Flame Quenching Distance Calculator

Flame Quenching Distance Calculator

Flame arrestors, spark plug gaps, and safety mesh screens all rely on a real physical limit: a flame cannot propagate through a gap narrower than its quenching distance, because the walls conduct away heat faster than the reaction can sustain itself.

The Formula

d_q = Pe × δ

The quenching Peclet number (Pe) for many hydrocarbon-air flames falls in roughly the 40-50 range, multiplied by the laminar flame thickness (δ).

Worked Example

A flame thickness of 0.05 mm with a Peclet number of 45: d_q = 45 × 0.05 = 2.25 mm.

This is close to real-world quenching distances measured for methane-air flames, which is part of why standard flame arrestor mesh openings are sized well below this range.

How to Use This Calculator

1. Enter the quenching Peclet number (or use a typical value around 40-45 if unknown).
2. Enter flame thickness in mm - get this from the Laminar Flame Thickness Calculator if needed.