Cooling systems
Don’t forget it is the whole cooling system that represents the risk not just the tower so you need to make sure that the whole system is cleaned when required, that you look for deadlegs throughout the site and that you consider the heat transfer areas where special issues are created.
Written Scheme of Control
This is a key area of managing a water cooling system to prevent risks from legionella pneumophila and other legionella bacteria. You need to ensure it complies with local legislation and guidance as it exists. In the UK HSG 274 has a comprehensive list of what it expects to see in a Written Scheme. One key area is a section on “what-ifs” in other words what do you do if something is not correct or you have a non-compliance. Failure to include these important descriptions in advance is enough for the HSE to issue an Improvement Notice so ensure you include them. An examples may be how you ensure that your biocide level is correct and stays so immediately on restarting the system after a shutdown.
Langelier and Ryznar Indices
In the UK calculating these indices is an important tool in managing your cooling system so do you, or your water treatment company know how to calculate them? A simple spreadsheet can be used to calculate these important indices, which let you know whether your system has a tendency towards forming scale or being corrosive so you know which chemicals to use on site to counteract the problem. If you don’t know how to calculate these you can get a copy via the link below.
Thermostatic Mixing Valves
These valves help prevent scalding however due to the strainer baskets found on the inlets they can collect debris that encourages Legionella. Also the outlet temperature is ideal for Legionella bacteria to grow and proliferate. These valves need to be serviced and cleaned annually so some system for ensuring this is done is important. Obviously this will involve a logging system but also consider a simple coloured cable tie tied around to identify the year it was cleaned. If you change all cable ties each year for a different colour you will have a quick visual check to see that the valve has been serviced.
Little Used Outlets
How do you know if an outlet is little used or not. One way to avoid an outlet becoming little used is to clean it regularly (at least once a week if you are not a healthcare site). If you ensure that whilst cleaning the sink the hot and cold water are run then your sin is no longer a little used outlet. Don’t forget all those external taps, such as garden bib taps used to connect your hosepipe, they should also be flushed weekly.
Keeping Records
How do you know if an outlet is little used or not. One way to avoid an outlet becoming little used is to clean it regularly (at least once a week if you are not a healthcare site). If you ensure that whilst cleaning the sink the hot and cold water are run then your sin is no longer a little used outlet. Don’t forget all those external taps, such as garden bib taps used to connect your hosepipe, they should also be flushed weekly.
What if it all goes wrong and somebody catches Legionnaires’ disease
Don’t panic, Collaton Consultancy Limited can help you with crisis management or work for your solicitor if the situation become legal. Contact us early to minimise the issues.
Other risk systems
Almost any water containing system may be a Legionella risk, though there are some that are not a risk, such as a heating system (due to insufficient oxygen being present). There is a list of other risk systems in HSG 274 Part 3 and whilst it is a long list it is not an exhaustive one. The solution then is to carry out an on site risk assessment looking for where water is used and then take a view based on what you find.
Can you help me?
Of course. Whilst Collaton Consultancy Limited do not sell chemicals or equipment, which therefore makes us independent, we have over 39 years of experience in the industry and hence can offer expert technical help and advice and work with you and your water treatment company to ensure you achieve the best results for your cooling system and protection of your staff.