Accuracy Grade Definitions

Grade 2A –
Permissible error of 0.5% across full scale

Grade 1A –
Permissible error of 1.0% across full scale

Grade A –
Permissible error of 2.0% across lower 1/4 of scale
Permissible error of 1.0% across middle 1/2 of scale
Permissible error of 2.0% across upper 1/4 of scale

Grade B –
Permissible error of 3.0% across lower 1/4 of scale
Permissible error of 2.0% across middle 1/2 of scale
Permissible error of 3.0% across upper 1/4 of scale

ASME B40.100-2005  – Pressure Gauges and Gauge Attachments