Preface   

This is the seventh edition of CSA 3.8, Gas-fired equipment for drying farm crops. It supersedes the previous editions published in 2014, 1999, 1986, 1977, 1972, and 1968. The seventh edition of this Standard has been updated to reflect current industry practice and address CSA Group's guide on drafting Standards. The major changes to this edition include the following: 

a) input rating has been increased from 12 500 000 BTU to 20 000 000 BTU; 

b) Annex I has been added. This Annex permits manufacturers to offer certified fuel conversion kits; 

c) this Standard has been updated to align with changes in CSA B149.3:20; 

d) warning boxes have been revised; 

e) inhabited building by dwelling units have been replaced; and 

f) criteria have been added for stacked dryers. This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. 

Scope 

1.1 Applicable equipment This Standard applies to newly produced direct gas-fired crop dryers of the recirculating or non- recirculating type, hereinafter referred to as "dryers", the primary purpose of which is to provide process heating to dry farm crops. These dryers are used in non-occupied spaces and are constructed of non-combustible materials having input ratings of 20 000 000 Btu/h (5 861 421 W) or less, constructed entirely of new unused parts and materials. A stacked dryer composed of individual burner units or modules, each having an input rating of 20 000 000 Btu/h (5 861 421 W) or less, and where each individual burner unit or module is equipped with its own burner control, is also considered to be within the scope of this Standard. 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 CSA B149.1 and 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 Applicable fuel types Dryers covered under this Standard are for use a) with natural gas; and b) with propane in the liquid and vapour phase. 

1.3 Applicable installation location This Standard applies to dryers intended for outdoor use only. 

1.4 Forced draft burner limitation This Standard is limited to dryers that are equipped with forced draft burner(s) which rely on combustion air supplied by a mechanical device, such as a fan or blower. 

1.5 Construction requirements The construction of dryers for use with the above-mentioned gases is covered under Clause 4. 

1.6 Performance requirements The performance of dryers for use with the above-mentioned gases is covered under Clause 5. 

1.7 Pressure references All references to pressure throughout this Standard are to be considered "gauge" pressure, unless otherwise specified. 

1.8 Measurement units 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.