# Water piping sizing & Legionella



## GAN (Jul 10, 2012)

Legionella cases may be on the rise. A big cause is looking like the older water sizing charts that deal with WSFU's (at least Illinois does) combined with the new water saving technology is not letting the potable water turn over as much as needed. The chemicals get weak and the next thing you know bacteria starts growing in the system.

If the potable water is sized to allow for the lower flow devices your not loosing as much chemical and the water turns over faster in the lines. In a municipalities system more frequent main flushing helps but will do no good in a building.

This pattern is showing up so much Illinois is going to look at reworking the sizing charts to contend with this.


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## Plumbus (Aug 4, 2008)

That is a good reason for the model codes to take look at their antiquated pipe sizing tables. While they are at it, they should look at the waste fixture unit tables as well.
Both were formulated using research (Hunter Curve) done by the National Bureau of Standards in the 1920's. 
https://aspe.org/sites/default/file...1/20110708/HighEfficiencyPlumbingFixtures.pdf
A few years ago I thought there was hope, but I haven't heard anything since.
https://www.aspe.org/node/1267


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## 5onthefloor (Sep 13, 2017)

Plumbus said:


> That is a good reason for the model codes to take look at their antiquated pipe sizing tables. While they are at it, they should look at the waste fixture unit tables as well.
> Both were formulated using research (Hunter Curve) done by the National Bureau of Standards in the 1920's.
> https://aspe.org/sites/default/file...1/20110708/HighEfficiencyPlumbingFixtures.pdf
> A few years ago I thought there was hope, but I haven't heard anything since.
> https://www.aspe.org/node/1267


When I did full service I saw this all the time with older homes that installed low flow toilets. They'd get clogs in the branch that carried waste from new toilet. Not enough water to carry paper and solids. Sometimes I would send camera first from co to house and find the affected branch and sure enough there's be a huge wad of paper and solids. 

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## rjbphd (Feb 5, 2010)

That would throw LEED right out of the window. .

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## sparky (Jan 8, 2014)

rjbphd said:


> That would throw LEED right out of the window. .
> 
> Sent from my SM-G386T using Tapatalk


Thank god


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## wyrickmech (Mar 16, 2013)

Legionella is a major problem brewing like a pot of coffee. Other than low flow warm water is needed for major growth to occur. The bio film can be controlled with flushing heat or chemical treatment but can never be removed completely from a system. So low flow storage vessels and heat sources need heavy regulations.


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## Alan (Jun 18, 2008)

I thought legionella needed warm water to survive?

I'm not a scientist, but Isn't the answer to turn up the heat on the water heater and install safety devices at every fixture?

:vs_laugh:


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## Tango (Jan 13, 2018)

Alan said:


> I thought legionella needed warm water to survive?
> 
> I'm not a scientist, but Isn't the answer to turn up the heat on the water heater and install safety devices at every fixture?
> 
> :vs_laugh:


It survives better in cooler water. For example cooling towers are notorious for that and is a big problem to anyone around as a pedestrian to people working in other buildings.

As water is cascaded outside to cool off it evaporates and the wind carries it to anyone breathing around. Any building that has a cooling tower is supposed to have weekly inspections and water testing against the nasty stuff. But alas it is not done by careless owners. Either that or they have not been educated or regulated by government inspections.


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## ace4548 (Feb 10, 2015)

This is a very interesting topic. Having just gone through water sizing in school, I have to wonder how this will change things. We haven’t had a big problem here in Wisconsin, but a push for water conservation is not there yet.

I do have to ask, as I’m curious. How many residential guys do a water Calculation when they build, or remodel a home? All the commercial work I do, is engineered(although wrong a lot).. but that’s another topic.


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## canuck92 (Apr 1, 2016)

ace4548 said:


> This is a very interesting topic. Having just gone through water sizing in school, I have to wonder how this will change things. We haven’t had a big problem here in Wisconsin, but a push for water conservation is not there yet.
> 
> I do have to ask, as I’m curious. How many residential guys do a water Calculation when they build, or remodel a home? All the commercial work I do, is engineered(although wrong a lot).. but that’s another topic.


When i did residential we never pulled out the code book to size water lines. I just 3/4 to the last fixtures or at least high volume fixtures. Sizing it for a house isnt really nessisary unless its a 10 M $ home with 14 bathrooms an a water feature in the house. In ontario they just made this a new code " 3/4 distribution piping must be supplied to all bathroom groups" but i always did it like that anyways. 

I dont hear about legonella where im from. But i would think running rec-circ lines would help the problem a bit.


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## Gargalaxy (Aug 14, 2013)

wyrickmech said:


> Legionella is a major problem brewing like a pot of coffee. Other than low flow warm water is needed for major growth to occur. The bio film can be controlled with flushing heat or chemical treatment but can never be removed completely from a system. So low flow storage vessels and heat sources need heavy regulations.[/quote
> 
> @wyrickmech glad to see you again brother.


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## mtfallsmikey (Jan 11, 2010)

Tango said:


> It survives better in cooler water. For example cooling towers are notorious for that and is a big problem to anyone around as a pedestrian to people working in other buildings.
> 
> As water is cascaded outside to cool off it evaporates and the wind carries it to anyone breathing around. Any building that has a cooling tower is supposed to have weekly inspections and water testing against the nasty stuff. But alas it is not done by careless owners. Either that or they have not been educated or regulated by government inspections.



We have a very aggressive condenser water treatment program at my buildings, we test for Legionella quarterly, both condenser/potable water. one of my buildings has been setting a long time, hence the "Friday flush", we go to all floors and run all fixtures for 20 min. or so.


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## Plumbus (Aug 4, 2008)

On a take off, I always use the tables when sizing. When you're bidding houses like the one I did today (10 wcs, 13 lavies, 5 sinks, 3 big tubs, a couple of showers and 3 washing machines), not using the tables could lead to trouble (in the form of litigation) down the road. 
I've been using the tables for so long, using them has become second nature. I've even used the Hunter curve on occasion to avoid over sizing.


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## The Dane (Feb 19, 2015)

Plumbus said:


> .
> I've been using the tables for so long, using them has become second nature. I've even used the Hunter curve on occasion to avoid over sizing.


Hunter curve? Please explain.


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## Plumbus (Aug 4, 2008)

The Dane said:


> Hunter curve? Please explain.
> 
> 
> Sent from my BLN-L24 using Tapatalk


Hunter’s Curve was created by Roy B. Hunter in 1940 for the U.S. Department of Commerce. Hunter considered a plumbing fixture’s water flow, duration of flow, and the probability that it would be in use.
His original calculations were based on a maximum of 300 WFU's, which has since been expanded by others. From what I read, the measuring apparatus he used (pitched troughs supported by saw houses) were quite primitive by modern standards to formulate his graphs.

http://engineermate.com/Plumbing/HW/ModifiedHunterCurve.htm


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