Effect of Environmental Factors on Bunker Temperature and Pressure; A Study from Region with Harsh Tropical Weather

Abstract

Background: Stabilization of weather factors especially temperature, pressure and humidity in bunkers that housed the Linear accelerators is necessary for safety of equipment and their efficient function for our patients. Daily variation of such factors can lessen the performance of Linear accelerators resulting to an error in their output and wrong dosimetry. Sokoto centre being located in the North-Western region of Nigeria with three unique seasons (Dry hot, Harmattan winter and Wet raining seasons) require a study of this kind to ascertain the influence of those harsh environmental factors on bunker's internal air condition. Methods: Daily records of Linac bunker temperature and pressure were measured using Precision mercury-in-glass thermometer and Opus barometer (OPUS 10 THI) from January 2019 to December 2021. Similarly, the corresponding daily external environmental temperature and pressure for the study period were obtained from Nigerian Meteorological Agency. The values were grouped according to the months of year, mean values of temperature and pressure for each month of the year were generated and graphs and bar-charts were plotted for both bunker and external environment. Similarly, an overall mean score for both temperature and pressure of each month of the three years period were generated and graphs were plotted with those values for bunker and external environment. Results: The overall mean external temperature for the study period was 35.7°C, ± 3.82 as standard deviation (SD) and with a range of 26.0 – 43.6 °C, while for the overall mean bunker temperature it was 27.1°C ±1.7 SD and a range of 23.1 - 31°C. For the external environmental pressure, the overall mean value was 78.1hpa ± 1.5 as SD and a range of 68.1– 83.1hpa, while for the bunker it was 977.2 hpa ± 2.55 as SD and a range of 966.9 – 988.7 hpa. Using the pearsons correlation, it indicate that there is a significant association between environmental and bunker temperature (p-value=0.002). Conclusion: External environmental temperature showed a significant influence on bunker temperature despite the presence of chillers. But for environmental and bunker pressure, the relationship is complex and non-significant. Similarly, the seasons of the year also influenced bunker temperature.