During a safety test of a hyperbaric chamber, the internal pressure is estimated to reach 18 bar18\text{ bar}18 bar.
The technician has a choice of four analog pressure gauges, G1G_1G1, G2G_2G2, G3G_3G3, and G4G_4G4, with different ranges as shown below:
- Gauge G1G_1G1: range 0 to 5 bar0\text{ to }5\text{ bar}0 to 5 bar
- Gauge G2G_2G2: range 0 to 15 bar0\text{ to }15\text{ bar}0 to 15 bar
- Gauge G3G_3G3: range 0 to 30 bar0\text{ to }30\text{ bar}0 to 30 bar
- Gauge G4G_4G4: range 0 to 150 bar0\text{ to }150\text{ bar}0 to 150 bar
Which pressure gauge should the technician use to measure a pressure of 18 bar18\text{ bar}18 bar accurately? Explain your choice.