building system looks like and then develop some sort of a faulty, and to understand what the risks are and what the potential threats are to the system and so we did that and we understood that we were dealing with one particular approach to maintaining the occupant with a fire inside of a dwelling unit and that is typically visibility and the ability to see and to get out of the building and that would be impaired by smoke. you are looking at a corridor that is damper that will be activated by a fire by a smoke detector probably to keep the smoke that is in the unit from traveling into the corridor. and these kinds of smoke or fire smoke dampers are commonly employed in the building components that separate an

area, where you don't want the smoke from the fire, if those operate correctly, they will have a good proven track record. if they don't, they will let the smoke in the area that you don't want it, what we are assessing here is whether or not the pressurized corridor system that is being proposed somehow adversery effects the operation of those dampers and the ability of those dampers to keep the smoke in the room of the fire and the short answer is no, it doesn't from our study, it does a good and the system performs, and if the damper activate and the system performs as it should, maintaining in it for the occupants trying to escape for a range of simulated conditions. >> those conditions included a fire that has grown beyond the sprinkles ability to control it and so a large fire and the

fire that is controlled by sprinklers and we are looking at the conditions by which the glass has broken out and we looked at the wind on the fire fa said and we looked at the temperature and the low temperatures in the winter and the top and bottom floor and we looked at whether or not the supply sands in the corridor failed, the exhaust fans failtd, both failed, and we looked at whether the dampers failed and whether, 25 percent failed and whether they all worked or whether they all failed. okay? it is a pretty big matrix to run through and we ran through it using a term called contam which is a network model and it solves a series of equations that say that if you have the high pressure in this room and the low pressure in the hall the air will flow from this room to the hall through a series of openings that will allow you to go through a whole bunch of these simulation and look for bad okay tore and that is what we did, and we took those bad actors and ran them through a comprehensive model.

it allows us to run those quickly and it heats our offices, the result of both of those sets of that if all of the dampers worked fine, everything is safe. despite the fans operating or not operating, and also showed that if you have 25 percent damper failure and one damper is in the room of fire origin, that is bad. that smoke is go to get into the corridor and it may or may not get into the adjacent rooms if one has failed in an adjacent room. >> the supply or the exhaust fans in the corridor, being active, are not active, makes

no difference on either of those scenarios. operational smoke damper here is good and stays good. and i will stop there and answer any questions. >> so i have questions about power, in the event of a power outage that is prolonged like during an earthquake, what happens to these systems? so the assumption is that the dampers fail to a closed position. >> okay. >> we also assume that the supply and exhaust fans fail under those circumstances. the damper might also activate with power intact, but, fail in an open position. so they could fail into the open position, irrespective if there is a power supply failure

or not. so the power supply issue, becomes irrelevant because the supply and exhaust fans being operational or not did not make a difference on whether the dampers failed open or operate td normal. >> it was not working and didn't make a difference. >> plan and exhaust working did not make a difference. if they worked normally, supply and exhaust working no difference, and supply and exhaust not working made no difference. do you follow all that have? >> yes. >> the matrix is a little hard to keep track of. >> so my guess, is and you sort of answered my question and the default is not that big, when there is a failure that they remain open and so i guess that i was looking at it in the event that there is no fire, that there is just an outage, and in the building, and it is sealed. you know, and folks, like, elderly folks, and the people who can't necessarily get out after a long time. you know? there is no default that these things will just remain open.

there are others here that will be able to comment on this subject. and my understanding is that you will be able to employ a failed, closed damper. >> okay. >> there is no back up battery that is mandated. >> in low rise, no. in high-rise, you will have the back up power supplies. >> okay. >> and again not really my area of specialty. but, that is my understanding. >> thank you. >> others can correct me. >> thank you. >> we will go to commissioner walker and lee. >> i guess that i wanted to clarify the dampers, the dampers will be important in a fire because it would and we are assume thating they get activated by the smoke alarm. is that what you are saying? in a power outage they would not need to close, maybe we are getting too detailed but i get it now. >> yeah. >> the dampers could be activated by a smoke control

system, or by an alarm system. >> right >> building wide bu, they could be activated by a detector placed nearby the... >> yeah, by the smoke or somewhere in the air. >> okay. >> yes, in that case we want them closed as a default in the case of a power outage it does not matter. >> okay, commissioner lee, thank you. >> that brings up my question about what happens after the failure? do we need to go back into the building and rebalance everything, to make sure that it is working? >> probably? >> now i am really outside of my area. i am not sure. that is something for people who specialize in balancing, air balancing of buildings, and that would certainly be done initially. i believe that it is something that would need to be done periodically. that there are requirements for it to be done periodically and the inspection of the smoke dampers will need to be done. >> and then i have a question f that and you can't answer that, then what happens inside of the building when the people living

there and how would they know if it is working or not? >> i mean, how would they, fuel that and this is going to suppose to work the way that it is supposed to be done? and so the smoke and fire control systems are require to adhere to a certain schedule of inspection testing and maintenance. >> and that schedule would vary based on code requirements but, i think that that is the basis for answering a question for an occupant does my system work? >> i see. >> okay. >> and i believe that we have got the fire consultant here that could probably dig a little bit deeper on the technical questions if you need. my question is related to the pressurized hall, is it pressurized by the system, or is it pressurized by the fire, and how, and let's stable that required pressure. >> so the whole, according to

the requirements of the enhanced ventation ordinance, or the implementation as described in mr. oneal's document i would have i believe two air changes per hour within the corridor and then a requirement to have air flow from the corridor into the dwelling units based on the factors related to the units and the number of occupants. >> that ability to push in the air to the dwellings requires the corridor be pressurized. >> yes, okay. >> the corridor could also be influenced by wind and what is called stack effect in the building which is an effect which arises during times when the building is hot relative to outside or cold relative to outside. >> okay. >> so the corridor could see the changes in pressure, yes. >> and there is something that regulates that within the system? >> yeah, and sort of out of my area, there are what are called compensated fans, which would allow for regulation of

pressure in a space. whether those fans would be implemented in a given scenario i am not sure. >> i believe that we might have more questions for you dr. rich, but we really appreciate you explaining that in the layman's terms and we got a good understanding and i appreciate the kind of excuse on the fire drill that you had to go through for the last week to get this and give us this presentation here today. >> sure. >> but in summer, you think that basically, that the fire dampers are an option for us here? to put this implementation of our (inaudible). >> this implementation does not adversely effect the operation of smoke and fire dampers, and at protecting people in the event of a fire. >> thank you very much. >> i appreciate it. >> okay. thank you. >> is somebody from fire, did

you want to weigh in on this? >> no you didn't. >> yeah. >> yeah. >> no, i will call you back up, dr. rich if we need it. >> okay. >> you could state your name for the record, please? >> my name is john and i am a fire protection engineer, and with the fire department. >> and our position on this matter is that we are concerned about life safety, and the okay ccupant egress and we would like to see that fully vetted and come to a conclusion that these types of systems don't impact life safety, egress, of the occupants and especially in the residential buildings where the people tend to and not be aware and in the early hours of what is going on.

i am reviewing the analysis and it is not complete, but so far, it looks like it is coming up with the results that are valid. and so at this point, to say more about it, would not be, you know, helpful. but, because there, and there are many possible scenarios that could be evaluated, and we are really just focusing on what has been presented by the paul oneal in the cb engineering article, and so, otherwise, than that, that is pretty much where the fire department is right now. >> okay. >> and what..., could you, commissioner? >> thank you. and what would be the egress issues?

>> okay. >> so, when you have a fire in one of the units, and you have failure of systems, basically, the fire and the smoke dampers, that protect the corridor, where the people would have to evacuate. and you would allow the smoke into those corridors. that you potentially block egress, because the people can't get out of their units and in the article 38, there are no windows that are operatable. and so, we have no egress windows. and however, certain code cycles have required egress windows. and so, when you don't have an egress window there is no alternative escape route. and one thing that i did note in the article 38, write up, is that there seems to be a discrepancy between a low rise

and a high-rise. and in the article report that i read, low rise was defined as three stories and below. correct me if i am wrong. and with the requirements of 62.2? of the energy code. right. and then, high-rises are defined anything above 4 stories. >> well, in the building code, we define a high-rise as anything above 75 feet of the last occupiable floor level and so what we are evaluating right now, are low rise buildings that are 75 feet or less. in height. and so, the important distinction because the high-rise buildings present a higher challenge for the fire department to address occupant

safety and response, and firefightering tactics and things like that. and it we can't reach higher than 75 with what is called a master stream. so essentially we have to fight the fire from inside and not outside. so, right now, what is being looked at is the what, the building code, and it will define it as a low or maybe even a mid rise, and we just say that it is not a high-rise. and so, the egress getting back to your question, is of a very important concern because there is very little time usually in a fire for the occupants to respond. and escape. and if that fire is progressed to the point that the smoke is coming through the corridor, because the failure in the fire smoke dampers to close, and the corridor is blocked, then the occupants can't escape. and essentially, if they tried to, they will smoke

inhallation, and it will overcome them. and they can't see, a lot of things happen and they become disoriented and we have a problem and the same thing with the firefighter response and we come into a floor and we can't see. and we can't see where to go. there is and it works, you know, either way, but we are, primarily we are concerned with the people getting out. so, in the case of a failure, which does happen often with the fire smoke dampers and because they are not as reliable as we would like them to be. then that would present a problem with the egress and the corridors. >> okay. and thank you. >> okay. >> i appreciate you giving us that update and at this stage, if i may, i think that we have

the city mechanical here as well. but if we could just probably hear from maybe somebody from the consultant from the fire, and the authority and mr. metta? >> maybe just to comment on what you think that you heard here today and what you think will be a possibility of going forward. >> thanks. >> jeff maddox with the fire control and you can hear me through the microphone okay? >> yes. >> i would like to see the results of the studies we have also been doing studying various ducted systems with our cfd analysis, and for the buildings that are under construction and design and i am curious to see how there are results compared with this corridor air scheme. and so i would... and one of the things that i would like to think about though, is john, you mentioned that if air or smoke has moved into the corridor and the egress problem? and i think that we could use a study to evaluate just how much smoke it takes to make that

corridor untenantable and is that something that is included in your study so far. >> yes. >> i think that is a big part of it to figure out if there is an opening where the damper fails, how much time there is in the corridor, for the rest of the tenants to respond and get out. >> the idea that there is be no smoke in the corridor is a very conservative and how long they can be in the space, and that is really where we need to go. and i do want to talk about some of those questions about whether dampers fail, and how, and failures, because there is a couple of terms that are a bit confusing when we see the dampers fail closed what that means is when the power is removed from the electrical device, it closes, when it experiences a failure, that means in my mind, that is does not move to a closed position, it is hung up and the mechanism does not allow it to close to a

safe position and so john is suggesting that the dampers experience failures yes, they do. and in this case, though, the word fail, closed, is not the failure. that is what we want, we want it to close, right? >> and the question of whether they run all of the time, the fans and the question is that they will run all of the time in the normal mode, when the power is gone, they will not have back up in the low rise buildings, the fan will turn off but at that point, if there was a fire that damper will close to the closed position and it will not matter as dr. rich said, whether the fan is running or not, as long as that closes we are safe. in general we are having the problems with this, because the building code had a prohibs to use the corridor to convey the air and i think that that is a

hold over, more from one corridor were used as a return and think about that and if you have a space and an office or residential and whatever and your return air is going through the corridor and that is exactly where the smoke is going to go in a fire and so i think that the genesis of this prohibition is the return side, if we are pushing the air through the corridor to the units that is less of a problem, the smoke is not going to tend to go through the corridor, as it was in the return mode and i would like to see more of that study as well and you mentioned that it did not work, when in the corridor remained, positively pressurized, and again, i would like to see how much time there is involved in that, or whether it was the any smoke is a failure sort of a question. >> and any questions. >> commissioner walker? >> yeah, i think that i am in returning to the issue of how much smoke is allowed in the corridor for it to become a

problem, that would tie-in also to the condition of the stairwell, or the down exiting, egress, correct? so, you have to, you might have a different set of rules for the stairwell, requiring outside source or something. which would then be more important in the higher buildings. you have that issue, so, just i want to bring that up that that might be considered, and then you are talking about the return air, coming in and so you are assuming that a system that just might push in the air and go out from some of the other source within. and so it will go out, and not in the corridor. >> right. and that, and i think that it paul's design or in tent, the air comes in from the core and it gets relieved, either through the exterior openings or the windows or the exhaust shafts that are serving the other functions as well. >> okay. >> and you mentioned that is

the air pressurization idea, thank you very much. and you know, we do the exact same thing that we are proposing for the corridor and we do it for stairs as a requirement of the building code for high-rise buildings, it is the same idea. if you are a pressurizing that stair so the smoke can't go in and then the stair is safe. >> the idea is to pressurize the corridor and it is not quite the same pressure, and i am not claiming that it is the same as the air pressurization but it is the same concept. >> but one more question here. >> okay. >> what is the standard now for allowing the smoke into these corridor and stairwells? >> what is the standard for that? >> there is not one defined in the building code. >> i understand that, and the reason that i asked if we are allowing the smoke to get into the corridors we are actually changing the people's perception of what is happening in those corridors, the layman people, may not recognize it, and this is not, this is safe. and there is smoke in here, but this is safe. >> right. >> that is one of my concerns,

about allowing the smoke into the corridors and only into the stairwell, and i can tell you from experience, and in my college days i lived in an apartment and there was a fire in the corridor and where there was a fire somewhere, once i saw the smoke i didn't go in the corridor i went out the back and through a window, that is throughout, and i don't think that layman's original public, general residents living in those buildings, will recognize, oh, this is safe enough for me to go through. >> that is a good point. >> you know, in modern and fire protection and engineering we look at this to look at a lot of smoke conditions and it assumes if you can go through the smoke you will. but it is a good point that some people will just see it as an eversion to the unit space.

they have a requirement for the rescue windows and that is not change withing this proposal. and so this is still that option in the buildings that require it. >> yeah. >> and i don't know if you are the person to ask, but with regard to that discrepancy and the high-rise and the 75 feet and verses the four stories here how do we address that? by thank you for taking the time for keeping an eye on this and we appreciate you are input when we get the closure on it >> and i would like to continue to be a part of the process. >> could you close out mechanical? >> good morning, commissioners. thank you for your time. and i would also like to thank the department of public health and listening to my proposal, and moving along to the various

departments of the city, and particularly the fire department, and the building department, and like to thank, dr. rich for his study and i was, i was pleased to hear the results and the initial results and i know that we are looking for a final report but the positive information at this point, regarding the corridor of the outside air proposal and just as a background on the conducting engineer in san francisco and i have worked in the city since 88 and in our firm, we specialize in the high-rise and the low rise multy family housing in the project and so we see this system as an enhancement and not just in the 38, but the enhancement on the various building, and ventilation aspect and just an improvement from over all building, and science, and stand points and to hear that the fire and life safety, potentially could not be impacted, and it will be a

good step. and i wanted to address a couple of the questions that came up if i may. i think that one of the questions is the difference between the high-rise and the low rise and so in my proposal, i address the ventilation requirement of the california, 2010, not 2013, energy code that differentiates the buildings up to three stories as low rise, and everything, four stories and higher is a high-rise, residential in terms of energy and ventilation. life safety is 75 feet and higher, but the study that is being performed right now, is the environment in the low and high-rise, from a life safety standpoint, and the ventilation is a separate issue but it has the same terminology but in a different application. of the height of the building.

but either way, both have to be ventilated for the code, both building types and there was a question about what happens after an events. if the power is restored to the event and the all clear is given to reoccupy and the normal power is restored and they go back open and the mechanical system goes into the 100 percent ventilation mode and the building assumes the normal activity and so there is no rebalancing required after an event. but you know, over time, perhaps, a recommissioning of a fire system, is a good idea. and but there is no rebounds, required once it is set, and operational. >> so, let me ask, so, after an event like that, for example the fire alarms you just reset it and say that it should be working properly again and so

are we assuming the same for this system and the system that everything is going to be working properly until the next inspection? >> it is an interesting question, and i have not been personally involved in the restart of a building after an event and i think that we should address that with the fire departments specifically. but from a technical, air flow standpoint if that fan was turned on it will be able to deliver the air for the floor. >> and let me ask you, that sort of like a smoke detector and the carbon monoxide detectors and we can plug that into the wall and we know that there is something wrong. is there something like that for this system? >> so, each fire smoke damper and there are many ways and we are getting to some details at this point, but there are many ways to control the fire smoke dampers and the simple way is with a local detector at the device and the other one is using ai detector in the unit to be in the fire alarm system.

to activate that damper. >> they close within 15 seconds. >> and so, there was a question, earlier about the amount of smoke into the corridor. and that damper is going to close in 15 seconds or earlier and so, the event moving the smoke into the corridor is very limited and i'm assuming that it will be addressed in the study. >> all of the details are not flushed out. i think that we have little time, once we get through this initial phase, to further those. i also want to address the high-rise exhaust method, so in a high-rise building if an event occurred and the fire smoke dampers closed and the supply fan operates on 100 percent of outside air, we will also employ an exhaust riser which is used to evacuate the corridor egress, as in a current normal high-rise life

safety building soe. we are not changing that and it will be off in normal mode. i think that they are the main items, could i answer any questions from anybody? >> no i think that we are good, mr. mayor, thank you for your time that you put into this. and we, you know, we look forward to a conclusion on this within the next couple of months. >> i do, and i remine committed to assist. >> thank you for coming out and taking the time out of work to be here. if mechanical just want to weigh in that you like what you are hearing here? that in the land of milk and honey when this is done you will be tiebl plan check something like that >> good morning, my names is james van and i am the mechanical supervisor of dbi before i start i would like to make a correction that he