Engineering reference
Lighting specifications that survive contact with a site
Most lighting problems are not lighting problems. They are a maintained illuminance read as an initial value, a driver chosen on wattage instead of current, a UGR figure quoted from a catalogue that assumed a room nothing like yours. These notes cover the parts of a commercial LED specification where the datasheet and the installed result diverge.
Metrics & standards
What illuminance, glare, colour rendering and flicker figures actually mean, how they are measured, and the specific ways each one gets misread on a tender document.
Read the metrics notes
Selection & calculation
Drivers, dimming protocols, ingress ratings and emergency gear — the choices that decide whether a fitting works in year five, and the arithmetic behind them.
Read the selection notes
Retrofit & economics
Fluorescent and discharge replacement: what changes beyond the lamp, and how to build a payback case a finance department will sign off.
Read the retrofit notes
Acceptance & QC
Incoming inspection, colour consistency and ageing — checks that cost an afternoon and save a re-lamping campaign.
Read the acceptance notes
Calculators
Four browser-based tools: luminaire count by the lumen method, LED strip power and voltage drop, retrofit payback, and driver headroom. Each one shows its formula.
Open the calculators
Who writes this
We manufacture LED lighting and write the control software that drives it. These are the internal reference notes we use when specifying and inspecting our own product.
About this siteHow to read these notes
Two conventions run through every page here, and both exist because they are the places engineering writing usually goes wrong.
Standards are cited, not reproduced. Where a value comes from EN 12464-1, GB 50034, IEC 62717 or an IES document, we name the clause and tell you what it governs — we do not copy the tables. Those tables are the licensed product of the standards bodies, they are revised, and a number transcribed into a web page is a number nobody updates. Where a figure appears here it is either from a published manufacturer datasheet, with the source named, or it is an example calculation whose inputs are stated so you can redo it.
Measured data is labelled as measured. Pages that will carry our own bench measurements show the measurement procedure and an empty results table until the numbers exist. An empty table is honest; a plausible table is not. If a page is marked data pending in a section index, the method is written and the readings are not taken yet.
What this site is not
It is not a design service and not a substitute for one. Lighting design for a real building involves fire strategy, emergency egress, controls commissioning and electrical safety, all of which need a qualified engineer with drawings in front of them and professional indemnity behind them. What you will find here is the layer underneath that: how the numbers work, so that you can read a proposal critically and ask the question that matters.