B Surendar

For quite some time now, extract ducts in car parks have come in for attention from some quarters. There is a school of thought that believes extract ducts take up space, increase fan pressure and tend to conflict with such services as lighting and pipework. Taking cognisance of these, there has been a firm push towards jet fan ventilation, which, according to its proponents, offers such benefits as reduction in fan pressure, SFP, sound and cost; an increase in parking space; and the avoidance of ducting, which in turn, means avoidance of cleaning or maintenance. And there is no obstruction of other services.

Further, the proponents of jet fan systems say, a ducted system, with the extract at high and low levels, will extract hot smoke only at high-level extract point, thus reducing the smoke extract from the area; on the other hand, a jet fan system operates at high level and induces hot smoke towards the extract point.

There are equally strident claims coming from the duct school of thought, making for a rather interesting churn.

There’s a bigger churn, though, in which the entire ventilation industry has joined forces to allege that ventilation, as an aspect, is not getting its due importance and that, it is often treated as a part of cooling and is, thereby, marginalised. “That is how it ought to be, though,” argue several consultants, considering that we live in a region where there is a need to condition the air, keeping in mind not only high-ambient conditions but also dust and humidity. The ventilation folk, though, say that it has reasons to stand on its own, with car park ventilation being a case-in point. “It is as specialised as can be,” they contend.

We treat car park ventilation – and healthcare-related ventilation – as areas that require specialised expertise. Much in the same way, we have been focusing on air filtration and going into the micro details. This issue carries Part 7 of our ongoing campaign on air filtration. We hope you are finding it useful. We would love to hear from you what else you want us to cover within the subject. Do send us your feedback to surendar@cpi-industry.com; we will respond to your observations.

– B Surendar