Supply pipe depth and into building questions

[Digmixfill]

I'm looking at the trenching needed for the water supply into the building. My supply is from a well so i don't need to comply with utility requirements, but i'd like to have something in place that could be used for mains if needs be.

 

Most of the details i'm turning up suggest a minimum of 750mm for the trench holding the pipe. Some form of ducting through the foundations and insulation in the ducting if the pipe penetrates the floor at less than 750mm from the edge of the building.

 

What i haven't managed to determine yet:

 

Does the supply pipe have to penetrate the foundations at 750mm?

How much insulation is needed in the ducting?

 

[PeterW]

Pipe should come through at 750mm and be a slow radius bend. A 110mm rest bend is good for this, and a 110 downpipe adapter makes a good transition for a duct. 

 

You dont need to insulate at these levels below ground as it’s a pretty constant 7-8c. It can be worth pushing some insulation down the MDPE as it emerges from the foundations but if it’s inside the building envelope then it’s not really needed.  

[Digmixfill]

Put the 110mm pipe and bend in over the weekend. A test piece of water pipe goes through without too much force.

 

[epsilonGreedy]

On 29/03/2019 at 21:04, Digmixfill said:

Some form of ducting through the foundations and insulation in the ducting if the pipe penetrates the floor at less than 750mm from the edge of the building.

 

 

I arrived at the same conclusions a few months ago when looking at the Anglian Water installation guide.

 

My interpretation is that if freezing temps can penetrate 700mm down into the ground then there is a similar risk of freezing temps penetrating the same distance horizontally under the house footprint. With thicker levels of floor insulation coupled with a ventilated suspended floor void I feel the greatest freezing risk is where the pipe emerges from the oversite soil up to the underside of the floor.

 

On 29/03/2019 at 21:04, Digmixfill said:

How much insulation is needed in the ducting?

 

 

The same Anglian Water guide recommended 75mm insulated ducting, so that would equate to standard 22mm pipe insulation.

 

In practice I get the impression these standards are applied loosely by the building trade. I had a partially insulated 25mm mdpe pipe running overground to my static caravan all winter and experienced the occasional splurt of frosty slush coming through an internal tap.

 

I suspect these regs originate from a era before plastic mains pipes and are scaled to the worst case scenario of an unoccupied unheated house during the winter. Even so I am complying with all the rules because otherwise I would not sleep well during cold winter nights.

[Digmixfill]

2 hours ago, epsilonGreedy said:

The same Anglian Water guide recommended 75mm insulated ducting, so that would equate to standard 22mm pipe insulation. 

With the 110mm in place there is plenty of room for me to slide a length of 22mm foam pipe insulation over the water pipe once it is in place.