Every system was somebody's package. The places where they had to talk to each other belonged to nobody.

A mixed-use development is not one project. It is a stack of separate contracts that has to behave as one building on the day it opens. Everything below follows from that, and none of it is technical.

1. The developer holds the programme, not the systemsThey contract packages and expect them to arrive working together. Nothing in that structure makes anyone responsible for the joins.
2. The PMC holds the programme, not the cause and effectA programme manager tracks whether a package is delivered. Whether it does the right thing when a fire alarm activates is a different document, and it is usually nobody's.
3. Six trades have to be reached intoLift, HVAC, electrical, ironmongery, AV and fit-out. Each has its own contractor, its own programme and its own definition of finished, and none of them is us.
4. Interfaces cost nothing before award and a great deal after itLift recall is the usual casualty. It is a line in the lift contractor's scope if it is written before tender, and a variation if it is not.
5. The facility team inherits all of itThey were in the room for none of the decisions, and they will run the building for twenty years.

Named rather than counted. A total tells a reader nothing they can act on; this list tells them what to go and ask about on Monday.

1. Fire alarm to access controlEvery controlled door on the escape route releases on alarm, and proves that it released.
2. Fire alarm to liftsRecall to the designated floor, doors open, out of service. The most commonly missed interface on any development, and the one nobody discovers until the fire officer asks.
3. Fire alarm to HVACDampers, shutdown and stair pressurisation. Owned by the HVAC contractor, triggered by a system that is not theirs.
4. Access control to surveillanceA door forced or held open is worth nothing without the camera that saw it, and the two systems are almost always bought separately.
5. Intrusion to the command roomAn alarm nobody is contracted to answer is a noise.
6. Everything to the building management systemThe graphics the facility team will actually look at, and the point list that has to exist before anyone can build them.
7. The public address overrideWhose message wins when two systems both want the speakers, decided in writing rather than on the day.

1. Before tender it is a scope line, after award it is a variationThat is the whole argument, and it is commercial rather than technical. It is also the reason this conversation belongs at design stage and not at commissioning.
2. Every interface needs a named owner and a defined pass criterionNot a note on a drawing. A party, and a test that either passes or does not, so that at commissioning there is nothing left to negotiate.
3. Interfaces outside our package are raised at BOQ stageLift recall, damper actuation and pressurisation belong to other contractors. Named in their scopes before award, because after award they cost money nobody has budgeted.
4. Commissioning tests the response, not the devicesA device test proves a device. Only the response test proves a building.
5. Handover is a set of documents, not a set of keysAs-builts, the signed matrix, configuration records, test results, and an O&M written for the team who will inherit it rather than for the file.