Definition(s)
Substantive Change
Change that potentially affects the performance or rating of the tool in the intended service as evaluated by a qualified person at the supplier/manufacturer.
Source:API SPECIFICATION 19TT, Specification for Downhole Well Test Tools and Related Equipment, First Edition, October 2016. Global Standards
Substantive Change
Change identified by the manufacturer that affects the performance of the product in the intended service.
Source: API SPEC 6A, Specification for Wellhead and Christmas Tree Equipment, Twentieth Edition, October 2010 (Addendum November 2012). Global Standards