Hello all,
I need to run a hot, cold and waste pipe for 4m externally.  I am planning to box this in and fill with insulation to hopefully prevent freezing.  Will this be sufficient or do I also need to trace heat the pipes which is common practice for exposed pipework in industry?
All help appreciated.
Big-e

I suspect there are variables in this arrangement which make giving a clear answer difficult.

For example, are the hot/cold supplies running fairly continuously? If left to stand overnight or for several days without the water moving then freezing is a possibility regardless of the amount of lagging you put in place. Water in hot pipes cools down fairly rapidly once it has left the heat source.

No real harm putting traces in just in case surely? Could be expensive if you get a burst pipe.

Andrew

You could also dig a deep enough trench for the pipes so that's it below the frost level. I think it needs to be about a metre or more down to be frost free.