What is ISO 21925‑1 about?
ISO 21925‑1 is part one of a multi-series of international standards on fire resistance tests which covers fire dampers for air distribution systems.
ISO 21925‑1 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.
Note: ISO 21925‑1 is not intended to be used for dampers used only in smoke control systems, for testing fire protection devices that 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. "Air transfer" is a low-pressure application through a fire separation door (or wall, floor) without any connection to an air duct
Who is ISO 21925‑1 for?
ISO 21925‑1 on the determination of the resistance of fire dampers to heat is useful for: 
- Mechanical fire damper manufacturers
- Air distribution systems designers
Why should you use ISO 21925‑1?
Fire dampers are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts to prevent the spread of fire inside the ductwork through fire-resistance-rated walls and floors. Fire/smoke dampers are like fire dampers in fire-resistance rating and prevent the spread of smoke inside the ducts. Air-distribution systems comprise air handlers, ductwork, and associated components for heating, ventilating, and air-conditioning buildings. They provide fresh air to maintain adequate indoor air quality while providing conditioned air to offset heating or cooling loads.
ISO 21925‑1 helps alleviate the risk of fire and smoke spreading from one fire compartment to another through an air distribution system by providing a test method for the determination of the resistance of fire dampers to heat.
What’s changed since the last update?
BS ISO 21925‑1:2018 supersedes BS ISO 10294‑3:1999, BS ISO 10294‑1:1996+A1:2014, BS ISO 10294‑2:1999 and BS ISO 10294‑4:2001+A1:2014, which are withdrawn.
BS ISO 21925‑1:2018 has integrated the requirements for mechanical dampers, which were published as four separate parts in the former ISO 10294series, into a single document as a technical change.
