Armatherm FRR is one of the most widely specified structural thermal break plates in North America. STB-1 is a Canadian-made thermoset composite plate for the same steel-to-steel and steel-to-concrete connections. This page puts the published numbers side by side so you can decide whether STB-1 meets your specification.
Side-by-Side Comparison
| Property | STB-1 | Armatherm FRR* |
|---|---|---|
| Material | Thermoset, reinforced composite | Reinforced thermoset resin |
| Compressive strength / maximum loading pressure | 48,000 psi | 43,000 psi |
| Shear strength | 16,326 psi | 16,000 psi |
| Compressive modulus | 400,671 psi (1″ thick) | 835,000 psi |
| Thermal conductivity | 1.055 BTU·in/hr·ft²·°F | 1.056 BTU·in/hr·ft²·°F |
| Fire rating | ASTM E84 Class A; Euroclass B | Euroclass B |
| Operating temperature | -20 °F to +250 °F | -60 °F to +220 °F |
| Standard thicknesses | 1/4″, 1/2″, 3/4″, 1″, 2″ | 1/2″, 3/4″, 1″, 2″ (other thicknesses available) |
| Manufactured in | Canada | — |
| Typical lead time (cut parts) | 5–7 days | Contact manufacturer |
*Armatherm FRR values as published on Armatherm’s FRR data sheet (US). Verify current data with each manufacturer before specifying.
What the Numbers Mean
- Thermal performance is effectively equal. Both plates have a thermal conductivity of about 1.06 BTU·in/hr·ft²·°F, so the same pad thickness gives the same heat flow reduction.
- STB-1 has higher compressive and shear strength (48,000 vs 43,000 psi in compression, 16,326 vs 16,000 psi in shear) and a higher maximum operating temperature.
- Armatherm FRR has a higher published compressive modulus and a lower minimum operating temperature. Check these against your connection design.
- Fire ratings match: both are Euroclass B, and STB-1 also carries an ASTM E84 Class A rating.
Switching an Armatherm FRR Specification to STB-1
Most specifications list performance requirements followed by a basis-of-design product “or approved equal.” To submit STB-1 as an equal:
- Send us the specification section and connection drawings.
- We provide the STB-1 data sheet for the substitution request.
- The engineer of record confirms the properties meet the design, including compressive modulus and shear where they govern.
- We fabricate pads, washers and bushings to the approved shop drawings, typically in 5–7 days.
You can also start from our ready-to-edit structural thermal break specification.
Why Teams Choose STB-1
- Made in Canada by the manufacturer, with no distributor markup or cross-border delays
- Fast turnaround on cut and machined parts
- Washers and bushings machined in house to match
- Direct access to the people who make the material
See full STB-1 product data.
Request a Quote or Data Sheet
Send us your connection drawings, bolt schedule or load requirements and we will quote STB-1, TBF, washers and bushings cut and machined to your specification. Data sheets and design support are available for engineers and architects.
Call 800-580-4195 or use the form below. STB-1 typically ships in 5–7 days; TBF in as little as 3 days.