Hep2o (Hep20) Information

[MortarThePoint]

Here's some information about Hep2O pipe pressure and temperature.

 

   

 

This old document has some pipe dimensions in: https://www.hep2o.com.au/downloads/Hep2o_Parts_Users_Guide_Australia_2018.pdf

 

Here's the installation guide:

F-47058-0.pdf

 

Here's  link to a performance sheet: http://www.tglynes.co.uk/downloads/tgl-coshh-tech-hep20-performance.pdf

[MortarThePoint]

The stated diameter is the OD of the pipe, so if you come across the image below ignore it. I double checked with Wavin technical. Some IDs are:

   OD        ID          Area or volume/metre

   10mm   6.7mm    0.35cm2 or l/m

   15mm   11.3mm   1.00cm2 of l/m

   22mm   17.7mm   2.46cm2 or l/m

 

 

[MortarThePoint]

My volume figures were wrong (school boy Maths error):

    Q.) How much water does Hep2O pipe hold per metre?

    A.) 10mm pipe = 32ml 15mm pipe = 110ml 16mm pipe = 120ml 22mm pipe = 260ml 28mm pipe= 400ml

[MortarThePoint]

Here's an important one from the Hep2O FAQ:

Q.) Can we use expanding foam on Hep2O?

A.) No, due to the chemicals when in its liquid form, these could harm the pipe. Once the expanding foam has cured Hep2O pipe can be safely fed through it. Alternatively the Hep2O could be sleeved to give the required protection.

https://plumbpal.co.uk/image/catalog/Documents/Hep2O_FAQs.pdf

[MortarThePoint]

How to size Hep2o pipe (check out pages 60-62 of https://www.hep2o.com.au/downloads/Hep2o_Parts_Users_Guide_Australia_2018.pdf)

 

Image below if for COLD supply.

 

As I understand it, you work out you acceptable pressure loss in metres per 100 metres (which is the same as mbar/m) and then draw a straight line through the required flow rate and that hits the pipe size scale and so you pick the next number up. The dashed line is an example of 14.9m / 100m head loss with required flow of 0.3l/s giving 22mm pipe needed.

 

0.3l/s would provide 90l of bath water 5 minutes, but of pure cold.

 

My most extreme situation will be around 0.3l/s over 15m, but I'll round that up to 20m to cover elbows / isolators. They (page 60) assume 0.8m head loss across the tap, I'll round that up to 1m (so 0.1bar). If I'm happy with 1bar pressure loss then:

Head Loss = 0.9bar / 20m = 45mbar/m = 45m / 100m

Using the cold water nomogram shows 22mm is needed for that. 15mm would be OK up to around 0.17l/s.

 

There is a domestic hot water nomogram as well, but I suspect that just assumes something like the flow is 67% hot and 33% cold. With 65C hot water and 12C cold water that would make for an average of 30C. To use that and use 15mm pipe I would have to accept a head loss of 80m / 100m which equates to 1.6bar over 20m. Round that up to 2bar. My mains is 5.5bar at no flow, but I don't know what that would drop to at 0.3l/s.

 

 

Cold:

 

Hot:

 

[MortarThePoint]

Based on the Domestic nomograph, a shower at 20m equivalent run, 1bar pressure and assuming 1m head loss across the shower taps/head with a flow rate up to about 0.2l/s or 12l/min. That's along the orange line of the first Hot image above.

Edited June 14, 2022 by MortarThePoint

[MortarThePoint]

For shaving, so assuming pure hot water, it would be good to fill the basin in under 1 minute. Assuming the water in the basin basin is 300mm x 300mm x 100mm that equates to 9l, so the desired flow rate is 9l/60s = 0.15l/s. That's OK for 15mm pipe up to around 20m with 1bar loss. 10mm pipe and 1bar@20m yields a flow of something like 0.06l/s (or 2.5min to fill basin).

 

Using their head loss tables, gives a pressure drop of 5.4bar over 20m at 0.15l/s for 10mm pipe. For shaving, a 10mm pipe run is probably limited to 10m if a dynamic pressure of 3bar is available. If only 1bar, you'd fill a square foot basin to 2 inches (shallow but can start shaving, 4.5l) in 1 minute at 10m (it's very non-linear remember).

For hand washing a flow of 3l/min = 0.05l/s is probably acceptable and it's not pure hot. If it was all through one pipe for 20m I estimate a pressure drop of 0.8bar which is fine to be under 1bar including the tap loss.

 

If you have an en-suite, a family bathroom basin would be ok at 20m with 10mm hot feed until a son started shaving.

[MortarThePoint]

He's a rough table using the Pegler equation but Hep2o ID dimensions:

 

 

[Note: 1bar across 20m is 0.5bar across 10m]

 

So at 10m and using 15mm pipe it would take about 2 minutes to put 100 litres of  2:1 water in a bath if 3bar dynamic pressure was available. It would take 4minutes if the dynamic pressure was only 1bar.

Edited June 14, 2022 by MortarThePoint

[MortarThePoint]

Clearer units:

[Nickfromwales]

Have you allowed for the restriction of the outlet that each pipe terminated into? VS what will come out of the end of the pipe?

 

All completely academic imho, as larger pipes / higher dynamic flow rates etc are all arrested by the outlet and its governed output rate as set by the European standards for the max typical flow rates ( in line with water consumption regs ).

 

The gross variables involved make this nigh-on incalculable afaic. The flow rates will all shift the second another outlet is opened elsewhere too, so further reducing the dynamic flow rates.

 

For actual real world experiences, I have done multiple 10mm and 15mm radial whole of house installations, with pipe runs up to and beyond 30m, and there are no real world issues at all. Either install a HRC or just wait. As for filling a basin, you simply start shaving BEFORE the basin is full  Simples!!

 

Too much maths here, and I genuinely fear you're worry over nothing.

[MortarThePoint]

10 hours ago, Nickfromwales said:

Too much maths here, and I genuinely fear you're worry over nothing

You're right, I'm just trying to avoid newbie mistakes 🙂

Edited June 15, 2022 by MortarThePoint

[Nickfromwales]

1 hour ago, MortarThePoint said:

You're right, I'm just trying to avoid newbie mistakes 🙂

Don't worry, we'll learn you good, Jethro  

[MortarThePoint]

10 hours ago, Nickfromwales said:

Don't worry, we'll learn you good, Jethro  

I hope so, thanks 🙂 

 

I'm going to need to invest in a pressure testing pump as I need to high pressure test at something like 10bar.

 

 

[Nickfromwales]

On 16/06/2022 at 09:19, MortarThePoint said:

I hope so, thanks 🙂 

 

I'm going to need to invest in a pressure testing pump as I need to high pressure test at something like 10bar.

 

 

Why test at 10bar? 1-3 is average, over 5-6 you’ll need a PRedV to drop it to 4. Just hook up to the cold mains and use that? 

[markocosic]

If you're ever passing Cambridge you're welcome to borrow my pressure tester.

 

10 bar will find any fittings that you forgot to nip up. You'd be surprised what will hold at 1 bar then potentially pop off later!

 

I bought it for testing / prestressing some underground district heating mains - take to something like 20 bar, wait for it to stretch, then take back to 20 bar and hold overnight / verify that the drop is as specified.

 

Only then do you trim to length and make the final connections. (it stretches it bucketload and it you don't do this then when it's warm and at normal operating temperature you'll find it creeping into the houses...)

[Nickfromwales]

8 hours ago, markocosic said:

If you're ever passing Cambridge you're welcome to borrow my pressure tester.

 

10 bar will find any fittings that you forgot to nip up. You'd be surprised what will hold at 1 bar then potentially pop off later!

 

I bought it for testing / prestressing some underground district heating mains - take to something like 20 bar, wait for it to stretch, then take back to 20 bar and hold overnight / verify that the drop is as specified.

 

Only then do you trim to length and make the final connections. (it stretches it bucketload and it you don't do this then when it's warm and at normal operating temperature you'll find it creeping into the houses...)

I very rarely test a domestic system like that. District often has 100’s of m’s of pipe in a linear run so it’s part of the installation guidelines. For domestic a blast with the cold mains ( typically around 2-4bar average ) will be more than suffice. Domestic never sees north of 5bar tbh. 

[Russell griffiths]

@MortarThePoint mate, you need a bit more tonic in your gin. 🤣🤣

[MortarThePoint]

14 hours ago, Russell griffiths said:

@MortarThePoint mate, you need a bit more tonic in your gin. 🤣🤣

 

A fair call. I find I only have two tools to compensate for my inexperience, asking and researching/analysing. Asking is much preferred but I feel a bit guilty asking so many questions sometimes.

[MortarThePoint]

On 15/06/2022 at 22:29, Nickfromwales said:

Don't worry, we'll learn you good, Jethro  

 

Another hopefully simple question for you. Do you just use pipe and a couple of elbows (all Hep2O) to prepare for a 150mm pipe spacing shower bar mounted on a plasterboard wall (with OSB layer behind the plasterboard)?

 

I've got my OSB and plasterboard wall up and want to poke the pipes through and seal up the wall. I as planning to just use a couple of Hep2O elbows and pipe to do this. Is that how you do it?

 

I'd then use the Easy-Fix style of connector with its included olive to attach to the Hep2O pipe.

[Nickfromwales]

7 hours ago, MortarThePoint said:

 

Another hopefully simple question for you. Do you just use pipe and a couple of elbows (all Hep2O) to prepare for a 150mm pipe spacing shower bar mounted on a plasterboard wall (with OSB layer behind the plasterboard)?

 

I've got my OSB and plasterboard wall up and want to poke the pipes through and seal up the wall. I as planning to just use a couple of Hep2O elbows and pipe to do this. Is that how you do it?

 

I'd then use the Easy-Fix style of connector with its included olive to attach to the Hep2O pipe.

Normally a couple of bends and then copper tails projecting out at 150mm c’s is fine. For a bar mixer you’ll need a fast / easy fit kit to mount the shower with, as with this approach h you’ll be binning the supplied cranked 1/2”x3/4” fittings.

LINK

[MortarThePoint]

58 minutes ago, Nickfromwales said:

Normally a couple of bends and then copper tails projecting out at 150mm c’s is fine. For a bar mixer you’ll need a fast / easy fit kit to mount the shower with, as with this approach h you’ll be binning the supplied cranked 1/2”x3/4” fittings.

LINK

 

Why the transition to copper?

 

Thanks for the link, exactly what I'm after.

[markocosic]

What are the thoughts on this style?

 

https://www.screwfix.com/p/contemporary-bar-valve-fixing-kit-chrome/76919

 

(bombproof mechanically as far as the physical strength of the bar mixer mount is concerned)

 

I guess that's more off a pita to get the depths set vs sticking copper tails out and trimming to suit after tiling?

[MortarThePoint]

30 minutes ago, markocosic said:

What are the thoughts on this style?

 

https://www.screwfix.com/p/contemporary-bar-valve-fixing-kit-chrome/76919

 

(bombproof mechanically as far as the physical strength of the bar mixer mount is concerned)

 

I guess that's more off a pita to get the depths set vs sticking copper tails out and trimming to suit after tiling?

 

Looks sturdy, but won't that need to be installed prior to the plasterboard that it goes through? Or do you attach it to a pattress and then mount the pattress on the studs.

[markocosic]

Before plasterboard - onto underlying blockwork or noggin 

[MortarThePoint]

I still don't know why the transition to copper. It seems to be common practice (see below) but I'm in the dark ( @Nickfromwales )?