What exactly is ACH?
The easiest way to calculate airflow is in cubic feet per minute. An air change is how many times the air enters and exits a room from the HVAC system in one hour. Or, how many times a room would fill up with the air from the supply registers in sixty minutes.
A 10,000 CFM system will be needed to replace all of the air in a 10,000 ft3 room every minute.
How to Measure the Volume of a Specific Space?
Multiply length × width × height to measure the volume of a room. A room that is 50 feet long, 40 feet wide, and 20 feet tall is 40,000 feet³ (50× 40 × 20 = 40,000).
Some areas have irregular walls, bent ceilings or other characteristics that render measurement more difficult. Complicated shapes can be broken down into basic shapes to be measured and the results can then be added up to get the sum.
Simply multiply the total area by the average height to get the volume of any shape.
CFM (Cubic Feet per Minute) is an airflow measurement unit used in HVAC calculations.
Most of the time, we need to measure CFM for a room in order to instal fans, air purifiers, air conditioners, and other similar devices.
Example:
We have a standard bedroom of 600 square foot. How much CFM should the fan of that room have if we need to change all air twice per hour (every 30 minutes)?
CFM Calculation:
The airflow must be powerful enough to exchange the air of the entire volume of a 600 square foot space with an 8 square foot ceiling height twice per hour.
Volume of a room = 600 sq ft x 8 ft = 4,800 ft3. To change it 2 times per hour (ACH = 2), we need to deliver 9,600 ft3 per hour. CFM is a ft3 per minute unit. That’s why we need to divide the total volume by 60; hence 9,600/60 = 160 CFM.
Answer For CFM Conversion:
We need a 160 CFM airflow for a 600 sq ft standard room and 2 ACH).
Here’s a neat CFM calculator that calculates CFM based on length of room , width of room and ceiling height, and the number of air changes per hour (ACH).
I am really impressed with your writing skills and also with the layout on your weblog. Is this a paid theme or did you modify it yourself? Anyway keep up the nice quality writing, it抯 rare to see a nice blog like this one today..
Thanks