Correct Placement of HEPA Filters in Baghouse Ventilation System

Where is the HEPA filter in your industrial baghouse ventilation system located? Before or after the fan?

In this Tip of the Month Video, IAC Process Engineer Luis Castano explains how, as filtered air leaves the baghouse, proper HEPA filter placement is critical to optimal performance of downstream processing systems and prevention of possible contaminated air leaks.

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Video transcript:  

Hi, my name is Luis Castano with IAC’s Tip of the Month. In the last couple months, we’ve discussed the HEPA filters in a baghouse ventilation system in other tip-of-the-month videos. HEPA filters are high efficiency filters, and they’re made to handle the possibility of leakage in a regular baghouse, which should have PTFE membrane filters. But in the case of a torn filter bag, we’re going to get dust out of this baghouse which is unacceptable when you’re dealing with certain types of dust.

We use a HEPA filter, and we’ve discussed the importance of differential pressure, but per my drawing we have the HEPA filter before the fan, which is really the way it should be. There are many systems that have the HEPA filter afterwards, and we just want to make it clear that before is a better option.

Why is having the HEPA filter before the fan a better option? Because in case of a problem, the HEPA filter will handle any dust leakage from the baghouse before reaching the fan. If we put the HEPA filter after the fan, any leakage will go through the fan and be captured in the HEPA filter, possibly causing damage in the fan, and also making the HEPA filter operate at a positive pressure.

That can be a big problem because if you have any air leak on the HEPA filter housing then you have air blowing out, possibly contaminated, defeating the purpose of the HEPA filter. So, keep that in mind if you’re going to install a new project with the use of HEPA filters after a baghouse. Those HEPA filters go before the fan as a general recommendation.

If you want to discuss this in more detail, please contact one of our engineers and we’ll be happy to help.

If planned maintenance at your industrial facility includes dust collection equipment such as baghouses, cyclones, cartridge collectors, or bin vents and ventilation systems, contact IAC and ask about our Baghouse and Ventilation System Maintenance Training Seminars.

For a very reasonable cost, Luis Castano, or one of our other highly trained system experts, will provide hands-on training at your facility with presentation materials customized for your process systems and your plant's equipment, regardless of original manufacturer.


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