Engineering approach
Systematic clash detection across federated MEP, structural and architectural models — with prioritised issue management, tolerance governance and verified resolution before construction issue.
Clash reduction applies structured geometric testing to federated BIM models to identify hard conflicts, clearance violations and workflow clashes between disciplines. Tests run against current approved model revisions with documented tolerance rules — not ad hoc visual inspection.
Issue management assigns clashes to responsible appointments with priority classification and target resolution dates. Resolution occurs in authoring models; clash environments are used for detection and verification, not permanent design modification.
Unmanaged clash programmes generate noise that overwhelms resolution capacity, or miss genuine conflicts that become costly variations. A governed clash programme aligned to coordination milestones gives contractors and clients evidence that critical interfaces have been reviewed and resolved.
Early clash identification reduces site rework, programme disruption and contractor claims. Design teams resolve routing and clearance conflicts when alternatives remain viable. Clients receive traceable coordination records supporting construction issue gates.
Not every geometric intersection is an actionable clash. Tolerance tables, zone rules and construction sequence context filter results to prioritise constructability-critical conflicts. Critical and major clashes are tracked to verified closure before milestone approval.
Define hard, clearance and workflow tolerances per zone in the BIM execution plan.
Build clash tests with selection sets and discipline pair rules.
Execute initial test establishing baseline counts and hotspots.
Classify results as critical, major or minor based on constructability impact.
Allocate clashes to responsible appointments with target dates.
Discipline teams update source models to eliminate or accept conflicts.
Confirm closure on updated federation before status change.
Publish cycle metrics showing new, resolved and open clash counts.
Navisworks or equivalent coordination platforms federate Revit, IFC and specialist models without altering authoring files. Clash tests reference element GUIDs and model revision metadata for traceability. Results export to CDE issue trackers with viewpoints and markup for discipline teams.
IFC exports supplement native Revit federation where third-party models require open format exchange. Model origin, shared coordinates and file naming are verified before each clash cycle to prevent false positives from misaligned federations.
Clash reduction succeeds when disciplines design with shared clearance rules and coordinated routing strategy — not when coordination is deferred to a single clash meeting. Integrated workshops establish routing hierarchy, ceiling zone ownership and structural penetration protocols before detailed clash cycles begin.
MEP, architecture and structure teams align on maintenance access, fire compartment boundaries and builder's work requirements as part of clash resolution — not as post-clash surprises.
Physical intersection between elements occupying the same space.
Minimum separation distances for insulation, access, cable bend radius and maintenance.
Sequence, access and temporary works conflicts beyond pure geometry.
Zone and discipline boundaries defining test coverage per cycle.
Documented exclusions for known acceptable intersections.
Design-intent conflicts formally approved without geometric resolution.
Clash records linked to CDE workflow with status audit trail.
Defined open-clash thresholds before construction documentation approval.
MEP vs structure
Ceiling void services
Full federation
| Milestone | Element | Purpose | Responsible | Geometric | Alphanumeric | Documentation | LOD / LOIN | Control | Acceptance |
|---|---|---|---|---|---|---|---|---|---|
| First federation | MEP vs structure | Identify major routing conflicts | BIM coordinator | LOD 300 federated models | Clash test ID, tolerance | Baseline clash report | LOIN 3 — coordination | Test configuration audit | Baseline report issued |
| Design development | Ceiling void services | Optimise routing and clearance | MEP BIM lead | All services in void zone | Priority, status, assignee | Cycle clash report | LOIN 3 — coordination | Trend review meeting | Critical clashes assigned |
| Pre-construction | Full federation | Construction issue gate | Lead coordinator | Current approved federation | Closure evidence per clash | Gate review report | LOIN 4 — issue readiness | Sign-off register | Gate criteria met or accepted |
ISO 19650
buildingSMART IFC
ASHRAE Guideline 36
AIA E202
| Standard / Reference | Full title | Organization | Application area | Relevance | Edition status |
|---|---|---|---|---|---|
| ISO 19650 | Organization and digitization of information about buildings and civil engineering works, including building information modelling (BIM) | ISO | Information management across the asset lifecycle | Defines information management roles, exchange requirements and CDE governance for coordinated delivery. | Current adopted edition to be confirmed at project commencement |
| buildingSMART IFC | Industry Foundation Classes (IFC) data schema | buildingSMART International | Open data exchange between authoring and coordination platforms | Supports federated model exchange, quantity take-off and lifecycle handover workflows. | Current adopted edition to be confirmed at project commencement |
| ASHRAE Guideline 36 | High-Performance Sequences of Operation for HVAC Systems | ASHRAE | Mechanical control sequences and operational performance | Informs modelled system behaviour, commissioning logic and performance verification criteria. | Current adopted edition to be confirmed at project commencement |
| AIA E202 | Building Information Modeling Protocol Exhibit | AIA | BIM scope and responsibility allocation | Supports clash responsibility mapping and model use definitions in contract context. | Current adopted edition to be confirmed at project commencement |
Applicable standards depend on the project jurisdiction, information requirements, contract documents, delivery method and authority requirements. The adopted editions shall be confirmed at project commencement.
Cycle reports with test configuration, counts and priority breakdown.
Clash records with assignee, status and linked viewpoints.
Documented clearance rules per zone and system type.
Formally approved design-intent conflicts with authority sign-off.
Cycle-over-cycle metrics for coordination programme review.
Evidence pack for construction issue clash status assessment.
Verify clash test scope and tolerances match BEP before each cycle.
Confirm models match approved CDE revisions.
Closed clashes confirmed by re-run, not manual status alone.
Critical/major/minor rules applied uniformly across cycles.
Periodic review of exclusion rules and noise reduction.
Formal assessment against open-clash criteria before issue.
Number of unresolved critical clashes at each coordination cycle.
Clashes closed per cycle relative to new clashes identified.
Clash runs completed per agreed schedule without skipped milestones.
Share of results marked as non-actionable after review.
Elapsed time from clash assignment to verified closure.
Clash results reflect federation currency; delayed model updates produce stale outcomes.
Clearance rules require project-specific agreement; generic defaults may not suit all zones.
Shop drawing level detail may reveal clashes not visible at design coordination LOD.
Incomplete or incorrectly oriented consultant models affect test reliability.
No. Clash reduction minimises coordination risk through governed detection and resolution. Site conditions, fabrication detail and late design changes may still produce conflicts requiring field resolution.
Frequency aligns to coordination milestones — typically at design development intervals and before construction issue. Cadence is defined in the BIM execution plan based on project complexity and programme.
Hard clashes are physical intersections. Clearance clashes violate minimum separation for insulation, access, bend radius or maintenance. Both are configured with distinct tolerance rules.
Resolution responsibility follows BIM execution plan role allocations. MEP routing clashes are typically resolved by the relevant discipline lead in authoring models, with coordinator verification.
We can define scope, coordination milestones, information requirements and performance metrics for your project — and prepare a formal proposal.