Zone Accuracy


Detect3D uses a point cloud with each fire zone to calculate coverage statistics and to provide a data set for the contours and isovolumes. Although this point cloud is never visible to the user, each time a zone is updated, the visibility of each point to all detectors is calculated. In many cases the number of points will be greater than one million. The spacing between these points, or “resolution”, affects the accuracy of the statistics, contours and isovolumes. However, the resolution of the flame detectors also affects the accuracy of the calculation. In fact, in most cases the resolution of the flame detector is the primary driver of accuracy. Even so, the refinement of the zones must also be considered.


A good way to think about the relative aspects of the zone and detector resolution is to think of the points in the zone as representing the accuracy of the detector. If the zone resolution is poor, then the overall accuracy will be low. However, if the zone resolution is excellent, but the accuracy of the detector is poor, the result will again be an overall low accuracy.


This section will cover how to increase the resolution of zone containing an isovolume and a contour. Increasing the resolution of a zone can be chosen when adding one from the Add Item tab - just select the desired resolution from the dropdown menu. Detect3D allows for resolutions from Coarse (points spacing of 0.5m) to Very Fine (point spacing of 0.0625m) from the dropdown menu.


The images below show a comparison of increasing the resolution of a fire zone with varying FOV resolutions. Notice that the top right image has a fire zone with a high resolution but does not give a good representation of the geometry due to the low resolution of the flame detector's FOV. The bottom right image gives a much more accurate representation by increasing the field-of-view resolution even though the fire zone resolution has just 12% of the number of points that the first image has. The option to increase the flame detector resolution keeps computation time low while maintaining good accuracy in the calculation.




Contents of Zone Accuracy: