48. The authorization holder must comply with the following firing procedure:(1) before proceeding with the firing, the person responsible for the blasting must ensure that the persons present have taken shelter;
(2) the following sound signals must be emitted with a siren of at least 120 decibels:(a) immediately before blasting, 12 short horn signals at one-second intervals;
(b) 30 seconds must elapse between the last warning signal and the time of firing;
(c) after blasting, once the blasting area is safe, one continuous 15-second horn signal must announce that work may be resumed in the area;
(3) the person responsible for the blasting must make sure that workers take shelter outside the blasting area before the first signal and that they remain there until the 15-second signal is sounded;
(4) a code of sound signals reserved for blasting operations must be written in coloured letters 150 mm high, against a contrasting background, on a board 1.2 m high by 2.4 m wide, placed at all points of access to the blasting site.