Which of the following is true?
a. Fire resistant cable does not allow fire to propagate quickly in surrounding
b. Flame retardant cable does not burn quickly & continue to operate for some time in fire.
c. Fire resistant cable is used for critical application & Flame retardant cable is used for non-critical application
d. Fire resistant cable is used for non-critical application & Flame retardant cable is used for critical application
Correct Answer : (c )
Fire resistant & flame-retardant type cables are used for fire safety. However, each type of cable is having different purpose.
Fire resistant cable resist high temperature & tend not to burn quickly during fire. This allows cable continue to operate under fire.
However cable can not resist fire indefinitely, it only delays the burning, giving valuable time for emergency signals to work.
Typical example where we use fire resistant cable is ESD signals. After fire broke out, ESD cables (Fire resistant cables) continue to operate executing critical shutdown activity minimizing damage to property, life & environment. It is governed by standard IEC-60331 & BS 6387. As per IEC 60331 cable shall with stand 750 Deg C for 3 hours.
On other hand, flame-retardant cable burns very slowly and reduce the amount of heat generated. This creates resistance for fire to propagate quickly. This cable does not give priority to continuation of operation rather focus more on burn slowly & resist fire. Slow propagation of fire minimizes the damage to property, life & environment. Gives much needed time to respond to situation. Fire retardant cable is widely used for all non-critical operations like DCS cables. It is governed by IEC-60332 & BS 4066 standards.