Fire protection in a powder booth

Coating powders consist of a mixture of pigments, fillers, reactive polymers, hardeners and additives. They are applied using electrostatic guns, a technique which demands that the products be finely ground. The maximum diameter of powder designed for electrostatic application is 80 μm.

Lower explosion limit

The lower explosion limit of commercial powders ranges from 35 to 90 g/m3. (DIN 55990-6 or ISO 8130-4). Powdering installations should be designed so that half that concentration cannot be exceeded. In the absence of precise values, a level of 10 g/m3 is retained. The concentration applies to the overall booth volume, but it is difficult to precisely know the concentration figures for the gun spray area.

Increased risk near spray guns

The most likely risk of ignition is in the vicinity of the guns, where two major parameters can come into play: the concentration of a flammable material and an energy source. Spread of fire towards the filter may cause explosion. In conformity with ATEX guideline 1999/92/EC all measures should be applied to prevent an explosion or limit the consequences.

Fire protection to limit down time

We have developed a range of safety devices for the instant detection of flames and their extinction, thereby preventing their propagation. The device guaranties that the fire is contained and that the shutdown of the production is limited.

Detection in an electrostatic powder booth

Flame detection is by infrared detectors that monitor the powder spraying zone. The detectors are connected to the control panel.

Indication in an electrostatic powder booth

A flashing light and a sound alarm are fixed on the upper part of the information cabinet. They are activated whenever an alarm occurs.

CO2 is the extinguishing agent for an electrostatic powder booth

CO2 cylinders are located inside the booth. The extinguishing systems consist of steel pipes, hoses and nozzles for the protection of the filter.

Extinguishing a fire in an electrostatic powder booth

The fire is detected in its incipient stage by the flame detectors that send a signal to the indication panel. The interlocking contacts are immediately activated in order to interrupt the powdering process.

The CO2 is sent to the spray nozzles which keep spraying until the CO2 cylinder is empty. This way, a CO2 wall is created, preventing the propagation of the fire to the filters and removing the risk of an explosion. After use, the cylinder always needs to be either refilled or replaced. Our cylinders are equipped with solenoid valves for affordable and simple refilling.