Hi all, I'm looking for some advice regarding fire stopping.

I've recently seen some service penetrations (cable trays, wire bundles) that have been 'fire stopped' with what looks to be off cuts of fire rated plasterboard and mastic. The work was carried out by a general builder, not a fire stopping specialist and no fire stopping labels were present.

I've put in my report that it was not possible to confirm that the products used meet the required fire resisting properties etc.

So my query: Can fire stopping be done with FR plasterboard or should it always be a fire batt/FR mastics etc. I was under the impression that FR plasterboard was only for wall and ceiling linings and not for penetrations and stopping.

Thanks in advance.

If it has been installed correctly, there is nothing wrong with using fire rated plasterboard to repair (any plasterboard patch repair in a fire-rated wall or ceiling must fully restore the original level of fire resistance).  It would make sense however to use something like Intumescent Pillows - FireSealsDirect on cable trays as it will make maintenance easier should they need more cables run.

Do not forget about internal sealing of wiring systems such as trunking and ducting. Where the internal area exceeds 710mm2, BS7671 requires fire stopping to be applied. 710mm2 sounds a lot but consider the commonly used 50x50 (2x2 in old money), that is 2500mm2. So even the smallest trunking needs sealed internally.