Types of foam water spray systems
Foam water systems are generally divided into the following four (4) categories:
- Wet pipe systems
- Dry pipe systems
- Deluge systems
- Preaction systems
Wet pipe spray systems: A sprinkler system employing automatic sprinklers or nozzles
that are connected with a piping system that contains water.
Dry pipe spray systems: A sprinkler system employing automatic sprinklers or nozzles
that are connected with a piping system that contains air or
nitrogen under pressure, the release of which permits the water pressure to open a valve.
Deluge spray systems: A sprinkler system similar to the wet pipe spray system, with the
exception of employing open discharge devices.
Preaction Spray Systems: A sprinkler system similar to the dry pipe spray system with the
addition of a supplemental detection system installed in
the same area as the sprinklers. Preaction systems are generally used in areas where damage
from inadvertent operation of water spray systems must
be avoided. Preaction systems generally divide into two (2) groups: single interlock preaction
systems and double interlock preaction systems. Double
interlock preaction systems require two independent events in order to activate. Firstly, the
sprinkler piping loses air or nitrogen pressure due to the
operation of one or more sprinklers, and secondly, the solenoid valve is triggered by the
operation of a fire detection device.
Types of foam concentrate
Various types of foam concentrate exist, in accordance with the application considered. Typical
foam concentrate types are the following:
- Aqueous Film-Forming Foam Concentrate (AFFF).
- Film-Forming Fluoroprotein Foam Concentrate (FFFP).
- Alcohol-Resistant Foam Concentrate, used for fighting fires on materials usually destructive to
regular AFFF or FFFP foams as well as fires involving
hydrocarbons.
- Fluoroprotein Foam Concentrate.
- Synthetic Foam Concentrate.
In general, different types and/or brands of foam concentrates shall not be mixed together.