The symptoms include a flu-like illness, followed by a dry cough which frequently progresses to pneumonia. Approximately 30% of people infected may have diarrhoea and vomiting and 50% may show signs of mental confusion. The incubation period is from 2-10 days.

Who is at higher risk?

Men more than women, people over 50, smokers, alcoholics, diabetics, people with a chronic underlying disease and/or a weakened immune system.

Legionella bacteria are widespread in natural sources of water including rivers, streams and ponds and may even be found in soil. It has never been isolated in salt water so vessels that make all their potable water by evaporation or reverse osmosis have a lower risk of the bacteria being present. They are significant when found in man made recirculating and hot and cold water systems

Only when water contaminated with Legionella bacteria becomes aerosolised so that it can be inhaled does it pose a risk to health.

For example:

• When having a shower
• When running sink taps when using a hot spa tub
• Warm moist air circulated by air conditioning, heating units & humidifiers
• When using fire hoses (if fresh water is used)
• Washing down the hold super structure (if freshwater is used)

To drink water contaminated with Legionella bacteria will NOT cause you to be infected and there has been no evidence of person-to-person transmission.

Assess the water systems of the vessel and identify all risk areas.

1. Study the hot & cold water system plans and identify all water outlet points and in particular those that are rarely used ‘dead legs’, any potential ‘blind ends’ (blanked off pipes where the water cannot circulate) or long pipe runs.
2. Check the water temperature of ALL hot & cold water points, i.e taps, showers, hoses.

• hot water should reach >50°C within 1 min. and cold water 20°C or less within 2 mins
• the boiler output temperature must be above 60°C and the return not less than 5°C lower than the output temperature
• the hot supply must be greater than 50°C at the outlets
• the cold supply must be less than 20°C at the outlets

3. Check what actual cleaning, maintenance and disinfection routines are in place on the vessel at present.
4. Assess and identify ALL points where water could be made into an aerosol and breathed in by the crew, passengers & visitors.
5. Document your findings so that the information can be included in the planned maintenance or ISM procedures which can be referred to by any Master or responsible officer.

An ideal vessel at least risk is one where the temperature readings are satisfactory, you have no ‘dead ends’, the ‘dead legs’ are used frequently, the vessel makes all its potable water by evaporation or reverse osmosis, and cleaning & disinfection procedures are in place.

The condensed water from the air conditioning should flow to waste and not to a tank for reuse.

Any pressure washers used should be regularly drained and disinfected.

Any water features (Fountains) and hot spa baths must be regularly cleaned and disinfected.

The minimum recommended requirements are as follows:

1. The hot water boiler outlet temperature must be greater than 60°C
2. Dismantle, inspect, clean and soak the shower heads and pipework for a few hours at least once every 3 months in a disinfectant/chlorine solution. Remove any sediment, algae or calcified deposits found.
3. Locate and eliminate all ‘blind ends’ and ‘dead legs’.
4. Super chlorinate the fresh water tanks twice a year and flush the water through all outlet points ‘dead legs’.
5. Any crew or passenger cabin that has been out of use for 2-4 weeks must have tall outlets flushed and have the shower head and hose cleaned and soaked in a chlorine solution prior to the cabin being used.
6. Have the water bacteriologically tested if you find hot & cold water temperatures are outside those recommended.

The symptoms include a flu-like illness, followed by a dry cough which frequently progresses to pneumonia. Approximately 30% of people infected may have diarrhoea and vomiting and 50% may show signs of mental confusion. The incubation period is from 2-10 days.

Men more than women, people over 50, smokers, alcoholics, diabetics, people with a chronic underlying disease and/or a weakened immune system.

Legionella bacteria are widespread in natural sources of water including rivers, streams and ponds and may even be found in soil. It has never been isolated in salt water so vessels that make all their potable water by evaporation or reverse osmosis have a lower risk of the bacteria being present. They are significant when found in man made recirculating and hot and cold water systems

Only when water contaminated with Legionella bacteria becomes aerosolised so that it can be inhaled does it pose a risk to health.

For example:

• When having a shower
• When running sink taps when using a hot spa tub
• Warm moist air circulated by air conditioning, heating units & humidifiers
• When using fire hoses (if fresh water is used)
• Washing down the hold super structure (if freshwater is used)

To drink water contaminated with Legionella bacteria will NOT cause you to be infected and there has been no evidence of person-to-person transmission.

Assess the water systems of the vessel and identify any risk areas. Remove or reduce possible sources of contamination through risk assessment, routine maintenance and regular cleaning, to reduce the chance of infection.

YOU REDUCE THE CHANCE OF INFECTION

Questions to ask yourself

• Is the hot water boiler temperature hot enough to ensure temperatures of above 50°C or below 20°C are achieved at all outlets ?
• Have I ensured hot cold pipes are insulated and do not affect one another?
• Have I identified any other risk factors and corrected them?
• Have I identified all ‘dead ends’ within the hot cold water system and removed them?
• Have I reduced the risk on board the vessel?

If you have answered ‘YES’ to all the questions above you should have successfully reduced the risk of Legionella being present on board the vessel.

Assess the water systems of the vessel and identify all risk areas.

1. Study the hot & cold water system plans and identify all water outlet points and in particular those that are rarely used ‘dead legs’, any potential ‘blind ends’ (blanked off pipes where the water cannot circulate) or long pipe runs.
2. Check the water temperature of ALL hot & cold water points, i.e taps, showers, hoses.

• hot water should reach >50°C within 1 min. and cold water 20°C or less within 2 mins
• the boiler output temperature must be above 60°C and the return not less than 5°C lower than the output temperature
• the hot supply must be greater than 50°C at the outlets
• the cold supply must be less than 20°C at the outlets

3. Check what actual cleaning, maintenance and disinfection routines are in place on the vessel at present.
4. Assess and identify ALL points where water could be made into an aerosol and breathed in by the crew, passengers & visitors.
5. Document your findings so that the information can be included in the planned maintenance or ISM procedures which can be referred to by any Master or responsible officer.

An ideal vessel at least risk is one where the temperature readings are satisfactory, you have no ‘dead ends’, the ‘dead legs’ are used frequently, the vessel makes all its potable water by evaporation or reverse osmosis, and cleaning & disinfection procedures are in place.

The condensed water from the air conditioning should flow to waste and not to a tank for reuse.

Any pressure washers used should be regularly drained and disinfected.

Any water features (Fountains) and hot spa baths must be regularly cleaned and disinfected.

The minimum recommended requirements are as follows:

1. The hot water boiler outlet temperature must be greater than 60°C
2. Dismantle, inspect, clean and soak the shower heads and pipework for a few hours at least once every 3 months in a disinfectant/chlorine solution. Remove any sediment, algae or calcified deposits found.
3. Locate and eliminate all ‘blind ends’ and ‘dead legs’.
4. Super chlorinate the fresh water tanks twice a year and flush the water through all outlet points ‘dead legs’.
5. Any crew or passenger cabin that has been out of use for 2-4 weeks must have tall outlets flushed and have the shower head and hose cleaned and soaked in a chlorine solution prior to the cabin being used.
6. Have the water bacteriologically tested if you find hot & cold water temperatures are outside those recommended.