Not all buildings are occupied. Not all buildings are occupied all the time. Some are empty because new tenants are yet to move in, for example, and some are empty some of the time due to school holidays and similar. What happens to your legionella control in these situations? Can you stop checking and monitoring? Can you stop bothering with legionella control?
The answer – as you might have guessed – is no. The building you have responsibility for needs to be as safe as possible at all times, no matter whether it happens to be occupied or not. In fact, when you have an empty building to look after there are some additional tasks that you will need to add to your schedule of works when it comes to legionella control and health and safety.
One of the main issues regarding an empty building is that the turnover of water won’t be as frequent as when the building is occupied – it might not even happen at all. Stagnating water is exactly the right place for legionella bacteria to proliferate, meaning that if the water simply sits in your tanks and pipework, legionella could be growing, and quickly. This means that one of the additional tasks to add to your to do list is flushing. You will need to flush all the pipework and tanks through regularly to ensure that the water does not have a chance to stagnate.
Not only that, but the temperature of the water within an empty building is likely to be lower than in a building that is occupied. For entirely sensible reasons, it makes no sense – financially – to heat the water in an empty building. However, this means that legionella bacteria can grow more quickly, as if water is being store below 60oC the bacteria really has free reign.
There are some choices to be made. Either the water needs to be heated so that it is stored at more than 60oC (costing money), or you need to have more regular checks by a legionella expert to ensure that no bacteria is present. Simply leaving the cooler water to sit and stagnate is not an option.