If you’re a general contractor or architect, do yourself a favor and make sure the exterior walls of your project comply with NFPA 285 long before the building inspector shows up on site.
Given the daunting title of “Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components,” NFPA 285 is simply a test that analyzes how fire spreads on different non-combustible exterior wall assemblies that contain a combustible component.
Why Was the NFPA 285 Test Created?
The National Fire Protection Association (NFPA), a global nonprofit organization dedicated to increasing public safety, conducts research and testing to create fire safety standards for many industries, including construction. Like NFPA 285, many of NFPA’s standards are adopted by the IBC (International Building Code) and become building code requirements.
NFPA released its first edition of NFPA 285 in 1998. However, testing of flammability in exterior walls began in the late 1970’s due to increased interest in foam plastic insulation amid rising environmental concerns. By that point, foam plastic had been around for a while – it was developed by the U.S. military in the early 1940’s – but its use in residential and commercial construction had just begun.
Spurred on by foam plastic’s increasing popularity for use in construction, the Society of the Plastics Industry (SPI) began testing the use of foam plastic insulation in exterior walls for fire safety in the early 1980’s. SPI’s work led to the adoption of UBC 17-6, the first iteration of what would eventually become NFPA 285.
When is NFPA 285 Compliance Required?
The requirement to comply with the NFPA 285 test is found in IBC 2603.5.5 Foam Plastic Insulation which states: “Exterior walls containing foam plastic insulation in buildings of Type I, II, III or IV construction of any height must comply with NFPA 285.”
It is important to note that NFPA 285 is a test for exterior wall assemblies, not individual components of the wall. There are two exceptions to IBC 2603.5.5, but they are quite narrow. The majority of construction projects that call for foam plastic insulation will need to specify NFPA 285 tested wall assemblies for exterior walls.
If your exterior wall details deviate from NFPA 285 tested assemblies, they are not in strict compliance. In that case, an engineering judgment would be necessary to approve the modified NFPA 285 assembly, or a test of the proposed assembly would be required.
At this point, you might be wondering how the NFPA 285 test is conducted and what the criteria is for compliance. During NFPA 285 testing, a 2-story mockup of an exterior wall is built according to the assembly to be tested, then set on fire for 30 minutes.
In order for the exterior wall assembly to meet the test’s criteria, the horizontal and lateral flame propagation cannot spread beyond specified limits. In addition, the temperature within exterior wall panels, and within the air cavity between walls panels and the wall itself, cannot exceed specified limits. For more information, including additional criteria not described here, see Section 10.2 of the 2019 edition of NFPA 285.
The Benefits of Foam Plastic Insulation in Exterior Walls
From its military roots in the 1940’s, foam plastic insulation has evolved into a sophisticated rigid insulation material used in a wide variety of construction applications that offers many benefits, including:
High R-Values
Rigid foam plastic insulation’s high R-value per inch of thickness means it is extremely efficient and effective compared to other types of insulation.
Prevents Air Leakage
Rigid insulation provides a continuous seal around the building which keeps indoor air from escaping and outdoor air from entering.
Prevents Thermal Bridging
Thermal bridging occurs when air is allowed to pass through a conductive building material (like a stud) without being blocked by insulation, which causes heat loss. Continuous rigid insulation prevents this from happening.
Moisture Control
Continuous rigid insulation protects wall components and interior sheathing from the damaging effects of moisture.
Energy Efficiency
By providing a continuous seal that prevents air leakage and thermal bridging, rigid foam plastic insulation helps regulate indoor air temperature, which means buildings use less energy for heating and cooling.
For these benefits and more, rigid plastic foam insulation is an excellent choice for your project. As a leading manufacturer of polyiso insulation boards for over 35 years, Rmax has developed solutions for a wide range of construction applications, including NFPA 285-compliant exterior walls.
Rmax Polyiso Rigid Insulation Boards - The Superior Choice for NFPA 285-Compliant Exterior Walls
When it comes to NFPA 285-compliance, Rmax has solutions. Their polyiso insulation boards provide superior energy-efficiency, thermal performance, and durability. Rmax TSX-8510®, Durasheath®, Thermosheath®, and EVOMAXci® rigid insulation boards all passed the stringent NFPA 285 test.
A variety of NFPA 285-compliant assembly configurations are possible using TSX-8510®, Durasheath®, and Thermosheath®. Assembly guides are available at www.rmax.com to assist you in the design of your exterior wall assemblies.
EVOMAXci® is intended for use in conjunction with the innovative EVO™ Architectural Panel System.
Rmax TSX-8510: Continuous Insulation for Exposed Interior Use
Rmax TSX-8510 is designed to be exposed on the interior with an attractive and durable white modified acrylic coating on the exposed face. TSX-8510 is an energy-efficient thermal insulation board composed of a closed-cell polyiso foam core bonded to glass fiber reinforced aluminum facers on both sides.
Construction Applications
Pre-engineered metal buildings
Tilt-up construction
Wood stud basement & crawl spaces
Farm or storage buildings
Parking structures
Laminate panels and other similar applications
Rmax Durasheath®: Building Envelope Insulation
Rmax Durasheath® is intended for use in exterior walls with stucco veneer, concrete sandwich panels and many other building envelope applications. Its non-metallic, inorganic polymer-coated glass fiber mat facers make it the perfect choice when a permeable faced product is preferred.
Exterior Wall Applications
Stud walls
Cavity walls
Masonry walls
Exterior stucco
Rmax Thermasheath®: Insulation for The Envelope
Rmax Thermasheath® is a lightweight thermal insulation board with reinforced aluminum foil facers that protect against water, air, vapor, and UV.
Exterior Wall Applications
Exterior Walls (Type I-IV):
Masonry
Steel Stud
FRTW Stud
Wood Stud (Type V)
Below-grade exterior walls
EVOMAXci®
Continuous Insulation for use with the EVO™ Architectural Panel System
The innovative EVO™ Architectural Panel System is the product of a partnership between Rmax, EVO™ Architectural Panel System and Larson® by Alucoil®. The wall system components are:
ECOMAXci® FR Air Barrier thermal insulation board
Rmax R-SEAL 3000 tape and R-SEAL 6000 flashing
Larson® Aluminum Composite Panels (ACM)
EVO™ Architectural Panel by Carter
What ECOMAXci® by Rmax brings to the EVO system is its first line of defense: an air barrier and continuous insulation with enhanced R-values and zero infiltration. It has glass fiber-reinforced aluminum foil facers on both sides, to provide superior durability, dimensional stability, and fire performance.
Choose Rmax Superior Rigid Polyiso Insulation Foam Boards for Your NFPA-Compliant Exterior Walls
Rmax has been providing exceptional insulation products for over 35 years. Built on decades of rigorous scientific research and testing, Rmax polyiso insulation boards are second-to-none in efficiency, effectiveness, and durability. If you need help with an NFPA 285-compliant assembly for your project, or would like more information about Rmax products, reach out to our team today.