This document provides the definitive methodology for calculating and reporting uncertainty in performance tests (e.g., turbine heat rate, pump efficiency, fan flow). It replaces earlier ANSI/ASME standards and aligns with ISO/IEC Guide 98-3 (GUM), but with engineering-specific simplifications.
"Performance Test Code on Pressure Transmitters"
Uncertainty analysis is not just a theoretical exercise; it is a fundamental requirement for almost all ASME Performance Test Codes. For instance, the codes for , compressors (PTC 10) , and fans (PTC 11) all mandate that engineers conduct both pre-test and post-test uncertainty analyses as a core part of the test. asme ptc 191 pdf
The Vital Role of ASME PTC 19.1 in Engineering Precision ASME PTC 19.1
The primary goal of ASME PTC 19.1 is to replace ambiguous terms like "precision" or "bias" with clear, technical definitions that align with international standards like the . For instance, the codes for , compressors (PTC
The to estimate those errors. Rather than guessing the accuracy of a performance test, engineers use this code to calculate an exact numeric interval (e.g., a power output of 500 MW ± 1.5%) with a verified confidence level—typically 95%. Key Document History & Revisions
ASME PTC 19.1 is an American National Standard titled . The core purpose of this standard is to provide a consistent, mathematically sound procedure for evaluating uncertainties in performance tests. In practical terms, when you are measuring a plant’s power output or its heat rate, you are never 100% certain of the true value because every measurement instrument has limitations. This standard helps you quantify that doubt, giving your test results a defined confidence level. Rather than guessing the accuracy of a performance
, typically calculated using statistical methods like standard deviation from repeated measurements. Systematic Errors (Bias):
: It details how to mathematically move from the uncertainty of a single sensor (like a thermometer) to the uncertainty of a complex calculated value (like thermal efficiency).