COMPLIANCE & RISK ASSESSMENT
LEGIONELLA AFTER LOCKDOWN
Organisations planning to take water systems out of use for as little as two weeks must take steps to prevent the build-up of microbiological contaminants, says Spencer Culley, Managing Director of Churchill Environmental.
Any employer planning to welcome staff back to the workplace over the next few weeks cannot ignore the health and safety risks associated with water management. Harmful levels of the bacteria Legionella can build-up quickly in water systems that are left unused and unmanaged for even a short period. Anyone who inhales tiny droplets of water containing the bacteria – often from potable water sources and air-conditioning units – may develop Legionnaires’ disease, a severe respiratory infection that causes death in 10-15% of cases.
The HSE states that water systems must be properly and safely recommissioned following a full or partial closure before they are reinstated for use by the occupants. In June 2018, BUPA was fined £3m (subsequently reduced to £1.5m) for admitting a breach of health and safety regulations following the death of a resident in one of its Essex care homes after failing to flush and disinfect pipework.
Any organisation planning to decommission a building or take water systems out of use for as little as two weeks must take steps to prevent the build-up of microbiological contaminants and biofilm.
Health and safety managers should implement a comprehensive flushing regime to mimic normal operational use of the system, while outlets should be flushed until the temperature stabilises alongside the incoming water supply. Legionella thrives between 20°C and 46°C, so both hot water services and cold water systems need to be recirculated at temperatures below 20°C.
For buildings that are still partially in use, systems should be flushed to mimic normal operational use and the water stored in tanks should be reduced so that it can be turned over within 24 hours. Monitoring the temperature will also help to control thermal gain in cold water, while point-of-use filters at designated areas will keep occupants safe.
However, buildings or water systems out of action for extended periods require a more substantial plan to prevent the contamination and colonisation of bacteria. In most cases, except for small offices, systems should be kept filled, as draining them is difficult and likely to dry cistern joints, corrode the metal pipework and create a build-up of biofilm.
The next challenge comes as organisations prepare to welcome back their employees and other building users. The Health & Safety Executive (HSE) states
32
that water systems must be safely and adequately recommissioned before occupants can return.
“Legionella thrives between 20°C and
46°C, so both hot water services and cold water systems need to be recirculated at temperatures below 20°C.”
A full water system disinfection is the most effective way to do this, which can be a highly complex undertaking depending on the system configuration. Technicians should inject the selected disinfection solution into a specific point at the upstream end of the supply pipe, or downstream if there is double- check valve or backflow protection device protecting the incoming water supply. Testing of sentinel outlets will determine whether the required concentration levels have been achieved, while all other outlets should be subject to fast and simple tests that indicate the presence or absence of the disinfectant.
Organisations need to leave adequate time between the disinfection work and reopening the building. Two to seven days after the work is complete, Legionella samples should be taken from sentinel taps and other outlets. Any readings in the 48 hours following the treatment may give false-negative results.
It is also important to consider the unusually warm spring weather during lockdown. The high temperatures combined with the extended period of office closures mean that systems may become colonised with bacteria, so repeat disinfections may be required to guarantee the total removal of Legionella.
Organisations are responsible for everyone’s safety during this period and in the future, including returning employees, the staff carrying out the recommissioning, and the essential workers doing their bit to prepare buildings for their reopening. Those involved in the flushing and disinfection work should have personal protective equipment as well as limited exposure to the potentially dangerous air particles. Signage should be fitted near all areas and outlets affected by the disinfection warning cleaners, security and maintenance staff of the dangers.
The combination of a Legionnaires’ outbreak and coronavirus in the workplace would be catastrophic. It is the responsibility of health and safety managers to ensure that doesn’t happen.
www.churchillservices.com/environmental/
www.tomorrowshs.com
"
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
