Depending on the amount of work planned, maybe you should consider alternatives.
If you have power available ... by all accounts, you' can't beat a heating blanket. I haven't yet had the luxury, but others tell me they're awesome - but you MUST plug the pipe ends.
If there's no power ... well, I've had awesome results with an ordinary charcoal BBQ. The best aspects are an even heat over a large area, and the fact that you only need light it once. I've used this for up to 3" Schedule 80.
