1. (1) Restricted or prohibited use.

   1. (a) Safety fuse and detonators, used for conventional blasting, must be in the following:

      1. (i) When extraneous electricity or radio frequency transmissions make the use of electric detonators and wire systems dangerous.
      2. (ii) When overhead electric transmission lines cannot be deenergized and there is danger that blasting wires may be thrown onto the overhead lines during a blast.
      3. (iii) For avalanche control hand charges.
      4. (iv) For specialized applications when detonators and fuses are more suitable than electric or other nonelectric initiation systems.
   2. (b) Mudcap charges. A detonator and fuse cannot be used for firing mudcap charges, unless the charges are separated to prevent one charge from dislodging other charges in the blast.
   3. (c) Drop fuse method. Dropping or pushing a primer or any explosive with a lighted fuse attached is prohibited.

   4. (d) Damaged fuses.

      1. (i) Deteriorated or damaged fuses cannot be used.
      2. (ii) It is prohibited to hang fuses on nails or other objects, which causes sharp bends in the fuse.

2. (2) Fuse length. Fuses:

   1. (a) Must be cut long enough to reach beyond the collar of the drill hole.
   2. (b) Must be three feet or longer.

3. (3) Fuse burning rate.

   1. (a) Safety fuse burning rates must be:

      1. (i) Measured.
      2. (ii) Posted in conspicuous locations.
      3. (iii) Brought to the attention of all workers.
   2. (b) A fuse must burn between forty and fifty-five seconds per foot or it cannot be used.
4. (4) Blaster safety. When blasting with safety fuses, the length and burning rate of the fuse must allow sufficient time for the blaster to reach a place of safety.

5. (5) Fuse capping.

   1. (a) Capping location. Fuses:

      1. (i) Must not be capped in any magazine or near any possible source of ignition.
      2. (ii) Must be capped in a place designated for this purpose.
      3. (iii) Must be capped at least one hundred feet from any storage magazine.
   2. (b) Fuse ends. Before capping a safety fuse, a short length must be cut from the end of the supply reel to guarantee a freshly cut end in each detonator.

6. (6) Crimpers.

   1. (a) Design. The design of detonator crimpers used for attaching detonators to safety fuses must be approved.
   2. (b) Condition. Crimpers must be in good repair.
   3. (c) Accessibility. Crimpers must be accessible for use.
7. (7) Waterproofing. The joint between the detonator and fuse must be waterproofed with a compound for use in wet locations.

8. (8) Primers.

   1. (a) Site selection. Primers must:

      1. (i) Not be made in magazines or near possible sources of ignition.
      2. (ii) Be made in a place designated for this purpose.
      3. (iii) Be made a minimum of one hundred feet from any storage magazine.

   2. (b) Making primers. When making primers:

      1. (i) Make only enough for one day's use.
      2. (ii) Only nonsparking skewers must be used for punching the hole in the cartridge to insert the capped fuse.
      3. (iii) A detonator cannot be inserted in explosives without first making a hole in the cartridge of proper size or using a standard detonator crimper.

   3. (c) Storage. Primers must:

      1. (i) Be stored in a box type magazine.
      2. (ii) Not be stored in magazines where other explosives are stored.

9. (9) Hand lighting.

   1. (a) No one may light more than twelve fuses at a time when hand lighting devices are used.

   2. (b) Two fuses may be considered one fuse when two or more grouped safety fuses are lit as a single fuse by:

      1. (i) An igniter cord

         or

      2. (ii) Other similar fuse lighting devices.
   3. (c) When multiple detonators and blasting is done by hand lighting methods, at least two people must be present.

[Statutory Authority: RCW 49.17.010, [49.17].040, and [49.17].050. WSR 02-03-125, § 296-52-67095, filed 1/23/02, effective 3/1/02.]