When lab data is committed and exceedance detection runs, Piper compares each AnalyticalResult's normalizedValue against all ThresholdValues in ThresholdSets assigned to the result's site. If a result concentration exceeds the limit in the applicable direction, Piper creates an Exceedance record. The exceedanceRatio tells you how significant the exceedance was — a ratio of 2.0 means the measured concentration was twice the regulatory limit. The exceedanceType (from the ExceedanceType enum) categorizes the nature of the violation. If isNonDetect is true on the exceedance, it indicates the detection limit itself exceeded the threshold — a method sensitivity issue that also requires reporting in many programs. The sampleDate on the Exceedance enables trend analysis and regulatory report filtering by sampling period.
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Exceedance
An Exceedance is created automatically when an AnalyticalResult's concentration breaches a ThresholdValue. It captures the resultConcentration and resultUnit alongside the thresholdConcentration and thresholdUnit from the ThresholdValue, and computes an exceedanceRatio to show how far above (or below) the limit the result was. It also records the siteId, wellId, analyteId, sampleDate, and the timestamp when it was detectedAt.
Technical section
Data model, API, and internals — visible to developers.