Using 25mm MDPE pipe - any reasons not to?

[dan_aka_jack]

Hi,

I'm planning to have a 1,500 L rain water tank in the back garden which'll gravity feed garden taps in the front and the back garden.  Total pipe run is about 25m.  I was originally planning to use standard 15mm plumbing pipe but then I found that MDPE pipe (for mains water use) is much cheaper and wider diameter.  My thinking is that there won't be much pressure (because the tank is only about 0.5m higher than the taps) so I want the widest pipe I can fit through the holes in my wall.  I can get tank connectors, tap back plates etc for 25mm pipe from http://www.cityirrigation.co.uk/acatalog/Philmac_mdpe_Fittings.html

25m of 25mm pipe is £14.10 incl VAT which sounds pretty reasonable

Any reasons why I shouldn't use 25mm pipe?!?

[Amy]

MDPE is designed for mains pressure, so no issues there.

I dont think it has the same barrier properties found in pex pipe but that doesnt matter for what you want so go for it

[dan_aka_jack]

Great, many thanks for the quick reply!

[dinitro]

only thing I can think of is UV stability/ light ingress.... I think they do black MDPE for surface and blue for underground...


dinitro

[dan_aka_jack]

Ah, many thanks - good point.

What's the worst that could happen if I did expose blue MDPE to direct sunlight?  Does the UV weaken the pipe?  Or is it a case of the UV doing something strange to the water (can you tell I'm a newbee at this rainwater harvesting thing?!)

[Amy]

Farmers use miles of it above ground for water troughs in fields, probably cos its cheap and even idiots can couple it together 

[dan_aka_jack]

Farmers use miles of it above ground for water troughs in fields, probably cos its cheap and even idiots can couple it together 

Do the farmers near you use blue or black MDPE?  (I think I've seen both in use on farms, but I wasn't really paying attention to the pipe colour)

[renewablejohn]

Farmers use miles of it above ground for water troughs in fields, probably cos its cheap and even idiots can couple it together 

Amy

As a farmer does that mean I am an idiot.  

I use it all the time just protect it with chicken wire above ground down to one foot below ground as rats love it. It also freezes easily in winter so insulation is required again loved by rats and mice.

I normally use blue and leave black for power cables

[Chanireland]

I have 300m of the black stuff 3/4 inch heavy gauge running  cross fields through river.
the black pipe also  pre heats the water stops you shocking the veg on a hot day with cold water  

be aware  that 3/4 heavy gauge   use 1inch com-presion fittings, and 3/4 inch normal gauge doesn't fit normal 3/4 inch or 1 inch so you have to get cant remember  what they called bits of brass to make the  fittings fit. work out in the shop with the pipe b4  you order bits on line....

 

[Amy]

Mostly blue.
I think black MDPE is available but traditionally, black plastic pipe was alkathene. Class C and D, just denoted different wall thicknesses.  Typical sizes were 3/8  1/2   3/4  and 1''.

It saw service performing many duties from water carrying, electrical conduit, sheathing for electric fencing and shorter lengths, usually after being flattened snd split by driving over, it made good sticks for whacking cows asses. 

[Amy]

Farmers use miles of it above ground for water troughs in fields, probably cos its cheap and even idiots can couple it together 

Amy

As a farmer does that mean I am an idiot.  

I use it all the time just protect it with chicken wire above ground down to one foot below ground as rats love it. It also freezes easily in winter so insulation is required again loved by rats and mice.

I normally use blue and leave black for power cables

No offence was personally intended towards Farmers,  - other idiots are available. 

[Chanireland]

definaty the definitive whacking stick round hear....

must be surrounded by idiots so....  

[dan_aka_jack]

Good advice, thanks.  Pesky rats.

Hmm... the rodent problem slightly concerns me.  I'm planning to run the MDPE under our living room floor boards (we're rebuilding the floor at the moment so it's easy to do) but I'd be a bit worried about rodents chewing into the pipe and releasing rainwater under our living room floor.  But, then again, I'm planning to put chicken wire under the joists anyway to hold the underfloor insulation so I could just run the MDPE pipe above the chicken wire (which I should do anyway to minimise the chances of it freezing under the livingroom floor).

If rodents love it, I wonder if our dog will take an interest in the pipe?

[Chanireland]

also has been use to build polly tunnels with, pushing  rebare through it and the  pipe  protecting the plastic....

[Chanireland]

had rats a winter or 2 ago never went near the  black pipe hydroder as we call it.

dont  feed the rats and they should **** off....

but they have been known to burrow through concreat