This part of ISO 21927 specifies the product performance requirements, classifications and test methods for smoke barriers, which comprise the barrier itself, with or without associated activation and drive devices, designed for use in smoke and heat control systems. It covers only barriers installed in buildings, i.e. it does not cover barriers made of part of the building’s structure. This part of ISO 21927 provides the test methods for, and conformity assessment of, the smoke barrier systems. Smoke barriers are only covered by this part of ISO 21927 when calculation methods exist for the determination of the leakage rate of smoke. This requires the smoke barriers to be sufficiently fixed and guided on any free joints between two adjacent smoke barriers. Figure E.4 illustrates a design to which this part of ISO 21927 does not apply.