air duct silencer

eruss wrote:

rod gervais wrote:

There is a timer in the hall way. It is one of those dials you turn and it winds down till it shuts off. I can set it for 5 minutes or 30 minutes, or just turn it off.

eruss, who in the world installed that?????????????????????? SO you have somewhere in your duct feed - you have a mechanical damper opening and closing? Or do you have a VAV box (variable air volume) ? My question is - why isn't this installed within your rental unit - using a standard cooling/heating thermostat? What is installed is a violation of the building / mechanical codes.

I sat in that room last night with all the lights off an nobody around with the doors shut and the AC on. I could here the crinkling of the insulation I just put up but no noise at all comming from the air duct. Remember the AC units are another 30 feet above where my silencer is. Those ducts you see in the pic are NOT the main trunk. The main trunk is big enough to crawl in and it runs maybe 150 feet from the main unit before it gets to where my ducts are wich then runs another 30 feet before it gets to my silencer. Could that be why I don't hear anything? I have been a recording engeineer for 25 years. I am trained to here stuff for a living. I would think that if the AC made noise I would certainly here it. If Insulation does not crinkle then my head makes noise, but not the AC. Maybe something will be different once the Dry wall goes up?

[/quote] We'll just have to wit and see...........

rod gervais wrote:

who in the world installed that??????????????????????

lol!! I don't know.

SO you have somewhere in your duct feed - you have a mechanical damper opening and closing? Or do you have a VAV box (variable air volume) ?

I don't know that either. I think it is the damper kind. I think the owner mentioned something about that.

My question is - why isn't this installed within your rental unit - using a standard cooling/heating thermostat?

There is a thermostat. It is actually in the live room. We are going to move it though. There is also the switch I mentioned. This used to be an ATT call center building.

What is installed is a violation of the building / mechanical codes.

Then the inspector who inspected it did not know that. :lol:

We'll just have to wit and see

I have a way back in to access it if I have to. It wont be fun, buy I have one.

eruss wrote:

There is a thermostat. It is actually in the live room. We are going to move it though. There is also the switch I mentioned. This used to be an ATT call center building.

The rooftop unit that supplies the conditioned air to your building also supplies the fresh air required........ the control for that damper should be the thermostat, and it shouldn't even shut down the damper to 100% closed during occupied hours - it should only close to the point where you are receiving your 15cfm per person fresh air required within the space....... thats from the International Mechanical Code (IMC) Chapter 4 - Ventilation section 401 (General) sub-section 401.3 which requires fresh air to be supplied when the building is occupied. Thus a perentage of your air is suposed to be fresh air- besed on occupancy load and fresh aur provided. It can close down 100% to save energy when the building is unoccupied. The it will only cool or heat when required, T\During occupied hours the controls should cause the damper to open anywhere between full open and min air to maintain constant temperatures. Where does your fresh air come from if someone forgets to run out every 15 minutes to torun the control back on? Unhook that control and have your HVAC contractor switch it over to the T-stat.

What is installed is a violation of the building / mechanical codes. Then the inspector who inspected it did not know that. :lol:

That doesn't surprise me- you would be amazed at the things I catch that building officials miss........ Rod

rod gervais wrote:

The rooftop unit that supplies the conditioned air to your building also supplies the fresh air required........ the control for that damper should be the thermostat, and it shouldn't even shut down the damper to 100% closed during occupied hours - it should only close to the point where you are receiving your 15cfm per person fresh air required within the space....... thats from the International Mechanical Code (IMC) Chapter 4 - Ventilation section 401 (General) sub-section 401.3 which requires fresh air to be supplied when the building is occupied.

Maybe it is the other kind then. I don't know.

Where does your fresh air come from if someone forgets to run out every 15 minutes to torun the control back on?

The unit does not run continuously for sure. The building is not full of people everyday. Only on Sunday and a few weekday nights. Even then, it is not full like on Sunday. THere does not seem to be a problem with ventalation. I will ask the owner about theses things you are talking about.

Unhook that control and have your HVAC contractor switch it over to the T-stat.

I am not the one to make that call. He likes it the way it is because it safes alot of money being able to shut it off. The bill is still between 3 and 4 thousand dollars per month as it is.

That doesn't surprise me- you would be amazed at the things I catch that building officials miss........

Me neither. You are used to doing work as a contractor for your paying clients where you strive hard to meet code to keep your licencese and so forth. The owner of this building has a different point of veiw. He wants it to be the way he wants it. If the building inspector tells him to correct somehing, then he corrects it. If the inspector does not tell anything then he does not.

Then perhaps someone should quietly ask the building inspector the question - him saving money isn't going to do you or your clients any good if his building develops "sick building syndrome" http://www.epa.gov/iaq/pubs/sbs.html. I understand what you're saying about the equipment running constantly (although in order to meet codes the fan is supposed to) but we're only talking the fan here - that isn't what costs him the money to run - it's the compressor that runs the big bucks....... SO - you're telling me that the only way your system works is if you get uncomfortable - and then go into the hallway to turn it on for 15 minutes max? That is insane- and especially insane for your business. The requirements I noted in my last post - that's for general buildings - not super duper air tight recording studios - where there is NO air infiltration due to the construction. Once you're done weatherstripping those doors - what the hell are people supposed to breathe? You have a very bad - VERY unsafe situation there - and if i were you I would seriously consider making your landlord do something about it....... I would hate to be a person in your iso booth for 10 to 15 minutes breathing in my own carbon-dioxide instead of oxygen....... you had better be installing co2 alarms in this studio of yours. Sincerely, Rod

rod gervais wrote:

Then perhaps someone should quietly ask the building inspector the question - him saving money isn't going to do you or your clients any good if his building develops "sick building syndrome" http://www.epa.gov/iaq/pubs/sbs.html. I understand what you're saying about the equipment running constantly (although in order to meet codes the fan is supposed to) but we're only talking the fan here - that isn't what costs him the money to run - it's the compressor that runs the big bucks....... SO - you're telling me that the only way your system works is if you get uncomfortable - and then go into the hallway to turn it on for 15 minutes max? That is insane- and especially insane for your business. The requirements I noted in my last post - that's for general buildings - not super duper air tight recording studios - where there is NO air infiltration due to the construction. Once you're done weatherstripping those doors - what the hell are people supposed to breathe? You have a very bad - VERY unsafe situation there - and if i were you I would seriously consider making your landlord do something about it....... I would hate to be a person in your iso booth for 10 to 15 minutes breathing in my own carbon-dioxide instead of oxygen....... you had better be installing co2 alarms in this studio of yours. Sincerely, Rod

I don't have a landlord. This is a private studio. We don't have clients. There is a compressor. So maybe the fan does run. I don't know. I'll ask. I CAN turn on the system with out the compessor. I know that cause me and the owner talked about it yesterday. Or I can open the door. All this disscusion really makes me think. I appreciate it alot. I am not worried about some kind of syndrome. The doors are open when I and others are there. I suppose you would have to see it to understand it. If I have to leave the system on to get fresh air then I will. You are right. If it is air tight then we will. So, I will. 8) What about putting plants in to give off oxygen? Only they need water, so what will the evaperation do to the studio?

eruss wrote:

I don't have a landlord. This is a private studio. We don't have clients. There is a compressor. So maybe the fan does run. I don't know. I'll ask. I CAN turn on the system with out the compessor. I know that cause me and the owner talked about it yesterday. Or I can open the door. All this disscusion really makes me think. I appreciate it alot. I am not worried about some kind of syndrome. The doors are open when I and others are there. I suppose you would have to see it to understand it. If I have to leave the system on to get fresh air then I will. You are right. If it is air tight then we will. So, I will. 8)

eruss, 1st - either i missunderstood something - or yu didn't explainsomething well......... you said that the switch for the fan was in the hallway - and was a timer......... if that's true - then the only thing your thermostat does is tell the compressor to turn on - and that is only when the timer supplies power to the system......... that being the case - there is no air moving through the building - so you having doors open into a building with no fresh air isn't helping you very much............... then you say - "if it is air tight then we will" and I get confused - I thought you were building a studio - you said control and tracking room - and express concern about construction required to acheive sound isolation between rooms - did you think that this came without it being air tight? Possibly? let's put it this way - if the rooms aren't air tight - then forget them being isolated - if they are isolated then they will not allow enough infiltration to keep people alive if left in the room long enough......... As far as your not being concerned with some kind of syndrome I have a feeling you didn't pay much attention to the post I lft for you to read........ that isn't bulls**t....... it's a real condition that develope in buildings and has been associated with people developing some pretty serious illnesses..........

out putting plants in to give off oxygen? Only they need water, so what will the evaperation do to the studio?

you could not put enough plants in a room to provide oxygen with enough volume to keep anyone alive if even if you had enough plants so you couldn't fit in it yourself......... Never going to happen - and not code compliant either - you have a choice - open windows (directly to the outside worls) or mechanical ventilation - isolated studios don't have open windows and mechanical ventilation has to run 100% of the time that the space is occupied..... period....... end of conversation...... sincerely, Rod

rod gervais wrote:

that being the case - there is no air moving through the building - so you having doors open into a building with no fresh air isn't helping you very much...............

Either I am wrong about our system or you don't know your business very well. I go in the building everyday. You don't. If it were stuffy or unsafe I would know. There is a timer. There is ventilation in the building. You have never been to the building. You really could not say for sure what helps and what does not in our case now could you? If air was not moving though you would not know for sure because you have never been there to see or feel if it was. When there is a door open at one end of the building and I swmell the air from the other, what does that mean Rod? Do you have a calculation for that? As far as my room being air tight, it will depend on how well I do in construction. I am an amuture. I might screw it up some how. That is what I meant. Also you might not realize that I am in Southern CA. We don't have weather exteams like you have there. We don't have the humidity you have there either. You act like people are going to die in our room. That is a little extreme, but I appreciate the concern though. Has there been a study done on building where there was poor ventalation and no one got sick? How about the buildings where people got sick and there was great ventalation? Where is the study on that? People need a study to know when to go to the bathroom these days. :roll:

eruss why you got such an attitude. people are trying to help you out. dont forget your the one with the problems.

eruss why you got such an attitude. people are trying to help you out. dont forget your the one with the problems.

eruss wrote:

Either I am wrong about our system or you don't know your business very well. I go in the building everyday. You don't. If it were stuffy or unsafe I would know. There is a timer. There is ventilation in the building. You have never been to the building. You really could not say for sure what helps and what does not in our case now could you? If air was not moving though you would not know for sure because you have never been there to see or feel if it was. When there is a door open at one end of the building and I swmell the air from the other, what does that mean Rod? Do you have a calculation for that?

I suppose it's quiet possible that you don't have a clue about the things you tell me - and therefore you're wrong about your system...... because I am quite cetrtain that I know my business as well or better than you know your own.

As far as my room being air tight, it will depend on how well I do in construction. I am an amuture. I might screw it up some how. That is what I meant.

Like I said - even if your room isn't air tight it wouldn't matter - the codes I am quoting you are for normal buildings - not studios.....

Also you might not realize that I am in Southern CA. We don't have weather exteams like you have there. We don't have the humidity you have there either.

I know - and that lack of humidity and the more even weather patterns have suddenly created air in your reigon of the world that has a higher oxygen content than the rest of the world....... those are 2 of the most important ingrediants for fresh air with high oxygen content.......

You act like people are going to die in our room. That is a little extreme, but I appreciate the concern though.

No you don't - you're an obnoxious little troll who apparently likes to let people know what he's doing (under the guise of asking questions) and then when it's suggested that he might be heading in a wrong direction becomes indignant........

Has there been a study done on building where there was poor ventalation and no one got sick? How about the buildings where people got sick and there was great ventalation? Where is the study on that? People need a study to know when to go to the bathroom these days. :roll:

Nope they don't study buildings that no=one gets sick in - and they have never investigated (to my knowlege) a building where the occupants were having problems with illness across the board that did not end up with a building that you could find the cause....... Like I said - it must be beneath someone like you to read and educate himself- because if you had read the article - you would have found that there are quite a few things that can cause SBS - fresh air is only one of them - an important one abiet - but still just one. Well, tell you what - seeing as you obviously have everything completely under control - I won't bother wasting my time here........ believed me I do have better things to do than spend my time here bucking heads with you........ Rod

You can get mad if you want, but the building does get ciculation. How silly to get mad and quit over this. And do it as some kind of threat. But I am not missing anything. Most of what you have siad has turned out not to be the true. I'll be chcking the city code tomorrow. I'll guess that you are wrong there too.

rod thank you for your help on this subject it has been helpful to me as we are not that big on hvac in the uk in the homes and im sure it has helped many others. your help is very valuable to us on the site. but as you know from working in the trade yourself theres always one. lol

eruss wrote:

You can get mad if you want, but the building does get ciculation. How silly to get mad and quit over this. And do it as some kind of threat. But I am not missing anything. Most of what you have siad has turned out not to be the true. I'll be chcking the city code tomorrow. I'll guess that you are wrong there too.

eruss, I am not mad- just tired of wasting my time. And I am not "quiting" anything - this isn't a job for me - I don't make a penny out of this. When people want my services they pay me well for them - I earn over 6 figures a year and have over a billion dollars of successful construction in my resume...... including world class movie and recording studios - convention centers and high rise 4 diamond hotels....... I also do complete studio design including HVAC systems. I'm a sought after speaker for construction conventions, a published author, and am considered in my industry to be an expert in code interpretation......... I don't need conformation from you as to what is or isn't correct about either good design parameters or the building / mechanical codes. Generally when you help people for free and save them the hundreds of dollars an hour that they would pay for architectural / engineering services they are grateful - not hostile - you are definately not the former...... and I do not feel the need to be debased by some person who is not an expert in my field just because he's feels like doing so. Seeing as you obviously don't want help - but rather would just have people sing your praises....... I will spend my time more productively helping people who appreaciate what I give to them freely. It's good that most people aren't like you - because if they were - I (and the rest of the professionals like me who take time out of their busy schedules to visit these forums) wouldn't give two seconds of our day offering free advice to anyone visiting these boards. I should have known when I read your response in the other thread (regarding the fire treatment of fabrics) that you wern't worth my time - but I really tried to give you the benefit of the doubt....... but your reactions in here were consistent with what you portrayed in there - which is that you'll do what the heck you want to do - and if someone doesn't look at things the way you do - then there obviously must be something wrong with them. I'm sorry I wasted your time - but not 1/2 as sorry that i wasted my own....... good luck with your studio Rod

No problem Rod. You did not waste my time. I just wish you were thicker skinned so I could talk to you. I do need help, but I don;t just accept what a so called expert says merely because they say it ecspecialy when what I see with my own eyes contradicts what they say. When I am wrong, as in the fabric, I admit it. I did not know you held a grudge about that. I don't. I would be glad to pay you for your time.

Hey Eruss, I think you r on the wrong forum. People here want to share their problems and try to build with good advices and there s a lot of kind people here with a huge amount of good advices. Maybe some apologizes... Hey Rod don t take it personaly, help people who like to be helped , don t waste your time with people that are sure that they are better than professionnals. I m french and my english s not so good, Ive worked hard to read your book and I like to read you on this forum. Thanks very much Peace ! We are working hard to make some music.

sharward wrote:

Rod's last post is one of the most informative HVAC-related posts on the forum and includes information that (I think?) doesn't yet exist in the current edition of his book. You would be wise not to be too fixated on your own anecdotal experience and pay very close attention to his decades of hands-on and pens-on experience in studio and HVAC (and studio HVAC) design. If I may, with all due respect, I'm seeing a pattern of your asking questions and posting reports/pictures of your progress, but then when challenged about your techniques or assumptions, you tend to be rather defensive. I observed this in your "to bolt or not to bolt soleplates to slab" decision point, at which time the unanimous recommendation was to use bolts, especially given your area's seismic risk, yet you used nails anyway. :roll: Then there was your cavalier attitude about fire safety with your "Let it burn!" remark! :shock: I don't worship Rod's words, but I do take them seriously. He also never seems to take offense at being challenged about the facts, about the whys... It usually leads to more learning and he always appears to welcome that. I guess I'm just saying that we all want you to be successful, but it's getting hard (for me at least) to watch you getting terrific advice -- the kind many would pay big bucks for were it not for this forum and its generous-with-their-time membership -- which is often/typically ignored or challenged on its merits. I hope this I coming across the way I intend it to. I really do care about the outcome of your project, but it's truly getting to the point that I may just have to cover my eyes. Respectfully, --Keith :mrgreen:

I just had to quote myself as reiteration of my recommendation that you (eruss) need to open your mind to the viewpoints of others who are being extremely generous with their time to help you. Unfortunately for you (and everyone else it seems), I no longer care about the outcome of your project. I just hope you do what it takes to keep your occupants safe. If you hurt yourself in the process of ignoring the most valuable advice you've been receiving, that's your business... But when you put others in harm's way, it's not fair to them. 100 people lost their lives at The Station in Warwick, Rhode Island, all because a couple of people had the same disregard for safety as you apparently have. Rod, I'm sorry you feel that your time has been wasted, but I can assure you that it was not. This thread will be linked to in the future as reference material anytime someone chooses not to take ventilation seriously, and I'm sure it will come up in searches and educate many, many people who want to be educated. Your effort-to-help ratio is quite high, my friend. I'm going to close this thread now. If anyone has follow-up questions for Rod regarding their own ventilation (or other) needs, please start a new thread.