High Flow Shower Waste - how do they work?

[zappastix]

Hi

It looks like I'm going to have to fit a low profile shower tray because I cannot find a standard tray with enclosure at a decent price.

(1000 x 800 offset quadrant).

The bathroom is on the ground floor and is concrete.

So I will have to raise it somewhat.

MY QUESTION

1) How do these new 'high flow' shower wastes shift so much water (32 litres per minute)?

2) Is it because they have a fat body?

3) When they say 50mm & 90mm traps - do they mean;

4) Performance - i.e. quicker?

5) Or do they mean the height of the trapped water?

Many thanks.

Stephen

 

[Hugh Jaleak]

Any trap is only going to be as good as the waste pipe leading away from it. Use of elbows as opposed to swept bends in the waste would likely slow the flow down, and the length of the waste may also be a factor. Then, over time if the pipes become clogged with soap and hair etc, this could provide additional restrictions.

Do you mean 19mm or 50mm traps? This refers to the depth of the water seal. 50mm is required where the shower waste connects to a stack, 19mm is ok if waste is discharging to an open gulley or similar.

 

[zappastix]

Thanks Hugh.

I see what you mean know - I have just found this at;
http://www.tradeplumbing.co.uk/MX-90mm-High-Flow-Shower-Waste-Chrome-Dome_p_6931.html

View media item 24471
MX 90mm High Flow Shower Waste Chrome Dome

Suitable for any shower tray that has the British standard waste hole (92mm). Specially designed to enable water to flow from the shower tray at a rate greater than 32 litres per minute.

I suppose the 90mm refers to the width of the body.

And it's 50mm high by default?

Does it extract that amount of water because it's a chunky body?

 

[Hugh Jaleak]

I cant really see that this particular trap is much different to others costing half that price! The flow capacity is always going to be restricted to whatever the waste pipe will carry, whilst the trap will allow 32l/min throughflow, if that flow cannot get away along the pipe at that rate it will simply back up into the tray. In some circumstances if a high flow shower is to be installed it may be necessary to upgrade to 50mm dia waste to ensure adequate drainage.
As for dimensions, I'd guess its 50mm diameter and 90mm in height to allow for a 50mm water seal. (50mm seal is required by building regs when connecting a shower to a stack, and a correction to my first post, 38mm is the minimum depth of seal if discharging to a gulley.)

 

[zappastix]

The 50mm dia waste pipe is a jolly good idea. I'll definately fit that. That should help just in case there is problem.

Many thanks.