Answer to Question #253712 in Mechanical Engineering for angel

Question

A root cellar receives an input of 0.1µCi of radon-222 per hour through the dirt floor. Radon-222 has an approximate half-life of 3.8 days.

Answer 1

The part of question left out is:

If the volume of the room is 10m³ how much outside area must be supplied to keep radon levels below the EPA recommended limit of 4pCi/l.

EPA recommended level of radon=4pCi/L

Volume of the room= 10m³ =1000L

Allowed limit of Rn-222=40000pCL=$4.0e^{-8}Ci$

Input radiation=$1.0e^{-6}Ci/hr$ =1.0pCi/L/hr

By supplying air of 2500L/hr the concentration is always maintained at $\frac{1.0e^{-6}}{2500}=4.0e^{-10}L$

All the input radiation is distributed over the incoming air and flushed out

Air to be supplied =2500L/hr

=2.5m³/hr