NFPA 285 is a standard test method for determining the fire propagation characteristics of exterior wall assemblies and panels used as components of curtain wall assemblies that are constructed using combustible materials or that incorporate combustible components. The results from an NFPA 285 test determine how an exterior wall assembly will perform if a fire occurs in a multistory application.

 

Basics of NFPA 285

NFPA 285 Fire PropagationThere are two definitions we must keep in mind when looking at NFPA 285 requirements: combustible and noncombustible. Chapter 3, Section 3.3.2 of NFPA 285 defines combustible material as a material that, in the form in which it is used and under the conditions anticipated, will ignite and burn; a material that does not meet the definition of noncombustible or limited combustible.

Chapter 4, Section 4.1 defines noncombustible material as a material that complies with any one of the following:

  • The material, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat.
  • The material is reported as passing ASTM E136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C.
  • The material is reported as complying with the pass/fail criteria of ASTM E136 when tested in accordance with the test method and procedure in ASTM E2652, Standard Test Method for Behavior of Materials in a Tube Furnace with a Cone-shaped Airflow Stabilizer at 750°C.

The International Building Code’s (IBC) Section 703.3.1 states that materials required to be noncombustible shall be tested in accordance with ASTM E136. Alternatively, materials required to be noncombustible may be tested in accordance with ASTM E2652 using the acceptance criteria prescribed by ASTM E136.

The definitions between NFPA 285 and the IBC are nearly identical; however, the flexibility from condition one in NFPA 285 is not provided under the IBC definition.

The type of construction in the adopted code determines when and how combustible building materials may be used. For example, the International Building Code (IBC) defines five major Types of construction (Type I through Type V), loosely described in the table below.

 

IBC Construction Types

 

NFPA 285 Fire Propagation Testing Flow ChartThe NFPA 285 Compliance Flow Chart provides a glimpse into the questions a manufacturer must ask themselves when considering the need for NFPA 285 testing. Notice that several questions are two-part questions. Manufacturers need to meet both parameters for the assembly to require NFPA 285 testing.

Authorities having jurisdiction expect evidence that assemblies containing combustible building materials used in Type I – Type IV construction pass an NFPA 285 test or are included in a Design Listing, a type of certification specific to the assembly. Otherwise, if the building or building material qualifies for one of the exceptions provided in the locally adopted code, NFPA 285 compliance is not required.

 

NFPA 285 Performance Criteria

NFPA 285 is a thirty-minute test that ultimately results in one of two outcomes: Pass or Fail. For a wall assembly to pass NFPA 285, it must meet all the following criteria:

  • No flame propagation to the interior of the second story.
  • Flames did not reach 10-ft above the top of the window opening or 5 ft from the center line of the window in either direction.
  • Thermocouples located throughout the assembly did not exceed designated temperatures.

If a wall assembly fails to meet even one of the criteria, the entire assembly fails the NFPA 285 test. Further details for determining the performance criteria are provided in Chapter 10 of the standard.

 

Common Misconceptions with NFPA 285

Misconception: Materials or components can be NFPA 285 compliant.

Because NFPA 285 is a test method used to determine fire propagation characteristics of exterior wall assemblies, the test method cannot be used to determine material or component compliance. If you are interested in determining compliance for materials or components, you can test them with tests such as ASTM E84, ASTM E136, and ASTM E1354 or seek engineering judgments to evaluate whether a material can be substituted into an NFPA 285 compliant exterior wall assembly.

Misconception: If a wall assembly passes NFPA 285, you can substitute brands and/or materials and/or components without retesting.

The results of an NFPA 285 test are assembly-specific, including the brand of materials used, methods of attachment, and position and orientation of materials within the assembly. You also cannot change the position of any materials or components in the assembly.

Any change made to a wall assembly requires retesting. When new assembly compliance is needed, there are two typical options: a new NFPA 285 test or an engineering judgment supported by additional evidence to justify the substitution. Third-party certification agencies often use engineering judgments to add new options to Design Listings of a Listing Report, such as an ICC-ES Evaluation Service Listing (ESL).

Like many test standards related to fire performance, NFPA 285 provides a complex and intricate framework to test and evaluate assembly and product performance. Manufacturers often find navigating the intricacies of the standard to be complex and confusing, especially when they have multiple products or assemblies they want to use or substitute. These manufacturers are best served by an experienced, accredited third-party agency to discuss their needs and build a test plan before the manufacturer begins testing.

About ICC NTA, LLC: As an accredited third-party agency and part of the International Code Council (ICC) Family of Solutions, ICC NTA provides code evaluation, inspection, engineering, plan review, and product testing services, as well as independent quality and standards compliance verification for building product manufacturers. With offices, testing labs, and training facilities in Nappanee, Indiana and Bryan, Texas, ICC NTA serves residential and commercial builders, code officials, manufacturers, and suppliers throughout the building industry.

Sources:
ASTM International. “ASTM E84-22 Standard Test Method for Surface Burning Characteristics of Building Materials.” ASTM, https://www.astm.org/e0084-22.html. Accessed on 06/28/2022.

ASTM International. “ASTM E1354-22a Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter.” ASTM, https://www.astm.org/e1354-22a.html. Accessed on 06/28/2022.

ASTM International. “ASTM E136-19a Standard Test Method for Assessing Combustibility of Materials Using a Vertical Tube Furnace at 750°C.” ASTM, https://www.astm.org/e0136-19a.html. Accessed 06/28/2022.

NFPA 285 Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components. National Fire Prevention Association, 2019.

National Fire Prevention Association. “NFPA 285.” NFPA, https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=285. Accessed 06/28/2022.

“SAF NFPA 285 Course.” YouTube, uploaded by Southern Aluminum Finishing Co, Inc., 12 May 2022, https://www.youtube.com/watch?v=bjgt5E4xOIs&ab_channel=SouthernAluminumFinishingCo%2CInc. Accessed 06/24/2022.