Step by step
- Identify both services. Read each element's system, size, insulation and owner: a supply duct, a chilled-water main, a sprinkler branch and a domestic cold-water pipe are four different decisions.
- Decide which one gives way. Compare what each change costs: the system, the size and insulation, and what it would affect. Gravity drainage never gives way; if the cheaper change is on another trade's element, it is their decision, not yours.
- Measure the space around the clash. Check the room above, below and to each side of the moving service up to the next obstacle, the ceiling line and the project's clearance, insulation included.
- Prefer the move that stays in its zone. A sideways move inside the trade's height zone usually beats a drop out of it; between two valid moves, take the one with fewer added fittings and less added length.
- Apply the offset. Split the run either side of the duct, offset the middle segment, add fittings at 45° where there is room (90° where there is not) and reconnect.
- Re-check what the change affects. Re-test the clash and the run's neighbours. A new high point on a pressurised pipe needs an air vent and a new low point a drain; a change to a duct needs an airflow and pressure re-check by the HVAC engineer.
How ClashFree handles it
ClashFree resolves every pipe and duct to a system class (supply, return or exhaust duct, smoke-extract duct, kitchen exhaust, sprinkler, chilled or heating water, domestic water, condensate, gravity drainage and more) from its category, system classification, size and insulation. Each class carries the cost of a change: per fitting, per millimetre moved and added, per new high or low point.
The side that moves is the one whose estimated disruption is lower, the class cost scaled by size, so a small water pipe gives way to a large supply duct and a large insulated main can outweigh a small duct. Ties go to the smaller run. The reason is written into the group, so you can see why the pipe moves.
For the moving run, ClashFree lists the offsets with room in each direction, scores them (sideways inside the zone, fewest fittings, least length), and names what the fix affects for that class: pressure_loss for a duct, hydraulic_calc for a sprinkler, head_loss for water, a vent or drain for a new high or low point.
Every fix is a preview inside one Revit transaction group: ClashFree applies it, checks that the clash is gone and that no new clash appeared against the host model and the linked models, and shows you the result. Keep commits it as one undo step; Reject restores the model exactly. Linked models and other trades' elements are never edited.
If the cheaper change is on another trade's element, ClashFree does not touch it: the clash goes to the Coordination list for that trade or a person to decide.
help/img/duct-pipe-proposal.png