Fire Warning and Evacuation Systems and Smoke Extraction: How They Save Lives

The fire alarm has detected a fire. What next? People must be warned and led out, and smoke must be kept out of corridors and stairwells. That is the job of the warning and evacuation system and of smoke extraction.

Here is how they work, which types exist and why they should be designed together with the fire alarm.

What is a fire warning and evacuation system?

It is the system that warns people of a fire and helps them get out safely: with sounders, lights, voice messages and illuminated direction signs. In Russian-language standards it is called SOUE.

There are 5 types: from simple sounders (type 1) to voice systems with zones and evacuation control from a central desk (types 4–5). The required type depends on the building's use, height and occupancy.

Why is a voice alarm better than a siren?

A siren only says "something is wrong". A voice message explains what to do: "Attention! Fire alarm. Please leave the building calmly by the nearest exit." In shopping centres, hotels and schools people react faster to speech and panic less.

A voice system can also be used for announcements and background music.

What are sounders and beacons, and what types are there?

They include sirens, illuminated exit signs, combined sounder-beacons and voice speakers. For example, the S2000R-Sirena sounder-beacon works over radio and needs no cabling.

The type of devices follows from the required warning system type, which the standards set according to the building's use and occupancy.

What is a smoke extraction system and why is it needed?

Most fire deaths are caused by smoke, not flames. A smoke extraction system removes smoke from corridors, stairs and rooms, while pressurisation keeps smoke out of stairwells and lift shafts.

We have installed smoke extraction systems at the LUKOIL office and Tashkent International Airport, among others.

What is a fire damper?

It is a shutter inside a ventilation duct. A normally open damper closes in a fire and stops flames and smoke spreading through the ductwork. A normally closed (smoke) damper does the opposite and opens to extract smoke.

Dampers are controlled by the fire alarm. We install and test them together with smoke extraction systems.

Our experience: smoke extraction and dampers on major sites

DITI SERVICE has installed smoke extraction systems and fire dampers at the LUKOIL office in Uzbekistan and at Tashkent International Airport, and installed and maintained warning systems at the Ministry of Foreign Affairs, the National Bank, the House of Radio and Westminster International University.

We design the fire alarm, warning system and smoke extraction as one package — with no gaps between contractors.

How the type of warning system is chosen

The type depends on the building's use, number of storeys, floor area and occupancy. A small warehouse may only need sounders and exit signs (types 1–2); a school, hotel or shopping centre needs a zoned voice system (types 3–4); large mixed-use complexes need evacuation control from a central desk (type 5).

The designer determines the required type according to current standards.

Testing and maintaining warning and smoke extraction systems

Warning systems are tested for audibility in every room, operation of illuminated signs and switchover to backup power. Smoke extraction is tested for fans starting and dampers opening on a fire signal, fire dampers closing and pressurisation working.

These tests are part of the maintenance schedule and must be recorded in the logbook.