Pressure and Vacuum Measurements and Standards

Pressure and vacuum measurements are widely used in many industrial, aerospace, and transportation applications to achieve product/process quality, throughput, and performance requirements, and in many cases, to provide for health and safety. NIST disseminates pressure and vacuum measurement standards primarily through instrument calibration services, research projects and measurement comparisons. Research activities fill knowledge gaps anticipated in overcoming technical barriers of future measurement and standards needs of industry and government. NIST also seeks to enhance international trade through the mutual recognition of national measurement standards. Current research efforts include efforts to develop a non-artifact primary pressure standard based on the dielectric constant of helium, which is calculable from fundamental physical principles; an improved vacuum gauging technology having potential to supplant ionization gauges. NIST is actively leading, participating, or has recently completed, over 16 measurement comparisons at the national, regional and international level. NIST ensures that the country has the most accurate measurement standards, stimulates the development of new approaches to improve industrial processes, provides high-accuracy capabilities for critical scientific measurements, and catalyzes harmonization of measurements across different principle techniques.

• Move Pressure and Vacuum Standards Laboratories to the AML: Complete implementation of NIST Quality System supporting NIST pressure and vacuum calibration services
• Piston Gauges as Primary Pressure Standards: Establish 35 mm diameter piston gauge as primary pressure standard based on dimensional measurements to assign area values, values have been validated by comparison to the Ultrasonic Interferometric mercury manometer, NIST's primary pressure standard.
• Quantify Performance of Leak Artifacts: Initiate first-ever interlaboratory comparison of helium leak artifacts for low gas flow. Helium leak artifacts are widely used quantify the performance of leak detection equipment used for food packaging and pressure and vacuum vessel integrity evaluation.
• CSTL researchers are developing a novel primary standard for pressure in the range 0.3 MPa to 5 MPa. The new standard will determine the pressure p ( e , T ) by measuring and calculating the dielectric constant e ( p , T ) of helium with extraordinary accuracy. Measurement uncertainties from electrical and temperature measurements will be smaller than the uncertainty of existing pressure standards (piston gages). Two methods have been developed to measure the dielectric constant of helium, one based on cross capacitors and on quasi-spherical microwave resonators. Recent experimental results have uncertainties approaching those of piston gauge pressure standards.

• NIST Calibration Services