Radiation Leakage from Microwave Ovens Used in an Academic Institution.

An academic institution with numerous microwave ovens in routine use never systematically inspected their operating condition nor checked for radiation leakage. Because employees were concerned about the possible risks associated with radiation exposure from ovens used in their workplace, a research survey was initiated to collect information on the ovens’ characteristics and condition of operation. A microwave survey meter (Model HI-1801, Holaday Industries Inc.) was used to check the appliances for radiation leakage. Of the 112 appliances located in the institution, 77 were in common rooms, 30 in research laboratories, 3 in the cafeteria kitchen and 2 in clinics. Characteristics of the appliances included physical condition (excellent 14%, good 40%, average 37% and poor 9%), years of service (>10 years 29%, 6-10 years 35% and < 6 years 34%), total volume (average 58 L and range 20-152 L), compliance with 21 CFR Subchapter J (94%), operating power (120-2400 W), output power (500-1400 W), output frequency (2450 MHz 100%), functional interlock (98%), and interlock shut-off (temporary 14%, permanent 86%). At less than 5 cm, 76% of ovens showed no detectable radiation leakage, 21% showed leakage from 0.02-0.75 mW/cm2, and 3% showed leakage from 0.75-2.5 mW/cm2. Mean leakage for ovens in poor condition was 0.5 mW/cm2 and for ovens in average or good condition was 0.1 mW/cm2. None of the ovens in excellent conditions showed leakage. The mean leakage for ovens used for >10 years was 0.2 mW/cm2 and for others was 0.1 mW/cm2. In conclusion, radiation leakage in 97% of ovens was less than 0.75 mW/cm2, the amount of radiation leakage decreased as the years of service for the ovens decreased, and radiation leakage decreased if the ovens were kept in better physical condition.

کلیدواژه ها:

Radiation Leakage ، Microwave Ovens ، Academic Institution