(Deeming et al. 1977)
| BI-1978 | Potential Flame | Fireline Intensity (BTUS/SEC/FT) | Narrative Comments |
|---|---|---|---|
| 0-30 | 0-3 | 0-55 | Most prescribed burns are conducted in this range. |
| 30-40 | 3-4 | 55-110 | Generally represent the limit of control for direct attack methods. |
| 40-60 | 4-6 | 110-280 | Machine methods usually necessary or indirect attack should be used. |
| 60-80 | 6-8 | 280-520 | The prospects for direct control by any means are poor above this intensity. |
| 80-90 | 8-9 | 520-670 | The heat load on people within 30 feet of the fire is dangerous. |
| 90-110+ | 9+ | 670-1050+ | Above this intensity, spotting, fire whirls, and crowning should be expected. |