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ASTM E648 Critical Radiant Flux Test

Critical Radiant Flux Test for Floor Coverings and Panels

The test method ASTM E648 offers a standardized approach to determine the progression of fire across flooring systems — such as panels, tiles, and coverings — when they’re exposed to a source of radiant heat energy. This particular ASTM International test is aimed at discovering how resistant the types of flooring typically used in corridors are to fires emanating from adjacent rooms.

Since many floor coverings like resilient tiles and filled vinyl are not usually considered fire hazards, they’re often exempt from the flammability standards of construction materials issued by organizations like the National Fire Protection Association — or NFPA — and other building code oversight bodies. However, ASTM E648 offers valuable flammability data that can aid state, federal and other agencies in the proper selection of safe flooring materials intended for use in the hallways of hospitals, medical facilities, and other public buildings.

VTEC — Your Trusted ASTM E648 Test Lab

With more than three decades of materials testing experience, VTEC Laboratories is your trusted ASTM E648 test lab. We serve local, state, federal and commercial entities, and our knowledge and expertise as a licensed test facility are fully backed by our A2LA and ISO accreditations.

Whether it’s strictly ASTM E648 testing or some form of customized onsite testing, we’re always happy to provide you with cost-effective, timely and professional results.

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What Is the ASTM E648 Critical Radiant Flux Test?

Unlike the ASTM E84 tunnel test that places specimens in a test chamber’s ceiling, the ASTM E648 critical radiant flux test offers a much more accurate assessment of a flooring material’s flammability. The design of the test simulates real-world conditions where a corridor flooring material is exposed to an ignition flame, as well as a radiant heat source that replicates the heat from a fire in an adjacent room.

The ASTM E648 test involves placing a 9” x 41” specimen on the test chamber’s floor. It’s positioned so that 8” x 40” of the specimen is exposed to a radiant heat source that’s fed by a gas-air fueled panel situated above the specimen and inclined 30° toward it. The panel produces a radiant flux output across the length of the specimen varying from 1.1 W/cm— or Watts per square centimeter — at its closest proximity to 0.1 W/cmat its furthest distance.

There’s also a gas-fed pilot burner present to initiate the specimen’s ignition.

After heating the specimen for five minutes under the panel, the pilot burner is brought in contact with the closest end of the specimen to the suspended panel. If flaming occurs, the test continues until the flooring’s burning eventually extinguishes.

This particular point is referred to as the “critical radiant flux at flameout.” The distance from point of ignition to extinguishment is measured, and the shorter the distance, the higher the value and subsequent classification of the flooring specimen.

ASTM E648 Classification System

As a result of the ASTM E648 test, flooring materials can be classified as either Class I or Class II. As previously stated, higher values of critical radiant flux indicate materials that are more flame resistant.

Accordingly, Class I materials — valued at 0.45 W/cmor greater — are typically chosen for use in the corridors of nursing homes, medical facilities, hospitals, daycare centers and other public institutions.

Recommended Tests to Pair with ASTM E648:

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