Primary options include:

• Installation of Limited Combustible (LC) cabling – lower cost per drop (materials & labor)
  
  This alternative provides the greatest ongoing flexibility with regard to future cabling installations at the lowest total long-term cost. The use of Limited Combustible cabling is a passive and therefore reliable fire protection system, providing the best possible total fire protection.
  
  
• Installation of combustible cabling & plenum-sprinklers – higher cost per drop (materials & labor)
  
  This alternative enables businesses to use combustible material in plenum spaces provided that the materials are adequately sprinkled in the event of a fire. Plenum-sprinklers are inherently “active” systems, requiring adequate electricity and water pressure in the event of a fire. Sprinkler systems in tall buildings can fail to control up to 40 percent of fires, and so provide somewhat less fire protection than possible.
  
  
• Installation of combustible cabling in metal conduit – higher cost per drop (materials & labor)
  
  Many jurisdictions currently allow the use of metal conduit as a means of protecting combustible cabling in plenum spaces. Fire safety research has shown that metal conduit joints can fail in exposure to fires that reach 1,000 degrees Celsius, raising questions about the long-term availability of this option. Additionally, any previous and subsequent installations of cabling would also require encasement in conduit, which is difficult and costly in concealed spaces.