NFPA850-851 directs you to IEEE 979,384,525. There are a lot of "shoulds" so all are recomendations related to consider risk of fire spreading along cable trenches, trench sepration, cable separations, cable and tray materials, fire stops along trench, fire detection, fire extinguishing with water or CO2 mainly. It is a complicated issue since there is a not a simple obligation.
Thanks for the reply, we have a cable trenches under a switchgear room and equipped with trench separation, cable separations, cable and tray materials are according NFPA, fire stops along trench.my question is based on your experience, a linear heat detectors shall be provided also? or the above consideration are enough?
It´s difficult if the company does not define a standard since all are recomendations.
Cable damage may be detected earlier with smoke detection if feasible. If I´d had the conditions, I´d consider: regular spot photoelectric, air sampling, Vesda special cable combustion air sampling.
