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- In BIMpedia
Most projects pass the model from one party to the next: the designers model, the contractor checks, the trades remodel for fabrication. Integrated project delivery (IPD) works differently. The owner, the lead designers and the builder, often with key trades, sign one agreement, and their profit depends on how the whole project turns out. They work together from early design, usually in a shared office called the big room.
Under IPD, costs are reimbursed and profit goes into a shared pool, paid against targets for cost and quality. Liability between the parties is often limited. Decisions are taken by a joint team with members from each party. See the IPD entry for the details.
On a design-bid-build hospital, the architect issues the riser layout. Eight months later, the mechanical subcontractor models its ductwork and finds the riser 300 mm too narrow. An RFI goes back to the design team, a variation follows, and the argument over who pays takes longer than the redesign.
On an IPD hospital, the mechanical trade models the main ducts during design development. In the big room, the coordinator puts the federated model on the screen; the riser is visibly too tight. The architect, the structural engineer and the mechanical foreman agree a wider riser in twenty minutes, and the decision is logged with its effect on the cost target.
What changes for the BIM person
| In a traditional project | In IPD and the big room |
|---|---|
| Designers model, then hand over | Designers and trades model the same zones at the same time |
| Clash reports go out by email | Clashes are resolved on screen with the people who can decide |
| Trades remodel for fabrication | Trade models are the design models, developed to fabrication |
| Decisions in RFIs and minutes | Decisions logged in the room, against the model and the target |
Borrowing the habits
Few projects use full IPD. Many borrow its habits under ordinary contracts: early contractor and trade involvement, a weekly coordination session on the shared model, decisions logged with the model view that prompted them.
You coordinate a clinic project under ordinary contracts, but the client wants "big-room working". Sketch the week: which sessions, who attends, and what the model must show at each.
A big-room week
Put the week’s sessions in a sensible order.
- 1Coordination session: open issues decided on screen
- 2Model refresh: every team uploads, the coordinator federates
- 3Cost and programme check against the week’s decisions
- 4Look-ahead with the foremen: what is missing for the next weeks
Key takeaways
- Under IPD, the owner, designers and builders share one agreement, and their profit depends on the whole project.
- The big room is where decisions happen: the federated model is on the wall, and the people who can decide are in the room.
- Trades model early, so coordination moves from 'design, then check' to 'design together'.
- Even without IPD, borrow the habits: early trade input, a shared model, decisions logged in the room.