The Legionella Control Association discusses how to address legionella.
Legionella is something that is often in the news but often the reporting lacks the underlying facts involved.
The Bibby Stockholm situation recently and the temporary closure earlier in the year of the Police College at Tulliallan are examples of legionella news concerning government buildings. Both situations were reported in some quarters as outbreaks or as extremely dangerous events, which was not accurate.
Positive samples from the water system is not an outbreak of legionnaires’ disease.
If a building is in the public or political spotlight, reporting can sometimes exaggerate risks and failings.
Overview
Legionnaires’ disease is a potentially fatal type of pneumonia, a bacterial lung infection. The disease is contracted from bacteria of the genus Legionella, within a water-based aerosol, entering the lungs. Exposure is generally preventable if water systems are properly maintained. There are legal implications where there are failures to control this risk.
Legionella growth is considered a risk regardless of the strain or species of Legionella. If you are responsible for a building with a water system, then you have a legal duty to control the risk.
The risk associated with legionella and human infection was first identified in 1976, following an outbreak of a previously unidentified disease at an American Legion convention.
The most recent data from Health and Safety Executive (HSE) suggests that on average there are over 250 clinically diagnosed cases of Legionnaires’ Disease in the UK every year.
Legionella proliferation
There are fundamental principles that reduce the risk of Legionella growth: avoid legionella growth temperatures (20-45oC); avoid stagnation so legionella doesn’t have time to grow; avoid materials of construction that will support growth; and control the release of water spray to minimise transmission risk.
You should also keep the system and the water in it clean so nutrients for legionella are minimised; use water treatment techniques, particularly where any of the above cannot be controlled; and maintain the system properly.
These principles form the basis of the requirements of HSEs Approved Code of Practice for the control of Legionella in water systems and underpin all the UK guidance.
In practice, some of these can be a challenge. Pipework is often re-configured post-construction and dead ends (sections that go nowhere so water does not move) can inadvertently be created in the pipework. Some areas of a building will have higher footfall/usage than others, so water can stagnate more readily in some areas with no design fault. Heat can be lost or gained through poor insulation, lack of circulation or failing non-return valves. All these scenarios are common, and all increase the risk of Legionella proliferation.
When the conditions for growth are right, then Legionella can grow. Once present, Legionella can be a challenge to remove. So, what does the law say?
Legionella & the law
The Law applicable to Legionella control in most settings is the Health and Safety at Work Act (1974).
This describes how it is the responsibility of an employer to protect their employees and any other stakeholders from risks that may arise from their undertaking. Stakeholders are any persons who may come into contact with your water systems or aerosol produced by those systems during normal use.
Legionella bacteria is considered a hazardous substance under The Control of Substances Hazardous to Health (COSHH) (2002) Regulations. Risks must be assessed, and any identified risks must be either eliminated, substituted for lower risks or where this is not possible, control measures must be put in place to mitigate residual risk.
Details of what must be done to control Legionella are published by HSE in the Approved Code of Practice for Legionella (ACoP L8). ACoPs have special legal status and you must either follow the provisions of an ACoP or be able to show that you have complied with the law in some other way, or a court will find you at fault.
Detailed guidance and examples of how to comply with the law is published by HSE in Health and Safety Guidance (HSG) 274; this comes in three parts: the control of Legionella bacteria in Evaporative Cooling Systems; the control of Legionella bacteria in Hot and Cold water systems; the control of Legionella bacteria in other risk systems.
ACoP L8 and the HSE guidance outline how to comply with the law and keep safe. They highlight the legal requirement for risk assessment; to assess the risk posed by your undertaking that may allow Legionella to proliferate. Where risks are identified, a written scheme of control is required to manage the identified risk. This is commonly achieved through maintaining control of water temperature, use of water treatment, regular cleaning of commonly fouled components, etc. together with regular monitoring and inspection to ensure the regime is effective.
Legionella Control Association (LCA)
The LCA Code of Conduct is highlighted in ACoP L8 (Paragraph 83) as guidance to what standards service users should expect. A voluntary membership with around 400 Members, LCA registered companies are specialists in Legionella Control.
The Code has 28 requirements that must be followed with specific Service Delivery Standards for the eight Legionella control service areas. The LCA emphasises management procedures that members must have in place to deliver a consistent and compliant service.
Members are audited for compliance with the code and service delivery standards requirements. Evidence is checked that procedures are being followed in practice. Where we find a member’s performance lacking, either at audit or as part of a complaint to us, we will suspend them in the short term and their membership will be terminated unless improvements are made.
Risk assessment
Premises where the Health and Safety at Work Act applies must have a Legionella Risk Assessment. This identifies risks associated with water systems and includes recommendations for elimination or substitution of the risk and for Control Scheme tasks to mitigate residual risk.
Risk assessment should be specific to water systems; with consideration given to individuals who may be exposed.
Control measures
Any risk that is present needs to be controlled to an acceptable level. The HSE uses the term as low as reasonably practicable (ALARP), and this is the target level of risk.
Legionella control measures usually include maintaining temperature, use of water treatment, flushing and physical control.
Positive Legionella results
Around 13 per cent of all samples in the UK return a positive, so it’s not uncommon to have positive Legionella results.
It’s important to act on a positive result to address the immediate risk (the symptom) and the underlying issues (the cause). Cleaning and disinfection is commonly used as an immediate risk reduction measure but a review of the risk assessment and identification of the underlying cause of the Legionella growth is critical.
Interim measures may be required until any identified issue can be resolved.
Summary
Legionnaires’ disease is potentially fatal but is preventable. Employers and those in control of premises have a legal duty to ensure risks are identified and controlled.
Legionella prosecutions can result in large fines and custodial sentences, and it is not necessary for there to be a death or case of disease for a successful prosecution.
If your water system exposes stakeholders to risk of harm, you are committing an offence.
