The Kidde Wet Chemical System provides fire protection for commercial kitchen applications such as appliances and ventilation.
The system uses a liquid chemical called Aqueous Potassium Carbonate (APC) as its agent. APC, a solution of potassium carbonate in water, suppresses fires through a process of:
- Saponification of surface grease (turning it into combustion-resistant foam/soap).
- Cooling effects of water vaporisation,
- Inerting effects of resultant steam formation, and
- Interruption of the chemical chain reaction of combustion.
Hazards and equipment that can be protected using wet chemical extinguishing systems are
- Restaurant, commercial, and institutional hoods
- Plenums, ducts, and filters with their associated cooking appliances
- Special grease removal devices
The wet chemicals used in the Kidde WHDR Wet Chemical System are stable at both low and high temperatures. The upper storage temperature limit for the system is 120°F (49°C). The lower temperature limit is 0°F (-18°C).
APC wet chemical agent is applied in a concentrated liquid spray to a burning surface, reacting quickly with the hot grease or oil to produce a foam blanketing the surface. The layer acts to smother a fire and with the cooling effect of the APC wet chemical agent, also reduces the possibility of fire reflash.
Hazardous material information, HMIS rating for APC wet chemical is as follows:
- Health (H) = 2
- Flammability (F) = 0
- Reactivity (R) = 0
Upon system alarm notification, all personnel must evacuate the protected space. Failure to do so may result in temporary respiratory difficulties, disorientation, or personal injury.
Wet chemical fire extinguishing agent is considered nontoxic, but is classified as a skin/eye irritant, and may cause temporary irritation to the eyes, skin, or respiratory system. Avoid unnecessary exposure.
No unusual cleanup procedure is required. After the appliances have completely cooled, the residue from the discharge may be cleaned up with a wet cloth or sponge. Wear rubber gloves while cleaning. If skin or eyes come in contact with the agent, flush thoroughly with water.
APC wet agent is electrically conductive. To avoid electric shock, de-energise all electric circuits to appliances, outlets, and wiring by disconnecting or turning off the electric power at the main fuse or circuit breaker box. Do not clean up APC wet agent or touch electric appliances, outlets, power cords, or other wiring with electrical power on.
The Wet Chemical system holds UL and ULC listings as a pre-engineered system.
The classification of fire is defined as the following:
- Class A: Surface Type Fires; wood or other cellulose-type material (ordinary combustibles)
- Class B: Flammable liquids
- Class C: Energised electrical equipment
- Class D: Combustible metals (such as magnesium, sodium, zirconium, potassium, and titanium)
- Class K: Combustible cooking media (vegetable or animal oils and fats)
Note: Kidde Wet Chemical system is suited for Class K type of fire.
The system utilises stored pressure agent gas cylinders, powder-coated, welded mild-steel shell conforming to DOT/TC specification 4BW/4BA construction and NFPA standards. The valve is forged brass with nickel plating. The plating and cylinder coating makes it corrosion resistant.
The system can be activated mechanically from manual release, thermo-bulb links, and fusible links. The system can be activated electrically with a 24 Vdc compatible alarm control panel that is tested and listed with the Kidde XV Control System. Both automatic detection and manual release devices are used on control panels.
Other actuations are available, such as mechanical gas valve closure or dry contacts for annunciation and electrical shutdowns.
Upon actuation, the wet chemical is discharged through agent distribution piping and specially designed nozzles positioned throughout the protected area.