Following your Legionella Risk Assessment you need to implement Control and Prevention measures and record them in a Legionella Logbook. The HSE's ACOP L8, HSG 274 and HTM 04-01 gives guidance on effective control and prevention measures. Failure to competently establish, maintain and record the measures undertaken can result in substantial fines and prosecution.
What Measures Do You Need
Every site should have a site specific Legionella Control Scheme which is a requirement of the HSE's ACOP L8. The control scheme details what tasks and measures are required and their frequency.
Unfortunately, we are finding that very few Legionella Risk Assessments are detailing site-specific measures. Instead, more and more service providers are only including a general table of measures and leaving their customers to figure out which measures to apply.
Often a copy of "checklist 2.1" from HSG 274 part 2 is used but this table is described as an indication of measures and frequencies. Any control scheme should take into account local conditions.
Control and prevention measures need to be carried out by someone who is "technically competent". Whilst measures may vary there are common tasks that should be in place for every site such as flushing infrequently used outlets, regular temperature monitoring, cleaning and descale of spray outlets as well as the regular servicing of water heaters, cooling towers and air conditioning systems.