Disinfecting premises using fog, mist, vapour or ultraviolet (UV) systems during the coronavirus outbreak
During the coronavirus (COVID-19) outbreak, fog, mist, vapour or UV treatments may be suitable options to help control the spread of the virus, by cleaning and disinfecting a larger space or room. Any use of these treatments for these purposes should form part of your COVID-19 risk assessment. Users must be competent and properly trained.
Select the correct treatment
If you choose to use fog, mist, vapour or UV treatments as a way of cleaning and disinfecting surfaces, discuss your requirements with your manufacturers/suppliers (this may include fumigators), to help you decide if a product/system meets your needs. The treatment you use will depend on:
- the size of the area to be treated, its shape and how easily it can be sealed off if delivering an airborne product
- whether there are hard or soft surfaces - soft furnishings may act as a 'sink' for the airborne chemicals and emit them for some time after treatment (it may be possible to remove items such as sofas before treatment)
- the type of business you have - some areas may be better suited to UV surface treatments than airborne chemicals or vice-versa
Fog, mist, vapour method
If using the fog, mist, vapour method you will need to ensure the correct concentration of the active chemical is used, this means there is enough for it to work properly, but not so much as to leave a residue which may remain at unsafe levels for some time after treatment ends.
There are different types of source disinfectants that can be applied as a fog, mist or vapour treatment. Some are liquid disinfectants used to create a fog, mist or vapour, such as hydrogen peroxide, others are generated from gases, for example ozone from air. Seek advice on what is appropriate to the environment that requires treatment.
An advantage of UV over disinfectants applied as a fog, mist or vapour is that no chemical residue is left behind.
Rooms with complex configurations/interior designs may not be suitable for UV treatments due to the limitations of shadowing effects, unless multiple systems can be deployed. Similarly, very small spaces, such as small sanitary areas, may not be suitable for treatment via UV carousel as they need to be a minimum distance from walls etc to be deployed safely. Some disinfectant technologies are scalable so are typically more flexible in this respect.
Disinfectants applied as a fog, mist or vapour may reach harmful levels during delivery and UV systems may cause eye/skin damage if people enter an area undergoing treatment. Discuss with suppliers what safety features they can provide to prevent inadvertent access to a room during treatment. For example, safety sensors, simply locking rooms during treatment if feasible, or safety signage as part of a safe system of work.
Do not spray people with disinfectants
Do not spray people with disinfectants (such as in a tunnel, cabinet, or chamber) under any circumstances. This practice could be physically and psychologically harmful and would not reduce an infected person’s ability to spread the virus through droplets or contact. Even if someone who is infected with COVID-19 goes through a disinfection tunnel or chamber, as soon as they start speaking, coughing or sneezing they can still spread the virus.
Do not disinfect large outdoor spaces
In outdoor spaces, large-scale spraying or disinfecting in areas such as streets or open marketplaces for the COVID-19 virus or other pathogens is not recommended. Streets and pavements are not considered as routes of infection for COVID-19. Spraying disinfectants, even outdoors, can be dangerous to people’s health and cause eye, respiratory or skin irritation or damage.