This is a smaller out building not the main hosp. Not a steril environment. No surgeries or anything in this bldg. there are other separate units for fresh air.
again if you want to dig into this further get the installation material, mechanical drawings, (if any) and warranty stuff and read through it. but what you will find at the end, they got what they paid for.
If anything the plenum should have been lined with opening on top with a filter rack there to baffle some of the noise. That looks ugly, hard to access filter but I don't think it will affect operation at all. Hopefully that's not how the engineer drew the details then I would hate to see the rest.
It does give you a filter rack with a larger filter (given the angle) and it will reflect some of the insertion noise from the unit ( vs if the filter was right on the end of the unit.
This will not win any sheet metal craftsmenship awards but no technical rules broken as far as I see
You have got to learn from other people's mistakes! Because God knows you don't live long enough to make them all yourself !!!!!!!!
Daikins are odd sizes to get filters for. The usual setups we are used to don't work. The company I work for has been installing these for a few years. Many growing pains involved. Filter bases and sizes included. I think the systems are great tho. Adapt or disappear.
Since this is a hospital, CYA, once you sign off, could leave you open for a lawsuit. Daikin vrv's r decent equipment, but that would suggest to me that their is adesign problem. Simple as the wrong type box, mounted in that location. Do yourself a favor and ring it up to your boss.
I can't tell by the pics but is that a ducted return. If so the holes make the sub ceiling a plenum. Depending on size of the sub ceiling there might be a fire code problem.
Reasons for poking holes in returns..Not enough RA. Access to filter, coil, drain pan.
By the work it looked like someone was in a hurry and wanted a quick fix.
From the pics it looks to me that the sealed duct coming into the left side of the return air plenum is you make up air. I believe Diakin requires it to be already conditionded by another unit. It also looks like it is a plenum ceiling return system like some other guys mentioned. Make sure you have return grills in the drop ceiling. And as already mentioned if it is plenum return everything in the drop ceiling has to be rated for it to be code. I know those little AHUs do not produce much static also and duct work can be an issue. As for the filter replacement the service guy is never thought of. It would would cost more money to install to make it properly servicable.