Extinguishing fires involving ammonium nitrate stock with water: Possible complications

摘要

Violent decomposition and explosion of ammonium nitrate induced by a fire present potentially a serious threat to personnel, facilities, and nearby community. One of the most recent incidents involving ammonium nitrate occurred on 17 April 2013, in West, Texas, killing 15 people and injuring more than 250 people; this incident has caused heated discussion again on the safety issues associated with ammonium nitrate including firefighting issues. In terms of fire protection, water suppression systems have been widely used in chemical process facilities as an active protection layer, and they have been successful in tackling most of the fires. However, where water is the only agent to fight a fire in an ammonium nitrate store, acting as a cooling and hence combustion extinguishing agent, it does not limit the oxidant supply as this is contained within the ammonium nitrate molecule. Under some circumstances, the addition of water may also favor the conditions for explosion. In this article, the possible role of water interfering physically and to some extent chemically with ammonium nitrate stock in a fire is discussed, calling for more research to develop an optimal procedure to fight ammonium nitrate fertilizer fires.