Expanding foam

[MattF]

Will it survive if encasing a hot water pipe?

 

[eLuSiVeMiTe]

A immersion tank is covered in the stuff (not quite)
A quick Google suggests it won't harm the copper but may degrade a bit over time

 

[MattF]

It's only to block up the hole where the washer pipes come through the wall, so some degradation wouldn't be an issue. I've noticed a fair draught comes through that hole.

 

[Tom O]

Should be good for that.