4 Replies Latest reply on Jun 12, 2015 11:18 AM by Frank Wakeley

    Are users of the “gas valve isolation tool”, having difficulties using the squeeze tool (specifically for companies who may have many gas main edges that are several hundred feet in length)?

    Frank Wakeley

      Attached are three exhibits (of the same area) which illustrate the limitation of the squeeze tool used when performing a gas valve isolation trace.

       

      Exhibit 1 depicts a line hit on a 500 foot main segment (Main Edge B).  Based on the valve placement in this area, it is clear that the best solution is to squeeze the plastic main on either side of this leak to minimize customer outages.  However, only one squeeze per main edge is allowed by the software.  To isolate this leak, the squeeze tool is placed below the leak on the 500 foot main, and north of this segment on the 100 foot main edge- as seen in Exhibit 2.  Since the valve isolation tool (VIT) cannot be placed on a segment that has a squeeze tool applied, valve #1127 is excluded from the trace and the VIT is placed on the 3” line (Exhibit 2).  Since it is necessary to run the tool in this manner, the Subdivision “ABC” is needlessly included in the trace.

       

      Ideally, and intuitive to field personnel, the squeeze tool is placed  just north and south of the leak which happens to be on the single 500 foot main edge segment.  The valve isolation tool would be snapped to the main segment between the squeeze tools to show the affected shut-down area (Exhibit 3).   So far, two tracing rules were violated: – 1) one squeeze tool per main edge and 2) selecting a squeezed main edge to run the valve isolation tool on.

       

      The limitations of this tool combined with our data (thousands of main segments that can be several hundred feet in length without a node break), does not allow us to use the squeeze tool effectively.

       

      Currently, the valve isolation tool is very useful for our gas operations group. However, removing the squeeze tool limitations, by allowing two squeeze tools applied to a single main segment and allowing a valve isolation trace on a segment with a squeeze tool applied, would make this application one of the most important tools used by our Field personnel.

       

      I am interested to determine if other utilities have data similar to us, and if they are facing the same issues with this application.

      Thank you for your time.