The following are basic formulas used in the calculation of single, dual and triple-layer shield designs. It is important to keep in mind that the permeability values used are dependent upon the material composition and the geometry of the shield. We welcome you to work on your own calculations, but we do encourage you to contact our experienced staff before finalizing your designs.

A= Attenuation @ DC
µ= Permeability value of material
RI= Inside Radius
RO= Outside Radius

Dual Layer
A= 1+S₁+S₂+(S₁S₂N₁₂)
A= Attenuation @ DC
S₁= Attenuation of inner layer (using formula above)
S₂= Attenuation of outer layer (using formula above)

RO₁= Outside radius of inner layer
RI₂= Inside radius of outer layer

Triple Layer
A=(µ/4) * [(1-Q₁Q₂Q₃)+(µ²/16) * (N₁N₁₂N₂N₂₃N₃)+(µ/4) *
(N₁N₃+N₁N₂-N₁N₂N₃) (N₁₂) + (N₁N₃+N₂N₃-N₁N₂N₃)(N₂₃)-(N₁N₁₂N₂N₂₃)]
A = Attenuation @ DC
µ = Permeability of the material
RI₁ = Inside radius of innermost layer
RO₁ = Outside radius of innermost layer
RI₂ = Inside radius of middle layer
RO₂ = Outside radius of middle layer
RI₃ = Inside radius of outermost layer
RO₃ = Outside radius of outermost layer
Q₁ = (RI₁²)/(RO₁²)
N₁ = 1-Q₁
Q₁₂ = (RO₁²)/(RI₂²)
N₁₂ = 1-Q₁₂
Q₂ = (RI₂²)/(RO₂²)
N₂ = 1-Q₂
Q₂₃ = (RO₂²)/(RI₃²)
N₂₃ = 1-Q₂₃
Q₃ = (RI₃²)/(RO₃²)
N₃ = 1-Q₃