FMs must ensure that workplaces are safe for a return to work – and that includes rigorous water management, says Spencer Culley.
Harmful legionella bacteria can multiply quickly in water systems if they are left unused and unmanaged for even a short period. People who inhale tiny droplets of water containing the bacteria risk developing Legionnaires’ disease, a severe respiratory infection that causes death in 10-15 per cent of cases.
In June 2018, private healthcare provider Bupa was fined £3 million (reduced to £1.5 million) for admitting a breach of health and safety regulations following the death of a resident in one of its Essex care homes after it failed to flush and disinfect pipework.
While everyone’s away
Decommissioning a building or taking water systems out of use for as little as two weeks requires action to avoid the build-up of microbiological contaminants and biofilm.
Facilities teams should implement a comprehensive flushing regime to mimic normal operational use. Outlets should be flushed until the temperature stabilises and levels with the incoming water supply. Legionella thrives between 20°C and 46°C, so hot water services and cold water systems need to be recirculated at temperatures below 20°C.
For partially used buildings, FM teams should flush systems to mimic normal operational use and reduce water stored in tanks 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.
Building water systems out of action for extended periods require a substantial plan to avert 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.
Preparing for a return
The next challenge comes as organisations prepare to welcome back their employees and other building users. For this, the Health & Safety Executive states that water systems must be safely and adequately recommissioned.
- Carry out a full water system disinfection
This is the most effective option, but it can be complicated depending on the system configuration. Technicians should inject the 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, and all other outlets should be subject to fast and simple tests that indicate the presence or absence of the disinfectant.
- Leave time between the disinfection work and reopening the building
Two to seven days after the work is complete, FMs should take legionella samples from sentinel taps and other outlets. Any readings in the 48 hours following the treatment may give false-negative results.
- Factor in the unusually warm spring weather during lockdown
High temperatures combined with extended office closures could lead to systems being colonised by bacteria, so repeat disinfections may be required to guarantee the total removal of legionella.
Remember – 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 preparing buildings for reopening.
Those involved in flushing and disinfection work should wear PPE to reduce exposure to dangerous air particles. Signage should be fitted near all areas and outlets affected by the disinfection to warn cleaners, security and maintenance staff.
The combination of a Legionnaires’ outbreak and coronavirus in the workplace would be catastrophic.
Spencer Culley is managing director at Churchill Environmental
