If you have an HVAC system in your building, it is an avenue that can contribute to the spreading of the fire — the only way to stop this to install functional fire dampers.

It is not a common occurrence to have fires destroy private homes and commercial buildings. However, you have to prepare for the low chance of occurrence, as it could happen anytime. A simple mistake as forgetting to switch off your cooker could result in a big, catastrophic fire.

If you have an HVAC system in your building, it is an avenue that can contribute to the spreading of the fire — the only way to stop this to install functional fire dampers.

Many people familiar with HVAC systems do not know what a fire damper is, how it works, where it is located, and how they are installed.

This article addresses these questions and show the benefits of having fire dampers installed in your buildings.

Fire dampers

What is a fire damper and what are the benefits of having them?

Fire dampers are specialized fittings placed on the ducting in a building. Their primary job is to shut off the duct in case of a fire and prevent a fire from passing from one section of a building to another. Where there are ventilation ducts passing through a wall or floor, there will be openings where smoke and fire can pass from one room into another. Correctly placed fire dampers can stop the smoke, fire and heat from getting through from one room to another.

They are designed and rigorously tested to be able to resist high temperatures and seal the passage for an extended period of time, commonly from 60 minutes up to 240 minutes.

The benefits of having fire dampers installed far outweight not having them. They are essential in fire compartmentation and they protect people’s lives and prevent extended property damage. They also provide enough time for the fire fighters to reach the scene, gives them a safe passage through the rest of the building and a more manageable situation to handle.

How do fire dampers work?

There are a variety of fire dampers and activation mechanisms available. Manual fire dampers do not need an input command to engage; they are designed to trigger automatically. They rely on a fusible link which melts at around 72°C and immediately activates the release mechanism to shut off the passage. They need to be set and locked at the open position manually

Fire dampers can also be activated remotely. These versions usually feature electric actuators or electromagnets that unlock by an electric impulse or by interruption. Additional from a motorised resetting option, they are usually preferred when a central fire fighting system is in place.

ommon features of both types described above are limit switches indicating the open/closed status of the blades and the presence of the fusible link.

Finally, there are intumescent fire dampers which work on a different principle which is described below.

Type of fire dampers

Most notable types of fire dampers are widely known as curtain fire dampers, intumescent fire dampers, and single/ multi-blade fire dampers

Curtain fire dampers

These are usually a sequence of interlocking blades that fold up to the top and are held open through a thermal release mechanism that activates at about 72°C or triggered electrically. Because of their metallic construction, they can be found in different material construction and duct connecting options.

Intumescent fire dampers

This type of fire damper incorporates materials that go through expansion when exposed to high temperature or flames. They typically have an appearance similar to ventilation grilles but when activated (usually around 100°C+) the slats come together to form a solid mass that seals the passage. They are most commonly used in doors and partitions instead of ducted applications.

Single/multi-blade fire dampers

This type of fire damper has one or more pivoting blades linked and framed. They are activated through a thermal release mechanism that triggers at about 72°C or electronically. The blades are typically of a composite material that will effectively block thermal radiation as well as flames and smoke. Their construction also allows for thinner casings and therefore minimal distances between multiple dampers.

Where are fire dampers located?

Fire dampers are located and installed in or near the wall or the floor, at the points where the ducts penetrate. This is because they want to retain the wall or floor's fire rating and integrity regardless of whether it is a ducted application or an open-plenum return application.

Fire damper installation

When it comes to fire protection, the method of installation is just as important as the product itself. Fire damper rating and certification is valid only under the installation conditions they were tested in and so the instructions provided by the manufacturer should be followed to the letter. Depending on the type and make of a fire damper the installation methods may vary and therefore to install a fire damper in your home or office, you need to employ the services of a professional certified installer.

Fire damper regulations

Some regulations guide the installation and maintenance of fire dampers. The International Building Code (IBC) and the National Fire Protection Association (NPFA) Code requires the inspection and testing for fire dampers' combination before installation and then tested again after a year.

The BS 9999 fire damper legislation also states that fire dampers must be immediately repaired or replaces when faulty. In the European Union, Regulation (EU) 305/2011 sets harmonising criteria regarding the behaviour of construction materials, including their performance in case of fire. In addition, fire dampers comply to a set of European standards, for example the standard EN 15650:100 which specifies the testing requirements for fire dampers intended to be used in HVAC installations. In European countries it’s common for an inspection to take place every six months.