Understanding NFPA 262: Plenum Fire Test Requirements for Cables

When it comes to building safety, National Fire Protection Association (NFPA) standards play a crucial role in establishing safety benchmarks. Among these many codes, NFPA 262 stands out as the most important standard for communications cables installed in air handling spaces. Let’s dive into what this standard entails, why it matters and what testing procedures it prescribes.

What is NFPA 262?

NFPA 262, formally titled “Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling Spaces,” establishes fire testing requirements for cables installed in plenum spaces. Plenum spaces are compartments that form part of an HVAC system and facilitate air circulation throughout a building. Typically, this refers to the area between a dropped ceiling and the structural floor above it.

The NFPA 262 standard is important because the cables installed in these spaces must meet stringent fire safety requirements to prevent the rapid spread of flames and smoke in case of a fire emergency. These spaces present unique fire hazards because:

●       As air circulation pathways, fire and smoke can rapidly spread throughout a building.

●       They often contain multiple combustible materials and potential ignition sources.

●       They're often hidden from view, making it difficult to detect a fire early.

The NFPA 262 Testing Procedure

Cables that don’t meet appropriate fire safety standards can fuel a fire, emit toxic smoke and cause flames to quickly spread. NFPA 262 addresses these risks by establishing measurable performance criteria.

The test method specified in NFPA 262 evaluates three key parameters:

Flame spread. Mounted horizontally in a test chamber, a cable is exposed to a controlled flame source at one end. The test measures how far the flame travels along the cable, determining its propensity to spread fire.

Smoke generation. During this test, photometers measure the amount of smoke produced as a cable burns. This measurement is important because smoke inhalation is often more dangerous than the flames themselves.

Peak optical density. This test quantifies the opacity of the generated smoke, indicating how severely the smoke might impair visibility during an evacuation.

In order for a cable to be classified as plenum-rated and compliant with NFPA 262, it must:

●       Have a maximum flame spread distance of less than 5 feet.

●       Produce a peak optical density of smoke less than 0.5.

●       Have an average optical density of smoke less than 0.15.

Cables that pass NFPA 262 testing are typically designated as “CMP” (Communications Plenum) cables. Building codes and the National Electrical Code (NEC) require the use of plenum-rated cables in air handling spaces. Using non-plenum rated cables in these areas violates building codes and creates serious safety hazards.

Flames on ceiling of office building

Flame-Retardant Compounds For Plenum Applications

Designed to reduce both flame spread and smoke production, SMOKEGUARD specialty vinyl and specialty olefin compounds are suitable for applications that must pass NFPA 262 plenum fire test requirements for communications, power, control, signal and specialty cables.

Their superior performance in flame tests and minimal smoke generation make them an ideal choice for critical installations where fire safety cannot be compromised, such as healthcare facilities and high-occupancy commercial buildings.

To learn more about SMOKEGUARD, please visit our product page.

SMOKEGUARD product page