How you will maintain positive in any room, what is the formula and how should we know the required CFM to maintain that pressure difference with surrounding.
To maintain positive pressure the return air must b less than supply air, like one room have supply air is 400 cfm return is 300 cfm and another room has 400 cfm and return is 250 cfm that one will have positive with respect to another. The minimum pressure differential is 2.5 pascal.
Sir ur teaching skills are great 🙏thax for sharing your learnings.....sir I request u to plz start a detailed course of HVAC design and heatload calculation a paid course🙏
Minimum ACH for OT is 20 and out of which 4 ACH needs to be fresh air. Consider a OT having 1000sqft, as per ACH equation EA will be 334cfm(20ach) and 4 ACH means 67cfm. Then if we want to size AHU what percent of RA needs to be mixed with OA and what should be the supply air to the OT Pls help me in this case.
hello sir ,, let me ask . what is the function of the exhaust fan in the hvac system in the operating room? and how do we calculate the exhaust fan capacity? Thank You
OT must be at positive pressure, when OT is pressurized some of air flows through door gaps, if the room is sealed tight then the fresh air needs to be exhausted. Because when fresh air is added and there are no escape gaps then it will increase pressure beyond limits and no room for further fresh air, because OT required constant 4 ACh of outdoor air as per ASHRAE 170.
Orthopaedic implant surgery have high risk of surgical site infection and the surgeons have their own temperature requirements as they have to work in their heavy surgical clothing in order to avoid infection whereas anaesthesist requires a slightly lower temperature. It was noticed in study that the rise in postoperative infections for the period when ventilation system of the theatre was substandard and the temperatures were high.
In positive pressure room ,the return air must be less than supply to maintain pressure, opposite for negative room. Watch this video for Pressure requirements and air adjustment. czcams.com/video/FuoMTa-9Y6Y/video.html
I explain this in previous comment. AHU RA depends on Supply, that how much pressure you want to maintain if you want to maintain more pressure in OT, RA will be less than SA and for Air balancing you have to add OA and exhaust some percent of Air for Air relief. Its better to use UV lights or UVGI.
First of all thanks for making a nice video over it. Can you please define more about the controls of AHU for OT? Supply air should be based on cooling load calculation results or according to 20 ach? Please answer
What is mean by 4 air changes out of total minimum 20 air change? NABH Guidelines for OT 2018 says "FA required to be min 4 Air changes out of total minimum 20." I'm a bit confused. In my case for 3535 CFM and 4590 vol I'm getting 44.6 ACH. How much fresh air to be considered in this case? Thanking you
You have to calculate the supply air by 20 ACH and fresh air or OA by 4 ACH. So the cfm calculated by 20 ACH will be supply air and cfm calculated by 4 ACH will be fresh air, so total supply air will be the cfm calculated by 20 ACH plus cfm calculated by 4 ACH and returns air will be only cfm calculated at 20 ACH. So the OT is at positive pressure hence cfm calculated at 4 ACH will maintain positive pressure.
@@passionateengineer04 NABH asks min 4 ACH (fresh air) out of min 20. Here I'm getting 39 supply air change. I got your point that 4 FACH would help in creating +ve pressure which is must in OTs, NOW my question is fresh ACH is 4 (that too minimum), but how much Max FACH could be considered? Is there any limit?
@@passionateengineer04 can you share knowledge if it’s possible to use same OT For positive and negative pressure application Like isolation and surgery or vice versa ?
OT can only be used for positive pressure. If you want to use it for negative pressure it will contaminate the OT with bacteria or virus, than you will do fumigation etc to use it again as OT
Hallo. I read from ashrae also that ACH for isolation negative press.room for covid is 12. But there is no explanation wheter ACH 12 is for fresh air only or fresh air Plus supplyr air. What is your opinion.
It will be covered in coil sizing and calculation topic. Coil temperature depends upon refrigerant flow rate and Air flow rate, if you need to maintain 16 deg in OT you have to design coil according to it at temp difference of 5c. Or during equipment selection manufacture can provide this data.
For Chilled water system we supply water 7c and return it on 12c to maintain 16c. But it all depend on manufacturer, if you want to achieve 16c room quickly its off coil temperature will be different and air flow will be different if you want to achieve gradually than its different.
5c difference in case of CHW 7c water supply temperature and 12c on return, but off coil temperature is different it depends on how quickly you want to achieve temp, normally for 16c its 6c coil temperature that is 10c difference.
Hi Sir, I am doing HVAC design for Fish market. Could you please provide me the reference documents related to the HVAC system design for fish markets. (mainly about ventilation rate required and RH control). I was searching in ASHRAE, where i couldn't able to identify the data related to Fish market design. Client is very concerned about the smell and condensation/ moisture since the market is very close to sea. Kindly help to provide reference documents if you have any. Regards Jayakumar
And what kind of fish are they selling? Lean fish, flat fish, glazed type etc because their storage temperature and ACH and other parameters are different.
Hi, thank you for your nice video sir.
Sir do you have the electrical technical specifications in a word file similar to the one you have shown here?
Share you email address
Boss, Can you Please work out an example for calculation of Airflow with room volume 5200 ft3 , 5-8 occupancy, Equipment Load of 7-9 Kw.??
Kindly check video description for OT documents
Dear ,Very good and brief explanation.THanks for sharing.Please provide details of Lab,ICU and other areas design.
Great Information. Thanks
Very Good Information 👍👍
Hi Sir very good explanation sir. Thanks for clearing this concept. Also provide video on RH control strategies or Heating kw calculation.
Thank you very much sir...it has really cleared my concept.
Can u pls make a video on indoor swimming pool designing 🙏.
kindly send to me the specifications in a word file, thank you
Please share your email address
Cau Send this document to download
Hi ! Could you please share the summary sheet that you explain in the video, thank you !
How to calculate heat load for 20'x20' sized OT using E-20 form?
Super video
Good video sir
As per the video what would have been the CFM of AHU at 20 ACPH 100% Fresh Air..?
100% Fresh air means that fresh air flow will be based on 20 ACH according to your question.
How you will maintain positive in any room, what is the formula and how should we know the required CFM to maintain that pressure difference with surrounding.
To maintain positive pressure the return air must b less than supply air, like one room have supply air is 400 cfm return is 300 cfm and another room has 400 cfm and return is 250 cfm that one will have positive with respect to another.
The minimum pressure differential is 2.5 pascal.
Nice video..
Sir ur teaching skills are great 🙏thax for sharing your learnings.....sir I request u to plz start a detailed course of HVAC design and heatload calculation a paid course🙏
I am already offering HVAC courses online, contact me for further details.
Naqqash.sajid@gmail.com
how to compute the return air
If u have notes sir plz provide..... Especially pharma note... Design..... Please upload one video of dehumidifier air plz
Dehumidified air calculation ans ahu coil calculation
Minimum ACH for OT is 20 and out of which 4 ACH needs to be fresh air.
Consider a OT having 1000sqft, as per ACH equation EA will be 334cfm(20ach) and 4 ACH means 67cfm. Then if we want to size AHU what percent of RA needs to be mixed with OA and what should be the supply air to the OT
Pls help me in this case.
In this case 334 cfm is SA and 67 cfm is FA so RA will be SA-FA=267 cfm
@@passionateengineer04 thanku sir
So now total SA will be 334cfm and as per this we have to select AHU tonnage...
400 cfm per ton
@@passionateengineer04 ok sir
Atmoshpheric pressure is 101,325 pasacl than how 2.5 pascal pressure is called positive pressure in operation theatre
Its differential pressure is not with respect to the atmosphere.
It is a mini pressure difference between rooms.
Thank you
hello sir ,, let me ask . what is the function of the exhaust fan in the hvac system in the operating room? and how do we calculate the exhaust fan capacity? Thank You
OT must be at positive pressure, when OT is pressurized some of air flows through door gaps, if the room is sealed tight then the fresh air needs to be exhausted.
Because when fresh air is added and there are no escape gaps then it will increase pressure beyond limits and no room for further fresh air, because OT required constant 4 ACh of outdoor air as per ASHRAE 170.
What does 2.5 pascal differential pressure
Pressure Difference between two spaces
Which two spaces pressure diff is 2.5 pascal sir. Means what is the reference space.
nice video
Sir ,can you please explain why temperature is lower in ortho OT as compared to other OTs?
Orthopaedic implant surgery have high risk of surgical site infection and the surgeons have their own temperature requirements as they have to work in their heavy surgical clothing in order to avoid infection whereas anaesthesist requires a slightly lower temperature. It was noticed in study that the rise in postoperative infections for the period when ventilation system of the theatre was substandard and the temperatures were high.
how to make air balancing in hospital room like positive and negative pressure room
In positive pressure room ,the return air must be less than supply to maintain pressure, opposite for negative room. Watch this video for Pressure requirements and air adjustment.
czcams.com/video/FuoMTa-9Y6Y/video.html
How to design AHu of OT for 16 deg.
Also how much return air we need to take for AHU
Do we need uv light in ahu
I explain this in previous comment.
AHU RA depends on Supply, that how much pressure you want to maintain if you want to maintain more pressure in OT, RA will be less than SA and for Air balancing you have to add OA and exhaust some percent of Air for Air relief.
Its better to use UV lights or UVGI.
Sir are HEPA filter is necessary for procedures such as hernia repair and hydrocele
Yes
HEPA is required in every cleanroom
Plz, can you make a video of the OT Heat load calculation
you can watch my video on clean-room heat load calcualtion.It will give you an idea, i will try to upload it soon.
Sir return air pick outside the ot ya inside Ot?
Some of them will be fresh air and some are return.
First of all thanks for making a nice video over it. Can you please define more about the controls of AHU for OT? Supply air should be based on cooling load calculation results or according to 20 ach? Please answer
You're welcome!
Do you need electrical controls?
Ventilation should be according to 20 ACH.
What is mean by 4 air changes out of total minimum 20 air change?
NABH Guidelines for OT 2018 says "FA required to be min 4 Air changes out of total minimum 20."
I'm a bit confused. In my case for 3535 CFM and 4590 vol I'm getting 44.6 ACH.
How much fresh air to be considered in this case?
Thanking you
You have to calculate the supply air by 20 ACH and fresh air or OA by 4 ACH.
So the cfm calculated by 20 ACH will be supply air and cfm calculated by 4 ACH will be fresh air, so total supply air will be the cfm calculated by 20 ACH plus cfm calculated by 4 ACH and returns air will be only cfm calculated at 20 ACH.
So the OT is at positive pressure hence cfm calculated at 4 ACH will maintain positive pressure.
@@passionateengineer04 NABH asks min 4 ACH (fresh air) out of min 20. Here I'm getting 39 supply air change.
I got your point that 4 FACH would help in creating +ve pressure which is must in OTs, NOW my question is fresh ACH is 4 (that too minimum), but how much Max FACH could be considered? Is there any limit?
FA will be 10 to 15% max of the total SA.
@@passionateengineer04 Thank you
Sir can we get the soft copy of word file
Share your email
Sir, What is size of ducts required for supply and return ducts for 3000cfm AHU for standard 20× 20 ×10 (ht) in fts of OT size.
Can you please explain, are taking about main duct or the duct inside OT connecting laminar diffuser.
Both Sir
And return ducts also with return ducts at three corners
Share your email, i will send you data regarding OT duct etc
Share at gnsingh97@gmail.com
plz mention about reheater size selection for RH control in OT
It depends on thr air flow rate and capacity
please send your whatsapp number. I will tell the problem thatI have faced while Designing HVAC system for OT
@@passionateengineer04 can you share knowledge if it’s possible to use same OT For positive and negative pressure application
Like isolation and surgery or vice versa ?
OT can only be used for positive pressure. If you want to use it for negative pressure it will contaminate the OT with bacteria or virus, than you will do fumigation etc to use it again as OT
Naqqash.sajid@gmail.com
Hallo. I read from ashrae also that ACH for isolation negative press.room for covid is 12. But there is no explanation wheter ACH 12 is for fresh air only or fresh air Plus supplyr air. What is your opinion.
In negative pressure room air is only fresh air, and exhaust air, so 12 ach is for OA.
@@passionateengineer04 how about for operation room but special for covid patient. Is the room positif press or neg press.
OT are always at positive pressure.
@@passionateengineer04 can you show me the reference or standard that OT fot covid patient is positive pressure.
OT cannot be at negative pressure because of the outoor contiminants, it doesn't matter whether its covide patients or not.
How much off coil temperature required to get 16 deg in OT
It will be covered in coil sizing and calculation topic. Coil temperature depends upon refrigerant flow rate and Air flow rate, if you need to maintain 16 deg in OT you have to design coil according to it at temp difference of 5c. Or during equipment selection manufacture can provide this data.
@@passionateengineer04 u mean to say if need 16 deg, off coil temp shall be 11 deg with 5C diff
For Chilled water system we supply water 7c and return it on 12c to maintain 16c. But it all depend on manufacturer, if you want to achieve 16c room quickly its off coil temperature will be different and air flow will be different if you want to achieve gradually than its different.
5c difference in case of CHW 7c water supply temperature and 12c on return, but off coil temperature is different it depends on how quickly you want to achieve temp, normally for 16c its 6c coil temperature that is 10c difference.
@@passionateengineer04 you cannot get 6 deg off coil when your entering chill water temperature is 7 deg C.
👏👍
Could i get this word please?!
Email please.
Hi Sir, I am doing HVAC design for Fish market. Could you please provide me the reference documents related to the HVAC system design for fish markets. (mainly about ventilation rate required and RH control). I was searching in ASHRAE, where i couldn't able to identify the data related to Fish market design. Client is very concerned about the smell and condensation/ moisture since the market is very close to sea. Kindly help to provide reference documents if you have any. Regards Jayakumar
Do you want to store fish for long time? Or just need to store for selling purpose?
And what kind of fish are they selling? Lean fish, flat fish, glazed type etc because their storage temperature and ACH and other parameters are different.
PASSIONATE ENGINEER Just need to store for selling purpose
@@JayaKumar-jl6qo Kindly check ASHRAE Handbook of refrigeration 2018, chapter 32 "Fishery products".
What is Hvac criteria for dialysis room or
Same criteria but ACH, temp and humidity is different, check ASHRAE code 170.
hi sir provide email i have few questions on hospital design
Naqqash.sajid@gmail.com
Can I have your contact
Naqqash.sajid@gmail.com
You can contact me on this
how to calculate or design 100% fresh air burn ward hvac system with AHU?
Check ASHRAE 170.
@@passionateengineer04 only given 2 outdoor ACPH & 6 Total ACPH. 100% FA not given. Could you please share sir...
If its per ASHRAE than you don't need 100% fresh air, you will require 2 ACH of fresh air.