Keep Legionella in check

Legionella is a bacteria that is found in many places but has ideal growth conditions in plants where the temperature in several places is between 25-60°C. Legionella can, by inhalation of atomized water (aerosols), for example, during showering – cause both Legionnaires’ disease (lung disease) and Pontiac fever (flu-like fever disease). Legionnaires’ disease can be fatal especially for people with weakened immune systems.

Legionella growth has several causes

Legionella growth has several causes

  • Dead ends with stagnant water
  • Circulation of the water is hindered by lime, sludge, rust etc.

Pipe Center Instruction 017 (Danish) has made a table of the risk of bacteria formation and Legionella conditional on the water temperature, see the table below:

TemperatureEffect on Legionella Growth
Under 20°C (68°F)Legionella can survive, but most often in a resting state (Legionella can survive in an ice cube)
20°C–50°C
(68°F–122°F)
Legionella can grow – the optimum temperature level is 35°C to 46°C (95°F-114,8°F)
Over 50°C    (122°F)Legionella can survive, but no growth occurs
55°C  
(131°F) 
Legionella dies within 5-6 hours
60°C  
(140°F)
Legionella dies within half an hour, but there is an increased risk of calcification
66°C
(150,8°F)
Legionella dies within 2 minutes

Conventional ways of avoiding legionella

There are two common ways of avoiding the risk of legionella buildup.

  1. A standard Emergency Shower installed in a ramification which requires a weekly flush. If legionella occours, there is no way of protecting the main pipe from contermination.
  2. A solution that prevents legionella from spreading to the main pipe. A check valve is installed right before the T-piece, and prevents stagnant water, from running back into the main pipe.

OBS: According to the EN 15154 as well as the ANSI Z358.1 norms, emergency showers should be flushed with fresh water. This to clear the supply line for any sediment build up and minimize microbial contamination due to stagnant water. Further, this will verify operation of the unit. The test is recommended to be done weekly.

Conventional ways of avoiding legionella

There are two common ways of avoiding the risk of legionella buildup. 

  1. A standard Emergency Shower installed in a ramification which requires a weekly flush. If legionella occours, there is no way of protecting the main pipe from contermination.
  2. A solution that prevents legionella from spreading to the main pipe. A check valve is installed right before the T-piece, and prevents stagnant water, from running back into the main pipe.


OBS: According to the EN 15154 as well as the ANSI Z358.1 norms, emergency showers should be flushed with fresh water. This to clear the supply line for any sediment build up and minimize microbial contamination due to stagnant water. Further, this will verify operation of the unit. The test is recommended to be done weekly.

Legionella-safe range based on piping dimension 3/4"

This range is optimal for smaller buildings, where a loss of water pressure isn’t a risk.

Body Shower, Wall-Mounted

#17544009

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Eye Shower, Wall-Mounted

#17543009

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 Combination Shower, Wall-Mounted

#17552009

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Legionella-safe range based on piping dimension 1 1/4"

This range is ideal for bigger building. It can be placed directly on the main water supply, to ensure that there won’t be any loss in water pressure even with multiple emergency showers and a fire hose on the same pipe.

Body Shower, Wall-Mounted

#17549009

Read more

Eye Shower, Wall-Mounted

#17548009

Read more

 Combination Shower, Wall-Mounted

#17547009

Read more

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