A water mist system is a fire protection system which uses very fine water sprays (i.e. water mist). The small water droplets allow the water mist to control, suppress or extinguish fires by: cooling both the flame and surrounding gases by evaporation, displacing oxygen by evaporation, and attenuating radiant heat by the small droplets themselves.

The effectiveness of a water mist system in fire suppression depends on its spray characteristics, which include the droplet size distribution, flux density and spray dynamics, with respect to the fire scenario, such as the shielding of the fuel, fire size and ventilation conditions.

These systems use devices that respond to the smoke particles produced by a fire.  Spot-type smoke detectors use the photoelectric principle of operation.  These systems are intended for early warning of a fire (versus very early warning). Some are designed for installation in ventilation ducts. (See NFPA 72, National Fire Alarm Code.) Properly installed, smoke detectors can detect smoke particles in early stages of fire in the areas where they are located. The selection of a particular detector or mixture of detectors should be made by a fire protection specialist and based on building and fire-load conditions.

The ionization principle of spot smoke detection was popular in the past but because of the challenge in sourcing radioactive material used in these detectors manufacturers have opted to discontinue their manufacture in favor of enhanced-performance photoelectric detectors.

An Air Sampling Detector consists of a piping or tubing distribution network that runs from the detector to the area(s) to be protected. An aspiration fan in the detector housing draws air from the protected area back to the detector through air sampling ports, piping, or tubing. At the detector, the air is analyzed for fire products. Air Sampling Smoke Detectors are capable of detecting a fire at its earliest stage.

Traditional "spot-type" detectors passively detect smoke or heat in their immediate area. Air Sampling Smoke Detectors actively pulls room air through a piping network to its detection chamber where it can detect the presence of particles that are created in the very early stages of combustion, even before smoke is visible.

There are newer tools for improved monitoring for lithium-ion battery healthy & safety that specialize in detecting any off-gas event from lithium-ion batteries. It’s a unique protection technology that offers the earliest warning to avoid catastrophic events.