Gas Trace Tasks

The ArcFM Gas Traces toolbars allow you select the trace you wish to perform and set the trace options before performing the gas trace. The ArcFM Valve Isolation trace and its associated tools reside on the Gas Isolation Traces toolbar while the rest of the gas trace tools are on the Gas Traces toolbar. Note: All ArcFM traces disregard definition queries on network layers.

Gas Traces toolbar

Tool	Description
Cathodic Protection Trace	Cathodic protection is used in natural gas distribution systems to prevent corrosion of pipes and devices. A gas cathodic protection trace allows you to identify which sections of your distribution system utilize cathodic protection.
Pressure System Trace	A pressure system is a section of the entire gas distribution system which is operating under the same pressure. Regulators are placed between pressure systems as separators. Regulators may be set between two pressure systems that are operating under the same pressure. In this case, the regulator does not separate the systems and they are viewed as one continuous pressure system. If the pressure is modified on either side of the regulator, it then becomes a system separator and the pressure system should be re-traced. Using the Gas Traces tab in the Gas Trace Options, you may choose to stop the trace at any regulator or only those regulators with different inlet and outlet pressures.
Squeeze Off Trace	A squeeze off trace allows you to determine whether pinching the pipes at a selected location will disrupt the flow of natural gas to a specific area. The results of this trace show the outage area and any open squeeze off points which need to be closed in order to isolate the area. The trace stops at any open squeeze off points, and ignores open valves. This tool is not displayed on the ArcFM Gas Traces toolbar by default. It may be added using the Customize menu.
System Trace	A gas system encompasses all the pipes and devices that can be reached from a town border or regulator station. The ArcFM Gas System trace begins at the flag placed by the user and stops at any closed valves (closed valves interrupt the flow of gas). Using the Gas Traces tab in the Gas Trace Options, you may choose to stop the trace at Town Border Stations, Regulators or both as well. It returns a list of devices and pipes that are connected to the feature and allow the flow of gas.
Clear All	This button clears the results if you have selected the Results as Drawings option. If you choose to view your results as a selected set, the Selection tab will NOT be cleared. This tool may clear temporary marks placed on the map using the tools on the Gas Valve Isolation toolbar. If you wish to include temporary marks in the Clear All, indicate which marks to clear using the Gas Trace Options.
Zoom To Results	Use this toggle button to elect whether to zoom to the trace results. When this button is depressed (or toggled on), the map view will zoom to the trace results.
Trace Options	Click this button to set various options for your gas trace.

Gas Isolation Traces toolbar

The tools for placing temporary sources and barriers discussed below work ONLY with the Valve Isolation trace. They are ignored by all other traces.

Tool	Description
Exclude Valve	Use this button to mark valves on the map that should be excluded from the valve isolation trace.
Include Valve	Use this button to mark a non-critical valve on the map that should be included in the valve isolation trace when the Critical Valve option is selected.
Temporary Shutoff	Use this tool to place a temporary shutoff point as a barrier that participates in the valve isolation trace (rather than as a feature).
Temporary Source	Use this tool to designate a gas pipe as a temporary source due to line pack. In most cases, this will be on a distribution main.
Clear Temporary	This tool allows you to clear any temporary marks on the map (e.g., exclude valve, include valve, temporary shutoff, temporary source). Click the Clear Temporary button, then click each temporary mark on the map to clear it. If you wish to clear multiple temporary marks with a single click, use the Clear All button.
Valve Isolation Trace	ArcFM Gas Valve isolation allows you to identify features that interrupt the flow of gas. On the Results tab, click Drawings to highlight the isolated area in the trace task result color. Click Selection to create a selected set composed of the valve(s) you would close to isolate an area. NOTE: When running the Valve Isolation trace, it is possible to return an empty results set. This may be because the area cannot be isolated or the layers may be set as unselectable. Squeeze Off Points: The Valve Isolation trace uses the Squeeze Off temporary barrier to indicate squeeze off points. It does NOT use the Squeeze Off feature class or the PipeType field.