Significance and Use
5.1 These test methods are intended to evaluate the ability of the HVAC duct system and its supporting construction to do the following:
5.1.1 Resist the effects of a standardized fire exposure, and
5.1.2 Retain its integrity.
5.2 These test methods provide for the following measurements and evaluations where applicable:
5.2.1 Ability of the fire-resistive material to resist flaming (combustion) when exposed to 1382°F (750°C).
5.2.2 Ability of the tested support system to carry the load of the HVAC duct and its fire-resistive material(s) during the entire duration of the standardized fire-engulfment test.
5.2.3 Ability of the firestops to meet the requirements of Test Method when used as part of a HVAC duct system.
5.2.4 Ability of the HVAC duct system to resist the passage of flames and hot gases onto its unexposed surface during a standardized fire-resistance test.
5.2.5 Transmission of heat through the HVAC duct system during a standardized fire-resistance test.
5.2.6 Ability of the firestop to resist the passage of water during a standardized hose stream test.
5.2.7 Comparative measurement of temperature aging of the fire-resistive material(s) when subjected to a standardized thermal cycling during the durability test.
5.2.8 Measurement of flame spread over the surface of the fire-resistive material or HVAC duct system.
5.2.9 Ability of the covering and lining to resist flaming, glowing, smoldering or smoking while in service.
5.3 These test methods do not provide the following:
5.3.1 Full information as to performance of the fire-resistive material, supporting construction, or the HVAC duct system constructed with components, densities, or dimensions other than those tested.
5.3.2 Evaluation of the degree by which the fire-resistive material or HVAC duct system contributes to the fire hazard by generation of toxic gases, or other products of combustion.
5.3.3 Measurement of the degree of control or limitation of the passage of smoke or products of combustion through the HVAC duct system.
5.4 The test specimens are subjected to one or more specific tests under laboratory conditions. When different test conditions are substituted or the end-use conditions are changed, it is not always possible by, or from, these test methods to predict changes to the characteristics measured. Therefore, the results of these laboratory tests are valid only for the exposure conditions described in these test methods.
5.5 These test methods require a test specimen to be exposed to a standard fire that is controlled to achieve specified temperatures throughout a specified time period. The engulfment test is followed by the application of a standardized hose stream test. These test methods provide a relative measure of the fire-test-response of comparable fire-resistive materials and HVAC duct systems under these exposure conditions. The fire exposure is not representative of all fire conditions because conditions vary with changes in the amount, nature and distribution of fire loading, ventilation, compartment size and configuration, and heat sink characteristics of the compartment. Variation from the test conditions or test specimen construction, such as size, materials, method of assembly, also affects the fire-test-response. For these reasons, evaluation of the variation is required for application to construction in the field.
Note 5: When the size of the HVAC duct exceeds the capability of the test furnace to test it, the authority having jurisdiction (AHJ) should be consulted to determine what test and evaluation of the variation is required for application to construction in the field.
Note 1: Use of the standard designation ISO 6944 refers to both ISO 6944:1985 and ISO 6944-1:2008.
1.1 These test methods evaluate the fire-resistive materials and the HVAC duct systems surface burning characteristics, non-combustibility, fire resistance, durability, and fire-engulfment with horizontal and vertical through-penetration firestops.
Note 2: The intent of these test methods is to provide authorities having jurisdiction a means to evaluate the fire performance of HVAC duct systems to enable their application and use.
1.2 These test methods evaluate the fire performance of HVAC ducts, including both supply (pressurized: Condition A – Horizontal and Condition B – Vertical) and return (exhaust: Condition C – Horizontal and Condition D – Vertical).
1.3 These test methods evaluate the ability of a HVAC duct system to resist the spread of fire from one compartment to other compartments separated by a fire resistance rated construction when the HVAC duct system is exposed to fire under one or more of the following conditions:
1.3.1 Condition A—Fire exposure from the outside of the horizontal HVAC duct system without openings,
1.3.2 Condition B—Fire exposure from the outside of the vertical HVAC duct system without openings,
1.3.3 Condition C—Fire exposure from the outside with hot gases entering the inside of the horizontal HVAC duct system with unprotected openings, and
Note 3: Unprotected openings are openings that are not protected by fire dampers.
1.3.4 Condition D—Fire exposure from the outside with hot gases entering the inside of the vertical HVAC duct system with unprotected openings.
1.4 These test methods provide a means for determining the fire-resistance of vertical and horizontal HVAC duct systems, when subjected to the standard time-temperature curve of Test Methods .
1.4.1 Condition A—These test methods provide a means for evaluating a horizontal HVAC duct system, without openings exposed to fire, passing through a vertical fire-separating element.
1.4.2 Condition B—These test methods provide a means for evaluating a vertical HVAC duct system, without openings exposed to fire and outfitted with a horizontal connection, passing through a horizontal fire-separating element.
1.4.3 Condition C—These test methods provide a means for evaluating a horizontal HVAC duct system, with unprotected openings exposed to fire, passing through a vertical fire-separating element.
1.4.4 Condition D—These test methods provide a means for evaluating a vertical HVAC duct system with a horizontal connection, and with unprotected openings exposed to fire, passing through a horizontal fire-separating element.
1.5 These test methods prescribe a standardized fire exposure for comparing the test results of the fire resistive materials and HVAC duct systems. The results of these tests are one factor in assessing predicted fire performance of HVAC duct systems. Using these test results to predict the performance of actual HVAC duct systems requires the evaluation of test conditions.
1.6 The values stated in inch-pound units are to be regarded as the standard. The SI values given in parentheses are for information only, unless the SI units are used consistently to perform all of the test methods referenced herein. In this case, the SI units will be regarded as the standard and will be used in Section , Report.
1.7 The text of these test methods references notes and footnotes which provide explanatory material and (excluding those in tables and figures) shall not be considered as requirements of the fire-test-response standard.
1.8 This document specifically excludes evaluating ducts that carry combustibles, flammable vapors, combustible gases, and commercial kitchen ventilation systems commonly called grease ducts or hazardous exhaust ducts, which are tested in compliance with Test Methods .
1.9 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 the materials, products, or assemblies under actual fire conditions.
1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.11 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these tests.
1.12 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.