User:Mattvoza/sandbox/active fire protection/assignment 6

Manual fire suppression
Manual fire suppression includes the use of a fire blanket, fire extinguisher, or a standpipe system.

fire blanket
a fire blanket is a sheet of fire retardant material that is designed to be placed over a fire to smother it out.

fire extinguisher
fire extinguishers are one of the most common manual fire suppression devices and are required in all commercial building and vehicles. fire extinguisher can be used with no training and are meant for small incipient stage fires. the most common extinguisher is the ABC extinguisher and are found in most offices and homes. it can be used on normal fires, liquid fires, and electrical fires. there are also special extinguishers for kitchen fires and for use on burning metals.

Standpipe
stand pipes are installed in most large, multistory buildings.there are two types of standpipes dry and wet. most standpipes are dry systems and can not be used buy the public. dry systems require a fire engine to pump water in to the system. most dry systems don't have pre-connected hoses and require firefighters to bring in hose. in wet systems there is always water in the pipes and can be used by anyone. wet systems will have hoses so building occupants can try and extinguish fires. wet systems are becoming less common with the increase of sprinkler systems being installed.

Automatic fire suppression
Automatic control means are any form of suppression that requires no human intervention these can include a fire sprinkler system, a gaseous clean agent, or Automatic foam suppression system. Most automatic suppression systems would usually be found in large commercial kitchens or other high-risk areas.

Gaseous clean agent
Gaseous clean agents are installed in places where water or dry chemical extinguishing agents will do more harm then good. they are mostly installed in server or computer rooms where water or fine dust particles will cause vast amounts of damage. the system works by flooding a area with a inert or a mix of inert gasses to break the fire tetrahedron. due to the inert gases displacing oxygen there is a suffocation risk when it is activated. Most systems have a short delay to give people the opportunity to evacuate.

foam suppression system
Automatic foam suppression systems come in three main forms low expansion, medium expansion, and high expansion.

Low expansion
Low expansion foam expands less then 20 times its original size. these systems can be installed in a a verity of places but are commonly found in places where hydrocarbons are stored. low expansion foam systems when using film forming work by making a blanket of foam over the burning liquid to both cool it down and suppress the vapors.

Medium expansion
medium expansion foam expands between 20 and 200 times its original size. these can be installed in outdoor settings like transfer stations or for use in open pits. medium foam is used outdoors because it is more dense then high expansion and wont blow away as easily it works buy covering what is on fire in a thick blanket of foam to smother it and suppress vapors.

High expansion
High expansion foam expands between 200 and 1000 times it original size. these systems are commonly installed in large volume areas like airplane hangars, mine shafts, and ship holds. these systems are normally installed inside and make a very light foam. they extinguish the fire by rapid smothering and cooling. its rapid rate of expansion enables it to fill large areas with foam rapidly. when used on LNG tanks they provide a added insulation layer that helps reduce the vapor rate.