## Abstract

This report describes a computer model that calculates shielding factors for indoor residence in multistorey and single-family houses for gamma radiation from activity deposited on roofs, outer walls, and ground surfaces. The dimensions of the buildings including window areas and the nearby surroundings has to be specified in the calculations.

Shielding factors can be calculated for different photon energies and for a uniform surface activity distribution as well as for separate activity on roof, outer wall, and ground surface achieved from decontamination or different deposition

velocities.

For a given area with a known distribution of different houses a weighted shielding factor can be calculated as well as a timeaveraged one based on a given residence time distribution for work/school, home, outdoors, and transportation.

Calculated shielding factors are shown for typical Danish houses. To give an impression of the sensitivity of the shielding factors on the parameters used in the model, variations were made in some of the most important parameters: wall thickness, road and qround width, percentage of outer wall covered by windows, photon energy, and decontamination percentage for outer walls, ground and roofs. The uncertainty of the calculations is discussed.

Shielding factors can be calculated for different photon energies and for a uniform surface activity distribution as well as for separate activity on roof, outer wall, and ground surface achieved from decontamination or different deposition

velocities.

For a given area with a known distribution of different houses a weighted shielding factor can be calculated as well as a timeaveraged one based on a given residence time distribution for work/school, home, outdoors, and transportation.

Calculated shielding factors are shown for typical Danish houses. To give an impression of the sensitivity of the shielding factors on the parameters used in the model, variations were made in some of the most important parameters: wall thickness, road and qround width, percentage of outer wall covered by windows, photon energy, and decontamination percentage for outer walls, ground and roofs. The uncertainty of the calculations is discussed.

Original language | English |
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Place of Publication | Roskilde, Denmark |
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Publisher | Risø National Laboratory |

Number of pages | 45 |

ISBN (Print) | 87-550-0933-6 |

Publication status | Published - 1982 |

Series | Risø-M |
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Number | 2270 |

ISSN | 0418-6435 |

## Keywords

- Risø-M-2270
- Buildings
- Computer calculation
- Decontamination
- Dose rates
- External irradiation
- Fallaout deposits
- Gamma radiation
- Radiation doses
- Shielding
- Surface contamination
- Surfaces