t = Spill Clearance Time in Minutes
V = Volume of Imaging Room in Milliliters
A = Maximum Activity Accidentally Released; Assumed As Dose Per
Patient. 20,000 Micro-curies
Q = Exhaust Air Volume in Milliliters Per Minute
MPC = 1 x 10-5 Micro-curies Per Milliliter Space Volume, per NRC's
recommendation for restricted spaces
4.12.3.2 Storage & Preparation Room: Using the Imaging Room spill time,
calculate the volume of exhaust air quantity required for the
Radiopharmacy Laboratory. The formula is:
Q = (-V) x ln (MPC x V)
t
A
Q = Exhaust Air Quantity in Milliliters Per Minute
V = Volume in Milliliters of Storage & Preparation Room
T = Spill Clearance Time For Imaging Room in Minutes
MPC = Maximum Permissible Concentration 1 x 10-5 Micro-curies Per
Milliliter of Space Volume
A = Assumed Spill Per Incident
= Dose Per Patient
= 20,000 Micro-curies
The air quantity, thus calculated should be increased, if required, to
meet the needs of the fume hood exhaust or the internal heat load.
HVAC DESIGN MANUAL
4-7
HVAC REQUIREMENTS FOR UNOCCUPIED AREAS
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