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Bleed Down Test Calculator
  CFM LEAK = (VR + VP)* (P2 - P1 (abs))*(60) / (T)*(PATM)*C  
    VR = Volume of Receiver in Gallons    
    VP = Volume of Piping in Gallons    
    P2 = Maximum Pressure at Unload / Stop    
    P1 = Minimum Pressure at Load / Start    
    T =  Time of Test from No Load to Load (Stop to Start) (Sec)  
    PATM = Atmospehric Pressure (Site Corrected)    
    C Correction factor (See note 6 below)
    Total CF=    
    System Leakage (CFM)    
1. Identify the complete storage capacity of the system (receivers, pipes, etc) in gallons.
2. If calculating for leaks: Be sure all prodction equipment is "off" and isolated. Isolate all auto. drains and bleeds
2a. If calculating for system flow demand: Be sure all production equipment is "on" and fully operational. All auto. Drains should be "on" and fully functional to allow for the additional demand.
3. Pump the system up to the cut-out/unload of the compressor. Record this pressure.
4. Record the time in minutes (and cut-in press.) required for the system to bleed down to the cut-in/load pressure.
5. Enter the recorded data into the proper cells in the formula above. 
6. Use 1.0 for 10psid or below. At wider than 10psi differentials between load and unload some allowance for rate of flow change as the pressure falls must be considered. For example: if the differential is 50psid then entering a "Correction" value of 1.25 will be relatively accurate. For 20psid a 1.12 correction factor will apply.
Contact Accurate Air Engineering, Inc for options to correct your compressed air systems inefficiencies
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