Improving indoor air quality (IAQ) has been a major focus in manufacturing, industrial, and other commercial environments for decades, given that poor IAQ can not only cause immediate deleterious effects but can also lead to long-term damage.
Then, COVID-19 entered the picture, and it became increasingly important to analyze the filtration systems in commercial HVAC units to gauge their effectiveness in reducing the spread of the virus.
Understanding the MERV rating system is important because not all filters are created equal when it comes to capturing airborne particles. See figure 1.1.
Not all particles are the same in type. Even within the two categories of aerosol – solid and liquid – and compounds, there are specific differences. Solids include coarse, fine, and ultrafine as well as nanoparticles (the same as ultrafine) and bioaerosols (airborne biological materials). Liquid particles include fogs and mists, while compound particles include smoke, smog, and environmental tobacco smoke.
MERV (Minimum Efficiency Reporting Value) rates the fraction of particles removed from the air passing through a filter under standard conditions – i.e., filter efficiency. MERV ratings range from 1 to 16. The higher the MERV number, the higher the efficiency of that rated filter. A filter capable of capturing very small particles (5 μm or smaller) will help reduce the risk of spread of infectious aerosols that can otherwise remain airborne for an indefinite period of time. See figure 1.2.
It’s also important to note that several factors affect the overall effectiveness of reducing particle concentrations, including the filter efficiency, airflow rate through the filter, the size of the particles, and the location of the filter in the HVAC system or room air cleaner.
Improving indoor air quality by installing higher-rated MERV air filters has documented physical advantages but the equipment in the work environment benefits as well. When HVAC systems are equipped with MERV 13-16 rated filters, more contaminants are removed from the air, reducing the number of particles that settle within the equipment, potentially damaging their components or degrading their performance.
The reduction of airborne particles through the installation of higher MERV-rated air filters combined with a regular HVAC maintenance schedule will ensure the air quality of the environment and the operational performance of the air handling equipment remain at an optimal level.
Parker HVAC Filtration recently introduced its Clean-Pak® extended surface synthetic bag filter – the first MERV 16 rated bag filter in the market – that can trap air particle sizes .3 to 1.0 microns.
In the past, hospital inpatient care, healthcare facilities, microelectronics manufacturing, and other commercial clients who required this level of particulate reduction had to install sub-HEPA or HEPA/ULPA air filters into their system. Clean-Pak MERV 16 bag filters are a sub-HEPA alternative.
Clean-Pak filters are designed with microfine synthetic media that is unaffected by moisture or humidity and provides maximum dust holding capacity. Other features include a rugged construction that reduces filter damage during transport and installation, sonically-welded filter pockets creating high strength and maintaining pocket integrity when in operation, and fabric ribbon separators sonically-welded inside the pockets to create aerodynamic channels for smooth air flow and low resistance.
Since the Clean-Pak synthetic bag filter is available in a variety of filter dimensions and pocket quantities, it easily replaces lower MERV rated filters while providing greater filtering results. Always check with a professional contractor or the system manufacturer when upgrading a filter since high-efficiency filters can affect the performance of an HVAC system.
This article was contributed by the HVAC Filtration Team.