Portable foam type fire extinguishers are most effective on（）.

A . Point the horn down B . Turn cylinder upside-down C . Break the rupture disc D . Pull pin，squeeze gri

A . carried by hand to a fire B . carried or rolled to a fire C . recharged in the field D . used on class "B" fire

A . increases the size of foam bubbles formed B . increases the rate of foam production C . improves the extinguishing properties of foam D . gives the nozzleman more freedom of movement，since it can be placed anywhere in the hose line

A . It is effective in controlling fire in flowing oil such as coming from a broken fuel line B . It absorbs heat from materials that could cause reignition C . Most foams can be used jointly with dry chemical extinguishing agents to attack a fire by two methods of extinguishment D . Once the surface is blanketed with foam and the fire is extinguished，no further foam is required

A . By cooling the oil below the ignition temperature B . By removing the fuel source from the fire C . By excluding the oxygen from the fire D . By increasing the weight of the oil

A . solid materials such as wood or bales of fiber B . flammable liquids C . electrical equipment D . metallic solid

A . generators B . oil drums C . the bridge controls D . combustible metal

A . solid materials such as wood or bales of fiber B . inflammable liquids C . electrical equipment D . metallic solid

A . shutting off the air supply B . cooling the fuel to below ignition temperature C . dispersing the fuel D . removing the source of ignitio

A . Dry chemical (cartridge-operated) B . Water (cartridge-operated) C . Water (pump tank) D . Carbon dioxide

A . the name of the unit on which it is located B . the date that it was installed on the unit C . the names of the individuals qualified to use it D . an identification number different from other extinguishers on the unit

A . turning it upside down B . pressing the foam lever C . squeezing the grip handle D . opening the hose valve

A . soild materials such as wood or bales of fiber B . flammable liquids C . a piece of electrical equipment D . combustible metallic solid

A . Point the horn down B . Turn cylinder upside-down C . Break the rupture disc D . Pull pin, squeeze gri

A . cooling B . chemical action C . smothering D . inerting the air

A . generators B . oil drums C . the bridge controls D . combustible metal

A . the name of the vessel on which it is located B . the date that it was installed C . the names of the individuals qualified to use it D . an identification number

A . Carbon dioxide B . Water (stored pressure) C . Foam D . Carbon tetrachloride

A.replaced in its proper location if weight loss is no more than 15% B.replaced in its proper location if weight loss is no more than 25% C.labeled empty and recharged as soon as possible D.labeled empty and replaced in its proper location regardless of weight