Do I need a legionella risk assessment?

18th August 2020

A competent Legionella risk assessment is essential for making sure water systems are not putting occupants at risk of Legionnaires’ Disease.

A legionella risk assessment is a legal requirement in buildings with a high footfall of people such as hospitals, schools and commercial properties. This is part of the compliance criteria for ACoP L8 (Approved Code of Practice L8 2013 – (The Control of Legionella Bacteria in Water Systems). HSG274 also contains guidance for Legionella control.

Cooling towers and HVAC systems are key risk areas for Legionella growth, but all sanitation and general plumbing should be checked as the bacteria can grow in any location where water is present.

Who is responsible for a legionella risk assessment?

Building owners, landlords, employers, building and facilities managers are all responsible parties. A water treatment company such as Guardian can undertake any work following a risk asssessment.

Expert legionella risk assessment support will ensure this important work is done correctly. All of our legionella risk assessors are competent and experienced engineers, able to quickly identify the conditions that could lead to an outbreak of Legionnaires Disease.

What does a legionella risk assessment cover?

Physical aspects of a system that may require remedial action
Current Legionella precautions and their effectiveness
Advice on pre-treatment equipment and any dosing equipment already used
Independent assessment of the monitoring and testing regime in place
Thorough evaluation of records and analysis
Overview of the composition of water in the system

Know your system

You or the person responsible for managing risks needs a good understanding of the water systems and associated equipment, such as pumps, heat exchangers and showers.

Is there a legionella risk?

Some water systems are more likely to be at risk of legionella than others, such as:

When the water temperature in some or all of the system is between 20–45 °C
Where water is stored or re-circulated
There is evidence of rust, sludge, scale, organic matter and biofilms
Areas where water droplets are produced and dispersed over a wide area – e.g. in showers and aerosols from cooling towers
Building occupants are more susceptible to Legionnaire’s Disease, including the elderly and other vulnerable groups, such as the sick or people with a weakened immune system.

Managing the risk

Any Legionella issues flagged by the risk assessment must be dealt with by a competent person – i.e. someone with sufficient authority, skill and knowledge of your water system to deal with the problem.

Someone within your business must take this responsibility. Where necessary, they can employ outside support to mitigate the risks posed. Make sure the external water treatment company and/or contractors you choose meet industry standards.

Guardian is a member of the Legionella Control Association.

Steps to prevent the risk of legionella might include:

Implement system cleaning regime, including flushing and chemical dosing
Proper control of any water spray
Temperature control – keeping water cool or hot to prevent favourable conditions for legionella
Removal of redundant pipework and re-design of any other locations where water can stagnate
Avoidance of materials that encourage legionella growth as detailed by WRAS
Replacing water-based HVAC plant, such as a wet cooling tower with a dry, air-cooled system
Water testing and monitoring to check any remedial works have been effective
Record keeping of the risk assessment itself and where maintenance and repair work has taken place – if you have five or more employees you have to record any significant findings by law.

Legionella risk assessments from Guardian

Guardian carries out legionella risk assessments, helping business to comply with ACoP L8.

Following a risk assessment, we can implement legionella control and treatment measures, including chemical and non-chemical options, where required.

Contact our expert team today.