D-3-3 High Expansion Discharge Devices
High expansion foam generator systems are common fire control and suppression systems for a wide range of hazard involved fire events including either ordinary combustibles, flammable or combustible liquids or a combinations of these. These systems are efficient against LPG and LNG pool fires too. These systems are calculated by using NFPA-11, EN 13565 standards to protect hazards in places like storage warehouses, aircraft hangars etc., where the fire risk depends on a variety of different materials and on an accordingly different reactions to fire. High expansion foam generating systems are the most effective solutions for indoor spaces since they are used to submerge a fire and to exclude the necessary air to sustain combustion.
A protected volume submerges rapidly to avoid any extensions of the fire and extinguishes it in the earlier phases by using reduced water content of the expanded foam, meaning that less water damage is inflicted on the items protected within the site. High expansion foam smothers the fire, insulates combustibles from air and penetrates into all three-dimensional spaces. High expansion foam is the most effective tool in total flooding of spaces such as warehouses, engine rooms, transformer buildings, cable tunnels, underground storage facilities, basements, ships’ hold, and aircraft hangars. As well as being used on liquid fires, it is also very effective for fires in combustible solids such as paper and wood. High expansion systems performance depends on multiple factors such as the foam concentrate type, the proportioning accuracy, the equipment feeding pressure and the available flow rate. Foam concentrates used for high expansion systems are specially formulated to give high surface tension to the premix when correctly mixed with water. High expansion foam generators feeding collectors connected to the firefighting network deliver the foam water solution to spray nozzles. The spray nozzles types, quantity and distance are specially engineered with the experience matured within years, to guarantee complete occupation of the expansion net area by the sprayed liquid. The travelling liquid’s mass creates a Venturi effect that aspirates air from the back side of the generator. Air pushes the liquid sticks to the expansion net to create bubbles with a volume-mass ratio up to 900:1 of the applied mixture. The expanded foam discharged from the generator’s outlet firstly covers the entire surface area by sticking to perimeter walls and surfaces of stored materials, and then rises up reaching submergence height, penetrating into all the spaces contained inside. The expanded foam catches out the oxygen necessary to the combustion and avoids further reignition after complete submergence by cutting the contact of the burning fuel from the surrounding atmosphere. High expansion generators may use internal air to expand the foam concentrate as well as aspirating the combustion air which carries smoke and pollution. Recommendation is to provide adequate smoke venting means in the protected space or feed generators with fresh air supply by feeding them with duct or positioning them at roof or perimeter walls to increase performance.
Consult with our company for actual certificates and performance values.
