Protecting plant from aircraft exhaust particles

[FishCustard]

Yep, it's a weird one!

 

Nothing to do with IT, but I though perhaps someone might have some useful knowledge to help our Facilities team.

 

We have a large number of air handling units on our roof (fancy new building, all air managed, etc.). Unfortunately we're right under one of the Heathrow landing flightpaths, and so their filters get dirty very quickly with aircraft exhaust particulate and unburnt fuel.

 

Apart from just changing the filters more regularly (which we are doing), is there anything we could put around them or on their intakes to limit the particulate load? Has any other school in a similar situation solved this problem and would be willing to explain?

[robyholmes]

Covers over the top of the intakes so anything falling straight down is caught and ideally washes away from the intakes by rain water? Otherwise you just going to put more filters on which need cleaning/changing. Admittingly larger filters will last longer.

[FishCustard]

Covers over the top of the intakes so anything falling straight down is caught and ideally washes away from the intakes by rain water? Otherwise you just going to put more filters on which need cleaning/changing. Admittingly larger filters will last longer.

 

We have angled intakes, but I fear the angle isn't acute enough to prevent ingestion of particles. I did suggest some ducting to take air from next to the side of the building - it's one of the solutions on the list.

 

Unfortunately the filters are internal and so can't be upsized - they need to fit in the cavity.

[robyholmes]

We have angled intakes, but I fear the angle isn't acute enough to prevent ingestion of particles. I did suggest some ducting to take air from next to the side of the building - it's one of the solutions on the list.

 

Unfortunately the filters are internal and so can't be upsized - they need to fit in the cavity.

 

Covered area on the roof over the intakes? New summer months IT office?

[FishCustard]

Covered area on the roof over the intakes? New summer months IT office?

 

Hahaha maybe! A covered area is what we were thinking, yes, anything to limit the influx. Thanks!

[bald_pig]

In theory, all you would need is an open box over the intake, with the opening area that air can flow through being at least the area of the intake, if that makes sense?

[FishCustard]

You'd want it to be a bit larger than the intake to account for losses caused by turbulent flow, but yes, it does make sense. I've been tempted to make something like that and try it out for a month or so for comparison. Might need planning consent though - would need to check.

[bald_pig]

You'd want it to be a bit larger than the intake to account for losses caused by turbulent flow, but yes, it does make sense. I've been tempted to make something like that and try it out for a month or so for comparison. Might need planning consent though - would need to check.

 

How big are we talking here?!?

[FishCustard]

The largest AHU we have is about 5 m x 1 m x 20 m. Huuuuge beasts. Apparently you also may need special consent for stuff under a flightpath (distractions, etc - even if the same colour as everything else!).