Gas distribution
Gate to meter
The Gas skill turns Nexma into a natural-gas distribution-design platform. It models the network from gate station to customer meter, validates pressure drop across regulators, and stages pressure down through tiers. Safety drives the ontology here — isolation segments and vent clearances are first-class constraints, not afterthoughts.
What this skill models
The ontology captures a pressure-staged distribution network with the entity types, link types, and constraints a gas engineer expects.
- Entity types.
GateStation,MainPipeline,DistrictRegulator,Meter,Vent,IsolationValve, andPressureSensor. Each carries typed properties — MAOP, regulator set point, valve class. - Link types.
GateFeedPipe,PipelineConnection,ServicePipe, andRegulatorConnection. Pipes carry diameter, SDR, material, and design pressure. - Key constraints. A maximum of 7 bar in distribution mains; regulator pressure-staging rules between tiers; isolation-segment coverage that bounds any failure; and vent placement clearances from buildings and roadways.
The ontology ships the reference data a designer relies on: ANSI/ASME pipe-class tables, ISO regulator capacity curves, and standard service-line sizes by meter class.
What Jax can do
Jax reasons about pressure tiers because the Skill binds its capabilities to this ontology.
- Generate distribution layouts. "Lay mains to every meter in this polygon. Hold inlet pressure at or above 1.4 bar at every meter. Stage from 4 bar down to 1.4 bar." Jax routes mains and places regulators on the tier boundaries.
- Stage pressure — sizes regulators and chooses pipe SDR per tier.
- Validate pressure drop across long mains under design demand.
- Plan isolation — proposes valve placements that keep any failure segment under an acceptable customer count.
- Audit vent clearances against building footprints and roadway clearances.
The pressure-drop simulation runs through the Nexma MathEngine and writes results back to the world model, so regulator set points and main flows update the instant a run completes.
Tip: Decide the tier structure before sizing anything. Regulator capacity and pipe SDR both follow from the inlet and outlet pressure of each tier, so fixing the staging plan first makes the rest of the design fall out deterministically.
Constraints and standards
The skill enforces the rules a gas design must satisfy to be safe and compliant.
| Concern | Rule enforced | Standard |
|---|---|---|
| Main pressure | 7 bar maximum in distribution | ANSI/ASME B31.8 |
| Pressure staging | Regulator set points per tier | B31.8 distribution design |
| Pipe qualification | SDR and PE fitting class | ISO 12176 |
| Integrity | Isolation-segment coverage | 49 CFR Part 192 (US) |
| Vent clearance | Distance from structures | Distribution safety code |
Export targets include GeoJSON, shapefile, and vendor-format files from Project to Export.
Out of scope today: LNG and storage-facility design, cathodic-protection survey workflows, and real-time SCADA writebacks (read-only telemetry only).
Where to go next
- Water distribution — pressurized networks with a different fluid model.
- Electric distribution — the same source-to-meter pattern for power.
- Skills overview — the full catalog.
- Nexma MathEngine — the simulation layer behind the pressure-drop solve.