A metric-driven method for designing daylit interiors that deliver useful illuminance, controlled glare, connection to the outside and circadian benefit — engineered through glazing, geometry and dynamic shading on South African projects.
Most disappointing daylit interiors are not under-glazed — they are under-specified. A brief for 'lots of natural light' produces impressive lux, intolerable glare, and blinds permanently down by mid-morning. This masterclass gives registered architects and designers a rigorous, metric-driven method to define the brief in four numbers, analyse a space on climate-based metrics (sDA, ASE, UDI), predict glare with DGP from the occupant's eye, protect view and circadian benefit, and engineer apertures, glazing and dynamic shading that hold all of it in balance — defensibly, and across South African clear-sky conditions.
If sDA tells you whether there is enough daylight, Annual Sun Exposure warns you when there is too much of the wrong kind — direct sun deep in the space, the precursor to glare, overheating and permanently lowered blinds. This lecture defines ASE, explains the LM-83 criterion ASE1000/250h, and shows how it acts as the essential counterweight to sDA. We unpack the definition — the percentage of floor area receiving at least 1,000 lux of direct sunlight for at least 250 occupied hours per year — and the IES guidance that ASE above 10% signals likely visual discomfort, with 7% or below preferred. We show how ASE is computed from direct-sun-only simulation with blinds open, why it is the metric that finally quantifies the glare-and-overheat risk DF and even sDA miss, and how it directly justifies dynamic shading. A west-facade case shows ASE at 28% explaining a space everyone hated despite an excellent sDA. By the end you can use ASE to size and justify a shading strategy.
Annual Sun Exposure is the metric that institutionalised a hard truth daylighting long ignored: more sun is not better, and beyond a threshold it actively harms a space, so ASE is the disciplined counterweight that stops sDA optimisation from running away into a glare-ridden, overheated result. Defined in IES LM-83 alongside sDA, ASE measures the percentage of the analysis-grid area that receives at least 1,000 lux of direct sunlight for at least 250 occupied hours per year — written ASE1000,250h or ASE1000/250h. Three features of the definition are decisive. First, it counts direct sunlight only: the simulation isolates the beam component reaching each grid point, ignoring diffuse and reflected light, because it is direct sun penetrating the space that produces the punishing high-luminance patches and the deep solar penetration behind glare and overheating.
A west studio posts an excellent sDA300/50% of 80% yet an ASE1000/250h of 28% (ceiling 10%) and an afternoon DGP of 0.46 (intolerable). The metrics read jointly explain a space everyone hated: ample light, but raw beam sun — so the blinds go down and stay down, and in-use daylight collapses. Selective glazing plus a DGP-driven external venetian drives ASE under 10%, cuts peak DGP to 0.33, and recovers the daylight because the automation retracts the instant glare passes.
Target audience: South African registered architects (SACAP), interior design professionals (IID), professional engineers (ECSA) and lighting/facade specifiers designing daylit commercial, institutional, healthcare and educational interiors.
Assessment: 10 application-based multiple-choice questions, minimum pass mark 70%. Certificate of completion on passing.
Your enrolment includes the full C19 package: the in-depth eBook, the practical how-to guide with the full assessment bank, and the A4 quick-reference cheat sheet.