To what accuracy must test pressure gauges be certified?

Test pressure gauges used in the servicing of portable fire extinguishers must be certified to an accuracy of +/- 0.5%. This level of accuracy ensures that pressure measurements taken during testing are reliable and precise, which is critical for maintaining the effectiveness and safety of fire extinguishers. If gauges were to have a lower accuracy, such as +/- 1% or +/- 2%, it could lead to erroneous determinations of whether a fire extinguisher is safe to use. An accuracy of +/- 0.1% is overly stringent for typical maintenance tasks, making it impractical and unnecessary for this application. Hence, recognizing that +/- 0.5% strikes the right balance for operational use is important for accurate compliance with industry standards.