CSA S500-14 (R2019)

1.1 Scope
This Standard provides requirements for all life-cycle phases of thermosyphon foundations for new buildings on permafrost, including site characterization, design, installation, and commissioning phases as well as for monitoring and maintenance phases. This Standard is meant to ensure the long-term performance of thermosyphon-supported foundation systems under changing environmental conditions.

1.2 Objectives
The objectives of this Standard are to
a) describe performance expectations for thermosyphon foundations together with monitoring requirements necessary to support an appropriate maintenance program;
b) specify the materials to be used in thermosyphon foundations;
c) foster an awareness and understanding of application technology, with a focus on factors that could compromise the functionality of foundation systems reliant on thermosyphons;
d) describe the typical phases of the life cycle of thermosyphon foundations for buildings on permafrost, including design, installation, commissioning, monitoring, and maintenance;
e) provide guidance to maximize the long-term viability of thermosyphon-supported foundation systems under changing environmental conditions; and
f) describe performance expectations for thermosyphon foundations together with monitoring requirements necessary to support a maintenance program.

1.3 Application
This Standard is intended to be used by designers, contractors, building owners, and operators. For owners, it provides an understanding of the design and construction processes required to permit verification that adequate measures are taken during these phases. The Standard also sets out monitoring and maintenance expectations for building operators.

This Standard is applicable to new buildings on permafrost sites. It is not intended to provide guidance for initial selection of the most appropriate foundation type for any particular structure on a permafrost site. It is assumed that a thorough review of alternative foundation systems has been undertaken and that that the site has been categorized as potentially thaw-unstable. Preservation of the permafrost for support of the structure has been identified as a design objective before this Standard is implemented.

1.4 Exclusions
This Standard does not cover
a) abandonment/demolition of buildings with thermosyphon foundations;
b) thermosyphons in areas of non-permafrost or retrofitting thermosyphons to existing buildings; and
c) thermosyphons used for infrastructure other than buildings.

1.5 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 normative clauses from 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.