A hydrocarbon dispensation line pressure sensor adapted to work without requirement of a separate closed valve. The system closes the dispensation line upstream via an isolation valve. The pressure can be sensed from the dispensation line through the valve to provide dispensation line pressure. A channel in fluid communication with the dispensation line may be provided to allow pressure measurement apart from the main dispensation line. Further, a method for measuring the pressure drop profile of a dispensation line and various methods to determine the pressure loss due to leaks in dispensation line.

In some embodiments, at least one processor determines a range of search directions to a suspected gas leak source by receiving data representative of a plurality of wind direction measurements relative to a geo-referenced location of at least one gas concentration measurement point. The range of search directions extending from the location of the gas concentration measurement point is calculated according to a variability of the wind direction measurements.

In some embodiments, at least one processor is employed to determine a boundary of a survey area. Data representative of the locations of measurement points adjacent to or outside of the survey area are received, as well as data representative of wind direction at the measurement points. The boundary of the survey area is determined according to the data representative of wind direction and a maximum detection distance value representative of an estimated maximum distance from a potential gas leak source at which a gas leak from the potential source can be detected.

In some embodiments, content is generated that includes a street map, at least one path on the map indicating a route of travel by a mobile gas measurement device, and at least one indicator on the map that indicates a survey area for a potential gas leak source. The survey area adjoins the path and extends in a substantially upwind direction from the path. The survey area has a boundary determined such that if the potential gas leak source is located in the survey area and has a rate of leakage meeting a minimum leak rate condition, then an estimated probability of detection of a gas leak from the potential source at one or more measurement points along the path satisfies a probability condition.

In some embodiments, a computer system generates display content indicating a likely direction and estimated distance to a potential gas leak source. The content includes a street map and at least one search area indicator on the map that indicates a search area suspected to have a gas leak source. The search area indicator has an axis indicating a representative wind direction relative to a geo-referenced location of at least one gas concentration measurement point. The search area indicator also has a width relative to the axis. The width is indicative of a wind direction variability associated with a plurality of wind direction measurements in an area of the gas concentration measurement point. The axis also preferably has a length indicating an estimated maximum distance to the potential gas leak source.