When choosing insulation, performance isn’t just about energy efficiency, it’s also about fire safety. One of the most important fire safety standards you’ll see associated with spray foam insulation is ASTM E84 Class 1. But what does that rating actually mean, and why does it matter?
WHAT IS ASTM E84?
ASTM E84 is a standardized fire test developed by ASTM International, officially titled:
Standard Test Method for Surface Burning Characteristics of Building Materials
The test measures how a material reacts when exposed to fire by evaluating two key factors:
The test is commonly referred to as the Steiner Tunnel Test.
WHAT DOES “CLASS 1” MEAN?
Under ASTM E84, materials are classified based on how quickly flames spread across their surface and how much smoke they produce.
ASTM E84 CLASSIFICATION SYSTEM
Class 1 (also called Class A) is the highest fire-resistance classification.
WHAT DOES ASTM E84 CLASS 1 MEAN FOR SPRAY FOAM?
When spray foam insulation is rated ASTM E84 Class 1, it means:
- Flames spread very slowly across the foam’s surface
- Smoke production is limited within code-approved thresholds
- The material meets strict fire safety standards for building interiors
In practical terms, Class 1 spray foam does not readily contribute to fire spread when properly installed and protected.
WHY IS CLASS 1 FIRE RATING IMPORTANT?
1. BUILDING CODE COMPLIANCE
Most residential and commercial building codes require interior materials to meet Class 1 / Class A fire performance standards.
2. INCREASED OCCUPANT SAFETY
Lower flame spread and smoke development means:
- More time for occupants to evacuate
- Reduced risk of fire spreading rapidly through a structure
3. APPROVAL FOR RESIDENTIAL & COMMERCIAL USE
Class 1-rated spray foam is commonly approved for:
- Homes
- Offices
- Warehouses
- Schools
- Healthcare facilities
DOES CLASS 1 MEAN SPRSY FOAM IS FIREPROOF?
No—this is a common misconception.
ASTM E84 Class 1 does NOT mean fireproof.
It means the material:
- Resists flame spread
- Limits smoke development
- Meets code-required fire performance when used correctly
Spray foam is still an organic material and must be installed according to code, often with:
- Thermal barriers (like drywall)
- Ignition barriers in attics and crawlspaces
OPEN-CELL VS CLOSED-CELL SPRAY FOAM
Both open-cell and closed-cell spray foams can achieve ASTM E84 Class 1, but only when:
- The product formulation is tested and certified
- The foam is installed at approved thicknesses
- Required fire protection layers are used
Always verify product-specific test reports, not just general claims.
HOW TO VERIFY A SPARY FOAM’S FIRE RATING
Before choosing a spray foam product, ask for:
- ASTM E84 test documentation
- ICC-ES or code evaluation reports
- Manufacturer’s technical data sheets
These documents confirm whether the product truly meets Class 1 fire performance standards.
BOTTOM LINE
- ASTM E84 measures flame spread and smoke development
- Class 1 (Class A) is the highest fire safety rating
- Class 1 spray foam spreads flames slowly and limits smoke
- It supports building code compliance and occupant safety
- Class 1 does not mean fireproof, Proper installation still matters
Because fire performance varies by product and installation method, Full Spectrum Environmental works with ASTM E84 Class 1–rated spray foam systems to ensure insulation solutions meet safety and building code requirements.