Each ThresholdSet contains many ThresholdValues — one per analyte covered by the regulatory table. For example, a state MCL table would have one ThresholdValue for benzene, one for toluene, one for arsenic, and so on, all linked to the same ThresholdSet via thresholdSetId. The direction on each ThresholdValue tells Piper whether a result exceeds the standard by being above the limit (most common for contamination screening) or below it (for indicator parameters like pH where low values signal a problem). The source field can record analyte-specific citations when limits vary by sub-table or compound class within the larger regulatory document.
Technical section
Data model, API, and internals — visible to developers.