Does underground cable trenches covered with cement structures need fire protection? What is the NFPA code for fire protection for underground cable trenches other than in cable tunnel or cable rooms?
2006-10-04 05:48:38 · 2 answers · asked by raj 1 in Science & Mathematics ➔ Engineering
A cable trench is a shallow trench that just holds cables, conduit lines, or piping. (See link below)
A cable tunnel is a wide tunnel that allows human acess for maintenance and inspections of the cables or conduits running through them. Often there are series of cable trays mounted along the walls on either side of the tunnel where the cables run.
I am not familiar with a code specifically for cable tunnels. I know most cable tunnel fire protection I have dealt with is in power plants. Most involved double interlock pre-action systems. Due to the high probability of damage to the sprinkler piping you don't want a wet sprinkler system. Linear heat cable or fixed heat detectors would be used to trigger the pre-action system in addition to a sprinkler head melting before activation.
The other option is gaseous systems (NFPA 12, 12A, 2001). However the system must be designed to handle the fire load. In addtion you have to have serious training and evacuation plans in place due to the hazards of killing someone in the tunnel if something like CO2 is used. Many gas options are safe for exposure to humans but not all. The cable tunnel may need such a high concentration of gaseous agent that it becomes unsafe for humans.
I have experience with a Halon systems for a cable room for a power plant, but very few new Halon systems are being put into service these days. There are many alternatives out there but Halon was one of the best.
2006-10-07 09:18:56 · answer #1 · answered by beatnik 3 · 0⤊ 0⤋
Generally would a trench be filled in when the cable is layed? As opposed to the tunnel which would still have open area where a fire could spread.
2006-10-04 10:22:19 · answer #2 · answered by Jeffrey S 6 · 0⤊ 0⤋
the trench is dig and line up ur cables
tunnels when u have sensitive partsor replacables or control pannels u need workers to walk in
2006-10-04 12:43:10 · answer #3 · answered by koki83 4 · 0⤊ 0⤋