RPR-09

Occupancy factor T

H = Ḣ T t. Occupied dose from a full-time rate.

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Barrier designNCRP 151 T

Governing equation

H=\dot H\,T\,t

$T \in \left[0.02, 1\right]$

where

\dot H: Full-occupancy rate (µSv/h)
T: Occupancy T (—)
t: Hours in period (h)
H: Occupied dose (mSv)

The figure, part by part

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①

Governing law — red

H=\dot H\,T\,t

$T \in \left[0.02, 1\right]$

$T = 0.02$ $H = 0.2$

Along the curve

②

Domain of the variable — blue

T_{\min} = 0.02,\quad T_{\max} = 1

$T \in \left[0.02, 1\right]$

$T = 0.02$ $T = 0.02$

Along the curve

③

Response curve — green

H=\dot H\,T\,t

$T \in \left[0.02, 1\right]$

$T = 0.02$ $H = 0.2$

Along the curve

④

Rate of change — amber

\frac{\mathrm{d}H}{\mathrm{d}T}

$T \in \left[0.02, 1\right]$

$T = 0.026$ $H^{\prime} = 10$

Along the curve

Lecture brief

Historical brief

Inverse-square, half-value layer, ICRP weighting and ALARA are the protection craft since the 1920s commissions. The lab computes transmission, equivalent dose and a shielding snapshot. This sheet (RPR-09 — Occupancy factor T) is the form associated with NCRP 151 T. Working symbols: $\dot H$ , $T$ , $t$ $\rightarrow$ $H$ . NCRP: T = 1 offices, 1/4 corridors, 1/8 waiting rooms, 1/16 outdoor unattended. T never exceeds 1.

Purpose

Purpose: compute

H

from

\dot H

T

t

in Radiation protection via

H=\dot H\,T\,t

H = Ḣ T t. Occupied dose from a full-time rate. Use it when a real radiation protection question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

\dot H = 5.000\,\mathrm{\mu Sv/h}

T = 1.000\,\mathrm{—}

t = 2000.000\,\mathrm{h}

, the governing relation

H=\dot H\,T\,t

yields

H = 10.000\,\mathrm{mSv}

. A room clock and a fraction of presence. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Full-occupancy rate \dot H5 µSv/hOccupancy T T1 —Hours in period t2000 h

Outputs

Occupied dose H10.000 mSv

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Narration of this film

A room clock and a fraction of presence.

NCRP: T = 1 offices, 1/4 corridors, 1/8 waiting rooms, 1/16 outdoor unattended. T never exceeds 1.

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