What Happens Between the Plot and the Installed Job

The drawing is rarely the problem. The gap opens between tender and handover, and it opens in the same six places every time: an equivalent product accepted on a marketing sheet, a driver swapped for a cheaper one late in procurement, fittings mounted at the wrong height because the ceiling grid moved, aiming done in daylight, scenes programmed by whoever had the laptop, and a maintenance regime nobody wrote down. None of those are design failures and all of them land on the design.

The equivalents are the most expensive. A substituted fitting that matches lumen output and colour temperature can still have a completely different intensity distribution, and a 30 degree beam swapped for a 40 degree one will miss the top of a facade by several metres. We now require full photometric files in IES or EULUMDAT format for every proposed alternative, and we run it through the model before answering. Roughly a third of submitted equivalents fail that test.

Aiming is the cheapest thing to protect and the easiest to lose. A focus session costs a few nights and it is the only moment where the design and the building are in the same room, yet it is routinely the first item compressed when the programme slips. We write it into the contract as a named activity with a minimum number of night shifts, and we insist the operator attends, because the person who will run the building afterwards should have watched it being set.