For eleven years I have been working on setting up fire extinguishing and smoke removal systems at facilities — from parking lots to chemical warehouses. It would seem that the topic is dry, technical. In fact, there are more real-life stories there than in half of the TV series.
I'll start with an example, not theory. There was a facility — an underground parking lot of a shopping center in Zhytomyr, three levels. The designer laid the smoke removal system according to the old standard solution, from the times when cars were smaller and the flammability of interior materials was lower. Seven years after the opening, tests were conducted — and it turned out that the valves for the smoke removal system were not opening synchronously, one was 40 seconds late. A trifle on paper. In a real corridor, when there is smoke, it is the difference between "having time to get out" and "not having time".
Drencher fire extinguishing system - where sprinklers cannot cope
A drencher fire extinguishing system differs from a conventional sprinkler system in one thing - open nozzles that work all at once, and not in one zone. It is installed where the fire spreads quickly: theater stages, hangars, warehouses with flammable liquids. And here is the thing - many customers confuse a drencher system with a sprinkler system even at the design stage, and this is a different logic of operation, different pumps, different water supply.
I remember how at one paint powder warehouse (I will not name the city, the customer asked) they calculated the water supply for the sprinkler system, and installed a drencher system. The result was that there was enough water for nine minutes instead of the estimated fifteen. Fortunately, there was no fire, the error was found during a routine inspection. It could have been worse.
Automatic fire extinguishing systems do not calculate "how much water to pour", but "how long it should pour until the rescue service arrives". These are different tasks, and confusing them is a professional mistake that I have seen more than once even by experienced designers.
Gas fire extinguishing systems - when water does more harm than fire
And what if extinguishing with water is simply impossible? Server rooms, archives, museum collections, electrical panels - there, water fire extinguishing systems will turn an accident into a second-level catastrophe: equipment that would survive local decay dies from water and corrosion in a few hours. Gas fire extinguishing systems operate here - based on inert gases or refrigerants, which displace oxygen or extinguish the chemical reaction of combustion without a single drop of liquid.
To be honest, gas extinguishing is the most expensive option of all, and customers often ask if it is possible to save money. Of course, it is possible. The question is on what exactly. You can save on the cylinder, but not on the tightness of the room. There was a case in Vinnytsia, in the server room of a small bank: gas was supplied, the concentration dropped faster than it had dropped, because a technological hole for a cable channel was left in the wall, which no one had covered after the repair. The system worked according to the passport. The room did not.
Designing smoke removal and automatic fire extinguishing systems together, not separately
This is where, in my opinion, the most mistakes are made on the market. Smoke extraction systems are often designed separately from fire extinguishing systems, different contractors, different deadlines, and in the end, the two "ideal" solutions simply conflict with each other on site. Smoke extraction opens valves to vent the house and heat, and the fire extinguishing system at the same time can create excess pressure or vice versa - a vacuum that interferes with the operation of the fans. Here is a list of things that I always check together, not separately:
- the sequence of operation of smoke extraction valves and sprinklers;
- compatibility of automation (do the systems "see" each other through the control panel);
- real, not passport, evacuation time for a specific planning.
In the end, the best system is not the one that won the tender by price, but the one that someone has actually tested once a year with a stopwatch in hand. It sounds simple. Until you stand in a smoky corridor and count the seconds it takes for a valve that hasn't worked to work.