Gauge readings acceptable for operation shall be in which portion of the gauge?

Gauge readings acceptable for operation shall be in which portion of the gauge?

• A. Lower Third
• B. Middle Third
• C. Upper Third
• D. Center Range

Answer: (B)

Reading must fall in the middle third of the gauge because this zone provides the most reliable, readable, and repeatable measurement. When the liquid level sits in the lower third, readings can be distorted by sediment, sludge, or a weak signal from the bottom portion, making the level harder to judge accurately. Near the top, foaming, surface movement, and parallax effects can distort the view and the gauge becomes less precise, increasing the risk of overfill or incorrect inventory. The middle third is where the gauge scale is most linear and the surface is clearly defined, so operators can base actions on readings with confidence. If the level isn’t in that middle zone, it’s best not to initiate operation from that reading until the level moves into the middle range.

Reading must fall in the middle third of the gauge because this zone provides the most reliable, readable, and repeatable measurement. When the liquid level sits in the lower third, readings can be distorted by sediment, sludge, or a weak signal from the bottom portion, making the level harder to judge accurately. Near the top, foaming, surface movement, and parallax effects can distort the view and the gauge becomes less precise, increasing the risk of overfill or incorrect inventory. The middle third is where the gauge scale is most linear and the surface is clearly defined, so operators can base actions on readings with confidence. If the level isn’t in that middle zone, it’s best not to initiate operation from that reading until the level moves into the middle range.