GDM Tables
The tables in the GDM directly related to facilities can be viewed as belonging to separate categories for the purpose of isolating information levels and maintaining reporting relationships. This hierarchy defines the elements that make up the model.
Gas System The Gas System category is delineated by data tables that illustrate the hierarchy of facilities as gas is delivered to a delivery point as well as the operational fittings, flow systems, valves and metering points in the system. In each case below the facilities of a sub-category are related to the category or sub-category above it. For example, gas valves and gas service pipe can be linked to either a gas main pipe or a gas service pipe.
Leak Inspection Leak inspections tasks can be performed on mains, services transmission lines, meters, regulators and valves. Each has a separate and distinct reporting method which can be captured via the base tables available in the GDM. Inspections may be based on geographic regions as well as facility types. The GDM has been modeled to take advantage of both the tabular and geographic data of inspections and Leak Reporting. Inspection results have the ability to be reported by geographic area or broken down to its smallest components of gas pipe or fitting. Each table in the Leak Inspection Category is related the Leak Inspection category and sub-categories as well as relationship to mains and services tables.
Cathodic Protection Much like the Leak Inspection tables, Cathodic Protection systems are modeled to represent multiple methods of protecting mains and services. The tables are modeled to allow for representing cathodic protection in a geographic or tabular manner by permitting identification of individual pipe as well as in a larger cathodic sub-system. The method of protection for gas pipes has also been modeled through identification of the manner in which it is protected. The GDM model was built to provide identification of rectifier systems or magnesium anodes. The GDM also has the ability to model current carrying cable as well as where current may break at insulated fittings and carried past those points with bond wire indicators. The tables of the Cathodic Protection category also have the relationship to other distribution facility tables such as gas mains and services and therefore, to Leak Inspection data as a result.
System Data The GDM category labeled “System Data” is modeled to recognize data tables that may reference all other categories, either to further enhance data or to be a repository of metadata for the rest of the system. |
