Legionnaire's disease

Re: Legionnaire's disease

This is an extract from the LPC Technical Bulletin regarding Legionnaires disease:

Fire Fighting Systems [FFSs] directly supplied with public mains water present no significant risk of infection with legionella.

? FFSs supplied with water from poorly maintained
private tanks present a theoretical risk of infection
with legionella, particularly to maintenance
personnel, fire-fighting professionals and in health
care premises.
? LPC recommended control measures:
? Incorporate FFS into any existing legionella
monitoring system for the site.
? Minimise production of aerosols during testing
and maintenance.
? Maintain tanks and piping at < 20°C by
shielding from possible heat sources.
? Annual inspection of tanks to monitor corrosion
and deposit build-up, with appropriate remedial
actions.
? Annual monitoring of water tank bacterial
concentration by dip slide. Concentrations
above 105 cfu/ml indicate that chemical
treatment of the water may be necessary.

Hope this helps

toshy67 | 15:31 08.04.2008| Report this answer as unsuitable

Re: Legionnaire's disease

Legionella bacteria are common and can be found in any water system, usually in low numbers. The bacteria can survive under a wide variety of environmental conditions and have been found in water at temperatures between 6°C and 60°C, though water temperatures in the range 20°C to 45°C seem to favour growth.

As legionella bacteria are commonly encountered in environmental sources they may eventually colonise manufactured water systems and be found in cooling tower systems, hot and cold water systems and other plants which use or store water. To reduce the possibility of creating conditions in which the risk from exposure to legionella bacteria is increased, it is important to control the risk by introducing appropriate control measures.

There is a general requirement to undertake testing for legionella for any system which may involve stagnant water that may be heated to between 20°C and 45°C. However, this testing should only follow an initial assessment of the system to identify if the system is at risk of legionella multiplying within the system. This risk assessment should be undertaken by a competent person and records kept of all findings.

Emergency fire sprinkler systems tend to be at the lower end of the risk scale as they are, for the most part, sealed systems. The initial risk assessment undertaken by the site should investigate all parts of the system, from the sprinkler heads back to the water storage tank or mains supply connection. Regular (weekly) temperature measurements would demonstrate that the site is undertaking an ongoing risk assessment for the system.

The Code of Practice for the Control of Legionella Bacteria in Water Systems provides details on the risk assessment that should be undertaken. Its Appendix mentions sprinkler or fire hose systems and provides further details, including recommendations for testing and maintaining the system.

Anonymous | 11:07 07.09.2007| Report this answer as unsuitable