ISO 21925-1:2018

This document specifies a test method for the determination of the resistance of fire dampers to heat, and for the evaluation of their ability to prevent fire and smoke spreading from one fire compartment to another through an air distribution system.
It is applicable to mechanical fire dampers. It is not intended to be used for dampers used only in smoke control systems, for testing fire protection devices which only deal with air transfer applications, or for dampers used in suspended ceilings, as the installation of the damper and duct can have an adverse effect on the performance of the suspended ceiling, requiring other methods of evaluation.
NOTE     "Air transfer" is a low-pressure application through a fire separation door (or wall, floor) without any connection to an air duct.