NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
The ASME Performance Test Code, PTC 19.3, establishes the service ratings of thermowells in terms of static pressure limitations and susceptibility of the thermowell to flow-induced resonance. It relies on a simplified method to establish the resonant frequencies of thermowells. To quantify the limitations of this method, its theoretical basis is examined and its predictions are compared with discrete element calculations. It is found that the current code estimate ceases to be a conservative for thermowell designs suited for extreme velocities. The impact of using improved critical frequency estimates on the existing rating method is discussed.
Bartran, D.
and Ripple, D.
(2007),
Critical Frequency Estimates for Thermowells, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=830920
(Accessed October 13, 2025)