Shop

Artificial Intelligence Notice: ISA prohibits the entry of any ISA intellectual property (“ISA IP”), including standards, publications, training or other materials into any form of Artificial Intelligence (AI) tools, such as ChatGPT. Additionally, creating derivatives of ISA IP using AI is also prohibited without express written permission from ISA’s CEO. In the case of such use, ISA will suspend a licensee’s access to ISA IP, and further legal action will be considered. Please review ISA's policies for Use of AI Tools, Intellectual Property and Terms and Conditions for further information.

Important Notice: Print books are temporarily unavailable. As of 12 August 2025, print books are no longer available for purchase on isa.org, but beginning 1 January 2026, they will be available for purchase through our publishing partner, Wiley. Kindle and ePub formats are still available via the links on each book's product page on isa.org. Learn More.

ISA107.3 focuses on noncontact clearance measurement systems for use in gas turbines.

The purpose is to develop a standard for gas turbine instrumentation used in the measurement of blade tip to engine casing clearance during engine running.

The scope of the specification in progress provides guidance on the standardization of the specification and qualification testing of high bandwidth, noncontact clearance measurement systems for use in gas turbines to measure blade tip clearances at high temperatures

The specification makes some references to the capacitive based technology. However, many parameters are generic.

Future updates of this specification will include details to the other emerging technologies, such as optical and radar (micro-wave).

The object of the specification is to provide a common language and agreed methods for testing different systems to the same standard.

The chairman of ISA107.3 is Paul Seccombe. For more information, please contact ISA Standards.