It doesn't need exhaust fan, it needs relief dampers, with smoke detector give signal to staircase pressurization than it starts to pressurize staircase and exceeding pressurize is relief through relief dampers. Smoke extraction fan have different criteria
Nice explanation. Thanks alot. Can you please explain on below. 1. Here in this example there is only 1 no. door on each floor but you have considered A1 and A2 which means 2 nos. of doors. This is just for example only or we have to consider A1 and A2 always for 1 door per floor. If not then can we put A2 as Zero. 2. You have considered A1 and A2 in parallel. This is also for example or we have to consider it this way in case of single door. As per my understanding, doors in series means one door besides other door and parallel means 2 doors in front of each other. Can you please explain as I am new to this.
As far as I know Parallel and Series means we have to consider the flow path. If same amount of air [or any physical quantity] passes through the doors in one path they are in series, else parallel. Thank you!
@@passionateengineer04 thank you for your reply. But the string values are shown immediately as I open the downloaded file. Meaning I didn't wrote any numbers, values etc. In your example I see that decimals are divided by dot, but when I open the file decimals are divided by comma. Don't know if this makes any reason. But also, line 16, drop down menu, I can't change from dot to comma (to see if comma is the problem).
Thank you. Good video. Do you have the calculator in the feet measuring system? We have a project where the engineer put a static pressure sensor in 1/3 of the stairwell height for a 9-floor building. Should it be a differential pressure transmitter? How should we choose the correct model number?
@@passionateengineer04 Thanks a lot. If the pressure range isn't provided, is there any way to figure it out besides an RFI? Couldn't find a link to the software.
If you have 3 fire exist than you have to select 3 in excelsheet ,depending on type. Select no of floors, Excelsheet will calculate airflow rate automatically
In outer space pressure will be atmospheric pressure but the difference should be maintained at 12.5 Pa for sprinklered buildings. However, the pressure in staircases should not exceed the threshold at which the force required to open doors exceeds 30 lbf.
There are different types of damper for smoke we use fire damper with smoke sensor inside the space. For pressure relief we use motorized damper with PT(pressure transducer) inside the duct when ever pressure increases above the set pressure PT sense the pressure and open the motorized damper to relief the pressure
How do you calculate the maximum relief air design flow rate? It must be the sum of the injection airflows minus the natural leakage rate (through gaps)? So, in this example it should be 7106l/s-520l/s=6586l/s? Why does row number 53 indicate relief air is 5420?
In design you have to set pressure behind the door and in staircase for example behind the door pressure is 302 pa and staircase is at 200 pascal so PD will be 102 pa. During air balancing you have to maintain that PD.
I want to know the sizing of ducts.. we do it like fixed losses like HVAC system design!! And I want to know the velocity of air in the duct 1600 FPM or what ?
One is velocity method and one is equal friction method, in velocity we consider standard velocity for sizing of duct and in equal friction method we select 0.08 wc/100 feet and 0.04 for return air duct.
Hi. It was a concise explanation for the stairwell pressurization calculation's. Can you share to me the excel table shown? Thanks in advance and would appreciate it much.
In UAE all ducts related to basements parking, makeup air unit, smoke extraction, staircase pressrization are fire rated. But you can also confirm from local code ie municipality etc.
Thank you for the informative video, I have a question for a case there is a pressurized smoke stop lobby before the staircase. How would the pressure difference be calculated assuming that the pressure difference bet. the smoke stop lobby and the corridor is 25 Pa
Pressure difference can be calculated, that how much air is in and how much air is out. In staircase the pressure is positive but in lobby the pressure will be negative for smoke extraction.
ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-X4F3zaObatQ.html Check the video description there is excelsheet, in which you can find the reference. It NFPA.
Dear sir nice video , but when does we require to install stair case pressurization system and smoke extraction system , I mean is there minimum area requirements or minimum ht of building or no of floor given in nfpa
There is requirement of distance between the start of building and exit door or mean of escape as per NFPA. Like for office building when distance between start of office where person is seated and emergency exist stair is greater than 61 meter than you have to install smoke extraction fan and there is hight requirement for different type of building like building height is greater than 75 feet required staircase pressurization system.
This Excel is not giving any results except Default Capacity which is 7106 l/s. I have tried to put my project values but Final Values is not changing...Please Help
@@passionateengineer04 Sir, I have input values until Door A1 and A2. Kept 25N and changed all the figures which has to be input... Trust me it is giving me same result...Please can u cross check it the excel file which you attached in the download link... It would be a great help for Me...Thanks
for Q2, we have considered the effective open doors area for one floor 5.82m2 with 1.02m/s velocity that comes out to be 5940 l/s. why don't we multiply this value with the number of floors (i.e. 5)?
Hi Bros ! Are you able to make a calculation sheet for ESP of the fan (of course a fan need flow/esp). I wonder why you plus air flow of leakage and air flow through the doors opened, because when any door open, pressure will become zero? And please advise how you estimate of the relief air requirement ? Thank you !
In staircase pressurization you have to consider these parameters, you must set the pressure behind the door and in staircase. When door opens the pressure in staircase and room will be equal.
@@passionateengineer04 I believe that operation of pressurization fan in a protected stair case is much different with an AHU, because it have some scenarios like when all door closed (minimum flow), when 3 doors open (maximum design flow). As well as "available static pressure" in the staircase.
The design is base on your requirements like one door is open you will required high flow so need to design for this flow rate and ESP. You have to use VFD drive fan with pressure sensor in stair to maintained that pressure and when door closes the flow reduces to avoid back pressure in duct.
Determine the heat release, smoke mass flow rate, you have to calculate smoke temperature and put it in equation to calculate air flow rate and than fan static pressure. I will make a video on this topic.