Draft Details

Designation:CSA Z341S1
Contact name:Pablo Fernandez Marchi
Review start date:Feb 3, 2023
Review end date:Apr 4, 2023
Contact email:thuy.ton(at)csagroup.org
Draft Scope/Description:

S1-1.1 Applicability

This Supplement sets out minimum requirements for the design, construction, operation, maintenance, abandonment, and safety storage of hydrogen and hydrogen blends in underground formations and associated equipment. The equipment considered includes

a) storage wellhead and Christmas tree assemblies;

b) wells and subsurface equipment; and

c) safety equipment, including monitoring, control, and emergency shutdown systems.

This Supplement is to be used concurrently with Z341.1 and Z341.2. Unless otherwise specified, all references to hydrocarbons or stored fluids in Z341.1 and Z341.2 shall be read as meaning hydrogen or hydrogen blend. Where no changes are identified in this Supplement, Z341.1 and Z341.2 shall apply.

This Supplement has been designed to complement provincial and/or federal regulatory frameworks and does not mandate regulatory requirements unless referenced in provincial and/or federal regulations. This Supplement provides advisory guidance that can be followed to demonstrate compliance with local and national codes and regulations and industry best practices. Alternative design codes and standards that are not specified in this Supplement may be used, provided that pertinent local and national regulations are satisfied and that it can be demonstrated that the design meets industry best practices.

There is no established safe percentage of hydrogen that can be blended in an underground storage system without first evaluating, including but not limited to, existing defects, partial pressure, metallurgy and microstructure, pressure cycling, and percentage of Specified Minimum Yield Strength (SMYS) on the wellbore materials and evaluating the reactivity impacts with the storage formation. Where the evaluation of these parameters indicates there is minimal risk from hydrogen, then existing Z341.1 and Z341.2 may be used.

The design, materials, and well completion requirements of this Supplement shall be considered for existing installations and installations under construction at the time of publication. The requirements shall apply to the testing, operation, extension, conversion, maintenance, and upgrading of such installations.

 Note: Hydrocarbons covered by this Supplement are restricted to natural gas.

S1-1.2 Scope diagram

The scope of this Supplement for reservoir storage of hydrogen and hydrogen blends is shown in Figure 1 of Z341.1. The scope of this Supplement for salt cavern storage of hydrogen and hydrogen blends is shown in Figure 1 of Z341.2.

S1-1.3 Excluded from scope 

This Supplement does not apply to



in-situ production of hydrogen; and

items in Clause 1.3 in Z341.1 and Z341.2.

S1-1.4 Limitations

It is not the intent of this Supplement to prevent the development of new equipment or practices, nor to prescribe how such innovations should be handled.

Where the requirements of this Supplement differ from the requirements of other standards or codes referenced herein, the requirements of this Supplement shall be considered as this was developed specifically for storage of hydrogen and hydrogen blends.

S1-1.5 Terminology

In this Supplement, “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.

You may comment on any section of this document by clicking the “Submit Comment” link at the bottom of the relevant section.