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I hate balancing air systems, so how to help you?

The answer is here . . . see user guide

Proportional balancing method with AirTAB superEZ program:

• light-weight, mobile and super easy tool for Air Testing And Balancing (AirTAB) at job site

• measure, record and calculate results at job site

• no guessing, arbitrarily, or trial and error 

• save hundreds of man-hour in air balancing

• specially designed to assist commissioning engineers and contractors in air TAB

With AirTAB superEZ program doing the most tedious part of the proportional balancing calculations, one does not need many days of field experience and learning to start using the proportional balancing method quickly and confidently.

Aim: creating a mobile design environment (ShowMe!) for the commissioning engineers & contractors in today's mobile world.

Results: Instant solutions at your fingertips at job site.

Highlights:

• proportional balancing calculations in accordance to SMACNA guideline.

• one "click" to instant results for immediate adjusting and balancing work at job site.

• super easy to use with no learning curve to start using proportional balancing method.

• input data independent of units.

• fully mobile & independent program (no setup is required).

• save inputs for retrieval.

• save results to pdf or text file for printing.

• copy columns and cells from Excel spreadsheet for inputs into AirTAB.

• copy results from AirTAB for pasting onto Excel spreadsheet, Words, etc.

• designed for Windows PC.

 So, What is Proportional Balancing Method?  

Proportional balancing method is a better, faster, preferred and most efficient method as compared to the stepwise or sequential balancing method. Absolutely no guessing, arbitrarily, or trial and error, the proportional balancing method is a systematic method of balancing based on physical laws of fluid flow with predictable results. Each outlet is only balanced (adjusted) once to the outlet with the lowest %D (= Measured/Design). Minimum time is required to balance a system as compared to stepwise balancing. Large systems can be tested and balanced more quickly and accurately, saving hundreds of man hours in the testing and balancing process. The biggest feature of proportional balancing is that once it is proportionately balanced and set, the quantity of airflow from each outlet will always remain in the same ratio to other outlets. The proportional distribution of air into the terminal outlets will remain unchanged even if the fan settings are modified.

The principles of proportionally balancing require that all the dampers in the distribution system be full open and that at least one outlet volume damper (the outlet with the lowest %D) will remain open. If the system has branch ducts, at least one branch volume damper (the branch with the lowest %D) will also remain full open. The proportional balancing approach can be used for both water and air balancing.

 Worked Example: Air Balancing by Proportional Method  

download (the images presented in the document are based on an older version of AirTAB): AirTAB comparison example with SMACNA's

Proportional balancing method is balancing from the terminal outlets back to the fan. The total system balancing is briefly described as follows. To learn more, consult SMACNA, ASHRAE, etc.

Consider the air system schematic as illustrated. All outlets and branch dampers are numbered (#1 to #11). The 1st airflow measurement is done and recorded with all dampers fully open, and fan at full output.

(1) Outlets (#4 to #9) balancing on Branch A:

Step 1: Enter Outlet number, Design and Measured value

Step 2: Click “Result” button.

The results are presented below. Note that the Outlets are rearranged from the lowest %D to the highest %D.

Adjust the outlets in sequence (from the lowest %D to the highest %D) to the values as calculated under the column “Adjust.To”. Note that the outlet with the lowest %D shall remain open and is not adjusted. The predicted airflow after adjustment is shown under the "Predicted" column. 

It’s done for the outlets (proportional balanced to each other) on Branch A - fast & easy!

(2) Outlets (#1 to #3) balancing on Branch B:

The 3 outlets on Branch B are proportional balanced to each other in the same manner. The printout results are shown below.

(3) Branch ducts (#10 to #11) balancing:

The two branches (A & B) are then proportional balanced to each other in the same manner. The printout results are shown below.

Note: After all the branch ducts are proportional balanced to each other, the predicted results calculated earlier for the terminal outlets also change. On Branch A, the predicted outlet airflow will go up to 180. On Branch B, it will go down to 180.

(4) Supply source/Fan balancing:

When all the outlets and branch ducts balancing are completed, then adjust (if needed) the main discharge damper (C) or fan capacity to bring the system to within 10% of the design flow.