INTRO: The purpose of this briefing document is for businesses to consider the risks in their premises, and to consider some recommended actions to take when buildings have been mothballed as a result of the Coronavirus shut down. Legionella bacteria thrive in certain conditions - when buildings become low in occupancy or closed completely for lengthy periods; the Legionella risk increases significantly.
Legionella bacteria thrive in certain conditions - when buildings become low in occupancy or closed completely for lengthy periods; the Legionella risk increases significantly.
LEGAL OBLIGATIONS: There are certain legal duties outlined in the HASWA 1974, Management of H&S at Work Regulations 1999, COSHH Regulations 2002, ACoP L8 4th edition, HSG 274 Parts 1-3 and specifically as follows: HSG 274 Part 2, Paragraph 2.52 – In general, systems are normally left filled with water for mothballing and not drained down. As a result moisture will remain within the system enabling biofilm to develop where there are pockets of water or high humidity. The systems should be re-commissioned as though they were new (i.e. thoroughly flushed through, cleaned and disinfected) before being returned to use.
LOW OCCUPANCY BUILDINGS: Where a building is still occupied, albeit at a lower occupancy, then flushing should continue, but the additional low use outlets that may now exist should be included. In the current situation with Coronavirus, maintenance staff or specialist contractors may not be able to attend site to undertake monthly temperature checks etc. In this case consider opting for twice weekly flushing (including shower heads if present) as a short-term measure to increase water turnover. Water temperatures still need to be maintained, but accessing buildings, especially those at higher risk of COVID-19 such as care environments may be difficult. In these cases, consider taking flow @ return temperatures from calorifier(s) only to minimise building footfall. Where there are site-dedicated staff (maintenance) monthly temperatures should be taken as normal. Hot supplies should be a minimum of 50 degrees C within one minute (55 degrees C in healthcare environments) & cold supplies should be below 20 degrees C within two minutes of running the cold tap. Action any non-conforming temperatures.
START-UP PROCEEDURE (MOTHBALLED BUILDINGS): Building re-occupation after prolonged periods of no use is where the greatest risk lies if certain procedures are not followed:
2-3 weeks prior to occupation:
• Consider conducting a building chlorination, especially where cold-water storage tanks are in place. The volume of stored water will have become stagnant and may have suffered thermal gain (>20 degrees C).
• Consider taking Legionella samples to confirm if the bacteria exist, this allows time for action prior to building re-occupation.
• If the quarterly showerhead cleaning and disinfection was due within the shutdown period, bring this up to date.
2-3 days prior to occupation:
• Raise temperature of the calorifier(s) / hot water storage vessel(s) to 60 degrees C.
• Flush and purge all outlets until the temperature at the outlet stabilizes and is comparable to supply water and purge to drain.
***CAUTION – Minimise exposure to aerosol droplets by removing shower heads, covering spray taps with a clean cloth, placing clean plastic bag over fixed showerheads and cutting the corner of bag. Once flushing has started it should be continued until all outlets are back in regular use (twice weekly flushing in healthcare buildings).
***Document all actions in site logbook.
THE PROBLEM: Outbreaks of Legionnaires’ disease occur from exposure to Legionella in systems where water is maintained at temperatures high enough to encourage growth. These include: cooling towers, evaporative condensers, air-conditioning systems, and hot and cold water systems - such as showers.
Controlling the risk from Legionella bacteria can be achieved by the use of suitable water system treatments, such as SCALE DOWN and LEGIONNAIRE.
THE SOLUTION: Controlling the risk from Legionella bacteria can be achieved by the use of suitable water system treatments, such as SCALE DOWN and LEGIONNAIRE. Both SCALE DOWN and LEGIONNAIRE are compatible with the approved code of practice (Legionnaires’ Disease - The control of legionella bacteria in water systems - L8) produced by the Health & Safety Executive in 2000.
Legionella bacteria can be found in a variety of purpose-built water systems. If conditions are favourable, the bacteria may grow, increasing the risks of Legionnaires’ disease - a form of pneumonia caused by Legionella bacteria penetrating the alveoli in the lungs. It is contracted by inhaling airborne water droplets containing viable Legionella bacteria. Conditions that can increase bacteria growth include:
• Water stagnation.
• Water temperatures between 20 degrees C and 45 degrees C.
• Systems containing nutrients for bacteria growth e.g. rust, sludge, sediment, scale, organic matter and biofilms.
WHO IS AT RISK: Everyone is susceptible to infection; the risk increases with age, but some people are at higher risk including:
• People suffering from chronic respiratory or kidney disease, diabetes, lung and heart disease.
• Anyone with an impaired immune system.
SYMPTOMS: Symptoms of Legionnaires’ disease include:
• Fever, loss of appetite, headache, tiredness, severe muscular aches, dry cough, breathlessness & confusion.
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