Polystyrene as boiler insulator?

[jonewer]

I have some thing (about 10mm) polystyrene left over and was about to use it as a boiler insulator when the thought occured to me that the plastic boiler might melt the 'styrene......

Is it safe?

Thanks!

 

[Kyral210]

I would imagine it will be fine. boil some water up, stick a piece in and if it doesn't deform then you know it is stable at 100°C and more than good to go!