Declaration of Hero FabriDuct™

Hero FabriDuct™ products are Polyester fabric supply air diffusion systems operating under positive pressure. The diffusion occurs through any combination of permeable and non-permeable fabric, and/or strategically designed linear slots.

Hero FabriDuct™ systems are available in round, “D” shape, or quarter-round duct configuration. These systems are designed to provide uniform air distribution in commercial, industrial, public warehouse environments, and homes. When tested in accordance with ASTM E-84, these Polyester fabrics have a flame spread index of less than 25, and a smoke developed index of less than 50.

Hero FabriDuct™ fabric products are limited to use in systems with a maximum positive design pressure equivalent to 3.1 inches of water column, a maximum operating velocity of 2,000 feet per minute, and a temperature range of 0° F to 250°F (-18°C to 121° C).

Installation instructions published and provided by Hero FabriDuct™ provide clear and
concise instructions for efficient installation. A copy of these instructions should be
available for reference at all times on the job site during installation.

Hero FabriDuct™ products are subject to the following conditions:

  • The products shall not pass through any fire resistive assembly or partitions required to prevent the passage of smoke
  • The products shall be used only as positive pressure air distribution components of mechanical ventilation systems
  • The products shall be used in exposed interior locations only


This report is a presentation of results of a surface flammability test on a material submitted by Hero FabriDuct™ .

The test was conducted in accordance with the ASTM International fire test response standard E 84-01, Surface Burning Characteristics of Building Materials, sometimes referred to as the Steiner tunnel test. This test is applicable to exposed surfaces such as walls and ceilings. The test is conducted with the specimen in the ceiling position with the surface to be evaluated exposed face down to the ignition source. The method, which is functionally identical to NFPA No. 255 and UL No. 723, is an American National (ANSI) Standard and has been approved for use by agencies of the Department of Defense for listing in the DoD Index of Specifications and Standards.

This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire-risk assessment of materials, products, or assemblies under actual fire conditions.


The purpose of the test is to provide the comparative measurements of surface flame spread and smoke development of materials with that of select grade red oak and reinforced cement board under specific fire exposure conditions. The test exposes a nominal 24-foot long by 20-inch wide test specimen to a controlled air flow and flaming fire adjusted to spread the flame along the entire length of a red oak specimen in 5.50 minutes. During the 10-minute test duration, flame spread over the specimen surface and density of the resulting smoke are measured and recorded. Test results are calculated relative to red oak, which has an arbitrary rating of 100, and reinforced cement board, which has a rating of 0.

The test results are expressed as Flame Spread Index and Smoke Developed Index. The Flame Spread Index is defined in ASTM E 176 as “a number or classification indicating a comparative measure derived from observations made during the progress of the boundary of a zone of flame under defined test conditions.” The Smoke Developed Index, a term specific to ASTM E 84, is defined as “a number or classification indicating a comparative measure derived from smoke obscuration data collected during the test for surface burning characteristics.” There is not necessarily a relationship between the two measurements.

The method does not provide for measurement of heat transmission through the surface tested, the effect of aggravated flame spread behavior of an assembly resulting from the proximity of combustible walls and ceilings, or classifying a material as noncombustible solely by means of a Flame Spread Index.

The zero reference and other parameters critical to furnace operation are verified on the day of the test by conducting a 10-minute test using 1/4-inch thick reinforced cement board. Periodic tests using NOFMA certified 23/32-inch select grade red oak flooring provide data for the 100 reference.

Test Sample

The test sample, selected by the client, was identified as FabriDuct™, a white polyester duct fabric. The material was conditioned to equilibrium in an atmosphere with the temperature maintained at 71 ± 2° F and the relative humidity at 50 ± 5 percent. For testing, a single 25 foot length was free laid over a 2-inch hexagonal wire mesh supported by 1/4-inch diameter steel rods spanning the ledges of the tunnel furnace at 24-inch intervals. This method of auxiliary sample support is described in Appendix X1 of the E 84 standard, Guide to Mounting Methods, Sections X1.1.2.2 and X1.1.2.3.

Test Results

The test results, calculated on the basis of observed flame propagation and the integrated area under the recorded smoke density curve, are presented below. The Flame Spread Index obtained in E 84 is rounded to the nearest number divisible by five. Smoke Developed Indices are rounded to the nearest number divisible by five unless the Index is greater than 200. In that case, the Smoke Developed Index is rounded to the nearest 50 points.


Test Specimen Flame Spread Index Smoke Developed Index
Reinforced Cement Board
Red Oak Flooring
FabriDuct 5 40

Specimen ignition over the burners occurred at 0.07 minute. Surface flame spread was observed to a maximum distance of 1.16 feet beyond the zero point at 0.33 minute. The maximum temperature recorded during the test was 518° F.


The Flame Spread Index and Smoke Developed Index values obtained by the ASTM E 84 test are frequently used by code officials and regulatory agencies in the acceptance of interior finish materials for various applications. The most widely accepted classification system is described in the National Fire Protection Association publication NFPA 101 Life Safety Code, where:

Class A 0 – 25 Flame Spread Index 0 – 450 Smoke Developed Index
Class B 26 – 75 Flame Spread Index 0 – 450 Smoke Developed Index
Class C 76 – 200 Flame Spread Index 0 – 450 Smoke Developed Index

Class A, B, and C correspond to Type I, II, and III respectively in other codes such as SBCCI, BOCA, and ICBO. They do not preclude a material being otherwise classified by the authority of jurisdiction.