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Guidelines for the Use of Explosives In or Near Canadian Fisheries Waters

Appendix II - General Equations to Determine Setback Distance for Confined Explosives to Meet Guideline Criteria of 100 kPa

Equation (A)

Equation (A) describes the transfer of shock pressure from the substrate to the water.

	PW	=
where:
	PW	=	pressure (kPa) in water
	PR	=	pressure (kPa) in substrate
	ZW	=	acoustic impedance of water
	ZR	=	acoustic impedance of substrate

Equation (B)

Equation (B) describes the relationship between acoustic impedance and the density and velocity of the medium through which the compressional wave travels.

where:
	DW	=	density of water = 1 g•cm-3
	DR	=	density of the substrate in g•cm-3
	CW	=	compressional wave velocity in water
		=	146,300 cm•s-1
	CR	=	compressional wave velocity in substrate in cm•s-1

Equation (B) (continued):

The following values are used for D_R and C_R for various substrates:

Substrate	DR (g•cm-3)	CR (cm•s-1)
Rock	2.64	457,200
Frozen Soil	1.92	304,800
Ice	0.98	304,800
Saturated soil	2.08	146,300
Unsaturated soil	1.92	45,700

Equation (C)

Equation (C) describes the relationship between the peak particle velocity (V_R) and the pressure, density and compressional wave velocity in the substrate.

Equation (D)

Equation (D) represents the scaled distance relationship and is used to equate the peak particle velocity to charge weight and distance.

	VR	=	100 (R/W.5)-1.6
where:
	VR	=	peak particle velocity in cm•s-1
	R	=	distance to the detonation point in m
	W	=	charge weight per delay in kg