Final answer:
To determine allowable test pressures, a technician must consider pressure tolerances of system components, standard atmospheric pressure, and apply Pascal's law, while accurately measuring and interpreting pressure units like torr.
Step-by-step explanation:
Determining Allowable System Test Pressures
To determine allowable system test pressures, a technician should take into account the pressure tolerances of the system components and the standard atmospheric pressure. Since air pressure is about 80% of the standard atmospheric pressure at sea level, and assuming standard pressure is 760 mm Hg, which has three significant figures, the technician must calculate the test pressures accordingly. This implies that the technician needs to understand and apply principles such as Pascal's law and the relationships between force, area, and pressure in a hydraulic system.
When dealing with devices like a sphygmomanometer or a closed-end manometer which measures pressure, the technician must be able to read and interpret the measurements accurately, in units such as torr for example. Moreover, if testing valves for pressure tolerances, the technician should also be capable of conducting statistical tests to compare the performance of different valve types under certain pressure levels, like the example given where valves are tested under 4,500 psi.