Importance of a Legionella Risk Assessment

Legionnaires Disease breeds under the right conditions in cooling towers and a building’s fresh water storage supply system. If these are not regularly cleaned, disinfected and maintained it could lead to creating the right conditions for the Legionella bacteria to multiply.

The government’s safety advisory body, Health & Safety Executive, in its AcoP L8 guidelines recommend that to ensure the safety of all staff and visitors building managers need to carry out maintenance and checks of water systems every six months.

The main processes in the management of Legionella include the conducting of risk assessment of the dangers, implementation of inspection and monitoring programs. There should also be a complete cleaning and disinfection of all water systems and replacement or refurbishment to any damaged elements of tanks and cooling towers.

Risk Assessment

The Legionella risk assessment should comprise a thorough inspection of the water system for any building with more than 5 occupants. Trained professionals conduct examinations of the entire system and water storage facilities whether used for supply of fresh water or as part of the buildings air conditioning or central heating.

Assessment of the hygienic conditions and how well they are being maintained is important for preventing the development of circumstances that will allow for the rapid breeding of Legionella bacteria. This assessment also looks at the management systems and how capable they are in controlling the threat of Legionella contamination.

The Legionella risk assessment examines all likely areas of potential threat for nourishing and encouraging bacterial growth if left unchecked. These include cooling towers, evaporation condensers, hot and cold water systems as well as all areas that contain water that are likely to reach a temperature over 20°C or involves the release of a fine spray or aerosol effect.

Monitoring & Inspection

Of primary importance in keeping Legionella bacteria at bay is the implementation of a successful monitoring and inspection process that ensures the cleanliness of all water systems. This includes the physical examination of all areas; testing of water temperatures and conducting dip slide measurements.

Cleaning & Disinfection

Water systems should be regularly cleaned out, removing any bio film, debris and rust that can act as nutrients for the bacteria. The water should also be treated with silver based hydrogen peroxide or chlorine biocide etc to guarantee the quality of the water. Tanks and cooling towers should also be cleaned of any built up scale using acid based chemicals.

System Refurbishment

Whether there are plumbing issues or a major system failure it is important to change any broken or missing parts immediately. Any poor functioning of the water system can lead to an increase in temperature and multiplication in levels of microbiological algae like Legionella bacteria.

Legionnaires disease is a very dangerous condition, which if not monitored carefully and the proper steps put in place to prevent its spread, can lead to infection of individuals and even death on an epic scale. Care should always be taken to inspect areas thoroughly and ensure tanks are cleaned and water systems kept safe.