Expanding foam etc etc

[Johnboy54]

Hello to all.
I've posed a couple of questions about expanded polystyrene coming in contact with cables etc.
Now my paranoia turns to expanding foam.
I've run polypipe and electric cables through gaps at the ends of RSJ's.
To stop draughts from the flat roof coming through it would be easier for me to fill the gaps in with expanding foam.
Will the foam eat the cables and pipes like polysterene does?

Thank you.

 

[r896neo]

I think its a no no around cables as it reacts with the pvc sheath, Couldn't be sure around the polypipe.

Run your cables in conduit?

 

[Johnboy54]

Thanks for the reply.
I've already run the pipes and cables, so conduit is not an option.
I suppose I could try and cram the gaps with loft-type insulation.
John

 

[mointainwalker]

If there is the space , nothing to stop you slicing a suitably-sized piece of flexible conduit along its length and then feeding it onto the wires/pipes.

The conduit will close up afterwards and then you could foam.

 

[TicklyT]

How about slitting bits of pipe insulation to fit around each pipe and conduit, then fill any remaining gaps with foam?

To stop up vacant spaces in cableways between different parts of telephone exchanges, we used to use 'bean bags' filled with......













.....Asbestos wool

 

[Johnboy54]

Thanks to all for the replies.
I can't use any of the methods described because it's a tortuous, confined route the cables and pipes take.
If ever I do it again, I'll know about polysterene problems and plan better.
Thank you.
John