Maybe, but maybe not. This drawing doesn't have the information to make that call as It doesn't indicate much, if anything regarding the ceiling construction.
SneakyPete
Nov 10, 23 4:41 pm
The answer is yes. It just is.
proto
Nov 11, 23 11:32 am
what else would you fasten them to if not?
Richard Balkins
Nov 11, 23 2:31 pm
If there is some kind of ceiling framework under the duct that can support the weight of the recessed lights, then yes. If the ceiling structure is only something thin like 1/2" or 3/4" thick strips of wood (not ceiling joists) or wood panel for glued on drywall, you might be facing problem especially if there is no space between the ceiling panels/framing structure and the ducting. Generally, you do not want to be directly attaching or fastening the recessed lights to the duct. Chris-chitect's answer is spot on for your project. We can't directly answer because there is not enough information from the drawings that we can give an answer directly to.
Short answer, it is possible to have recessed lights under ducts but it depends on the extant of space and framing details of the ceiling or ceiling/enclosure around the duct (interior ceiling soffit) that may be lower than the rest of the ceiling in the spaces.
There is more work for you to work on, possibly.
Here's an example on the web. You would likely have to modify the detail to fit the specifics of your project. What it important is the amount of space. Here:
In this example, most likely for a kitchen, there is interior cabinetry. However, without such, the recessed lighting could be centered. However, you have to think about how much the recessed lighting protrudes into the space. In this example, a duct could be running along the ceiling. Likely, a 6-7" diameter duct or 6 to 7 inch deep by maybe an 8 to 10 inch wide duct used.
If your soffit has enough space that the recessed lights and duct doesn't have issues of fitting in the same space. This is where attention to detail matters. Sometimes, you may just offset the lights so it isn't directly beneath the duct and sometimes, you can pitch the angle of the light coming from the recessed lights. They do not have to go straight down in terms of the light. Some lights may have the ability to angle to led or bulb inside and the light projects the concentration of the light off to an angle to say the seats in the sales room. As that may be wear anyone in the room would likely sit to read any of the sales brochures or magazines so you'll want the lighting more focused on those two spots.
It is unclear where you plan to have the lights or any such ceiling soffit.
Your plan above doesn't show any sort of soffit or lighting.
b3tadine[sutures]
Nov 11, 23 8:44 pm
This entire response is nothing short of dumb. I can't even begin to understand what it is you're talking about, every sentence is filled with wrong.
Richard Balkins
Nov 11, 23 9:44 pm
It is clear that you didn't read what I wrote.
Richard Balkins
Nov 11, 23 9:50 pm
To be more clear, the short answer is, it depends on how much space you have between the duct and soffit enclosure around the duct. Do you have enough space to insert the recessed light? That's the "it depends". You're not installing the recessed light in the duct? I don't think I or anyone was suggesting that.
b3tadine[sutures]
Nov 11, 23 9:53 pm
I read it, it's incomprehensible. First, it's not a residence. Second, the first two sentences don't make any sense. What is exterior cabinetry?
b3tadine[sutures]
Nov 11, 23 9:55 pm
The entire last paragraph demonstrates y your complete lack of knowledge.
b3tadine[sutures]
Nov 11, 23 9:56 pm
The lighting is fairly obvious in the drawing provided.
Richard Balkins
Nov 11, 23 10:04 pm
Ok, if that's unclear, I apologize as I was writing that while others were talking and had my attention distracted. I was referring to a ceiling soffit as in interior. On the exterior, the term soffit is also used so lets be clear that I am not talking about under eaves soffits. Yes, it is commercial but you may see soffits used in commercial and assembly use spaces. I have seen it. Nothing new. The detail was just an example. It is for illustrative purposes. In commercial spaces, you may have to modify.
b3tadine[sutures]
Nov 11, 23 10:07 pm
A soffit would not occur in the middle of the space.
Richard Balkins
Nov 11, 23 10:07 pm
I was assuming, such a soffit in the OP's example might be something like this (although not necessarily circular). Soffits are going to be framed very similar to the residential kind. You would use this to hide the unsightly things like PLUMBING pipes like the ones from your bathrooms toilets (for example) or ducts that are not as aesthetically appealing interior.
"Sometimes, you may just offset the lights so it isn't directly beneath the duct and sometimes, you can pitch the angle of the light coming from the recessed lights."
What the fuck does this even mean?
b3tadine[sutures]
Nov 11, 23 10:14 pm
"Generally, you do not want to be directly attaching or fastening the recessed lights to the duct."
Generally?? How about, never.
Richard Balkins
Nov 11, 23 10:18 pm
The soffits could be metal framed as well. Similar point, the soffit framing would be what you may need to tie and support your recessed light so you'll need the framing there to fasten to. It's not that hard to translate the wood framing in the residential soffit to a light metal framing you will often see in the metal framed commercial soffits. My point applies regardless if the framing of the soffit is wood or metal.
Richard Balkins
Nov 11, 23 10:22 pm
""Generally, you do not want to be directly attaching or fastening the recessed lights to the duct."
Generally?? How about, never."
Fair point. I wouldn't ever do such a thing. I am not going to rule out some odd possibility that someone else might do. I was getting the initial impression by another forum user suggesting that so I didn't want to say outright "never". You and I would never directly do that.
b3tadine[sutures]
Nov 11, 23 10:23 pm
Good lord. And to think you'd actually become an architect.
b3tadine[sutures]
Nov 11, 23 10:25 pm
You do understand construction sequencing? Right? In new construction, how do you think recessed lighting is attached?
Richard Balkins
Nov 11, 23 10:33 pm
""Sometimes, you may just offset the lights so it isn't directly beneath the duct and sometimes, you can pitch the angle of the light coming from the recessed lights."
What the fuck does this even mean?"
I was referring to recessed lights that do allow pitching the angle of the light coming from the bulb because it allows that adjustability of the bulb socket (or LED module) inside the recessed light fixture so the concentration and focus of the light would be over where you want it if it isn't directly below. So pitching the light 10-20 degrees from facing straight down may concentrate the light to a seat or table say... 2-3 ft. from directly below the light. I don't know the floor-to-ceiling height or the floor-to-bottom of the duct or its enclosing soffit of this project. I think that would be obvious and understood for the subpoint that was made. Was it that hard to grasp that?
Richard Balkins
Nov 11, 23 10:49 pm
"You do understand construction sequencing? Right? In new construction, how do you think recessed lighting is attached?"
Recessed lighting would be installed to the soffit framing. Therefore, you would have to plan for the recessed light so you have something to attach to. The framing parts have to be closely spaced enough to attach the recessed light fixture to the soffit framing.
Could you attached to the floor frame or ceiling above like you would those drop down ceiling and attachment of those flourescent fixtures? Possible. The duct would likely be in the way.
It would also be a dumb idea to secure the light to only the drywall. If there was OSB or plywood used to box sheath around the soffit framing and then drywall would be installed over, you might use the OSB or plywood for a fairly lightweight recessed light. That again is debating a sub-point out of the biggest point that there has to be physical space for the both the duct and the recessed light.
You have to plan for it. You need to properly coordinate that. The duct would be already installed before the soffit is framed. You won't be installing the duct afterward. We know that.
The recessed lights have installation instructions. So it will have certain assumptions.
Richard Balkins
Nov 11, 23 10:59 pm
Some of the newer recessed lights weigh much less than they used to so you may be able to rely on the drywall being sufficient. It depends on the light, of course.
Richard Balkins
Nov 11, 23 11:03 pm
Here's an example of the more heavier and bulkier recessed light and install video. If it was a soffit you would have soffit framing to attach to like a 2x3 or 2x4. You wouldn't necessarily need the 2x8 or 2x10 floor joist but something to attached the fixture to.:
Richard Balkins
Nov 11, 23 11:05 pm
See the attaching bars. You need framing for those to attach to so the fixture stay up there. You wouldn't want to depend on drywall alone to support that thing.
In some recessed LED lights, you still need to attach the junction box to some framing.
Richard Balkins
Nov 12, 23 12:51 am
"The lighting is fairly obvious in the drawing provided" OK. I think I see what is the lighting symbols represented. Since I didn't recognize the symbols for lights, I wasn't going to assume those were lights. It could be the image resolution but wasn't sure those were meant to be lights or not. My gut say yes but it's a little unfamiliar looking. Ones I usually seen or use would comply with ANSI Y32.9 or neca 100. It could be a brand new symbol by neca 100.
Richard Balkins
Nov 12, 23 1:18 am
Thank you for making me have to explain this in more depth than I wanted to at this point. If those are in fact the proposed lighting location, I would move the duct 12 to 14 inches to direction that is the top to the plans. Just enough so none of those lights have to be beneath the duct. This goes well with "reallynotmyname" suggested below.
Richard Balkins
Nov 12, 23 4:46 pm
Too much debating on this has been spent. So b3tadine, don't waste time responding. Seriously. I'm not needed and I am not responding to this further. The forum doesn't need us bickering to each other nor does it serve the OP.
Brian Benham
Nov 12, 23 7:46 pm
Richard, Thank you for your in-depth explanation and resolve to offer additional information and explanation to your answers.
reallynotmyname
Nov 11, 23 3:22 pm
Seems like moving the duct over 12-14" towards either the top or bottom of your drawing would solve the problem. If the person laying out the ductwork says they can't do it, they are lying.
Richard Balkins
Nov 11, 23 5:26 pm
I would agree with you on the ability to move it 12-14 inches. We do need more info from the OP to best answer the question as it pertains to the project.
gwharton
Nov 13, 23 5:44 pm
This ignores the First Law of Mechanical Engineering, which is "Ducts go where ducts go."
Richard Balkins
Nov 13, 23 6:26 pm
LOL!!!!
pj_heavy
Nov 11, 23 7:10 pm
I would never understand why someone would use their real profile (or is it?) asking this kind of question on online forum. … seriously
reallynotmyname
Nov 11, 23 7:33 pm
Well, lots of the MEP designers I've encountered are a-holes or just too lazy that they would never assist a junior architect with these kinds of questions. I suspect the OP may be dealing with some of that. Above-ceiling coordination is a rich source of errors and the resulting jobsite conundrums in the USA.
chris-chitect
Nov 12, 23 4:42 pm
This is so true! I didn't want to really elaborate as it raises my blood pressure. I had an absolute headache with consultants (I wasn't in the design team) when it came to ceiling plans. On one project the design lead treated the ceiling as something that the contractor would just figure out as they didn't have a clue on how to coordinate the drawings. They merely collected the electrical and mechanical plan and attached them to the architectural set with zero verification or coordination.
We had a light fixture and air supply grille in the exact same ceiling tile, which could have been immediately spotted by just overlaying a plan in autocad. Oddly enough both electrical and mechanical came from the same sub consultant yet the two designers clearly didn't talk to each other in the office.
But the worst was that no one ever thought about the ceiling in section. The design lead had a suspended ceiling tile assembly but only dropped the ceiling 8". The air supply and return had to cross each other yet each duct was 8" in diameter. Then there was to be a massive fan coil in these 8" and an ERV. Some how all of this was to fit in a very shallow ceiling assembly and no one could be bothered to overlay drawings or try out a quick and dirty section to verify.
pj_heavy
Nov 12, 23 6:40 pm
Understand , it's complex even with the well coordinated combined RCP there's always something clashing and misaligned. At the end of the day, we drive the whole aesthetic look within the MEP constraints. If it doesnt comply / it aint happening.
smaarch
Nov 12, 23 8:32 pm
I suspect it's an honest question from a young professional - I''ll always forgive inexperience and those that are inquisitive. We were all there once. Yet I have hard time to even begin to understand where this question comes from. Well actually yes I can. Preliminary design studies and research are there to take into account such basic things as floor to ceiling heights. The answer is Yes if you get the floor to floor right. The Architect takes the lead and coordinates with MEP for initial clashes. And adjusts accordingly. On any project of scale - the contractor then produces their own coordination drawings to resolve clashes. I find this happening less and less as the world goes go BIM/Revit and the Architectural team have less and less knowledge. I've never seen so many errors as I see now. Imagine we did this all on paper with better results..... go figure. Yeah for progress!
smaarch
Nov 13, 23 1:48 am
To the OP: yes you can place recessed lights under ductwork. I apologize for my side way conversation.
BulgarBlogger
Nov 12, 23 10:30 pm
Are these lights being installed in the ceiling below a roof? Do the lights have to be IC-rated? IC-rated fixtures generally have a protective box that exceeds the standard depth of most LED “high-hats”. Beyond that, I can only assume that the lights are LED to meet the max wattage output most current energy codes require; BUT in the off-chance they are not, make sure that the heat the lights emit do not cause melting of any components within the ceiling plenum. I would suggest that if the ceiling is used as a return air plenum (and indeed we just don’t have enough info based on the drawing you posted), this heat does not mix with the returned air in a way that compromises the ventilation temperature expectations.
Wood Guy
Nov 13, 23 9:59 am
It really depends on the space available and the type of fixture. On occasion I have had only 3/4" wood strapping or nothing but drywall below the ductwork, due to space constraints; no fixture I'm aware of will fit in those situations.
I often use LED wafer lights which will fit where there is 1" of clear space behind drywall. They are a tight fit though.
Conventional recessed lights need more depth.
Richard Balkins
Nov 13, 23 3:44 pm
Yes, indeed. Of course in commercial projects, it is more common to see the heavier bulkier LED fixtures used but we are seeing newer, thinner, and lighter LED recessed lights. These are more common in residential projects but sooner or later, those bulky fixtures will be a thing of the past because there is no reason for it to be bulky except for making it unnecessarily more expensive, in my opinion. Conventional recessed lights and recessed LED lights do need more depth. As others have suggested, why not move the main duct, say 12-14" to the top of the plan direction and just add a little more length to the smaller ducts on the one side and remove a little on the smaller ducts on the other side. Once that is done, it's pretty much no longer an issue of lights directly under the duct.
Richard Balkins
Nov 13, 23 3:46 pm
The smaller ducts may need to be adjusted left or right a little bit as well.
Archi-Fartsy
Nov 13, 23 10:05 am
Can you move the duct to eliminate the chance for a conflict?
Can we have recessed lights under duct?
Yes.
Maybe, but maybe not. This drawing doesn't have the information to make that call as It doesn't indicate much, if anything regarding the ceiling construction.
The answer is yes. It just is.
what else would you fasten them to if not?
If there is some kind of ceiling framework under the duct that can support the weight of the recessed lights, then yes. If the ceiling structure is only something thin like 1/2" or 3/4" thick strips of wood (not ceiling joists) or wood panel for glued on drywall, you might be facing problem especially if there is no space between the ceiling panels/framing structure and the ducting. Generally, you do not want to be directly attaching or fastening the recessed lights to the duct. Chris-chitect's answer is spot on for your project. We can't directly answer because there is not enough information from the drawings that we can give an answer directly to.
Short answer, it is possible to have recessed lights under ducts but it depends on the extant of space and framing details of the ceiling or ceiling/enclosure around the duct (interior ceiling soffit) that may be lower than the rest of the ceiling in the spaces.
There is more work for you to work on, possibly.
Here's an example on the web. You would likely have to modify the detail to fit the specifics of your project. What it important is the amount of space. Here:
In this example, most likely for a kitchen, there is interior cabinetry. However, without such, the recessed lighting could be centered. However, you have to think about how much the recessed lighting protrudes into the space. In this example, a duct could be running along the ceiling. Likely, a 6-7" diameter duct or 6 to 7 inch deep by maybe an 8 to 10 inch wide duct used.
If your soffit has enough space that the recessed lights and duct doesn't have issues of fitting in the same space. This is where attention to detail matters. Sometimes, you may just offset the lights so it isn't directly beneath the duct and sometimes, you can pitch the angle of the light coming from the recessed lights. They do not have to go straight down in terms of the light. Some lights may have the ability to angle to led or bulb inside and the light projects the concentration of the light off to an angle to say the seats in the sales room. As that may be wear anyone in the room would likely sit to read any of the sales brochures or magazines so you'll want the lighting more focused on those two spots.
It is unclear where you plan to have the lights or any such ceiling soffit.
Your plan above doesn't show any sort of soffit or lighting.
This entire response is nothing short of dumb. I can't even begin to understand what it is you're talking about, every sentence is filled with wrong.
It is clear that you didn't read what I wrote.
To be more clear, the short answer is, it depends on how much space you have between the duct and soffit enclosure around the duct. Do you have enough space to insert the recessed light? That's the "it depends". You're not installing the recessed light in the duct? I don't think I or anyone was suggesting that.
I read it, it's incomprehensible. First, it's not a residence. Second, the first two sentences don't make any sense. What is exterior cabinetry?
The entire last paragraph demonstrates y your complete lack of knowledge.
The lighting is fairly obvious in the drawing provided.
Ok, if that's unclear, I apologize as I was writing that while others were talking and had my attention distracted. I was referring to a ceiling soffit as in interior. On the exterior, the term soffit is also used so lets be clear that I am not talking about under eaves soffits. Yes, it is commercial but you may see soffits used in commercial and assembly use spaces. I have seen it. Nothing new. The detail was just an example. It is for illustrative purposes. In commercial spaces, you may have to modify.
A soffit would not occur in the middle of the space.
I was assuming, such a soffit in the OP's example might be something like this (although not necessarily circular). Soffits are going to be framed very similar to the residential kind. You would use this to hide the unsightly things like PLUMBING pipes like the ones from your bathrooms toilets (for example) or ducts that are not as aesthetically appealing interior.
Another example:
http://www.scf-arch.com/wp-content/uploads/2017/02/IMG_3316-500x375.jpg
"Sometimes, you may just offset the lights so it isn't directly beneath the duct and sometimes, you can pitch the angle of the light coming from the recessed lights."
What the fuck does this even mean?
"Generally, you do not want to be directly attaching or fastening the recessed lights to the duct."
Generally?? How about, never.
The soffits could be metal framed as well. Similar point, the soffit framing would be what you may need to tie and support your recessed light so you'll need the framing there to fasten to. It's not that hard to translate the wood framing in the residential soffit to a light metal framing you will often see in the metal framed commercial soffits. My point applies regardless if the framing of the soffit is wood or metal.
""Generally, you do not want to be directly attaching or fastening the recessed lights to the duct."
Generally?? How about, never."
Fair point. I wouldn't ever do such a thing. I am not going to rule out some odd possibility that someone else might do. I was getting the initial impression by another forum user suggesting that so I didn't want to say outright "never". You and I would never directly do that.
Good lord. And to think you'd actually become an architect.
You do understand construction sequencing? Right? In new construction, how do you think recessed lighting is attached?
""Sometimes, you may just offset the lights so it isn't directly beneath the duct and sometimes, you can pitch the angle of the light coming from the recessed lights."
What the fuck does this even mean?"
I was referring to recessed lights that do allow pitching the angle of the light coming from the bulb because it allows that adjustability of the bulb socket (or LED module) inside the recessed light fixture so the concentration and focus of the light would be over where you want it if it isn't directly below. So pitching the light 10-20 degrees from facing straight down may concentrate the light to a seat or table say... 2-3 ft. from directly below the light. I don't know the floor-to-ceiling height or the floor-to-bottom of the duct or its enclosing soffit of this project. I think that would be obvious and understood for the subpoint that was made. Was it that hard to grasp that?
"You do understand construction sequencing? Right? In new construction, how do you think recessed lighting is attached?"
Recessed lighting would be installed to the soffit framing. Therefore, you would have to plan for the recessed light so you have something to attach to. The framing parts have to be closely spaced enough to attach the recessed light fixture to the soffit framing.
Could you attached to the floor frame or ceiling above like you would those drop down ceiling and attachment of those flourescent fixtures? Possible. The duct would likely be in the way.
It would also be a dumb idea to secure the light to only the drywall. If there was OSB or plywood used to box sheath around the soffit framing and then drywall would be installed over, you might use the OSB or plywood for a fairly lightweight recessed light. That again is debating a sub-point out of the biggest point that there has to be physical space for the both the duct and the recessed light.
You have to plan for it. You need to properly coordinate that. The duct would be already installed before the soffit is framed. You won't be installing the duct afterward. We know that.
The recessed lights have installation instructions. So it will have certain assumptions.
Some of the newer recessed lights weigh much less than they used to so you may be able to rely on the drywall being sufficient. It depends on the light, of course.
Here's an example of the more heavier and bulkier recessed light and install video. If it was a soffit you would have soffit framing to attach to like a 2x3 or 2x4. You wouldn't necessarily need the 2x8 or 2x10 floor joist but something to attached the fixture to.:
See the attaching bars. You need framing for those to attach to so the fixture stay up there. You wouldn't want to depend on drywall alone to support that thing.
In some recessed LED lights, you still need to attach the junction box to some framing.
"The lighting is fairly obvious in the drawing provided" OK. I think I see what is the lighting symbols represented. Since I didn't recognize the symbols for lights, I wasn't going to assume those were lights. It could be the image resolution but wasn't sure those were meant to be lights or not. My gut say yes but it's a little unfamiliar looking. Ones I usually seen or use would comply with ANSI Y32.9 or neca 100. It could be a brand new symbol by neca 100.
Thank you for making me have to explain this in more depth than I wanted to at this point. If those are in fact the proposed lighting location, I would move the duct 12 to 14 inches to direction that is the top to the plans. Just enough so none of those lights have to be beneath the duct. This goes well with "reallynotmyname" suggested below.
Too much debating on this has been spent. So b3tadine, don't waste time responding. Seriously. I'm not needed and I am not responding to this further. The forum doesn't need us bickering to each other nor does it serve the OP.
Richard, Thank you for your in-depth explanation and resolve to offer additional information and explanation to your answers.
Seems like moving the duct over 12-14" towards either the top or bottom of your drawing would solve the problem. If the person laying out the ductwork says they can't do it, they are lying.
I would agree with you on the ability to move it 12-14 inches. We do need more info from the OP to best answer the question as it pertains to the project.
This ignores the First Law of Mechanical Engineering, which is "Ducts go where ducts go."
LOL!!!!
I would never understand why someone would use their real profile (or is it?) asking this kind of question on online forum. … seriously
Well, lots of the MEP designers I've encountered are a-holes or just too lazy that they would never assist a junior architect with these kinds of questions. I suspect the OP may be dealing with some of that. Above-ceiling coordination is a rich source of errors and the resulting jobsite conundrums in the USA.
This is so true! I didn't want to really elaborate as it raises my blood pressure. I had an absolute headache with consultants (I wasn't in the design team) when it came to ceiling plans. On one project the design lead treated the ceiling as something that the contractor would just figure out as they didn't have a clue on how to coordinate the drawings. They merely collected the electrical and mechanical plan and attached them to the architectural set with zero verification or coordination. We had a light fixture and air supply grille in the exact same ceiling tile, which could have been immediately spotted by just overlaying a plan in autocad. Oddly enough both electrical and mechanical came from the same sub consultant yet the two designers clearly didn't talk to each other in the office. But the worst was that no one ever thought about the ceiling in section. The design lead had a suspended ceiling tile assembly but only dropped the ceiling 8". The air supply and return had to cross each other yet each duct was 8" in diameter. Then there was to be a massive fan coil in these 8" and an ERV. Some how all of this was to fit in a very shallow ceiling assembly and no one could be bothered to overlay drawings or try out a quick and dirty section to verify.
Understand , it's complex even with the well coordinated combined RCP there's always something clashing and misaligned. At the end of the day, we drive the whole aesthetic look within the MEP constraints. If it doesnt comply / it aint happening.
I suspect it's an honest question from a young professional - I''ll always forgive inexperience and those that are inquisitive. We were all there once. Yet I have hard time to even begin to understand where this question comes from. Well actually yes I can. Preliminary design studies and research are there to take into account such basic things as floor to ceiling heights. The answer is Yes if you get the floor to floor right. The Architect takes the lead and coordinates with MEP for initial clashes. And adjusts accordingly. On any project of scale - the contractor then produces their own coordination drawings to resolve clashes. I find this happening less and less as the world goes go BIM/Revit and the Architectural team have less and less knowledge. I've never seen so many errors as I see now. Imagine we did this all on paper with better results..... go figure. Yeah for progress!
To the OP: yes you can place recessed lights under ductwork. I apologize for my side way conversation.
Are these lights being installed in the ceiling below a roof? Do the lights have to be IC-rated? IC-rated fixtures generally have a protective box that exceeds the standard depth of most LED “high-hats”. Beyond that, I can only assume that the lights are LED to meet the max wattage output most current energy codes require; BUT in the off-chance they are not, make sure that the heat the lights emit do not cause melting of any components within the ceiling plenum. I would suggest that if the ceiling is used as a return air plenum (and indeed we just don’t have enough info based on the drawing you posted), this heat does not mix with the returned air in a way that compromises the ventilation temperature expectations.
It really depends on the space available and the type of fixture. On occasion I have had only 3/4" wood strapping or nothing but drywall below the ductwork, due to space constraints; no fixture I'm aware of will fit in those situations.
I often use LED wafer lights which will fit where there is 1" of clear space behind drywall. They are a tight fit though.
Conventional recessed lights need more depth.
Yes, indeed. Of course in commercial projects, it is more common to see the heavier bulkier LED fixtures used but we are seeing newer, thinner, and lighter LED recessed lights. These are more common in residential projects but sooner or later, those bulky fixtures will be a thing of the past because there is no reason for it to be bulky except for making it unnecessarily more expensive, in my opinion. Conventional recessed lights and recessed LED lights do need more depth. As others have suggested, why not move the main duct, say 12-14" to the top of the plan direction and just add a little more length to the smaller ducts on the one side and remove a little on the smaller ducts on the other side. Once that is done, it's pretty much no longer an issue of lights directly under the duct.
The smaller ducts may need to be adjusted left or right a little bit as well.
Can you move the duct to eliminate the chance for a conflict?
What a thread...