By Eamonn Ryan

The collapse of some major utilities in South Africa has worsened outdoor air quality as businesses and individuals run diesel generators 16 hours a day for power and ever more freight uses roads instead of rail. Outdoor air quality soon affects indoor air quality.

A portable welding / grinding dust collector.

A portable welding / grinding dust collector. Image credit: ALPA

Michael Jackson (1958-2009) had such confidence in high-efficiency particulate air (HEPA) filters, he used to claim he would live 100 years because the air in his whole house was supplied through HEPA filters. His untimely death had nothing to do with the quality of air he breathed.

Since Covid-19, many more companies and individuals are concerned about their indoor air quality.

There is a growing need for fans and filters that can improve air quality by removing airborne particles, such as viruses, bacteria and allergens. This has led to an increased demand for HEPA filters, ultraviolet germicidal irradiation (UVGI) systems and other air purification technologies.

At the same time, fans and filters can consume a significant amount of energy, which can impact the overall energy efficiency of HVAC systems. There is a growing need for fans and filters that are designed to operate at higher efficiencies, such as variable-speed fans and low-pressure-drop filters.

Many filters are made from materials that are not environmentally friendly. There is increasing demand for systems that are made from sustainable materials, such as recycled plastics or biodegradable materials, or where possible that can be easily recycled at the end of their lifespan. At a minimum, they need to not end up in landfill.

Fans and filters require regular maintenance and replacement to operate effectively. The biggest weakness is that this rarely occurs, and so the R&D drive is for filters designed for easy maintenance and replacement, such as filter cartridges that can be quickly replaced.

As design of HVAC and refrigeration systems becomes more complex, there is a need for filtration that can be integrated seamlessly into these systems. This includes design for specific applications, such as cleanrooms or hospitals, pharmaceutical manufacturers and storerooms.

Natalia Coetzee, ALPA sales representative (left) and Shaun Little, ALPA sales specialist (right).

Natalia Coetzee, ALPA sales representative (left) and Shaun Little, ALPA sales specialist (right). Image credit: © Eamonn Ryan | RACA Journal

Keeping people, processes and product safe

The principle behind ventilation is to provide clean air inside a building by diluting harmful particles originating from the building while simultaneously removing harmful particles from within the building. Due to different types of combustion processes and diesel exhaust gases the outdoor air is alarmingly polluted. Therefore, various stages of filtration are imperative in order to ensure clean air quality. It goes without saying that if outdoor air quality is compromised and filtrated into a building, inside air quality will also be compromised and could result in health issues at a later stage.

Indoor Air Quality (IAQ) in commercial buildings is often overlooked, but this could reduce the number of sick days employees take annually and increase our productivity in the workplace. This can be achieved with primary, secondary and tertiary filtration stages and in some cases even carbon filters are required. Certain filters can only filter out particulate. This is when carbon filters are introduced to take care of certain gasses and volatile organic compounds in the air.

Shaun Little, sales specialist at ALPA explains that there are many applications that call for HEPA level filtration, such as surgical theatres, clean rooms, pharmaceutical manufacturing and even data centres. These industries require a high level of clean air that are laid out in the ISO 14644 standards. These regulations are in place to keep us as humans safe as well as the process of keeping product clean and free of contaminant.

He notes that large banks have also become extremely stringent on their air quality in the last few years, but many other industries like retail shopping malls and health clubs rarely install anything more than the most basic air handling systems.

“We always strive to educate all sectors and industries about the health risks present and of the best long-term solutions.”

“We focus on three major particle sizes: one micron, 2.5 micron and 10 micron. One’s nose and throat can take care of a 10 micron; 2.5 reaches your lungs; harmful bacteria is of one micron or less which enters your lungs and is absorbed into your bloodstream. That’s how people get respiratory infection. Healthcare facilities will want to protect against one micron or less particles, but for offices the major concern is 2.5 to 10 microns,” says Little.

Natalia Coetzee, sales representative at ALPA, attributes the common ‘sick building syndrome’ to poor air conditioning in which the air is simply circulated and minimal clean, fresh air is introduced from outside. “When one person sneezes that infected air gets actively circulated throughout the building to all other occupants.”

One-micron and less particulate is bad for the human body which it has little to no protection against. They enter our bodies through the respiratory system and into the blood stream and are the cause of mild to deadly diseases from heart attacks to cancer, according to research by Camfil, which is a product distributed by ALPA.

The reference papers listed at the end find that air pollution is:

  • Responsible for 5.5 premature deaths around the world every year
  • Camfil IAQ handbook
  • The fourth highest risk factor for death globally
  • Carcinogenic

One-micron and less particles account for about 90% of all particulate matter in outdoor air and the smaller the particle is the longer it can stay in the air, travelling potentially hundreds of kilometres.

“The more you increase your fresh air supply, which is from outside and filter it into the building, the more expensive that is as a means of air handling. The more affordable solution is to bring in between 10-20% fresh air (as an example) and recirculate the remaining air appropriately.

“We have standalone and in-line units available for air purification. The Camfil City M is a great example: quiet and stylish, it is capable of covering 75m2 with a double H14 HEPA filter as well as its carbon filter to take care of particulate and those unwanted odours,” says Little.

While filters are rarely recyclable because of their bacteria-catching function, Little says their products at least never need go to landfill as they are entirely incinerable – and should be incinerated or appropriately disposed of as per application guidelines. “There are incentives for filters to go greener, which we achieve with our zero-landfill mindset.

Rean Van Wyk, director (left) and Carel van Wyk, project manager, of Lab Craft.

Rean Van Wyk, director (left) and Carel van Wyk, project manager, of Lab Craft. Image credit: © Eamonn Ryan | RACA Journal

Lifecycle cost analysis ‘a hard sell’

On many products, and particularly in the case of Camfil’s, says Little, the filter is in an easy to pull out panel that anyone could do. He notes, however, that companies rarely do so and so the company offers maintenance contracts with service level agreement which includes disposing of the filter.

“Customers typically don’t want to either climb into an AHU or employ labour to do so. What typically happens is that someone washes it down, which in labour, water and fan energy is even more expensive over the life of a filter than replacement. Over the years, Camfil has re-engineered filters that last twice as long without compromising efficiency.”

Coetzee explains that filters of mediocre quality and an initial high-pressure drop can exert unnecessary pressure on the fan which in turn causes the fan to work harder and increase energy consumption. “Our filters are proven to offer a lower pressure drop there by allowing the pressure to build up gradually and therefore decreasing costs. On average an AHU consumes between 50-70% of a building’s running cost, which could include filters, labour, maintenance or just the general running of the system. Further to these factors, washing a filter could degrade the integrity and efficiency,” she adds.

Little says, “We have the software to give any industry a current overview of their expenditure when it comes to AHUs and can offer a cost saving alternative before the customer commits to even buying our product.” Unfortunately, in the South African market, for consultants to win a tender they have to be cheaper than their competitors while trying to adhere to the specifications.

Camfil reference papers:

  • Research led by the University of British Columbia, published in 2016
  • Professor Michael Brauer, University of British Columbia
  • Professor Kan Haidong, School of Public Health at Fudan University, Shanghai
  • Professor Yang Xin, Department of Environmental Affairs, Fudan University, Shanghai
“Some clients do insist on the correct filter and is willing to pay a bit extra so as not to have any comebacks and knowing it will last them much longer than the cheapest.”

“Some clients do insist on the correct filter and is willing to pay a bit extra so as not to have any comebacks and knowing it will last them much longer than the cheapest.” Image credit: © Eamonn Ryan | RACA Journal

Concern at lack of maintenance

Air-Box is the African representative of The Ulpatek brand of Turkey, which Rean Van Wyk, director of Lab Craft, describes as having a considerable focus on research and development (R&D) to manufacture filters that are ever more efficient and thus use less energy in the HVAC design.

“However, our biggest concern within the market is lack of maintenance of filters, even in such a vital place as a hospital. In some there are not even primary filters, and in others they don’t change the filters on a regular basis. Even in some pharmaceutical companies the maintenance is terrible, with mold in the ducting because they don’t frequently change the filters and clean the AHU (Air Handling Unit). We’ve seen in one manufacturing plant where the extraction system was placed inside the plant, that all filters were saturated with oil, requiring people to wear masks to breathe through an oily air one could scarcely see through. Less visible was that all the electrical components were breaking down due to the oil and dust throughout the environment. They got to that point after ignoring our advice to replace their filters and have a more rigorous maintenance plan in place,” says Van Wyk.

“The problem is mostly budget, but also poor knowledge of the maintenance regime required,” says Carel van Wyk, Lab Craft project manager. “On the one hand there’s the person who wants the cheapest filter knowing it may only last a short while due to the low quality of the filter media, and on the other, one who insists on the correct filter and is willing to pay a bit extra so as not to have any comebacks and knowing it will last them much longer than the cheapest.”

Carel van Wyk adds, “The lack of knowledge in the filtration industry stems from the fact there’s no ready way I know of in South Africa to study filtration – you have to do an engineering degree and within the degree a module of which may be on broader HVAC. Filtration is a specialised field and there’s no advanced filtration course or study material. The only way to gain knowledge is through experience. Many engineers approach us for advice or specifications on the design of the HVAC system within their projects.”

The first step in designing a system, spells out Rean van Wyk, is the URS (user requirement specification), covering what the client is working with: ice, antibiotics, vaccines, baby powder, packaged food and whatever chemicals they use. Next is the SOP (Standard Operating Procedure), a guide for establishing appropriate housekeeping procedures essential for the overall contamination control programme of the facility. Within each industry they normally have a specification as to how clean the facility must be, varying from sector to sector.

“It comes down not just to the correct filtration, but also the correct amount of air changes within that classified facility and the distribution of the air diffusers in the right places to get the correct ISO standard,” says Rean van Wyk.

“The impact of clean air is tremendous: for example, we’ve had reports from a chicken farmer as to how much quicker their chickens grew after installing HEPA filters in the supply air to the chickens.

“If it’s a storage facility for, say, raw materials, one has to look at what is the raw material: sealed, corrosive or non-corrosive, if in the cold chain does it have to be temperature- and humidity-controlled? From that one can determine the correct filters as they form part of the broader HVAC system.

“If it’s a facility where there’s fumes or odours from production, the air needs to be extracted – but while extracting, you need to provide fresh air from somewhere, and that needs a filter to keep out external dust and particles that can cause contamination,” says Rean van Wyk.

Carel van Wyk adds, “When simply providing fresh air to a standard office building, the first defense is primary filters (G2 to G4). They are often cheap, washable filters with a rule of thumb being to wash it three to four times and thereafter dispose of. There’s no fixed rule because it entirely depends on the circumstances, including their position in the HVAC system.”

The secondary defence is a pocket or a bag filter, and through the years the technology on these filters has improved considerably – for instance, instead of stitching the fabric it is today welded with what is called sonic fusion.

“It’s a good filter, but what we see in practice is maintenance people trying to clean it by vacuum, which causes damage. In the pharmaceutical or medical sector, these filters are inappropriate and instead a cassette filter should be employed for its very good dust holding capacity and greater longevity.”

The third defence in filtration is the HEPA filter for any microbial growth, viruses or germs. There are also different classifications as to efficiency of the HEPA filter, points out Carel van Wyk. Where filter technology is headed is to manufacture filters on which the pressure drop is lower, thereby requiring a smaller lower-energy fan motor. Fan technology has changed in terms of the fan design to also make the fan more energy efficient, especially the EC fan.

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