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United Airlines Makes Changes To Air Filtration System As Travelers Grow Comfortable With Flying Again
One year after the COVID-19 pandemic brought the airline industry to a screeching halt, some have said flying has never been so clean. Though Denver International Airport is still operating at a drastically reduced capacity compared to pre-pandemic numbers, United Airlines said they’re slowly but surely returning as time continues. Matt Miller, Vice President of the United Airlines hub in Denver, said United is currently operating at around 50% regular capacity. That number continues to rise as… (www.msn.com) Plus d'info...Sort type: [Top] [Newest]
This seems like old news. Speaking of old news I flew on a United flight in the 60’s that gave you a small pack of cigarettes with their meal service. They even had United’s logo on it. TWA did the same thing. I still have both packs. I’m not allowed to smoke.
In 1988, President Ronald Reagan signed a law making smoking illegal on all domestic flights of two hours or less...
I just want to know how often the HEPA filters are changed. Every article I've read up to now never mentions it!
HEPA filters don't need to be changed very often. Unless damaged, nothing gets through them, no matter how long they have been in service. In fact, HEPA filters get more effective at removing particulate from the air the longer they are in service. HEPA filter lifetimes are determined by the pressure differential across the filter. As the filter traps particulate, the pressure across the filter rises and/or the air flow through the filter drops. In clean environments (like semiconductor clean rooms) HEPA filters are rarely replaced. In many environments, air is passed through a pre-filter (much like the one in home heating-A/C units) that prevents the larger particles (dust, lint, dirt) from even getting to the HEPA filter, in order to lengthen its lifetime.
Regardless of how they work, or what the mechanism for determining replacement is, the question evolves into something like, "are they replaced often enough so that the filters in place are always effective" etc.
For instance, you wouldn't want the same filters in place for 100 yrs. What is the length of time - at the air pressure differentials utilized in this implementation - that these filters are effective considering the fact the fact that they are indeed getting clogged up constantly with various particles.
Are they effective for 3mo? 6mo? 1yr? And whatever that timeline per the pressures being used and the clog-rate being experienced sufficient to know that they are still working as intended to filter the air per HEPA definitions etc.
For instance, you wouldn't want the same filters in place for 100 yrs. What is the length of time - at the air pressure differentials utilized in this implementation - that these filters are effective considering the fact the fact that they are indeed getting clogged up constantly with various particles.
Are they effective for 3mo? 6mo? 1yr? And whatever that timeline per the pressures being used and the clog-rate being experienced sufficient to know that they are still working as intended to filter the air per HEPA definitions etc.
Effective really means more than just the property of removing particulate from the air. It includes providing for a reasonable pressure drop, which directly influences the airflow. Unless damaged physically, HEPA filters 'fail to be effective' when the pressure drop rises to the point of compromising airflow. Effectiveness is reliant upon the amount of particulate reaches the filter (air volumes treated x particulate density). I am not familiar with airliner filtration systems, but in semiconductor manufacturing cleanroom HEPA filtering systems, pre-filters were installed (and routinely changed), and they are effective at removing a very large percentage of particulate mass that would fill the HEPA filter. Pre-filtering rendered the required change intervals to be pressure differential triggered, not time triggered.
The question remains, in these implementations, how long on average is a HEPA filter effective and at what interval should they be replaced -> are they being replaced at those intervals? This is the question people are asking.