a) A very popular framework used for measuring Brand Equity is the Aaker's model. It can be sourced from "David A. Aaker, Managing Brand Equity, The Free Press, New York, 1994." Aaker suggests that his model can be applied to both goods and services.
b) You can also refer to the framework used in L L Berry's brand equity model that is specifically related to service organizations. The reference source is " Leonard L. Berry, " Cultivating Service Brand Equity", Journal of the Academy of the Marketing Science, December 2000,Volume 28, Issue 1, pp. 128-137.
You could make use of the above two frameworks to measure service brand equity.
Kotler and Keller (2012:277) identify two basic approaches to measuring brand equity. An indirect approach—assesses potential sources of brand equity by identifying and tracking consumer brand knowledge structures.
A direct approach—assesses the actual impact of brand knowledge on consumer response to different aspects of the marketing. The two general approaches are complementary and marketers can employ both.