Preface: This is the sixth edition of CSA 3.8, Gas-Fired Equipment for Drying Farm Crops. It supersedes the previous editions published in 1999, 1986, 1977, 1972, and 1968. Scope: 1.1 This Standard applies to newly produced direct gas-fired crop dryers of the recirculating or non recirculating type hereinafter referred to as "dryers", whose primary purpose is to provide process heating to dry farm crops. These dryers are used in non-occupied spaces and are constructed of noncombustible materials having input ratings of 12,500,000 Btu/hr (3 663 389 W) or less, constructed entirely of new unused parts and materials. This Standard refers to equipment in which heated air is used to reduce the moisture content of farm crops. The installation is to conform with local codes, or in the absence of local codes, in accordance with the Natural Gas and Propane Installation Code, CSA B149.1, and the Propane Storage and Handling Code, CSA B149.2. This Standard is intended to cover complete dryers with integral air moving components, i.e., those which are designed by, catalogued by, and built on a repetitive basis by the manufacturer and those in which the dryer and air moving components are tested as an assembly and available for separate sale. 1.2 Dryers covered under this Standard are for use: a) with natural gas; and b) with propane in the liquid and vapour phase. 1.3 This Standard applies to dryers intended for outdoor use only. 1.4 This Standard is limited to dryers that are equipped with forced draft burner(s), which relies on combustion air supplied by a mechanical device such as a fan or blower. 1.5 The construction of dryers for use with the above mentioned gases is covered under Clause 4. 1.6 The performance of dryers for use with the above mentioned gases is covered under Clause 5. 1.7 If a value for measurement as given in this Standard is followed by an equivalent value in other units, the first stated value is to be regarded as the specification. 1.8 All references to pressure throughout this Standard are to be considered "gauge" pressure, unless otherwise specified. 1.9 This Standard contains SI (Metric) corresponding to the yard/pound quantities, the purpose being to allow the standard to be used in SI (Metric) units. (Standard for use of the International System of Units (SI): The Modern Metric System, IEEE/ASTM SI 10 or ISO 80000-1:2009 Quantities and units — Part 1: General are used as a guide in making metric conversion from yard/pound quantities.) 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 value in other units are both specified as a quoted marking requirement, the first stated unit, or both shall be provided.