UL 1821

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This is a test method for determining values of flame propagation distance and optical smoke density for pneumatic tubing that is to be installed in ducts, plenums, and other spaces used for environmental air. The purpose of this test method is to determine whether the flame-propagation and smoke-generatin g characteristics of these tubes are in accordance with the provisions of Installation of Air Conditioning an d Ventilating Systems, NFPA 90A. Exception No. 3 of Section 2-2.1.2 of NFPA 90A states that pneumati c tubing having the required fire-resistant and low-smoke-producing characteristics are capable of bein g installed in the space between the ceiling and the floor or roof above, used as an air handling plenum.

This test method does not cover the construction requirements for tubes for pressure or other performance requirements.

A product that contains features, characteristics, components, materials, or systems new or different from those in use when the Standard was developed, and that involves a risk of fire, electric shock, or injury to persons, shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to mai ntain the level of safety for the user of the product as originally anticipated by the intent of this Standard.