CSA A93:2019 pdf download.Airflow ventilators for the unoccupied spaces of buildings
1.1 CSA A93 gives minimum requirements for ventilators used in buildings which are designed to permit venting of unoccupied spaces to the exterior so as to minimize the unwanted accumulation of condensation, moisture, and excess heat in the building component or assembly. These include
a) passive arflow ventilators for buildings; and
b) mechanical (powered) airflow ventilators for buildings.
Note: Forced-air ducted ventilators might have additional requirements which are not included in this Standard.
Information for these systems is included in Annex C.
1.2 This Standard includes physical, performance, and marking requirements. It also includes annexes giving recommendations for installation of ventilators to ventilate unoccupied building spaces, a guide for determining net free area, recommended properties of exterior apertures of ducted forced-air ventilation systems, and the mitigation of ingress of fire embers in areas of high fire risk.
1.3 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.
5.1 Basic design
Ventilators shall be so designed that each can be installed and securely fastened. Flashing joints shall be downslope. Intermittently-engaged mechanical ventilators should be equipped with a thermostat or a thermostat/humidistat to ensure that operation occurs when demand is present.
5.2 Materials
Materials used for ventilators shall be free from visible cracks and other defects, and shall be suitable for long-term use. In addition, they shall be made so that no protective coating is required at the building site, except for fasteners, shingles, or flashing sealing. Materials shall remain durable, semi-rigid, non-brittle, and firm, and shall not be significantly affected by exposure to ultraviolet radiation.
Note: The products used for installing the ventilator on a roof system should be compatible with the ventilator material in accordance with the NBC.CSA A93 pdf download.