CSA ANSI Z21.21-2012/ CSA 6.5-2012

Preface

This publication represents a basic standard for safe operation, substantial and durable construction, and acceptable performance of automatic valves for gas appliances. It is the result of years of experience in the manufacture, testing, installation, maintenance, inspection and research on automatic valves for gas appliances designed for utilization of gas. There are risks of injury to persons inherent in appliances that, if completely eliminated, would defeat the utility of the appliance. The provisions in this standard are intended to help reduce such risks while retaining the normal operation of the appliance.

Scope

1.1
This standard applies to newly produced automatic valves (Section 3, Definitions) constructed entirely of new, unused parts and materials. These valves may be individual automatic valves or valves utilized as parts of automatic gas ignition systems.

This standard also applies to commercial/industrial safety shutoff valves (Section 3, Definitions), herein after referred to as C/I valves.

This standard shall not apply to self-contained water heater, cooking appliance, or room heater thermostats, or self-contained automatic gas shutoff valves for hot water supply systems.

Components performing functions other than those of an automatic valve shall comply with applicable American National Standards or Canadian Standards.

Compliance of an automatic valve with this standard does not imply that the automatic valve is acceptable for use on gas appliances without supplemental tests with the automatic valve applied to the particular appliance design.

A control which incorporates two or more automatic valves and no other function, (as defined by combination control, see Section 3, Definitions), may be tested to this standard or the Standard for Combination Gas Controls for Gas Appliances, ANSI Z21.78 - CSA 6.20, at the discretion of the manufacturer.

1.2
The valve operator of an automatic valve may be actuated either directly or indirectly. In addition, it may be actuated by electrical means, by mechanical means, by means of a change of the absolute pressure of gas or air upon a diaphragm, or by other means.

1.3
This standard applies to automatic valves having maximum operating gas pressure ratings from 1/2 psi (3.5 kPa) up to and including 60 psi (413.7 kPa).

1.4
This standard applies to automatic valves which are to be mounted in the manufacturer's specified upright position or in one (1) or more of the optional mounting positions selected by the manufacturer. (See 5.1.1.)

1.5
This standard applies to automatic valves which are capable of operation at ambient temperatures of 32?F to 125?F (0?C to 51.5?C), unless a higher temperature, lower temperature, or both, are specified by the manufacturer. (See 5.1.2.)

1.6
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.

1.7
All references to psi throughout this standard are to be considered gauge pressures unless otherwise specified.

1.8
Additional provisions concerning electrical coverage applicable to units defined for use in the United States are outlined in Section 9, Items unique to the United States.

1.9
Additional provisions concerning electrical coverage, instructions and markings, applicable to units destined for use in Canada are outlined in Section 10, Items unique to Canada.

1.10
Section 2, List of Reference Standards, contains a list of standards specifically referenced in this standard and sources from which they may be obtained.