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ppm to lb/MMBtu Converter (F-Factor Method)

Convert ppmvd at a measured O2 to lb/MMBtu with an oxygen-based F-factor (Fd), or back. Formula, steps, and Method 19 reference shown.

Heat-input-based limits (lb/MMBtu) are compared with stack concentrations using a fuel-specific F-factor. Enter the Fd value for your fuel from EPA Method 19 or the value your permit specifies.

ppm to lb/MMBtu calculator

From Method 19 (40 CFR Part 60, Appendix A-7) or your permit.

Use the standard conditions the F-factor is expressed at.

Fill in every field to see the result.

Questions engineers ask

Where do F-factors come from?
EPA Method 19 (40 CFR Part 60, Appendix A-7) tabulates F-factors by fuel type and explains how to calculate them from a fuel analysis. Some permits specify the value to use.
Does it matter if my ppm is already corrected to 15% O2?
Use the O2 level the concentration is expressed at. A value corrected to 15% O2 uses 15 in the O2 term; a raw value uses the measured O2. Both give the same lb/MMBtu.

More converters: ppm to lb/hr, O2 correction, lb/MMBtu to lb/hr, g/hp-hr to lb/hr, lb/hr to tons/yr, ppm to mg/m³, Wet to dry basis.

How this works

Formula

  • E (lb/MMBtu) = C(lb/dscf) × Fd × 20.9 ÷ (20.9 − %O2d)
  • C(lb/dscf) = ppmvd × 10⁻⁶ × MW ÷ V̂

Before you rely on the number

  • Fd is fuel specific. AirPermitHub does not prefill it; take it from Method 19 or your permit so the source is on record.
  • The O2 entered is the O2 level the concentration is expressed at: the measured O2 for a raw result, or the reference O2 for a corrected one.
  • Many rules express NOx as NO2 when converting to mass. Check the rule that applies.
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