Legionella risk of expansion pipe to water tank

[Dotty]

Sorry stating the obvious, but - How do they figure out the vent pipe is risk of Legionella?
I guess they theory is the pipe is open to the atmosphere and the water inside it is heated to some extent. Storage tank water is exactly the same anyhow.
I would be careful about putting the vent to elsewhere where it could freeze or the hot water damage something. The end of vent pipe would need to be not too low or it would start a syphon and empty the cold tank.

Probably through a build up of scale on the end of the pipe.

Worries me that people are willing to ignore the water regs to try to minimise an already low risk situation. ...

 

[tolly]

Id be worried if it was rerouted elsewhere to discharge over a gutter or empty tank that someone in the future may come along, see an open end and cap it off.

 

[Last Plumber]

All sounds like ball cocks to me.
The risk from a vent pipe is aerosol/airborne spores ( eg in water vapour), Legionnaires disease is contracted by breathing in those spores.

The vent pipe is best put back through the sealed lid where it belongs.

Whether it vents over the existing tank or a separate one, it still vents.




In my opinion.

 

[lame plumber]

obey building regs and water regs. so feed n expansion back into tank. then all that is required is for the owners to have annual check, system clorination if need be and get them to ensure high risk areas dealt with, ie any shower heads, or places where water can mist, hence why watercooled roof top air con units are so at risk of legionaire build up.

 

[1Steven]

I thought it was to do with the fact that warm water in turn could warm up the cistern. That in turn would increase the risk of legionella. Have never come across this. Have come across faulty boiler stat, faulty cylinder stat, hot water forcing it's way up cwds. Vent was damaged in loft boxes placed on it!

 

[Last Plumber]

I thought it was to do with the fact that warm water in turn could warm up the cistern. That in turn would increase the risk of legionella. Have never come across this. Have come across faulty boiler stat, faulty cylinder stat, hot water forcing it's way up cwds. Vent was damaged in loft boxes placed on it!

No, that's another fault.
If your installation be it heating or hot water is correct, there should be no water coming out of the vent pipe, it is there to release gasses.
The cold feed pipe is designed as feed and expansion. It allows water to fill the system and expanding water to move into the tank.
The vent pipe also helps to ensure that the system is at atmospheric pressure at all times (open vented), on occasion water may purge from the vent under certain circumstances, hence its position, over the tank that feeds the system it is designed to be venting.