German filter specialist Freudenberg has introduced a number of innovations in response to the recently published VDI Guidelines 6022 governing the hygiene requirements for installing HVAC systems in industrial environments. Part 3 was published last November and specifies the filter classes needed for a range of manufacturing facilities, including foodstuffs, tobacco, pharmaceuticals, automotive and metalworking. Among other requirements, it is specified that the entire HVAC system must be made from materials that neither emit substances that are hazardous to health nor constitute a breeding ground for micro-organisms. According to the guidelines, filter frames made from wood or MDF are no longer suitable for use in manufacturing facilities as they are capable of sustaining microbiological growth. For this reason, Freudenberg has introduced alternative plastic constructions for frames and grids. On show for the first time was the MaxiLight Class H 13 HEPA filter for sterile air. With a frame depth of 292mm and a 280mm pleat depth, the MaxiLight features a new plastic frame made from halogen-free ABS that is 40% lighter than wood, distortion- and moisture-resistant, prevents growth of bacteria and moulds, and can be incinerated. The new frame has been in development for more than two years and is cheaper than either its stainless steel or aluminium equivalents, says Freudenberg. It is suitable for use in hospital environments, as well as for biotechnology, pharmaceutical and food manufacturing facilities. There is also a special polycarbonate protection grid available. Its main advantage is a tube-shaped opening that allows a straighter air flow for applications where laminarity is important.