Appendix B Separation Distance Calculator
This spreadsheet calculates the minimum distance required between the outlet of an exhaust system and the outdoor air intake to a ventilation system to avoid re-entrainment of exhaust gases. The new procedure addresses the technical deficiencies in the simplified equations and tables that are in Standard 62.1 (as of the 2022 edition) and in model building codes.

The new method, on which this calculator is based, is more accurate than the existing Standard 62.1 equation (as of the published 2022 edition), which underpredicts and overpredicts observed dilution more frequently than the new method. In addition, the new method accounts for the following additional important variables: stack height, wind speed, and hidden versus visible intakes. The new method also has theoretically justified procedures for addressing heated exhaust, louvered exhaust, capped heated exhaust, and horizontal exhaust that is pointed away from the intake.