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Burning Categories

Mixing height x transport wind speed = ventilation rate

Example 1: Mixing height 6000 ft x transport wind speed 14mph = 84000 ventilation rate (category 4)

Example 2: Mixing height 4000 ft x transport wind speed 10mph = 40000 ventilation rate (category 2)

Table 1: Burning Categories
Ventilation Rate Burning Category Explanation of Category
0 to 33,499 1 Low level inversion and stagnant air the entire day. NO BURNING
33,500 to 44,999 2 Inversion until early afternoon and very light transport wind. MID-AFTERNOON BURNING ONLY
45,000 to 59,999 3 Inversion until late morning. Light transport wind. DAYTIME BURNING
60,000 to 111,999 4 Little or no inversion. Moderate transport wind. BURN ANY TIME
112,000 or greater 5 No inversion. Strong and gusty transport wind. BURN WITH CAUTION. GOOD SMOKE DISPERSION, BUT POTENTIAL SEVERE FIRE BEHAVIOR
This page updated: Friday, January 6, 2017 15:58


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