Walking on air filters

People’s resistance to return to the office after experiencing the Covid-enforced work from home phenomena, is well documented. Several enticements have been forthcoming, with terms of employment in many instances being compulsory time spent in the office.

But the resistance has highlighted a relatively new requirement – a clean working environment. This includes bathrooms being spot-cleaned regularly, frequent sanitising of workplace surfaces and indoor air quality.

The introduction of cleaning concierges in larger premises takes care of the bathrooms and sanitising but indoor air quality is a bit more involved and affects a range of indoor environments, not just offices.

Think of all the areas where carpets are used in aged care facilities. For ambience and quietness carpets are often used in corridors and lounges and other large open areas. Carpets in residents’ rooms are becoming rarer due to practical issues such as incontinence.

Several studies have concluded that carpets act as a passive air filter. The studies have shown the carpet fibres trap dust plus airborne pollutants. On hard floors, such as those made of vinyl and ceramics, these pollutants can be propelled into the air by the people simply walking on them. Whereas carpet fibres tend to hold the pollutants therefore act as an air filter.

But like any filter, carpets must be cleaned regularly to work properly

The Carpet Institute of Australia’s Indoor Air Quality consumer health information sheet explains the following about carpets and airborne particles: “Carpet also has a beneficial effect by trapping small particles in the fibre mass and removing them from the air we breathe. A recent scientific study found that carpet reduces dust in the air to half of that found with hard flooring systems (German Allergie and Asthma Bund, Media Release 18 June 2005).

“Carpet made in Australia and New Zealand generally meets Australian requirements for indoor air quality including the National Occupational Health and Safety Commission occupational limits and the National Health & Medical Research Council Interim National Indoor Air Quality Goals.”

But like any filter, carpets must be cleaned regularly to work properly. Otherwise, they themselves become a source of contamination. Therefore maintaining and cleaning carpets becomes essential.

Vacuuming is the first stage. Straight suction is good but machines with a beater or brush action are better. The beater/brush is very efficient in releasing dust and dirt from the fibres. This added with the suction to get it into a disposable bag with an efficient air filtering system is ideal.

Many manufacturers fit their machines with high efficiency microfilters. These are placed where the air is being exhausted from the vacuum cleaner. Consider how a vacuum cleaner works – a motor blowing air to create a void that is filled by other air filling that void, and a catcher or dust bag is placed in the way to capture the air and anything it has picked up.

The catcher has to let air pass through it, by so doing it can miss collecting micro-organisms and pollutants so there’s need for additional fine filters.

HEPA – high efficiency particle air – filters are widely used. In Australia we tend to use the HEPA terminology but it is a USA standard. Europe has its own standards. There are grades of HEPA but any grade is better than none. Operating theatres and intensive care units in hospitals have certified HEPA filters to remove pollutants from incoming and exhausted air.

How often should carpets be vacuumed? Considering the amount of foot and trolley traffic in a facility and that the carpet is filtering the air, it should occur daily. The Australian standard AS/NZ3733-1995 is almost 30 years old and is currently being updated but Carpet Institute of Australia’s publication Commercial Carpet Cleaning fact sheet is an excellent guide.

Dry vacuuming is daily maintenance but shampooing on a regular basis is also essential. There are many methods of shampooing carpets. Hot water extraction – also known as steam cleaning though steam is rarely used – dry foam, bonnet cleaning, and many variations of the above.

Aged care facilities have unique problems. Washing carpets can be noisy so must be carried out when residents aren’t sleeping, but wet carpets have their own slip hazards.  

The period between shampooing has many variables. Some facilities have a germicidal tip clean each quarter, or even more frequently if required in high spillage areas, and a full deep clean by hot water extraction annually. Spot cleaning any spills as soon as possible is best practice.

There are methods such as Dry Fusion, where the carpets are pre-sprayed with a germicidal cleaning agent and then a rotary polishing style machine with a heated base plate is used with a premoistened cleaning pad. The chemical reaction between the pre-spray and the moistened heated cleaning pad, means good cleaning with exceptionally quick drying time.

There are combination self-contained hot water extraction machines that have a clean water tank dispersing the shampoo, scrubbing the carpets with a cylindrical brush and vacuuming the residue in the one process. Due to the scrubbing action the carpets are left reasonably dry. With training, in-house staff can carry out this operation as and when required.

Hot water extraction units can be truck mounted so that the only thing entering the facility is the hoses and operating wand. This means that all the noise is outside and the recovered water is filtered and dumped into a drain. Large areas can be cleaned quickly. The only negative is that an access point must be available for the hoses which can jeopardise security.

Carpets don’t last forever and should have a replacement program, seven to 10 years is not unrealistic, but in heavy traffic areas that require very frequent shampooing, it can be considerably less.

Qualified carpet cleaners can assist with a maintenance program that will ensure the full life of this important commodity – which must be appreciated for its additional benefits to the workplace environment.

John Taylor is an expert advisor to the cleaning industry with international acknowledgements in training and techniques whose primary focus is on consultancy to the health and aged care sectors

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