A first person account of how the humble air filter is often given the short shrift.

"Higher the efficiency, lower the longevity" With this key-phrase in mind, I went out to promote my company about a year ago. Usually any person begins from his native place, gains experience amongst his own people, and then sets out to win the world. But with a factory in West Bengal, and with an immensely ambitious nature, I began my marketing career in Orissa, Andhra Pradesh, Uttar Pradesh, Jharkhand, Haryana and Delhi NCR followed closely, and then finally I did a bit of marketing in Bengal as well. A one-year work experience may seem to be a pretty short time, but the amount of knowledge I have gathered by virtue of extensive touring is worth a life-time.

Air filter is perhaps one of the most neglected industries in India. Only because it is mentioned in the patent drawings and manuals that people are actually using air filters; or so I felt after conversations with numerous people. Otherwise they would have let their ACVS (Air Conditioning and Ventilation System) or AHUs (Air Handling Units) run without filters at all. Power plants, fertilizer plants and steel plants still try to maintain the standards a bit, though at many places, they also do not have proper arrangements to check their filters and have these replaced periodically, as per the norms. The rule, as per ASHRAE standards, is that a filter needs to be cleaned when the pressure drop goes up to three times its initial pressure drop in clean condition. But hardly a handful of people are aware of this fact.

To check this, pressure tappings and pressure gauges are the necessity. Another important thing I have noticed is that in most cases, the end-user is not at all aware of how to clean a particular type of filter. Media is the primary component of a filter. Whether the filter is to be cleaned by pulse air jets, or washed by water is totally dependent on the type of media used by the manufacturer. HDPE, for example is water washable, whereas water is a strict no-no for filters using felt as media.

Hospitals and shopping malls are perhaps the graveyard for filters, as well as filter manufacturers. I have seen certain places where the filter frame is there, the media, which used to be felt, has been totally washed away, and the AHU thus stands naked. They are constantly complaining to the AHU manufacturers about the system not working properly, but hardly do they ever think how dangerous a part dust plays in corroding the sophisticated, yet fragile AHU.

When I gave these particulars to the concerned people and a proper sample HDPE filter for testing, they complained after a few days. And what was the complaint? "Sir, the cleaning cycle is increasing as we can already see that the filter is getting dark. It is catching quite a lot of dust, we don't want such high efficiency."

I asked them if the AHU was getting choked or something; because I feared I may have got the flow calculation wrong. But everything was working fine. It was just that they wanted air filters just for the sake of fulfilling a condition, not for its actual usage. It is my earnest request to these humongous units and small industries alike - please try to understand the worth of air filters. Wherever there is an air intake or circulation system, please provide proper air filters in good working state. They are not at all a costly affair, but can save and increase longevity of other costlier components.

Cleaning of filters is not at all a tedious job, but just confirm from your manufacturer what type of cleaning should be carried out. If your filter is getting choked even in clean condition, it is usually because the total surface area of the media provided is insufficient to take in the amount of air. Increase the number of filters, or increase the number of folds of media in each filter. With rise in air pollution, air filters are the cheapest solution to let your industry breathe clean air.

I haven't been in the industry very long, having entered recently. I am only learning from seniors with whom I interact during my business tours. I have no intention of challenging or disrespecting any person or industry, as am myself a part of it. But as a newcomer, and future businessman, I have one, and only one motive - to see Indian industries at par with foreign standards. Hence, I just thought of sharing a few experiences that this young learning mind has gained.

(Akash Chatterjee is Partner, Filtech (India), Kolkata. He may be reached on mobile at 098307-47718, or email: akki440@yahoo.com)