CSA Group CSA/ANSI Z21.91:20 American National Standard Ventless firebox enclosures for gas-fired unvented gas log type room heaters

Preface

This is the fourth edition of CSA/ANSI Z21.91, Ventless firebox enclosures for gas-fired unvented gas log type room heaters. It supersedes the previous editions published in 2017, 2007, and 2001.

This Standard is considered suitable for use for conformity assessment within the stated scope of the Standard.

This Standard was prepared by the Joint Subcommittee on Unvented Gas-Fired Heating Appliances, under the jurisdiction of the Z21/83 Technical Committee on Performance and Installation of Gas Burning Appliances and Related Accessories and the Strategic Steering Committee on Fuels and Appliances. It has been formally approved by the Z21/83 Technical Committee on Performance and Installation of Gas Burning Appliances and Related Accessories.

This Standard has been approved by the American National Standards Institute (ANSI) as an American National Standard.

Interpretations: The Strategic Steering Committee on Fuels and Appliances has provided the following direction for the interpretation of standards under its jurisdiction: “The literal text shall be used in judging compliance of products with the safety requirements of this Standard. When the literal text cannot be applied to the product, such as for new materials or construction, and when a relevant CSA committee interpretation has not already been published, CSA Group’s procedures for interpretation shall be followed to determine the intended safety principle.”

Notes:

1) Use of the singular does not exclude the plural (and vice versa) when the sense allows.

2) Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the users of the Standard to judge its suitability for their particular purpose.

3) This Standard was developed by consensus, which is defined by CSA Policy governing standardization – Code of good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority, but not necessarily unanimity.” It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this Standard.

4) To submit a request for interpretation of this Standard, please send the following information to [email protected] and include “Request for interpretation” in the subject line:

a) define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch;

b) provide an explanation of circumstances surrounding the actual field condition; and

c) where possible, phrase the request in such a way that a specific “yes” or “no” answer will address the issue.

Committee interpretations are processed in accordance with the CSA Directives and guidelines governing standardization and are available on the Current Standards Activities page at

standardsactivities.csagroup.org..

5) This Standard is subject to review within five years from the date of publication. Suggestions for its improvement will be referred to the appropriate committee. To submit a proposal for change, please send the following information to [email protected] and include “Proposal for change” in the subject line:

a) Standard designation (number);

b) relevant clause, table, and/or figure number;

c) wording of the proposed change; and

d) rationale for the change.

1 Scope

1.1

This Standard applies to newly produced ventless firebox enclosures (see Clause 3, Definitions), herein after referred to as fireboxes, for unvented gas log type room heaters.

∆ 1.2

Fireboxes covered by this Standard are intended for use with unvented room heaters that comply with ANSI Z21.11.2 for installation in solid fuel-burning fireplaces.

1.3

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.

1.4

All references to “psi” throughout this Standard are to be considered gauge pressures, unless otherwise specified.

1.5

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 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 (nonmandatory) to define their application.