Some Calculation examples for your training

In an automobile industry a Free Air Delivery test and leakage tests were conducted for a 1000 cfm compressor, by operating the compressors with all equipment that use compressed air turned off.
The results of the Free Air Delivery test showed that the compressor delivers 90% output of the rated capacity.
The results of the leakage test were:
Compressor was on load for 8 minutes
Compressor was unloaded for 48 minutes
Compressor was consuming 144 kW

Calculate the following:
1. Free air delivery or the output of the compressor
2. Specific power consumption
3. % leakage in the compressed air system
4. Quantity of compressed air leakage
5. Power lost due to leakage


1. Calculate the free air delivery or the output of the compressor
Free air delivery
= 90% of rated capacity
= 0.90 x 1000 cfm
= 900 cfm

2. Calculate the specific power consumption
Specific power consumption
= actual output / actual consumption
= 900 cfm / 144 kW
= 6.25 cfm/ kW

3. Calculate the % leakage in the compressed air system
% leakage in the system


4. Calculate the quantity of compressed air leakage
Leakage quantity
= percentage leakage x actual output
= 0.142 x 900 cfm
= 127.8 cfm

5. Calculate the power lost due to leakage
Power lost due to leakage
= Leakage quantity / specific energy
= 127.8 cfm / 6.25 kW per cfm
= 20.45 kW

Disclaimer: The above calculations are for training purpose only. They are not based on AUGUST brand compressor. They should only be a guideline for you to understand calculations