Preface This is the sixth edition of CSA A23.4, Precast concrete — Materials and construction. It supersedes the previous editions, published in 2009, 2005, 2000, 1994, and 1978. This Standard has been revised to include all necessary technical requirements for precast concrete. This Standard refers extensively to CSA A23.1. To make it easier to navigate between the two Standards, Annex D lists the clauses of CSA A23.1 that contain provisions relating to clauses in this Standard. CSA Group acknowledges that the development of this Standard was made possible, in part, by the financial support of the Canadian Precast/Prestressed Concrete Institute. Scope 1.1 General This Standard specifies requirements for materials and methods for the manufacture, transportation, and installation of architectural, structural, and specialty precast concrete products. Note: This Standard should be specified for precast concrete elements used in segmental construction. 1.2 Shop drawings This Standard specifies the requirements, in addition to those specified in CSA A23.3, for precast concrete shop drawings. 1.3 Architectural precast concrete This Standard deals with the structural adequacy and architectural finishes of architectural precast concrete. 1.4 Precedence Where this Standard states that the content of a clause is required to conform to a referenced Standard and to additional clauses of this Standard and there is a conflict between the referenced Standard and the requirements of this Standard, the requirements of this Standard take precedence. 1.5 Terminology In this Standard, "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; and "may" is used to express an option or that which is permissible within the limits of the Standard. 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.