This review explains key updates to the British Standard BS 7592:2022, which focuses on legionella bacteria sampling in water systems. It outlines the importance of understanding why sampling is needed and covers topics like creating sampling plans, routine testing, outbreak investigations, and comparing the old and new standards.
What is BS 7592:2022?
BS 7592:2022 is a British Standard published in 2022. It outlines how to test water systems for presence of legionella bacteria in water systems. It applies to systems like hot and cold water systems, cooling towers, and spa pools that may pose a risk. The standard explains how to sample water, biofilms, and sediments and includes methods to support legionella control and monitoring.
BS 7592:2022 Revised
The last update to BS7592 for legionella sampling standards was in 2008. In 2022, a new version, BS 7592:2022, was introduced. This article explains the changes and why the updated standards are important.
Why are Legionella Samples Being Taken?
The updated BS 7592 standard highlights that water sampling for legionella bacteria should only be done when there is a clear need. Sampling is unnecessary if the water system is running properly, with no signs of contamination or elevated levels. Legionella sampling may be required in the following situations:
- The measures in place to keep the water system safe have failed.
- People at higher risk of Legionnaires’ disease are now using the water system.
Developing a Legionella Sampling Plan
If these situations occur, a plan for legionella sampling should be created. In large, complex water systems, this may involve members of the Water Safety Group (WSG). In smaller buildings, the responsible person will decide the best locations to sample the water supply.
These examples are not the only possibilities. Other risks identified in the legionella risk assessment may also require water sampling.
Additional Guidance Covering Legionnaires’ Outbreak Investigations
New annexes have been added to BS 7592:2022 to guide legionella bacteria sampling during a Legionnaires’ disease outbreak. These annexes focus on locations such as hotels, hospitals, and other healthcare facilities. Sampling plans must include an up-to-date legionella risk assessment, which is key to outbreak investigations.
The updated standard also includes advice on new water system installations, refurbished buildings, and potential variations in water systems.
Updated Advice for Legionella Sampling of Water Storage Tanks
The BS 7592 standard has been updated to advise against opening potable water storage tanks for sampling. This method, previously known as dip sampling, was once considered acceptable but is no longer recommended. Instead, two alternative methods should be used to collect samples without risking contamination from dust or other foreign particles.
1. Add a Valve for Sampling
The best option is to use a valve specifically made for sampling.
2. Use the Closest Outlet
The second option is to go to the nearest water outlet to the storage tank.
Routine Water Sampling
The updated British Standard includes guidance on routine sampling for Legionella in water. Samples should be taken before flushing (pre-flush), but post-flush samples are also important for high-risk water outlets. A legionella risk assessment will help identify these higher-risk outlets. After sampling, these outlets should be rinsed with clean water.
How to Review the New BS 7592:2022 Standard
To understand the changes in the new legionella sampling standard, it’s helpful to compare it with the old one. While some updates may seem minor, they are clearly aimed at improving safety. For example, instead of opening potable water storage tanks for sampling, the new standard emphasises minimising contamination risks and finding the best sampling points without opening tanks.
The annexes and guidance on sampling for new or recommissioned water systems will be helpful for many. The standard offers clearer guidance on important testing practices. Those involved in water safety for buildings should review the new standard as soon as possible to ensure compliance.
Leading Legionella and Water Safety Specialists – Comfort Services Group
We are Legionella and water safety specialists, helping businesses manage risks from waterborne pathogens like Legionella in the workplace. Our services focus on protecting employees, customers, and others from hazards linked to water systems while ensuring compliance with health and safety regulations.
Our expertise covers legionella sampling, including routine monitoring, water safety risk assessments, compliance audits, water quality testing, and training. We also provide health and safety risk management services to keep everyone safe.-
Contact Comfort Services Group if you would like to speak with one of our legionella specialists about improving your risk management processes.
FAQs
What are the requirements for Legionella sampling?
The UK’s Health and Safety Executive (HSE) Approved Code of Practice (ACOP) L8 outlines legionella sampling requirements. Water systems must be checked regularly for risks of legionella growth. Sampling is important in systems where water temperature, stagnation, or other factors could encourage bacteria. Testing should be done by trained professionals using approved methods to ensure accuracy. Regular checks and proper controls help reduce risks and meet UK regulations.
What is the gold standard for Legionella testing?
The UK uses culture testing as the gold standard for Legionella detection. This method involves incubating water samples on a special medium to identify and measure Legionella bacteria. It is highly reliable for detecting bacteria and determining their levels. Although results take up to ten days, this process provides precise and detailed information. UK regulations require culture testing for certain systems to meet health and safety standards. Accurate results depend on proper handling and trained staff.
What is the most accurate test for Legionella?
Culture testing is the most reliable method for Legionella testing. It involves growing bacteria from a water sample in a lab to confirm and measure contamination levels. This method is accurate and required under UK regulations. While it provides essential risk management data, results take longer compared to other methods.
What is the British standard for Legionella?
The British standard for Legionella is BS 7592. It explains how to sample, monitor, and test water for the bacteria. The standard sets procedures to assess water systems and lower risks. Following BS 7592 ensures safety and meets UK legal requirements. It is commonly used to manage Legionella in workplaces and public spaces.
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