ASME PTC 19.2 (Performance Test Code 19.2) is the industry standard for Pressure Measurement Instruments and Apparatus
. It provides uniform procedures for the selection, installation, and use of instruments to ensure accuracy in performance testing. The 2010 edition, often referred to as ASME PTC 19.2-2010
, is a significant revision of the 1987 standard and covers the measurement of static, differential, and dynamic pressures in various fluid systems. Key Content & Coverage
The standard is designed to help engineers standardize performance testing and minimize measurement uncertainty: Instrument Selection
: Guidelines on choosing the right device (e.g., liquid-column manometers, deadweight testers, elastic transducers, or electrical pressure transducers) based on the application. Installation Procedures
: Detailed requirements for pressure taps, connecting lines, and the use of control instrumentation to prevent errors from fluid dynamics or environmental factors. Measurement Types Static Pressure : Measurement in still or moving fluids. Differential Pressure : Essential for flow measurement using primary elements. Dynamic Pressure : Guidelines for rapidly changing pressure environments. Special Systems
: Considerations for two-phase fluid systems (gas and liquid mixtures) and hazardous or corrosive environments. Why It Matters Standardization asme ptc 192 fixed
: Ensures that pressure data collected across different facilities or by different vendors is consistent and reliable. Compliance
: Many regulatory and technical specifications, such as those from
for pressure relief devices, require testing in accordance with ASME code quality requirements.
: Provides the mathematical frameworks for calculating measurement uncertainty and correcting for variables like temperature and local gravity.
A fixed installation, correctly built to ASME PTC 19.2, yields repeatable measurements year after year. This is essential for trending turbine efficiency, compressor surge margin, and boiler drum level.
The most critical rule in the ASME PTC 19.2 fixed guidelines is that the pressure tap must be flush with the inner wall of the pipe. ASME PTC 19
The standard explicitly states: "The pressure tap hole shall be clean, round, and perpendicular to the inside surface. The edge of the hole at the wall shall be square and sharp."
A Fixed pressure measurement installation is defined as:
A permanently installed pressure sensing system, including all impulse lines, manifolds, transmitters, and displays, that is not intended for removal or replacement during normal operation or during a performance test.
Key characteristics of a Fixed system under PTC 19.2 include:
Before diving into the "Fixed" aspect, let us establish the foundation. ASME PTC 19.2 is a standard published by the American Society of Mechanical Engineers (ASME) under the Performance Test Codes (PTC) umbrella. Its full title is "Pressure Measurement Instruments and Apparatus."
This code provides uniform methods for the testing and calibration of pressure measuring devices. It applies to: Common Misconceptions about ASME PTC 19
The standard ensures that when an engineer reports a pressure reading during a performance test (e.g., turbine efficiency, pump flow, boiler output), the measurement uncertainty is known, quantified, and consistent with industry best practices.
The standard does not mandate a specific calendar interval but gives guidance based on usage:
However, ASME PTC 19.2 Fixed strongly recommends performing a “as-left, as-found” procedure—record readings before adjustment and after adjustment to track drift.
Per ASME PTC 19.2 Fixed, total uncertainty must include:
| Feature | Fixed Installation (PTC 19.2) | Portable/Test Gauge | |---------|-------------------------------|---------------------| | Uncertainty | ≤ 0.25% of reading | ≤ 0.5–1.0% FS | | Calibration Interval | Fixed 6–12 months | Per test only | | Dynamic Response | Limited by impulse line length | Direct, high speed |