Gravity drain (Legionnaires)

[Daz man]

People,

If I may, I would like some advice on something that I've come across this morning.

I was looking at a 'Fujitsu' wall unit in an office which was supplied off of a VRV.

The wall unit was fixed roughly about 3m up on a solid wall.

By the looks of things at some point there appeared to be a 'Little Giant' condensate pump installed but of which has now been removed (pump still in situ).

There is now a 3/4 white plastic drain which exits the wall unit to the right, is clipped to the top of the interior door frame (old house turned into an office complex, door architrave quite thick, so pipe not visible). Then it runs down the right hand side of the door frame, bends 90o and runs for 3m along the top of the skirting board under a radiator.

It looks like the people that installed the waste pipe opted not to cut out a 3/4 hole through the middle of the skirting board as its good old fashioned wood (really old house).

So instead they raised the drain up approx 3" with an elbow and exited through the wall. In affect kind of a 'trap' to look at.

Q is -

The 3m length of pipe that runs across the skirting board horizontally from the bottom of the door frame will always be full of condensate water as it will not find its own way out due to the slight rise before it goes out through the wall.

Over a period of time will this water go stagnant and most importantly will it cause legionnaires??

Feedback would be really appreciated!

[install monkey]

i didnt install it!- you will get slime in the drain building up if there is no constant fall of 1 cm per mtr- best option is to cut out the 3 inch bit and burst a hole through the skirting or re instate the pump- legionella breeds between 20 and 60 degrees and its the droplets that are nasty
http://www.bsee.co.uk/news/archivestory.php/aid/4239/Legionella_:_Something_is_still_bugging_us_to_death.html

Legionella bacteria are usually found in low numbers in natural environments such as rivers, lakes and reservoirs. They can survive temperatures as low as 6°C and as high as 50°C. While maximum growth occurs at temperatures in the range 20° degrees to 45°C, the bacteria seem to become most virulent at around 37°C. On the other hand they are killed by temperatures above 60°C.Problems begin when Legionella bacteria migrate from their natural environments into man-made water systems. Enclosed, warm storage vessels, complex pipe-work with lots of dead spots and underused water systems with stagnant water provide the ideal habitat, particularly if sludge, sediment and scale are present to encourage the growth of algae, amoeba and other bacteria on which the Legionella bacteria can feed.Legionnaire’s Disease - and the similar but less lethal respiratory illness known as Pontiac Fever- is generally contracted by deeply inhaling Legionella bacteria, either in tiny droplets of water (aerosol) or in droplet nuclei; the particles left after water has evaporated. Typical sources include cooling towers in industrial cooling water systems and in large central air conditioning systems, evaporative coolers, hot water systems, showers, whirlpool spas, architectural fountains, room-air humidifiers, ice making machines, misting equipment and similar disseminators that draw upon a public water supply. For the purposes of the Health & Safety legislation, this includes not just the main vessels but all associated pipe-work, pumps, valves and other ancillary equipment including heat exchangers and chillers.In one research project 40 to 60% of all cooling towers tested contained Legionella. Other studies have demonstrated that Legionella pneumophila can be spread at least 6km from its original source. An outbreak of Legionnaires’ Disease that killed 18 people in Pas-de-Calais, northern France in 2003–2004 was traced back to a petro-chemical plant cooling tower 6–7km from where most of the victims lived.Guidelines published by The European Working Group for Legionella Infections (EWGLI) on the actions to be taken to limit the number of colony forming units (i.e., the aerobic count) of micro-organisms per mL at 30°C (minimum 48 hours incubation)

[Daz man]

wow! what a responce! tar very much for that!

[Simeonx1]

put water through it into the indoor coil and warm water to wash slime out when you service it . if its done often it should be fine.

If you fed a small hose 4mm , the same size as they use on the pump , and fed it through the 20mm pipe . you could flush it out with clean water then siphon the rest out ,

[Tayters]

If there's room squeeze a Milton sterilising tablet in the drip tray, can't say how long it last mind. It'll stop the bacteria growing and the slime / nasties forming.
Worked well in the drain at the back of my fridge too!

Cheers,
Andy.

[Advanced-Eng UK]

Sorry to crash the thread but this sounds like a perfect case for our StayClean Strips. They'll continually dose the condensate for 6 months+, inhibiting the growth of bacteria.

Get in touch and we should be able to arrange a free sample.

Thanks

Rory

[Frikkie]

If there's room squeeze a Milton sterilising tablet in the drip tray, can't say how long it last mind. It'll stop the bacteria growing and the slime / nasties forming.
Worked well in the drain at the back of my fridge too!

Cheers,
Andy.

I've always used the sterilising tablets you get for mens urinal toilets, I just put on in the drip trays of my fridges every six months. They're very cheap but I'm not sure if they're as good.