Contractors
Contractor Schedules in a Shutdown: One Master Schedule
Keep one owner-controlled master schedule and make contractors feed it. Require submissions in an agreed exchange format such as P6 XER or XML, Microsoft Project XML, or Excel, with common activity IDs, a status date and a baseline kept under change control. GAO's guide says the master must integrate contractor and subcontractor schedules, even when built in separate software.
How MaintWiz helps: MaintWiz imports task lists as Microsoft Project XML or Excel and works with Primavera P6 through interoperability, so contractor plans load into one master with readiness gates and permits.
By Jai Balachandran · Technical review: Murali Nerur Pasupathy · Published · Last reviewed
What MaintWiz adds:Critical path and floatReadiness gatesPermits and isolationsChecklists with readings
Exchange formats
Which exchange formats can contractors use?
Agree the format in the contract and test it with one sample file before the stop.
| Format | Documented capability or limit | Source |
|---|---|---|
| Primavera XER | Proprietary; full project, resource and role data; supports scheduled exports; no baseline export or import | Oracle P6 Professional import and export guide |
| Primavera P6 XML | Industry-standard XML; baselines supported; stricter security and rollback on a failed import | Oracle P6 Professional import and export guide |
| Microsoft Project XML | Listed for Microsoft Project 2007, 2010 and 2013 | Oracle P6 Professional import and export guide |
| MPX | Listed for sharing with Microsoft Project and third-party tools | Oracle P6 Professional import and export guide |
| Excel (XLSX) | Listed for sharing information with spreadsheet applications | Oracle P6 Professional import and export guide |
Submission rules
What should every contractor schedule submission follow?
GAO's schedule guide describes the controls; the contract should state them.
- One master: the owner's schedule collects contractor and subcontractor work, and each contractor schedule rolls up into it even if built in different software.
- A baseline kept under change control: performance is reported against it, and changes go through a defined process.
- Common identifiers: the same activity IDs, area and trade codes, defined in a schedule basis document, so work can be filtered by contractor.
- A status date on every update, progress as actuals with the logic intact, and a short narrative of what changed.
- Few hard constraints in the baseline and official updates; document any that are unavoidable.
- Trained updaters: the people who update should understand critical path scheduling.
FAQ
Frequently asked questions
Should contractors work in the owner's scheduling tool?
Not necessarily. GAO says contractor schedules must roll up into the overall master even if built in a separate file or different software, so the owner needs an agreed exchange format and common identifiers.
Which file format keeps baselines when moving schedules between P6 databases?
Oracle's documentation says P6 XML supports baseline export and import; XER does not. XER supports scheduled exports and XML does not.
What should every contractor schedule update include?
GAO points to a status date, progress recorded as actuals with logic intact, a schedule narrative of changes, and coding defined in a basis document. Contractor-specific submission clauses belong in the contract.
Who controls the baseline?
GAO says the baseline is the target schedule under configuration management control, with performance reported against it. Changes should go through a defined control process.
Sources
Sources
GAO's schedule guide and the Oracle and Microsoft documentation, read on 30 October 2026.
Plan this work in the shutdown module
Book a demo and bring your next shutdown scope. We will show how the work, the permits and the results sit in one plan.