Preface This is the first edition of CSA HGV 4.9, Hydrogen fueling stations. Scope 1.1 This Standard specifies the design, installation, operation and maintenance of site-built and modular gaseous hydrogen fueling stations (HFS) for light duty vehicles, where light duty vehicles are defined by the Environmental Protection Agency as passenger cars and light trucks, minivans, passenger vans, pickup trucks, and sport-utility vehicles, also referred to as the "common category" which includes class 1, 2, 3 vehicles up to 14,000 lbs. The requirements are based upon United States and international codes and standards, but, where appropriate, local and federal codes and standards may supersede the requirements listed in this Standard. 1.2 Unless otherwise stated the standard conditions are: temperature 15 °C and pressure 101 KPa. 1.3 In case of conflict between this Standard and Federal, Provincial, State, or Local requirements, governmental requirements take precedence. 1.4 This Standard contains SI (Metric) units with corresponding yard/pound quantities, the purpose being to allow the standard to be used in SI (Metric) units. If a value for a measurement and a corresponding value in other units are stated, the first stated value is to be regarded as the requirement. The given corresponding value may be approximate. If a value for a measurement and a corresponding valve in other units are both specified as a quoted marking requirement, the first stated unit, or both are to be provided. Note: IEEE/ASTM SI 10 or ISO 80000-1 was used as a guide in making metric conversions to yard/pound quantities. 1.5 All references to pressure throughout this Standard are to be considered gauge pressure unless otherwise specified. 1.6 In this Standard, "shall" is used to express a requirement, i.e., a provision that the user shall 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 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.