The assessment of the amount, type and energy of radiation arriving at any component location cannot be performed without an accurate knowledge of the external environment and also an understanding of the attenuating effect of any material between the location and the external environment. This attenuation is commonly known as shielding.
Shielding occurs in two ways; “built-in” shielding, that is the fortuitous shielding afforded by materials already included in the design, and “add-on” shielding, which is added specifically for the purposes of attenuating radiation. This clause identifies the standard approaches to be used when calculating the effects of shielding on the radiation environment experienced by a component, system or astronaut.