Security Fog Knowledge Blog 安雾博客

What Is a Security Fog Machine and How Does It Work?

A security fog machine (also called a fog cannon or anti-theft fogging system) is an active burglary-protection device. Instead of only recording a crime like a CCTV camera, it physically stops the crime: within seconds of an alarm trigger, it fills the protected room with a dense, white, harmless fog. Visibility drops below 30 centimeters, the intruder cannot find the goods or the exit route they planned, and in almost every case they leave immediately with nothing.

The working principle

Inside the machine, a heating element keeps a vaporizing chamber at working temperature 24/7. When the alarm panel closes the trigger circuit, food-grade glycol fluid is forced through the hot chamber and instantly vaporizes. As the vapor meets cooler room air it condenses into microscopic droplets — the same principle as stage fog, but far denser and faster. Our SF-6 reaches zero visibility in under 10 seconds and the fog hangs in the air for 45 minutes or more.

Is the fog safe?

Yes. Quality machines use food-grade glycol that is safe to breathe and leaves no residue on merchandise, electronics or fabrics. After the room ventilates, there is nothing to clean. This is why fog systems are trusted in jewelry shops, pharmacies, banks and electronics warehouses worldwide.

Related: How to choose the right size fog machine for your room · Watch a live discharge video

Fog Cannon vs. Burglar Alarm: Which Protects Your Shop Better?

Shop owners often ask us: “I already have an alarm and cameras — why do I need a fog cannon?” The honest answer is that they solve different problems, and they work best together.

The time gap problem

A typical smash-and-grab burglary lasts three to ten minutes. A siren scares some intruders, but professionals know that police response usually takes longer than their raid. Cameras only help after the goods are already gone. The weakness of traditional systems is the time gap between alarm and response.

How fog closes the gap

A fog cannon acts in the first ten seconds, not after twenty minutes. It does not replace your alarm — it is triggered by your alarm through a simple IN+/IN− dry-contact connection, so any existing panel can fire it. The intruder is left standing in a wall of white with nothing to see and nothing to take.

Our recommendation

Keep your alarm and cameras for detection and evidence, and add a fog machine as the response layer. Insurance companies in several countries already recognize fogging systems with premium discounts. Ask our team which configuration suits your shop.

How to Choose the Right Security Fog Machine: 2, 4 or 6 Cans?

The most common sizing question we receive is how many fog canisters a room needs. Our SF-6 makes this simple because one machine offers three selectable modes — you choose the bank size with a switch, shown by the 2/4/6-Cans indicator LEDs on the housing.

Quick sizing guide

2-can mode (about 200 m³): small shops, offices, strong rooms and counters up to roughly 75 m² floor area at a normal ceiling height.
4-can mode (about 400 m³): showrooms, pharmacies and open-plan retail up to roughly 150 m².
6-can mode (about 600 m³): warehouses, stockrooms and large halls up to roughly 220 m².

Three more factors to check

First, mounting position: aim the nozzles at the entry path, not the back wall. Second, trigger logic: connect the fog machine after a confirmed alarm (two-sensor verification) to avoid false discharges. Third, refill plan: with sealed canisters like the SF-C01, unfired cans stay armed after a partial discharge and swaps take seconds.

Still not sure? Send us your floor plan by WhatsApp or e-mail and our engineers will size it free of charge.