Fire Sprinkler System: How It Works and What You Need

A sprinkler system puts water on a fire as soon as it starts, even when nobody is there. It is one of the best ways to protect a factory, warehouse, hotel or tall building.

Short answer: each sprinkler head has a small glass bulb. When the heat from a fire breaks the bulb, only that head opens and sprays water. The water comes from pipes that are always full and under pressure from the fire pumps.

Myth: all sprinklers go off together

This only happens in films. In a normal sprinkler system, each head opens on its own, only when the heat reaches it. Most fires are controlled by one or two heads.

How the glass bulb works

The bulb is filled with a liquid. When it gets hot, the liquid expands and breaks the glass. The colour shows the temperature. A red bulb, the most common, opens at about 68°C. Hotter areas, like near boilers, use bulbs with a higher rating.

Pendent or upright?

• Pendent sprinklers hang down from the pipe. They are used under false ceilings in offices, hotels and shops.
• Upright sprinklers point up from the pipe. They are used where the pipes are open, like factories, car parks and warehouses.

Pendent SprinklerPrice on requestGet a price
Upright SprinklerPrice on requestGet a price

The valves every system needs

• Alarm check valve: the main valve of a wet system. When water flows, it sounds an alarm.
• Zone control valve: controls each floor or zone, so one area can be closed for repair while the rest stays protected.
• Water flow switch: tells the fire alarm panel which zone is flowing.
• OS&Y gate valve: shows clearly if it is open or closed.
• Deluge valve: for high-risk areas where all heads should spray at once, like transformers.

Alarm Check ValvePrice on requestGet a price

Pipes and fittings

Most systems in Bangladesh use MS (mild steel) pipes and fittings. Flexible joints help where the building may move, and Y-strainers keep dirt out of the valves. See all sprinklers, valves and pipework.

Mistakes that stop a sprinkler from working

• Goods stacked too close under the heads. Keep at least 45 cm (18 inches) clear below each sprinkler, as NFPA 13 asks.
• Painted sprinkler heads. Paint can stop them from opening. Never paint a sprinkler.
• A closed valve after repair work. Check that all valves are open.
• No water in the tank, or a pump that does not start. Read our fire pump guide.

Common questions

Does a sprinkler system cause water damage?

Some, but much less than the fire, and much less than fire hoses. Only the heads near the fire open.

Is a sprinkler system required in my building?

It depends on the building type, height and use. Many factories, warehouses and tall buildings need one. Fire Service and BNBC set the rules.

How often should a sprinkler system be checked?

Check valves and gauges regularly, test the alarm, and get a full inspection every year.

Recommended products from our stock

These are the products this guide talks about, delivered all over Bangladesh. For items without a price, send us the quantity and we will reply on the same working day.

Pendent SprinklerPrice on requestGet a priceUpright SprinklerPrice on requestGet a priceAlarm Check ValvePrice on requestGet a priceZone Control ValvePrice on requestGet a priceWater Flow SwitchPrice on requestGet a priceOS & Y Gate ValvePrice on requestGet a priceMS PipePrice on requestGet a priceMS FittingsPrice on requestGet a price

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