406.4.3 Analog Gauges Used to Measure Pressure in the Magnitude of 5 psig (34.5 kPa Gauge)

Each analog gauge used to measure pressure in the magnitude of 5 psig (34.5 kPa gauge) shall meet the following requirements in addition to satisfying the minimum requirements set forth in Section 406.4.1:

1. The face of the gauge shall not be smaller than 2¹/₄ inches (57 mm) in diameter;
2. The gauge shall have a minimum of 270 degree (5 rad) dial arc;
3. The gauge shall be calibrated in increments not greater than one-fifth of a pound;
4. The range of the gauge shall not exceed 10 psig (69 kPa gauge) when a 2¹/₄ inch (57 mm) diameter gauge is used;
5. The one-fifth interval on the gauge shall not be smaller than one-tenth of an inch (2.5 mm) of arc;
6. The gauge shall be provided with an effective stop for the indicating pointer at the zero point;
7. The gauge shall be protected from excessive pressure with a shutoff valve and prior to using the 10 psig (69 kPa gauge) the snifter valve shall be tested with a tire gauge to determine the magnitude of pressure; and
8. The gauge shall have a calibration screw.