Skip to main content

Air Velocity and CFM calculation of HVAC

CFM



CFM and Air velocity measurement of HVAC system:-

CFM stands for the cubic feet per minute 
In HVAC system CFM is determined by measuring the velocity of air passes through the supply air grills and filters
And then calculated velosity is multiplied with total area of Unit within air passes

   CFM= AREA × VELOCITY OF AIR 

Air velocity is checked by Digital anemometer which keep in all corners and center of Area and velocity recorded.
Then average velocity determined.
 
Area of Unit determined by area of filter calculated and by sum of number of filter available in that area.

CFM of Room or Cubicle:-
For Calculation of room CFM we required two parameter. 

1)Air velocity coming in the room through supply Grill:-
First calculate the air velocity of one Grill in the room. Take velocity by anemometer at 5 point of that grill, Then calculate the average velocity.

2)Area of the grill:-
Second thing you need for CFM Calculation is area of grill.  Calculate the area of that grill which you have taken the air velocity before. 

Then calculate the CFM of one grill by multiplying average velocity into area of that grill.

You will get the CFM of that one grill.
For Calculation of room CFM, simply multiply the number of Grills available in the room with that one grill CFM.






Labels:

Comments

  1. UnknownDecember 15, 2020 at 6:20 PM

    Great Job Prashant

    ReplyDelete
  2. UnknownDecember 15, 2020 at 6:21 PM

    CFM information is good but give with example

    ReplyDelete
    Replies
    1. EasywayDecember 15, 2020 at 7:57 PM

      It is very easy to do..
      Just area × velocity that's why I not given any example

      Delete
  3. UnknownMarch 22, 2021 at 6:09 PM

    Good, but practically we can calculate every grill not just calculate one grill and multiple with number of grill in room because pressure factor, pressure of flow not equal in all grill if pressure different then cfm also different

    ReplyDelete
  4. John ClarkJune 21, 2021 at 10:04 PM

    Clearly, It is an engaging article for us which you have provided here about hvac. This is a great resource to enhance knowledge about it. Thank you.
    hvac cleaning services

    ReplyDelete
  5. UnknownOctober 28, 2021 at 3:15 AM

    Nice Blog !!

    Find here the best hvac duct suppliers in Jordan.

    ReplyDelete

Post a Comment

Popular posts from this blog

How to control Temperature and Humidity in Air Handling Unit

  How to control Temperature and Humidity in Air Handling Unit Overview Air Handling unit is a system used to supply temperature and Humidity controlled filtered air to the cleanroom. For air filtration various types of filters are used in AHU. And for temperature and Humidity controlling cooling and heating coils are provided in AHU. Goals Control the temperature of air used in the cleanroom  Control the humidity of air used in cleanroom  Air filters Specifications    The air Handling unit consists of Air filter  Cooling coil Heating coil Air blower HEPA Filter  Controlling of Temperature and Humidity  By Cooling Method  The cooling coil recirculates the chilled water having temperatures between 4°C to 6°C. This chilled water comes from the Chiller through centrifugal pumps. When we start the Air Handling unit blowers sucks the air through the pre filters of the air Handling unit. When blowers sucks air, it passes through the cooling co...
2 comments
Read more

AIR FLOW, AIR VELOCITY, ACPH, AHU CAPACITY

Air Changes per Hour AIR VELOCITY AND ACPH OF ROOM OR AREA   Procedure to be followed: Air Velocity Measurement and Calculation of Air Changes: Objective : To demonstrate  that the   air system is balanced and capable of delivering air velocities and providing number of air changes per hour in the respective rooms as   per requirement. Equipment to be used: Hotwire Anemometer or capture Hood Pre Requisite: Air Volumes through supply and return grills and filters should be adjusted as per the design requirement of Air Change Rate and Differential Pressure. Test Method : Ensure that the Supply blower of the AHU is "ON" prior to the start of the observations. For compliance of air change rate, velocity to be measured at 5   different locations to below the each terminal or Grill (Four Corners and center) with the help of calibrated Anemometer. Calculate the   average  velocity of the air coming from Plenum HEPA filter / supply air grill. Calculate the air...
4 comments
Read more

HVAC Validation In pharma Industries

HVAC VALIDATION As per ISO guidelines for HVAC validation. In HVAC Validation  below points are determined and validated that they are in within range as per designed which will pass the respective ISO standard class acceptance criteria. 1)Air velocity and CFM calculation 2)Air changes per hour 3) Installed filter leakage test 4) HEPA filter integrity test 5)Air flow pattern test or smoke test 6)Partical count test 7)Total variable count 8) Temperatur and pressure monitoring 9) Temperature and Humidity recovery test 10) Fresh air calculation All this points are determined recorded in documents.All this validation process done by validation contractors under observation of respective company Engineer. 1) Air velocity and CFM calculation :-   - Scan the area of the HEPA filter with probe of anemometer 6 inches from the filter face. - For accurate velocity take the velocity of air at five place of filters ( Four corners and centre of filter) - Record the air velocity i...
6 comments
Read more