56.6502—Safety fuse.
(a)
The burning rate of each spool of safety fuse to be used shall be measured, posted in locations which will be conspicuous to safety fuse users, and brought to the attention of all persons involved with the blasting operation.
(b)
When firing with safety fuse ignited individually using handheld lighters, the safety fuse shall be of lengths which provide at least the minimum burning time for a particular size round, as specified in the following table:
| Number of holes in a round | Minimum burning time |
|---|---|
| 1 | 2 min. 1 |
| 2-5 | 2 min. 40 sec. |
| 6-10 | 3 min. 20 sec. |
| 11 to 15 | 5 min. |
|
Code of Federal Regulations
308
|
|
| 1 For example, at least a 36-inch length of 40-second-per-foot safety fuse or at least a 48-inch length of 30-second-per-foot safety fuse would have to be used to allow sufficient time to evacuate the area. | |
(c)
Where flyrock might damage exposed safety fuse, the blast shall be timed so that all safety fuses are burning within the blastholes before any blasthole detonates.
(f)
Safety fuse shall be ignited only after the primer and the explosive material are securely in place.
(g)
Safety fuse shall be ignited only with devices designed for that purpose. Carbide lights, liquefied petroleum gas torches, and cigarette lighters shall not be used to light safety fuse.
(h)
At least two persons shall be present when lighting safety fuse, and no one shall light more than 15 individual fuses. If more than 15 holes per person are to be fired, electric initiation systems, igniter cord and connectors, or other nonelectric initiation systems shall be used.