Preface This is the second edition of the CSA A220 Series, Concrete roof tiles. It supersedes the previous edition published in 1991. 1 Scope 1.1 This Standard applies to concrete roof tiles and tiling accessories intended for use as weather-resistant roofing materials. 1.2 This Standard specifies the requirements and procedures for the sampling and testing of concrete roof tiles for dimensional tolerances, water absorption, water permeability, freezing and thawing resistance, transverse strength, and material quality. 1.3 In CSA Standards, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; "should" is used to express a recommendation or that which is advised but not required; "may" is used to express an option or that which is permissible within the limits of the standard; and "can" is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.