Sat, 02 May 2026 10:17:07 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9206#Comment_9206 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9206#Comment_9206 Sat, 10 Nov 2007 16:26:21 +0000 Neil K
The point is that in old buildings the loft was normally cold and the supply pipework was therefore running at low temperatures. This would mean that there was no 'cold' water sitting about at room temperature. We are planning to build a SIP house, so the envelope of the house will be warm. i.e. the roof space will also be within the insulated envelope and is likely to be at, or near, the living temperature.

Give that Legionnaires is known to like water around 20C I wonder if there is an issue with the routing of the cold pipes within the house. Should I, for example, run all the cold pipes in the ground below the insulated slab rather than through the warm loft? On the other hand does the chlorination in mains water deal with this?

Glad of a steer on this.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9208#Comment_9208 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9208#Comment_9208 Sat, 10 Nov 2007 17:45:29 +0000 nigel Minimise cold water storage.
Low use outlets should be upstream of higher use ones to keep water moving. And avoid dead legs in pipework.

Chlorination should deal with legionella but it is not guaranteed.

There is a code of practice Legionnaires’ disease: The control of legionella bacteria in water systems.
Approved Code of Practice and guidance L8 available from HSE.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9209#Comment_9209 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9209#Comment_9209 Sat, 10 Nov 2007 17:48:52 +0000 Mike George http://en.wikipedia.org/wiki/Legionella.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9217#Comment_9217 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9217#Comment_9217 Sat, 10 Nov 2007 23:02:31 +0000 tony
Ref insulated pipes. Whether or not the pipe is insulated the water in it will get to the same temperature as the house. Insulation does not of itself set up thermal gradients it just slows heat flow, it cannot stop the heat flowing though so temperatures will equilibrate.

The most dangerous place in my opinion would be in pipes after sink mounted water filters these remove chlorine and their pipes are sometimes translucent and not barrier type so they can allow oxygen in. Still I dont see it happening in houses even there.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9222#Comment_9222 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9222#Comment_9222 Sun, 11 Nov 2007 08:16:16 +0000 Mike George https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9225#Comment_9225 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9225#Comment_9225 Sun, 11 Nov 2007 09:40:40 +0000 nigel Posted By: Mike GeorgeAccording to the link above, legionella has to be inhaled to be a health risk. How is that going to happen in a domestic situation?

Showers are probably the highest risk. Also spray from taps.

Legionella needs two things to grown warmth and food. The latter is usually contamination such as limescale build up.

Below 20c legionella is largely dormant so insulating a pipe will reduce the possibility of it getting to 20c and given that cold water is used regularly it is not going to sit at that temperature for long periods.

In a domestic situation the cold water supply is low risk providing some basic precautions are utilised.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9227#Comment_9227 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9227#Comment_9227 Sun, 11 Nov 2007 11:12:10 +0000 biffvernon https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9233#Comment_9233 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9233#Comment_9233 Sun, 11 Nov 2007 13:11:40 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9242#Comment_9242 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9242#Comment_9242 Sun, 11 Nov 2007 20:05:24 +0000 nigel http://www.accepta.com/industry_water_treatment/legionnaires-disease-domestic-hot-water.asp

Also if you rent out residential property you are legally obliged to comply with approved Code of Practice under H&S regulations.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9246#Comment_9246 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9246#Comment_9246 Sun, 11 Nov 2007 20:57:06 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9250#Comment_9250 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9250#Comment_9250 Sun, 11 Nov 2007 21:27:01 +0000 nigel https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9251#Comment_9251 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9251#Comment_9251 Sun, 11 Nov 2007 21:36:27 +0000 biffvernon
The evidence for any deaths from Legionaires attributed to domestic water systems is thus rather thin.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9254#Comment_9254 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9254#Comment_9254 Sun, 11 Nov 2007 21:57:40 +0000 nigel
This report shows that there is evidence of domestic infection being significant. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=190637

Some 10% of of infections prove to be fatal. In 2006 there were some 500 infections and 44 deaths. It would be naive to think that there has never been a death from a domestic source just because it has not been reported as such.

Given that it is not that difficult to reduce the risk in a domestic system with modest and simple design criteria then I think it is sensible to do this.
This would be especially true if the occupant is in a higher risk category.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9261#Comment_9261 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9261#Comment_9261 Mon, 12 Nov 2007 07:46:10 +0000 biffvernon https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9263#Comment_9263 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9263#Comment_9263 Mon, 12 Nov 2007 09:14:53 +0000 nigel https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9264#Comment_9264 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9264#Comment_9264 Mon, 12 Nov 2007 10:02:02 +0000 tony
A recent suspected case in Reading caused an in depth search of domestic water systems in flats in Reading -- no legionella was found.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9267#Comment_9267 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9267#Comment_9267 Mon, 12 Nov 2007 10:38:36 +0000 nigel Therefore legionella does not occur in residential dwellings - QED

So nothing you hear on the green building forum that you have not heard elsewhere first is a problem.
If you are never going to learn something on here why bother reading it?

If it is the case tha there is no risk why has the HSE introduced regulations that require private domestic landlords to comply with the code of practice on legionella?
http://www.hse.gov.uk/pubns/indg376.pdf]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9270#Comment_9270 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9270#Comment_9270 Mon, 12 Nov 2007 12:54:03 +0000 tony
What is the difference between pipes in rented houses and owner occupied houses?????]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9291#Comment_9291 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9291#Comment_9291 Mon, 12 Nov 2007 19:28:16 +0000 Neil K
1. I believe a cleanerd caught legionnaires from the aerosols formed when filling a bucket in an underground station in Gateshead some years ago. The point being that this was a rarely used tap with a pipe in a warm environment. The aerosol was created from the impact of water into the bucket.

2. It strikes me that there is an increased risk now due to the general increase in living temperatures in houses, and also possibly by the routing of pipework within the heated envelope of the buildings. I think Tony is right, and insulation will not stop cold water getting to room temperature... it will just take longer. It will, however prevent additional warming from nearby hot water, so it seems to worth looking at. Luckily the bottom range for breeding bugs is about the top of the houshold temps.

3. I like the idea of trying to route the pipework so that the most used appliances are at the far end of the pipe run, so inducing maximum flushing, and minimising dead legs.

4. As to why Nottingham is popular: No idea, it certianly wasn't warmer when I lived there! :-)

On reflection I intend to route the main pipe run under the slab in the colder ground, and minimise the dead legs. An occasional draw off will also probably be worth putting into the maintenance regime.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9294#Comment_9294 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9294#Comment_9294 Mon, 12 Nov 2007 20:07:54 +0000 nigel Posted By: tonyOK then why is this guidance for private domestic landlords and not everyone????

What is the difference between pipes in rented houses and owner occupied houses?????

Probably the same reason that a private householder can remove asbestos in his own house and not comply with any guidance.
That doesnt mean that asbestos is safe if its in a private dwelling.

Me thinks your clutching at straws Tony.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9298#Comment_9298 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9298#Comment_9298 Mon, 12 Nov 2007 21:48:16 +0000 biffvernon
Never mind the Legionaires, I would have thought that having water coming out of the cold tap too cold and out of the hot tap too hot for the bugs would be pretty desirable. Any system that delivered luke warm water out of either tap would be pretty undesirable.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9330#Comment_9330 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=853&Focus=9330#Comment_9330 Tue, 13 Nov 2007 18:49:24 +0000 tony