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Pipe Clash Check

Checks every plan-view crossing between pipe networks for adequate vertical clearance: outer-wall-to-outer-wall gaps that are negative are conflicts (ERROR); gaps below the required discipline-pair separation are separation shortfalls (WARNING).

Command VDCCLASH · VDC QC tab › Design QC panel
Checks every plan-view crossing between pipe networks for adequate vertical clearance: outer-wall-to-outer-wall gaps that are negative are conflicts (ERROR); gaps below the required discipline-pair separation are separation shortfalls (WARNING).
At each plan crossing, sample both centerline Zs & compare the outer-wall gap to the discipline rule. CONFLICT, walls overlap (gap < 0) STORM 30" (crossing pipe) WATER 12" gap = −0.30 ft ERROR, physical conflict SEPARATION, below rule (0 < gap < req) SEWER 8" (crossing pipe) WATER 12" gap = 0.9 ft req 1.5 ft (water÷sewer) → WARNING Gap ≥ required separation → PASS (no finding) Rules: water÷sewer, water÷storm, water÷force-main 1.5 ft  |  sewer÷storm, sewer÷force-main 1.0 ft  |  else default 1.0 ft Output: <drawing> - Clash.csv + findings palette (double-click to zoom to the crossing)
Crossing pipe (in section)   Crossing pipe (cross-section)   Conflict (negative gap)   Separation shortfall   Pass

What it does, per run

  • Snapshot: reads every gravity pipe (storm/sewer) and pressure pipe (water/force-main) with its centerline and outer diameter.
  • Classify: each pipe tagged to a discipline by network-name substring; unmatched networks use the default rule.
  • Crossings: for each pair from different networks, finds the 2D plan intersection and interpolates each pipe's Z there.
  • Gap: computes outer-wall-to-outer-wall vertical clearance vs the discipline-pair rule.
  • Conflict = negative gap (walls overlap, ERROR); Separation = positive but below rule (WARNING).

Settings & options

  • Default separation: clearance when no pair rule applies (default 1.0 ft).
  • Skip same-network crossings: on by default, pipes within one network connect at structures; toggle off to include.
  • Discipline-pair rules: water÷sewer, water÷storm, water÷force-main 1.5 ft; sewer÷storm, sewer÷force-main 1.0 ft.
  • Prefix lists classify pipes into disciplines; report cap and rules edited in settings.json.
  • Settings at %APPDATA%\VDC\Clash\settings.json (VDC_CLASH_SETTINGS), schema-tolerant load.
  • Pressure pipes sampled by endpoints, a curved main is treated as straight for the test.

Dialog

Pipe Clash Check dialog
Pipe Clash Check, VDCCLASH

When to use it

  • Coordinating utility crossings - finding hard conflicts and separation shortfalls before plan production.

How to run it

  1. Run VDCCLASH; set the default required vertical separation and whether to skip same-network crossings.
  2. Click OK; the tool reads every pipe, classifies it by network name (storm / sewer / water / force-main), and tests each crossing.
  3. Review ERROR conflicts and WARNING shortfalls in the palette; double-click to zoom.

Options

  • Default separation: vertical clearance used when no discipline-pair rule applies (default 1.0 ft).
  • Skip same-network crossings: on by default - pipes within one network are not compared.
  • Discipline-pair rules: water-to-sewer / storm / force-main 1.5 ft, sewer-to-storm / force-main 1.0 ft (edited in settings.json).

Watch out for

  • Gap is computed from pipe outer diameters - overlapping walls (negative gap) are physical conflicts.
  • Crossing detection is 2D plan view; Z is sampled along each centerline at the crossing point.
  • Discipline is classified by network-name substring - a network not matching any prefix uses the default separation.

Related: Pipe QC · Pipe Crossings · Easement Widths