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Control Device Efficiency Calculator

Calculate removal efficiency from inlet and outlet measurements with typical range comparison

Free control device efficiency calculator. Enter inlet and outlet concentrations in ppm, mg/m3, gr/dscf, or lb/hr to calculate removal efficiency. Compare results against typical ranges for 15 device types including baghouses, ESPs, scrubbers, SCR, thermal oxidizers, and carbon adsorbers. Optional flow rate input calculates mass removal in lb/hr and tons/year.

Pro Tip: If your tested efficiency falls below the typical range for your device type, it usually means something specific. For baghouses, check for bag leaks, improper cleaning cycles, or wrong bag material. For scrubbers, check liquor flow rate, pH, and packing condition. For SCR, check catalyst age, ammonia injection rate, and temperature window. A low number is not just a data point - it is a maintenance signal.

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Control Device Efficiency Calculator
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How It Works

  1. Select Device Type

    Choose from 15 control device types. The calculator displays typical efficiency ranges and auto-selects the primary target pollutant.

  2. Enter Concentrations

    Input inlet and outlet concentrations in matching units (ppm, mg/m3, gr/dscf, or lb/hr). These typically come from simultaneous inlet/outlet stack testing.

  3. Add Flow Rate (Optional)

    Enter the gas flow rate to calculate mass removal rates. This converts efficiency percentages into lb/hr and tpy of pollutant removed.

  4. Compare Against Typical Ranges

    See how your calculated efficiency compares to the typical range for that device type. Results below the typical minimum suggest maintenance or design issues.

Built For

  • Stack test engineers verifying control device performance after installation
  • Compliance managers reviewing quarterly or annual performance test results
  • Environmental consultants evaluating control technology options for BACT analysis
  • Equipment vendors validating guaranteed efficiency during commissioning
  • Plant engineers troubleshooting underperforming pollution control systems

Assumptions

  • Inlet and outlet measurements are taken simultaneously during the same test period.
  • Gas flow rates are consistent between inlet and outlet measurement points.
  • Concentration units are consistent between inlet and outlet values.

Limitations

  • Does not account for fugitive emissions bypassing the control device.
  • Typical ranges are generalized and may not apply to all configurations.
  • Mass removal calculations assume constant flow rate during the operating period.

References

  • EPA Air Pollution Control Technology Fact Sheets
  • EPA RACT/BACT/LAER Clearinghouse (RBLC)
  • EPA AP-42 Chapter 1 Control Efficiency Notes
  • OAQPS Control Cost Manual (EPA 452/B-02-001)

Frequently Asked Questions

Removal efficiency equals (inlet concentration minus outlet concentration) divided by inlet concentration, multiplied by 100 to express as a percentage. Both concentrations must be in the same units and ideally measured simultaneously during the same test run. For mass-based efficiency, use mass flow rates (lb/hr) instead of concentrations.
For permit applications, use either manufacturer-guaranteed efficiency (for new equipment), your facility-specific stack test data (for existing equipment), or EPA presumptive RACT/BACT values for the device type. AP-42 control efficiency notes and RBLC (RACT/BACT/LAER Clearinghouse) entries provide precedent values that regulators will accept.
Common causes: baghouse bag leaks or improper cleaning, scrubber low liquor flow or wrong pH, SCR catalyst degradation or ammonia slip, thermal oxidizer insufficient temperature or residence time, carbon adsorber breakthrough (bed exhausted). Below-range efficiency is a signal to inspect and maintain the system, not just a number to report.
Disclaimer: Typical efficiency ranges represent general industry experience and vary by specific design, operating conditions, and pollutant characteristics. Control device performance guarantees and permit limits should be based on site-specific testing or manufacturer specifications, not generic ranges.

Learn More

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Baghouse, ESP, scrubber, SCR, thermal oxidizer, carbon adsorber — how to select the right air pollution control device for your source and pollutant, plus cost-effectiveness analysis.

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