Final answer:
The correct answer is option 15. Test gauges shall not have a pressure range not exceeding 15.
Step-by-step explanation:
The correct answer is option 15.
In the context of test gauges, the pressure range refers to the maximum and minimum values that the gauge can accurately measure. A pressure gauge with a pressure range not exceeding 15 would be able to measure pressures up to 15 units, but not higher.
For example, if a test gauge has a pressure range of 15 psi (pounds per square inch), it can accurately measure pressures up to 15 psi, but not higher than that.
For safety and accuracy, a pressure gauge should typically not be used at pressures above 75% of its maximum scale value. When selecting the appropriate pressure gauge for a specific application, such as a device for measuring negative pressure or vacuum, the full-scale range should be around four times the expected operating pressure to avoid over-ranging the gauge. In cases where extreme negative pressures are measured, as mentioned with the 25.0 atm negative gauge pressure example, the gauge selected should be properly calibrated to handle such conditions without sustaining damage or providing inaccurate readings.