Safety fuse blasting requirements

Safety fuse is allowed only when sources of extraneous electricity make using electric blasting caps dangerous. See 1926.907(a).

• Do not substitute safety fuse for electric caps unless there is a real electrical hazard (for example, nearby power lines or stray currents) that could unintentionally fire electric caps.
• Also note that any fuse that has been hammered or injured in any way must not be used (also in 1926.907(a)).

No — a safety fuse that has been hammered or injured in any way is forbidden for use. See 1926.907(a).

• Damaged insulation, kinks, crushed sections, or any visible deformity means the fuse must be taken out of service.
• Replace damaged fuse reels and report damaged stock so only intact fuses are used.

No — hanging a fuse on nails or other projections that create a sharp bend in the fuse is prohibited. See 1926.907(b).

• Sharp bends can damage the fuse and create an unsafe condition; route and store fuses so they are not kinked or pinched.
• Use proper racks or reels for hanging fuses without causing sharp bends.

Before capping safety fuse, a short length must be cut from the end of the supply reel to ensure a fresh cut end in each blasting cap. See 1926.907(c).

• This practice removes any frayed or contaminated end so the cap seats properly and reliably on the fuse.
• Make the cut with appropriate cutting tools in a safe location away from ignition sources.

Only a cap crimper of approved design must be used for attaching blasting caps to safety fuse, and crimpers must be kept in good repair and accessible for use. See 1926.907(d).

• Use only crimpers designed for blasting caps (approved by your jurisdiction or industry practice).
• Inspect crimpers regularly for wear or damage and store them where qualified personnel can reach them quickly when needed.

No — no unused cap or short capped fuse may be placed in any hole to be blasted; such unused detonators must be removed from the working place and destroyed. See 1926.907(e).

• Never leave spare or partially prepared detonators in blast holes; keep the blast area clear of unused detonators.
• Follow company procedures for safe disposal or destruction of unused detonators.

It is forbidden to cap safety fuse, or to make up primers, in any magazine or near any possible source of ignition. See 1926.907(f).

• Perform capping and primer assembly in designated safe areas away from open flames, electrical equipment, smoking, or hot work.
• Ensure magazines (explosive storage) remain free of capping operations to prevent accidental initiation.

No — no one is permitted to carry detonators or primers of any kind on his or her person. See 1926.907(g).

• Transport detonators only in approved containers and follow site procedures for movement between storage and the blast area.
• Prohibit pockets or belts as storage for any detonators or primers.

The minimum length of safety fuse to be used in blasting is the length required by State law, but it must not be less than 30 inches. See 1926.907(h).

• Comply with any State-specific longer minimum; the federal minimum is 30 inches.
• Verify and document applicable State or local fuse length requirements before work begins.

At least two men must be present when multiple cap and fuse blasting is done by hand lighting methods. See 1926.907(i).

• This requirement provides redundancy for safety, communication, and emergency response during hand-lighting operations.
• Ensure both workers are trained in the procedure and emergency actions.

Not more than 12 fuses may be lighted by each blaster when hand lighting devices are used; however, when two or more safety fuses in a group are lighted as one by means of igniter cord or similar devices, they may be considered as one fuse. See 1926.907(j).

• Limit hand-lighting tasks to 12 fuses per blaster unless using an approved grouped ignition method.
• When using igniter cord or similar devices to light a group simultaneously, count that group as a single fuse for the 12-fuse limit.

No — the so-called "drop fuse" method of dropping or pushing a primer or any explosive with a lighted fuse attached is forbidden. See 1926.907(k).

• Use approved procedures for placing primers so a lit fuse is not used to drop or push explosives into position.
• The prohibition reduces the risk of accidental initiation or improper seating of charges.

Cap and fuse shall not be used for firing mudcap charges unless the charges are separated sufficiently to prevent one charge from dislodging other shots in the blast. See 1926.907(l).

• Ensure physical separation or secure seating so an exploding mudcap won't disturb neighboring charges.
• If sufficient separation cannot be achieved, use an alternate firing method to prevent sympathetic detonation or dislodgement.

When blasting with safety fuses, the blaster must consider the fuse's length and burning rate so that sufficient time, with a margin of safety, is always provided for the blaster to reach a place of safety. See 1926.907(m).

• Calculate expected delay by multiplying fuse length by the burn rate and include extra time as a safety margin.
• Account for variables (e.g., wet fuses burn slower) and choose longer fuses if needed to ensure safe egress times.

When using hand lighting methods, at least two men must be present and each blaster may light no more than 12 fuses, with grouped fuses lit as one by igniter cord counted as a single fuse. See 1926.907(i) and 1926.907(j).

• Ensure both crew members know who is the designated blaster and who is the assistant/observer.
• Plan grouped ignition (igniter cord) methods in advance to reduce the number of individual fuses the blaster must light.

Crimping must be done with an approved-design cap crimper that is kept in good repair and accessible, and crimping or primer assembly must not be performed in any magazine or near possible sources of ignition. See 1926.907(d) and 1926.907(f).

• Designate a safe, non-ignition area for crimping and assembly, away from explosive storage and hot work.
• Inspect and maintain crimpers so that faulty tools do not compromise cap attachment integrity.

Unused detonators or short-capped fuses must not be placed in blast holes and must be removed and destroyed if present; additionally, no one is allowed to carry detonators or primers on their person. See 1926.907(e) and 1926.907(g).

• Transport detonators in approved containers and store them in authorized magazines until they are needed.
• Establish and train crews on procedures for handling unused or misfired detonators, including safe destruction methods.