Shielding

Radiological shielding is a problem of source, energy, material, geometry and time — not simply wall thickness.

PF_γ

ShelterFactor uses the conceptual external-radiation protection factor PF_γ = D_outside / D_inside. A higher value represents greater reduction for the defined geometry and scenario.

Use the building intelligently

Basements, internal rooms, masonry, concrete, soil and surrounding building mass can materially change external dose. Windows and lightweight envelope sections can be comparatively weak paths.

Groundshine matters

After deposition, external radiation from contaminated ground and surfaces can become an important exposure pathway. Air filtration does not remove this contribution.

Assessment before modification

Room selection and geometry can sometimes provide substantial benefit before additional shielding mass is considered. Any structural modification must also account for building loads and safe construction.