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Table 1 Conversion factors and constants used in the calculation of the effective dose

Abbreviation	Description	Value	Unit	Reference
CF_Rn	Conversion of ²²²Rn concentration to effective dose	9	nSv/(Bq h m^-3)	[1]
F_eq	Equilibrium factor ²²²Rn progeny	0.4	--	[1]
T	Total hours per year	8760	h/y	-
T_%	Fractional working time (1,752 h year^-1)	0.20	--	-
CF_Nat	Conversion of H_p(10) external natural radiation to effective dose	0.605^a	mSv/mSv	[8]
APF_x-rays	Apron protection factor [H_p(10)_x-rays /effective dose]	10	mSv/mSv	[4, 5]

^aDerived from the conversion factor from air-kerma to H_p(10), which for external gamma radiation of around 800 keV is 1.19 mSv/mGy, and the conversion factor from air-kerma to effective dose of 0.72 mSv/mGy assuming isotropic radiation geometry [8]