RACA Journal I April 2026 www. refrigerationandaircon. co. za 23
VENTILATION AND FILTRATION
Supplied by Multi-Wing
BYPASS AIR: A SMALL GAP WITH BIG CONSEQUENCES Another key topic addressed in a paper that Owen co-authored is bypass air, or air that leaks around the filter instead of passing
through it. Even small gaps between the filter and its housing can significantly reduce filtration effectiveness.
“ This issue becomes more pronounced as filter efficiency increases. Higher-efficiency filters, such as HEPA or high- MERV filters, create greater resistance to airflow. As resistance increases, air naturally seeks the path of least resistance, which often means flowing around the filter rather than through it if any bypass paths exist. Proper filter installation and sealing are therefore just as important as selecting the right filter.
Multi-Wing impellers used in an adiabatic cooler.“ ASHRAE Standard 52.2 provides the MERV rating system, which is widely used to compare filter efficiency. While higher MERV ratings generally mean better particle removal, selecting the highest possible MERV is not always the best solution,” she says.
Higher-efficiency filters can increase pressure drop, reduce airflow and raise energy consumption if the HVAC system is not designed to accommodate them. In some cases, upgrading a filter without evaluating system capability can lead to unintended consequences that negatively affect building performance.
Filtration can seem either overly simplistic or unnecessarily mysterious. Some assume that simply installing a filter – loosely or otherwise – is sufficient. Others are confused by why small leaks matter, why HEPA filters behave differently from lowerefficiency filters, or why energy and airflow considerations are so closely tied to filtration choices.
By understanding how filters actually capture particles, why installation details matter and how efficiency choices affect overall system performance, readers can move beyond guesswork and toward effective, evidence-based IAQ solutions.
MULTI-WING SOUTH AFRICA: CUSTOM FAN SOLUTIONS POWERING THE INDUSTRIAL COOLING SECTOR
By Eamonn Ryan
Rooted in decades of industrial fan expertise, Multi-Wing South Africa has evolved from a local distributor into a regional innovator.
Under the leadership of father-son duo Clinton and Kevin
Jones, the company blends modular Danish design with local precision manufacturing to deliver high-performance axial fans purpose built for harsh environments. With plans to expand its distribution network across southern Africa, Multi- Wing continues to strengthen its reputation for engineering excellence, reliability and service in the industrial cooling and HVAC & R sectors.
Kevin Jones explains:“ With 40 years of experience in the industrial fan sector my late grandfather, Marthin Naudé, established the Fan-Masters group in Cape Town in 1996 to meet the growing demand for high-performance custom ventilation solutions in the region. In 2001, the head office moved to Johannesburg to improve service delivery within the industrial hub of Africa, allowing for more direct engagement with key clients in the industrial cooling sector. In 2008 we officially rebranded as Multi-Wing South Africa to strengthen the presence of Multi-Wing across the region, further establishing the brand as a leader in custom fan solutions for demanding industrial applications. The group has recently marked its 30th anniversary.”
While Fan-Masters Cape Town continues to service the greater Western Cape, Multi-Wing South Africa has built partnerships with several distributors in Johannesburg to extend its reach. The company’ s engineered axial fans are designed to meet a broad range of performance requirements.
Manufacturing axial fan used for transformer cooling.
Supplied by Multi-Wing feature
RACA Journal I April 2026 www. refrigerationandaircon. co. za 23