Welding zone | Minimum air flow1 cubic feet/minutes | Duct diameter inches2 |
4 to 6 inches from arc or torch— | 150 | | 3 |
6 to 8 inches from arc or torch— | 275 | | 3 1/2 |
8 to 10 inches from arc or torch— | 425 | | 4 1/2 |
10 to 12 inches from arc or torch— | 600 | | 5 1/2 |
1 | When brazing with cadmium bearing materials or when cutting on such materials increased rates of ventilation may be required. |
2 | Nearest 1/2-inch duct diameter based on 4,000 feet per minute velocity in pipe. |
(2) Fixed enclosure. A fixed enclosure with a top and not less than two sides which surround the welding or cutting operations and with a rate of airflow sufficient to maintain a velocity away from the welder of not less than 100 linear feet per minute.
[Statutory Authority: RCW
49.17.010,
49.17.040,
49.17.050, and
49.17.060. WSR 15-24-100, § 296-24-71505, filed 12/1/15, effective 1/5/16; Order 73-5, § 296-24-71505, filed 5/9/73 and Order 73-4, § 296-24-71505, filed 5/7/73.]