Why size matters for disinfection

Getting up to speed on infection control has been a pretty steep learning curve since the beginning of this pandemic – for some more than others.

Those working in clinical or sterile environments, or involved the facilities management or hygiene sectors, were already well-versed in the technicalities of BS EN standards, which products could actually kill a virus and what disinfectant to use for which surface. 

But many people and organisations outside these sectors found themselves in the middle of a crisis with little or no concrete knowledge about how best to tackle a virus that threatened their livelihoods – and lives.

Over the past 12 months our nation as a whole has become much more clued-in about infection control, and from the hospital cleaner to the corner shop assistant, we all now know a lot more about the key ways to keep a virus in check.  As we move forward, the focus is shifting towards infection control that is not just effective, but also practical, convenient and sustainable.  For businesses, that means finding solutions that minimise operational downtime caused by hygiene processes – and that’s why a conversation on spray density feels timely.

What is spray density and why does it matter?

Spray density refers to the size of the tiny droplets that are created when a liquid is forced through a narrow spray nozzle or atomiser, which causes the liquid to break up into droplets.  The diameter of the nozzle and the pressure of the liquid passing through it will determine the droplet size or density.  Think about everyday products – for instance, the trigger spray you use to clean your kitchen worktops has a large spray density because it’s pressurised only by the force of your hand operating the pump, and the nozzle diameter is quite large.  But other sprays – especially the aerosols we use for products like deodorant and air freshener, are highly pressurised using propellants inside the tin, and have tiny nozzles – so the spray that comes out is very fine in density.  Spray density is measured in microns – or millionths of a metre.

Spray density affects the way that a liquid disperses over a surface, and also how long it remains suspended in the air after spraying.  So again, if we think of those household products – when you use a trigger spray in the kitchen, the product makes wet patches across your worktop with repeated spraying, and if you spritz it into the air it settles on the work surface very quickly, in visible droplets.  But when you spray that air freshener, the product creates a cloud that quickly spreads throughout the space – within a few seconds you’ll be able to smell it metres away, and if it settles on surfaces at all, it does so in a very fine veil.

OK, enough about air freshener.  What does this mean for disinfectant?

There are lots of disinfectant spray systems on the market, ranging from manual trigger sprays to aerosols, electrostatic foggers and continuous mist systems like Ramsol.  All of these different systems deliver different spray densities that affect their suitability for use in different areas, and the efficacy of the disinfectant itself.

A key point to remember is that a disinfectant only works when the specified contact time is observed.  You must apply enough product to cover the surface, and you must leave it there for long enough to kill germs.

Disinfectant sprays with a very large density, such as trigger sprays, are generally only suitable for manual cleaning because they require manual action to spread the product effectively over the surface, and also to wipe away any excess – otherwise they would take a very long time to dry, which could be hazardous. But the need for manual action after application vastly increases potential for error in that the solution is often wiped away before the requires contact time has elapsed, dramatically reducing efficacy.

Disinfectants with a very fine spray density, such as electrostatic foggers, deliver excellent coverage over large surface areas and don’t require manual action.  However, a bit like that air freshener, it can be difficult to control the spread of this very fine vapour, and it remains in the air for a long time.  As a result, fogging is not suitable for use in ‘live’ environments – spaces should be closed off, and only the fogging operative allowed in wearing PPE to prevent inhalation of the disinfectant, or contact with the skin and eyes.  Because that spray will hang around in the air for up to six hours, nobody can go back into that room or space until this time has elapsed.

What about Ramsol’s spray density?

Ramsol sits in between the two, with a spray density of 20 microns.  When developing the product, this was carefully engineered so that Ramsol could help users sidestep one of the biggest drawbacks of spray disinfection – exclusion time.

At 20 microns, Ramsol’s spray mist is much finer than a trigger spray.  It disperses widely over surfaces to give excellent coverage that can penetrate into awkward areas, leaving a fine veil that doesn’t need to be wiped away.  It’s dry in five to eight minutes, depending on conditions.  Ramsol’s droplets are larger and heavier than the mist delivered by a fogging system, which means that they fall out of suspension much more quickly. 

These factors make it much easier to control the way Ramsol spreads within a space.  Simply closing the door of an office or classroom means the mist won’t travel beyond, allowing activities to carry on while small, individual spaces are sanitised.  For larger or open plan spaces, people need only be excluded from the area for the duration of application and the subsequent ten minutes it takes for the mist to dry, and fall out of suspension.

The benefits of this are clear – Ramsol allows organisations of all kind to achieve fast, effective disinfection of their spaces with minimal disruption and downtime.  And that’s why spray density matters.

For further details about Ramsol and its use in your business or organisation, get in touch.