — cellular plastics compressive, tensile, water absorption, dimensional stability — ASTM International (2021)
- ASTM E84 — Surface Burning Characteristics of Building Materials — ASTM International (2023)
- Engineered Materials Handbook — Engineering Plastics (cellular polyurethanes) — ASM International (1988)
- Rigid closed-cell / open-cell spray foam system technical data (HFO and water-blown) — Covestro, BASF, Huntsman, Icynene-Lapolla (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.