CSA ANSI NGV 4.4:21

Preface:

This is the second edition of CSA/ANSI NGV 4.4, Breakaway devices for natural gas dispensing hoses and systems. It supersedes the previous edition published in 1999.

The major changes to this edition include the following:

• addition of vent line breakaway devices to the scope of the document;
• addition of requirements for self-separating vent line breakaway devices;
• addition of requirements for non-self-separating vent line breakaway devices;
• removal of shear valves from the scope of the document;
• addition of ozone testing for nonmetallic parts;
• updated marking requirements to current industry standards; and
• reformatting to current CSA editorial procedures.

This Standard represents a standard for safe operation, substantial and durable construction, and performance testing of breakaway devices for natural gas dispensing hoses and systems, within limitations given below and in the scope of this Standard.

This Standard is based on proven engineering principles, research, and the combined expertise of gas utilities, manufacturers, users, and others having specialized experience.

Nothing in this Standard is to be considered in any way as indicating a measure of quality beyond compliance with the provisions it contains. It is designed to allow compliance of products which may exceed what is specified in the provisions herein. In its preparation, full recognition has been given to possibilities of improvement through ingenuity of design. This Standard is subject to revision as further experience and investigation may show it is necessary and desirable.

Users of this Standard are advised that the devices/products/activities within its scope might be subject to regulation at the federal, state, provincial, or local levels. Users are strongly urged to investigate this possibility through appropriate channels. In the event of a conflict with this Standard, the federal, state, provincial, or local regulations should be followed.

CSA Group acknowledges that the development of this Standard was made possible, in part, by the financial support of Natural Resources Canada.

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.

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

Scope:

1.1 Inclusions
This Standard applies to newly produced compressed natural gas vehicle (NGV) dispenser fuelling hose emergency main line breakaway devices and vent line breakaway devices, herein to be referred to as devices.

1.2 Main line breakaway inclusions
Main line breakaway devices covered by this Standard are intended to
a) minimize the escape of natural gas by automatically shutting off the flow of gas from the dispenser and control the depressurization of the downstream hose; and
b) separate the fuelling hoses attached to the vehicle from the dispenser during an unintended drive- off event.

1.3 Vent line breakaway inclusions
Vent line breakaway devices covered by this Standard are intended to separate the vent line hose attached to the vehicle from the dispenser during an unintended drive-off event.

1.4 Exclusions
The Standard is not applicable to home or private use vehicle refueling appliances.

1.5 Pressure references
All references to pressure throughout this Standard are to be considered gauge pressures unless otherwise specified.

1.6 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 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.

1.7 Units of measure
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.