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How do fire dampers prevent the spread of fire?

Fire safety is important in any building to protect lives and property. Many buildings are fitted with heating, ventilation and air conditioning (HVAC) systems which contain passageways that deliver and remove air. This network of passageways, known as ductwork, ensures indoor air quality and maintains a comfortable temperature within the building. But in the event of a fire, these passageways may allow fire to spread quickly. A fire damper is a type of safety device installed within the ductwork that helps to prevent the spread of fire, smoke or toxic gases by automatically sealing off the duct and compartmentalising the fire. This facilitates safer evacuation routes and reduces damage to the building.

This article looks at how fire dampers prevent the spread of fire, including how they work, their benefits and the UK regulations governing their use.

A man maintaining the air conditioning system in a building.

How do fire dampers prevent the spread of fire?

As previously discussed, fire dampers are safety devices within a building’s ductwork (normally in HVAC systems), designed to prevent the spread of fire or smoke. These dampers are composed of several key components, including a:

Frame: Typically rectangular or square, the frame is constructed from fire-resistant materials such as galvanized or stainless steel, ensuring durability and protection in high-temperatures.

Blade: These are flat plates that move within the frame to either open or close the damper, this acts as a barrier against fire and smoke.

Fusible Link or Actuator: This is the mechanism that operates the fire damper and triggers it to close in the event of a fire. It can consist of:

  • Fusible Link: The fusible link is a metal alloy contained within the fire damper and is designed to melt at a certain temperature (around 74°C). The melting of the fusible link activates a mechanism that forces the damper blades to shut.
  • Actuator: Some systems have electronic or pneumatic actuators. An actuator is a device that moves, causing the damper blade to close and is triggered by a building’s fire alarm or fire protection system.

Additionally, some buildings have combination fire and smoke dampers. These systems detect both heat and smoke and utilise heat-sensitive mechanisms like fusible links or smoke detectors integrated with the building’s fire alarm systems to respond swiftly in emergency situations.

Benefits of fire dampers preventing the spread of fire

Fire dampers installed in the HVAC system offer several benefits. As already mentioned, fire dampers prevent the spread of fire and contain the fire and smoke within a specific compartment or area. By automatically closing upon detection of heat, fire dampers prevent the spread of fire and smoke through the ductwork, helping to:

  • Limit property damage and save the building’s contents.
  • Provide occupants with more time to evacuate safely and enable firefighters to respond to and control a fire.
  • Keep escape routes, such as corridors and stairwells free of smoke and ensure visibility and breathable air.Somebody evacuating down the stairs

Compliance with Building Codes and Regulations

Fire dampers have to be correctly installed, carefully maintained and tested by professionals to ensure they remain responsive to thermal triggers and are compliant with the latest building and fire safety regulations.

Here are some legislation/building codes that incorporate fire dampers into their guidance:

Building Regulations 2010 (England and Wales) – Approved Document B (Fire Safety)
This document provides guidance on compliance with the fire safety requirements of the Building Regulations 2010. It covers the use of fire dampers to prevent the spread of fire through ducts and other openings in fire-resisting walls and floors.

The Regulatory Reform (Fire Safety) Order 2005
The ‘Fire Safety Order’ applies to non-domestic premises in England and Wales. It requires a responsible person (usually the building owner, occupier, or manager) to carry out a fire risk assessment and implement appropriate fire safety measures, which may include the installation and maintenance of fire dampers.

BS 9999:2017 – Code of practice for fire safety in the design, management and use of buildings
BS 9999 provides recommendations and guidance on the design, management and use of buildings to achieve acceptable levels of fire safety for all people in and around buildings. It includes provisions for the installation, inspection, testing and maintenance of fire dampers as part of the building’s ventilation system.

BS EN 1366-2:2015 – Fire resistance tests for service installations
This European Standard specifies the method for determining the fire resistance of fire dampers installed in fire-resisting ducts. Compliance with this standard is often required to demonstrate that fire dampers will perform effectively under fire conditions.

BS 9990:2015 – Non-automatic fire-fighting systems in buildings code of practice
While mainly focused on fire-fighting systems, BS 9990 also touches on aspects of building design and construction that relate to fire safety, including the use of fire dampers.

This is a guidance document issued by the Heating and Ventilating Contractors’ Association (HVCA), provides recommendations for the installation, maintenance and testing of fire and smoke dampers. You can also refer to the VH001 document from the BESA.

Manufacturers installation details

Information in the manufacturer’s installation details indicates how the damper has been tested and defines how and where a damper can be installed. All damper manufacturers test their dampers in line with BS EN 1366 pt 2 which is the specific test. If the installation details have not been followed, this can lead to your damper not providing the required compartmentation and putting life and the building at risk.

Compliance and Enforcement

Compliance with these regulations and standards is essential for ensuring the safety of building occupants and the legal operation of buildings in the UK. Building owners and managers must ensure that fire dampers are correctly installed, maintained and inspected according to the relevant codes and standards to minimise the risk of fire spread and to comply with legal requirements. The enforcement of these regulations is typically carried out by local building control bodies and the Fire and Rescue Service, which may conduct inspections to ensure compliance.

Failure to comply can result in enforcement actions by local authorities or the fire and rescue service, including fines and orders to make necessary improvements to fire safety measures.

In conclusion, fire dampers are important to prevent the spread of fire through the principle of fire containment and operate through relatively simple technology. Understanding how fire dampers work, their benefits and the regulations that encompass the testing, maintenance and installation of fire dampers is also important. As many say, prevention is better than cure, a principle that remains at the core of fire safety.

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