IEC TS 60695-11-40:2021 presents a general characterization of small-scale test flames and associated confirmatory tests based on copper block calorimetry. Guidance is presented for the selection of critical parameters in confirmatory test designs. This basic safety publication is intended for use by technical committee in the preparation of safety publications in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the relevant publications. This second edition cancels and replaces the first edition published in 2002. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) former Clause 4 split into updated/rearranged new Clause 4 and Clause 5; b) Table 1 updated and moved to new Clause 4; c) former Clause 5 transformed to Clause 6; d) former Clause 6 transformed to Clause 7; e) former Clause7, Clause 8 and Clause 9 combined into an updated/rearranged new Annex A; and f) all figures were updated. This Technical Specification is to be used in conjunction with IEC 60695-11-2, IEC 60695-11-3, IEC 60695-11-4 and IEC 60695-11-5.