A123.23-15 (R2020)

Preface This is the first edition of CSA A123.23, Product specification for polymer-modified bitumen sheet, prefabricated and reinforced . This Standard is intended to provide minimum requirements for prefabricated and reinforced polymer-modified bitumen sheets used in roofing. It has been developed with the objective of replacing CGSB 37-GP-56, which was last amended in 1985. Scope 1.1 General 1.1.1 This Standard covers polymer-modified (styrene-butadiene-styrene block copolymer and atactic polypropylene) bitumen sheets intended for use as the plane of watertightness in roofing (including roof flashings). 1.1.2 This Standard covers polymer-modified bitumen sheets that are manufactured in a factory as a single, finished sheet and that are installed in a single layer or in multiple layers to form a system. 1.1.3 Although polymer-modified bitumen sheets also have other uses in the building envelope, this Standard does not consider these additional uses. 1.1.4 This Standard does not address system performance and design criteria such as resistance to fire or wind uplift, installation techniques, and accessory products. It is the responsibility of the designer to establish (and demonstrate to the authority having jurisdiction, upon request) that the selected sheet or combination of sheets is suitable for the intended use. 1.2 Classification 1.2.1 Types The following types of polymer-modified bitumen sheets are covered by this Standard: a) Type A - glass-fibre-reinforced polymer-modified bitumen sheets; b) Type B - polyester-fibre-reinforced polymer-modified bitumen sheets; and c) Type C - polymer-modified bitumen sheets reinforced with a mat composed of a combination of glass and polyester fibres. 1.2.2 Grades The following grades of polymer-modified bitumen sheets are covered by this Standard: a) Grades 1 and 2 - polymer-modified bitumen sheets intended to be exposed. Grade 1 is surfaced with mineral granules on the weather side. Grade 2 is either surfaced on the weather side with any other surfacing providing UV protection (such as factory-applied coating or film) or is unsurfaced; and b) Grade 3 - polymer-modified bitumen sheets not intended to be exposed. 1.3 Dual dimensions The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only. 1.4 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.