AC390 - Spray Polyurethane Foam Insulation
ICC-ES Acceptance Criteria for Spray Polyurethane Foam Insulation
Last updated: September 21, 2025
Overview
Spray Polyurethane Foam (SPF) insulation is a two-component chemical product that expands and hardens when applied to create continuous insulation and air barrier systems. Available in open-cell (low-density) and closed-cell (high-density) formulations, SPF provides excellent thermal performance, air sealing, and moisture control. This spray-applied insulation adheres to irregular surfaces and fills gaps and voids, making it ideal for both new construction and retrofit applications in walls, roofs, crawlspaces, and attics.
Purpose
This acceptance criteria provides a basis for evaluating spray polyurethane foam insulation systems that may not be directly covered by existing codes. It establishes testing protocols, fire performance requirements, thermal performance standards, and installation specifications needed for code approval of SPF insulation systems.
Benefits of Compliance
- Nationwide acceptance by building officials for SPF installations
- Streamlined approval process for spray foam insulation systems
- Third-party verification of fire safety and thermal performance
- Enhanced marketability for insulation contractors and manufacturers
Resources
Frequently Asked Questions
What is the difference between open-cell and closed-cell spray foam?
Open-cell spray foam is lighter, more flexible, and provides sound absorption but does not act as a vapor barrier. Closed-cell foam is denser, provides higher R-value per inch, acts as both an air and vapor barrier, and adds structural rigidity. AC390 covers both types.
Does spray foam insulation need a thermal barrier?
In most occupied spaces, building codes require a thermal barrier (typically 1/2-inch gypsum board) over spray foam to provide a 15-minute fire resistance rating. Some SPF products have been tested and approved for use without a thermal barrier in specific applications per their ESR.
Why is ICC-ES evaluation important for spray foam?
Spray foam is a two-component chemical system whose performance depends on proper mixing, application temperature, and installation technique. AC390 evaluation verifies fire safety, thermal performance, and air barrier properties, giving building officials documented assurance that the product meets code requirements.
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