Also posted on LinkedIn, but posts on there disapear like smoke in the wind….
So you’re minding your own business on a Saturday afternoon, casually reading ICRP-66 on the Human Respiratory Tract Model, and come across Table 6. For those who aren’t ‘initiated’, we generally use the worker breathing rate of 1.2 m3/hr in mining when calculating work category or SEG annual doses from long-lived radioactive dust (LLRD).
My heart skipped a beat – have I been wrong all this time?
No, of course not. And shame on you for thinking such a heresy. It turns out workers aren’t going full-tilt for 8 hours – the assumption is 5.5 hours of light exercise at 1.5 m3/hr, then 2.5 hours of sitting around doing SFA at 0.54 m3/hr. We’re not going to discuss the assumption that they never ‘do hard exercise’, a.k.a. work hard.
Keep the derivation of “1.2 m3/hr” in mind when extending worker shifts to 12 hours, as 5.5 and 2.5 may no longer be valid proportions over 12 instead of 8 hours.
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