This document provides instructions and guidance for the accurate determination of pressure values in support of the ASME Performance Test Codes. The choice of method, instruments, required calculations, and corrections to be applied de­pends on the purpose of the measurement, the allowable uncertainty, and the characteristics of the equipment being tested. It provides guidance for setting up the instrumentation and determining the uncertainty of the measurement. It also provides information regarding the instrument type, design, applicable pressure range, accuracy, output and relative cost.