NFPA 11A-1999 Standardfor Medium-and High-Expansion Foam Systems 1999 Edition

NFPA 11A-1999 Standardfor Medium-and High-Expansion Foam Systems 1999 Edition. 1-6.2.4 Susceptibility of the protected hazard to water damage shall be evaluated. 1-6.2.5 Medium- and high-expansion foam systems shall not be used on fires in the following hazards unless competent evaluation, including tests, indicates acceptability: (a) Chemicals, such as cellulose nitrate, that release sufficient oxygen or other oxidizing agents to sustain combustion (b) Energized uncnclosed electrical equipment (s 1-7.2.2) (c) Water-reactive metals such as sodium, potassium, and NaK (sodium-potassium alloys) (d) 1 lazardous water-reactive materials, such as triethylaluminum and phosphorous pentoxide (e) Liquefied flammable gas 1-6.3 Types of Systems. The types of systems recognized in this standard include the following: (a) Total flooding systems (b) Local application systems (c) Portable foam-generating devi:es 1-6.4 Systems Protecting One or More Hazards. 1-6.4.1 Scteim shall be permitted to be used to protect one or more hazards or groups of hazards by means of the same supply of foam concentrate and water except as provided in 1-6.4.2. 14.4.2 Where, in the opinion of the authority havingjurisdiction, two or more hazards can be simultaneously involved in fire by reason of their proximity, each hazard shall be protected with an individual system, or the system shall be arranged to discharge on all potentially involved hazards simultaneously. 1-7 Personnel Safety. 1-7.1 Hazards to Personnel. The discharge of large amounts of medium- or high-expansion foam can inundate personnel, blocking vision, making hearing difficult, creating some discomfort in breathing, and causing spatial disorientation. This breathing discomfort will increase with a reduction in expansion ratio of the foam while the foam is under the effect of sprinkler discharge. 1-7.1.1 Where possible, the location of foam discharge points relative to building exits shall be arranged to facilitate evacuation of personnel. Additional exits and other measures might be necessary to ensure safe evacuation of personnel. 1-7.1.2 To reenter a foam-filled building, a coarse water spray shall be permitted to be used to cut a path in the foam. Personnel shall not enter the foam. The foam is opaque, making it impossible to see when one is submerged in lilt is dangerous to enter a building in which there was a fire if one cannot see. 1-7.2 Caution. 1-7.2.1 A canister-type gas mask shall not be worn in the foam. The chemicals of the canister can react with the water of the foam and cause suffocation. If emergency reentry is essential, self-contained breathing apparatus...