Barrier Level means the Barrier Level as specified in § 1 of the Product and Underlying Data.
Working level (WL) means any combination of short-lived radon daughters in 1 liter of air that will result in the ultimate emission of 1.3E+5 MeV of potential alpha particle energy. The short-lived radon daughters are—for radon-222: polonium-218, lead-214, bismuth-214, and polonium-214; and for radon-220: polonium-216, lead-212, bismuth-212, and polonium-212.
Working level month (WLM) means an exposure to 1 working level for 170 hours (2,000 working hours per year divided by 12 months per year is approximately equal to 170 hours per month).
Trigger Level means with respect to an Index, the level specified as such in Annex 1 with respect to such Index
Base Level means the following amounts plus the percentage