Use existing wiring or not

[geochurchi]

Hi,we are in the process of upgrading a fire alarm system in a 4 story office building to an addressable system it has been suggested that we can use the existing wiring which is mainly in pipe for the ID's instead of removing that and installing a complete new system which obvisously a lot more money. Any thoughts?

 

[iwire]

My experience has been that is more costly than worthwhile if you have to keep the old system operational while the new one is being installed.

 

[MichaelGP3]

Is conduit required by your AHJ or job specifications?

What is the reason for the system being replaced?

What is the brand and model of the old system that's being replaced, and what is the brand and model of the new?

My short answer: yes, there can be significant cost savings, but there can be problems if old devices (even isolator modules) wind up residing on the new system.

 

[nhfire77]

Leaving the existing FA running while installing a new system is the simplest, IMO.

A lot of places around here in new england would require a 24/7 fire department fire watch if you took down the old system and installed the new system, unless you could do it in less than a day. Maybe you plan on that.

Personally, I would rewire the floors completely and then tie into the risers in the EMT, You can plan the cut over to start 0 dark thirty and have the new system installed and tested by 5pm on the existing riser wiring. IF you are good at it.

Then swapping the risers out in the pipe could be done on a per floor basis after the new system is up.

My vote to replace everything, but that's because I am good at spending my customers money.