Course content · 14 lessons · 96 minutes
The full curriculum
Lesson 01 · 6 min
When the Sun Became a Regulation: Why XA Exists
South Africa did not regulate building energy until SANS 10400-XA was first published in 2011 and made mandatory under the National Building Regulations. For decades a north-facing Johannesburg living room glazed wall-to-wall was a design preference; today it is a calculation that must pass before a local authority issues an occupancy certificate.
SANS 10400-XA:2021, Energy usage in buildings, is the current edition of Part XA of the National Building Regulations, issued by the South African Bureau of Standards (SABS) and given legal force through the National Building Regulations and Building Standards Act 103 of 1977 and its associated regulations. The first edition (2011) introduced mandatory energy-usage requirements for all new buildings and major alterations; the 2021 revision tightened the fenestration provisions, recalibrated the climatic-zone map, and clarified the relationship between the deemed-to-satisfy route within XA itself and the rational-design route that calls up SANS 204. Understanding why fenestration came first is essential to the whole course. In the South African envelope, the roof and walls are addressed by R-value (thermal resistance) requirements that are relatively easy to meet with conventional insulation; the glazing, by contrast, is a direct aperture for solar radiation and a thermal bridge, and it is the element most often pushed beyond prudent limits by architectural ambition. XA therefore places a hard cap on glazing area and a performance requirement on the glazing-plus-shading assembly.
In depth
The legal mechanism is important for the specifier to understand precisely. SANS 10400-XA sets the functional requirement — a building must be designed and constructed so that it uses energy efficiently. It then offers two compliance paths. The first is the deemed-to-satisfy route set out in XA Clause 4 and its tables: meet the prescriptive limits and you are deemed to comply without further calculation. The second is the rational-design route, where a competent person (typically a registered professional engineer or architect under the Engineering Profession Act or the Architectural Profession Act) demonstrates by calculation or simulation, using the methods of SANS 204, that the building achieves equivalent or better energy performance.
Shading lives at the heart of both routes: in the deemed-to-satisfy route it is one of the few ways to legitimately increase glazing area beyond the base allowance; in the rational route it is a primary input to the energy model. The 2021 edition also sharpened enforcement. An occupancy certificate under the Act may not lawfully be issued unless XA compliance is demonstrated, which means the shading specification is no longer a soft recommendation — it is a precondition for legal occupation. For the specifier the lesson is that every glazed elevation now carries a compliance argument, and shading is the instrument that wins it. The remainder of this course assembles that argument line by line: the glazing-area caps of Clause 4, the conductance and solar-heat-gain limits, the climatic-zone adjustments, the rational-design escape hatch of SANS 204, the CGSF calculation that decides the facade, and the documentation a local authority must receive.
Lesson 02 · 7 min
The Two Routes: Deemed-to-Satisfy vs Rational Design
Every XA submission travels one of two roads, and choosing the wrong one wastes weeks. The deemed-to-satisfy route is prescriptive: meet the tables in SANS 10400-XA Clause 4 — glazing area below the cap, conductance and solar-heat-gain within limits — and the local authority must accept it without further calculation.
The architecture of SANS 10400-XA:2021 rests on the same two-route logic that runs through the entire SANS 10400 family, but the consequences of the choice are sharper for energy than for any other part. The deemed-to-satisfy (DtS) route is defined in XA Clause 4. It is prescriptive and binary: the design either meets each numerical limit or it does not. The key DtS fenestration controls are the maximum glazing area expressed as a percentage of net floor area for the storey (XA Table, commonly cited as the Clause 4.3 fenestration provisions), and the requirement that the conductance and the solar heat gain of the fenestration not exceed the limits set for the relevant climatic zone and orientation. If every line passes, the local authority is obliged to accept the design without any energy modelling — that is the meaning of deemed-to-satisfy. The rational-design route is invoked when the DtS limits cannot or will not be met — most often because the architect wants more glazing than the cap permits, or a high-performance glass-and-shading assembly that the prescriptive tables do not reward.
In depth
Under this route a competent person, as defined in the National Building Regulations (a person registered under the Engineering Profession Act 46 of 2000, the Architectural Profession Act 44 of 2000, or an equivalent statutory council, and competent in the relevant field), prepares a rational design. The method is set out in SANS 204, Energy efficiency in buildings, which XA calls up by reference. The competent person constructs a notional (reference) building that just meets the DtS requirements, models the actual proposed building, and demonstrates that the proposed building's theoretical energy demand or consumption is equal to or less than the notional building's. This is the energy-equivalence principle, and shading is one of the most powerful tools for tilting the comparison: external shading that the DtS tables cannot fully credit can be modelled explicitly in the rational route, often unlocking far more glazing than the prescriptive cap allows. Vocabulary precision matters because submissions are rejected on it. A competent person is a statutorily registered professional accepting legal responsibility for the rational design; an unregistered drafter cannot sign one.
The notional or reference building is the DtS-compliant benchmark; the proposed building is the actual design. The rational assessment must state the climatic zone, the building classification (SANS 10400-A occupancy classes such as H4 dwelling house, A1 entertainment, G1 offices), the floor areas, the orientations, and the glazing and shading properties used in the model. A common and fatal error is to submit a rational design that simply asserts compliance without the notional-building comparison, or that uses shading values not traceable to a declared standard. The strategic takeaway for the specifier: the DtS route is faster and cheaper when glazing is modest, but on any contemporary, heavily-glazed scheme the rational route is where shading earns its keep, because only there can the full thermal value of an external or automated device be brought to bear on the numbers.
Lesson 03 · 7 min
The Glazing Cap: SANS 10400-XA Fenestration Area Limits
The first wall every glazed scheme hits is the fenestration-area cap. SANS 10400-XA:2021 limits the total glazing of a storey to a fixed percentage of the net floor area of that storey before any energy calculation is even considered — the deemed-to-satisfy baseline is a maximum total glazing of 15% of net floor area, with conductance and solar-heat-gain conditions that must hold simultaneously.
The fenestration-area provision is the gatekeeper of the entire XA fenestration regime, and the specifier who internalises it can triage any scheme in minutes. SANS 10400-XA:2021 expresses the deemed-to-satisfy fenestration limit as a maximum total glazing area for a storey equal to 15% of the net floor area of that storey, subject to the fenestration also satisfying the conductance and solar-heat-gain (CGSF) requirements for the relevant climatic zone. The 15% figure is the headline number, but it never stands alone: the standard pairs it with a fenestration energy requirement that limits the combined effect of glazing area, glazing conductance and glazing solar heat gain. The calculation procedure in the standard sums, for each glazing element, the product of its area and its solar-heat-gain and conductance properties, weighted for orientation, and compares the total against the allowance derived from the net floor area and the climatic zone. The practical consequence is that the 15% cap is the threshold below which the simplest interpretation applies; above it, or where high-conductance or high-SHGC glazing is used, the design must show by the standard's own arithmetic that the fenestration energy demand stays within the allowance, and this is precisely where shading enters. Consider a single-storey H4 dwelling house with a net floor area of 200 m².
In depth
The deemed-to-satisfy baseline glazing allowance is 15% — 30 m² of glazing. An architect proposing 42 m² of north-facing glazing has overshot by 12 m² and cannot use the simplest DtS interpretation as-is. Two legitimate moves recover compliance. First, reduce the effective solar heat gain of the over-cap glazing using shading and high-performance glass so that the fenestration energy total falls back within the allowance — external shading that cuts the effective SHGC from, say, 0.6 to 0.15 can make a larger glazed area carry the same or less solar load than a smaller unshaded one. Second, move to a full rational design under SANS 204, modelling the shaded facade explicitly. Orientation is decisive in the arithmetic.
South-facing glazing in the southern hemisphere receives little direct solar gain and is weighted accordingly; north-facing glazing receives the most and is penalised hardest, which is exactly why north elevations are the highest-value targets for shading in SA practice — the inverse of the northern-hemisphere intuition many imported textbooks carry. East and west glazing, taking low-angle morning and afternoon sun, are difficult to shade with horizontal overhangs and frequently drive the conductance and SHGC limits. Conductance interacts with area: a large area of high-conductance single glazing can breach the fenestration energy allowance even when the 15% area cap is respected, because the conductance term inflates the total. The specifier's mental model should therefore be three-dimensional — area, conductance and solar heat gain together — not a single percentage. The 15% cap is where the conversation starts, not where it ends.
Lesson 04 · 6 min
Six Climates, One Country: The SANS Climatic Zones
South Africa is not one climate, and XA does not treat it as one. SANS 10400-XA and SANS 204 divide the country into six climatic zones — from the cold interior of zone 1 around Johannesburg and Bloemfontein, through the temperate coastal belt, to the hot-humid subtropics of zone 2 and the hot-dry interior of zone 4 — and each zone carries its own fenestration conductance and solar-heat-gain limits.
SANS 10400-XA:2021 and SANS 204 share a six-zone climatic classification of South Africa, and the zone is the first datum a competent person must establish because it sets the conductance and solar-heat-gain limits that every fenestration calculation references. The six zones are, in the standard's classification: Zone 1, cold interior (the Highveld — Johannesburg, Pretoria, Bloemfontein, and the high-altitude interior, characterised by cold winters, warm dry summers and large diurnal swings); Zone 2, temperate interior (parts of the interior with milder profiles); Zone 3, hot interior (lower-altitude hot interior regions); Zone 4, temperate coastal (the southern and Western Cape coast — Cape Town, with its Mediterranean winter-rainfall pattern); Zone 5, sub-tropical coastal (the eastern seaboard — Durban and the KwaZulu-Natal coast, hot and humid); and Zone 6, arid interior (the hot-dry regions such as Upington and the Northern Cape interior). Local authorities and the standard provide a town-by-town schedule so the zone is determined by location, not by judgement. The shading logic differs sharply by zone.
In depth
In Zone 1 (cold interior), the design must reject high summer solar gain while preserving winter solar gain, because winter heating demand is significant and free solar gain through north glazing is a genuine asset — this is the classic case for fixed horizontal overhangs sized to block the high summer sun while admitting the low winter sun, or for retractable external devices that can be withdrawn in winter. In Zone 4 (temperate coastal, Cape Town), winters are mild and wet, summers warm and dry; solar control matters but the heating penalty of over-shading is smaller, and glare from low coastal sun and reflected sea light becomes a design driver. In Zone 5 (sub-tropical coastal, Durban), the regime inverts: there is little or no heating demand, cooling and dehumidification dominate, humidity suppresses the effectiveness of night-purge cooling, and aggressive year-round solar rejection plus ventilation is the priority — external shading and reflective glazing carry the load and there is little reason to preserve winter gain. In Zone 6 (arid interior), extreme summer heat and large diurnal range favour external shading combined with thermal mass and night-purge ventilation, exploiting the cold desert nights.
The conductance and SHGC limits in the standard tighten in the hotter zones and where cooling dominates. The fatal error is to import a single national rule of thumb: a deep north overhang that is correct in Johannesburg may waste valuable winter gain if mis-sized, while the same overhang in Durban under-performs because the thermal problem there is humidity and diffuse gain, not just direct beam. The competent person therefore fixes the zone first, reads the zone-specific limits, and only then designs the shading — never the reverse.
Lesson 05 · 8 min
The Decisive Number: CGSF and Effective SHGC
If you keep one number from this course, keep the combined glazing-plus-shading solar heat gain. The glazing's solar heat gain coefficient (SHGC) describes the glass alone — ordinary clear glazing transmits roughly 0.8 of incident solar energy.
The solar heat gain coefficient (SHGC, sometimes still written as the older solar factor or g-value) is the fraction of incident solar radiation that enters the building through a glazing assembly, on a scale from 0 (total rejection) to 1 (total transmission). For SANS work the critical quantity is not the glazing SHGC alone but the combined or effective SHGC of the glazing-plus-shading assembly, because that is what the XA fenestration energy calculation and any SANS 204 rational model actually use as the solar input. Clear single glazing has an SHGC near 0.80–0.86; a typical clear double-glazed unit near 0.70–0.76; solar-control coated glass can reach 0.25–0.40 on its own. Shading multiplies onto this. The physics that makes position decisive is the same physics that governs all solar shading: an external device intercepts and absorbs solar energy outside the building envelope, where convection and re-radiation carry most of the absorbed heat back to the outdoor air; an internal device absorbs energy only after it has already passed through the glass and entered the conditioned space, so most of the absorbed heat is released inward.
In depth
The result is that the same fabric, mounted externally, can reduce the effective SHGC roughly three to nine times more than when mounted internally, with the largest advantage on opaque light-coloured fabrics over clear glass. As an indicative worked example: a clear DGU at SHGC 0.75 with a light external screen can deliver an effective SHGC near 0.10–0.15; the identical screen mounted internally typically lands near 0.40–0.50 — a difference that routinely decides whether the fenestration energy total falls within the XA allowance. For a defensible SANS rational design the effective SHGC must be assembled from traceable data, not asserted. The cleanest route is to use a combined value calculated to a recognised method — internationally the EN 13363 / EN ISO 52022 family calculates the combined solar transmittance of glazing plus shading, and South African practice accepts such declared combined values as inputs to a rational design provided the source standard and the assumptions (glazing type, device position, fabric optical properties, ventilation of any cavity) are stated. Where only component data are available, the competent person must apply a recognised combination method rather than simply multiplying nominal figures, because the interaction between absorbed heat, cavity ventilation and inward re-release is non-linear.
The specifier should also record that the combined SHGC is only valid for the device mounted as tested — typically parallel and close to the glazing; a projecting awning or a louvre at an angle requires a geometric shading calculation instead, accounting for profile angle and sun position. The single most consequential design move in SA shading practice follows directly from this number: put the thermal duty outside. External shading drives the effective SHGC down hardest, which is exactly what the XA fenestration calculation rewards, and it is the move that most often turns a 42 m² north facade from a non-compliant liability into a rational-design pass.
Lesson 06 · 8 min
Reading the Sun: Orientation, Sun-Path and Overhang Geometry
Shading is geometry before it is fabric. In the southern hemisphere the sun tracks across the northern sky, so the north elevation takes the most solar energy and is the easiest to shade with a horizontal overhang; east and west take low-angle sun that overhangs cannot catch.
Effective shading design begins with sun-path geometry specific to the South African latitude band, which runs roughly from 22° south (Limpopo) to 35° south (Cape Agulhas). Because the country lies entirely in the southern hemisphere, the sun is in the northern sky for most of the day across the year, and the solar geometry is the mirror image of the northern-hemisphere conventions in most imported design literature — a frequent source of error. Two angles govern everything: solar altitude (the angle of the sun above the horizon) and solar azimuth (its compass bearing). At the summer solstice (around 21 December) the noon sun is very high — at Johannesburg's latitude of about 26° south the solar noon altitude reaches roughly 87°, almost overhead — while at the winter solstice (around 21 June) the noon altitude drops to about 40°. This large seasonal swing on the north elevation is the gift that makes fixed horizontal overhangs work: an overhang sized to block the near-vertical summer sun will automatically admit the low winter sun beneath it, delivering free winter solar gain exactly where Zone 1's heating demand wants it.
In depth
The sizing tool is the projection factor (PF), the ratio of the horizontal overhang depth to the vertical distance from the overhang to the window sill. The required PF to fully shade a window at a given solar altitude is PF = 1 / tan(profile angle), where the profile angle is the vertical sun angle projected onto a plane perpendicular to the facade. For a north-facing Johannesburg window, to fully shade the glass at the summer-solstice noon profile angle of roughly 87°, the geometric PF is small, but practical design targets shading across the high-sun months (roughly October to February) rather than the single solstice instant, which yields a more useful overhang depth — commonly a PF in the order of 0.4 to 0.6 for a typical north window, sized so the shadow line reaches the sill at the chosen cut-off date. The same overhang, at the winter profile angle of about 40°, leaves most of the glass in sun, admitting the desired winter gain. East and west elevations defeat horizontal overhangs entirely.
At sunrise and sunset the solar altitude is near zero and the azimuth is far to the east or west, so the beam strikes east and west glazing almost horizontally; no practical overhang depth can intercept a near-horizontal ray. The geometric answers on those elevations are vertical fins (effective when the sun is well off-normal in azimuth), or — more practically for the steep low-altitude morning and afternoon sun — operable external devices, deep reveals, or screens, because the sun's position changes too much through the day for any fixed horizontal element to track it. The cut-off angle of a louvre or screen — the profile angle beyond which the device blocks all direct beam — is the louvre equivalent of the overhang's PF, and it is set by blade spacing and depth. The competent person sizes shading by running the actual sun-path for the site latitude and the chosen cut-off dates, not by rule of thumb, because a few° of latitude between Polokwane and Cape Town materially changes the winter altitude and therefore the overhang depth that preserves winter gain without admitting summer heat.
Lesson 07 · 8 min
The Rational Route in Depth: SANS 204 Energy Modelling
When the deemed-to-satisfy tables will not bend, SANS 204 is the escape hatch. SANS 204, Energy efficiency in buildings, is the standard XA calls up for the rational-design route: it sets out the energy-efficiency requirements and the calculation framework a competent person uses to prove a building performs as well as or better than a deemed-to-satisfy reference.
SANS 204, Energy efficiency in buildings, is the companion standard to SANS 10400-XA and the engine of the rational-design route. Where XA sets the legal functional requirement and the deemed-to-satisfy prescriptive limits, SANS 204 provides the detailed energy-efficiency provisions and the calculation methodology by which a competent person demonstrates compliance when the prescriptive route is not used or not met. The rational-design workflow has a fixed logic. First, the competent person establishes the building classification (SANS 10400-A occupancy class), the climatic zone, the storey net floor areas and the orientations. Second, a notional (reference) building is defined — geometrically identical to the proposed building but with envelope and fenestration properties set exactly at the deemed-to-satisfy limits: glazing at the area cap, conductance and SHGC at the zone limits, reference insulation R-values, and reference services.
In depth
This notional building represents the maximum energy demand the regulations would permit for that form. Third, the proposed building is modelled with its actual properties — including its real glazing areas (which may exceed the cap) and its real shading devices, modelled explicitly with their geometry and optical properties. Fourth, the theoretical energy demand or consumption of the proposed building is calculated and compared to that of the notional building; compliance is demonstrated when the proposed building's demand is equal to or less than the notional building's. This energy-equivalence principle is what allows a heavily glazed, well-shaded facade to comply even though it breaches the prescriptive glazing cap — the shading buys back the solar load. Shading enters the rational model in two ways that the prescriptive route cannot fully reward.
First, external and operable devices are modelled with their true effective SHGC (Lecture 5) and, for projecting or angled devices, with their actual geometric shading across the sun-path (Lecture 6), so a deep external overhang or an automated screen receives full credit for the solar energy it intercepts hour by hour. Second, automated control can be modelled with a defined deployment logic — for example a screen that deploys above a set solar irradiance — which converts a device from an occupant-dependent assumption into a modellable engineering system, the same principle that makes automated shading defensible internationally. The modelling assumptions that make or break a submission are unglamorous but decisive: the weather data must be appropriate to the climatic zone; the occupancy, internal gains and HVAC assumptions must match between notional and proposed buildings so the comparison is fair; the glazing and shading optical properties must be traceable to declared standards; and the device geometry in the model must match the geometry in the specification and drawings. The most common rejection cause in rational designs is the same as elsewhere in compliance work — drift between the modelled building and the documented one: shading shown in the model that does not appear, by name and dimension, in the specification, or effective-SHGC values with no declared source. A defensible SANS 204 rational design is therefore as much a documentation discipline as a modelling one: the model proves the physics, the paper trail proves the model represents the building that will actually be built.
Lesson 08 · 7 min
Position Beats Product: External, Internal and Mid-Pane Shading
The single most important design decision in SA shading compliance is not which fabric but where it sits. External shading intercepts solar energy before it crosses the glass and rejects most of it to outside air; internal shading fights heat already admitted; mid-pane sits between.
The hierarchy of shading position is the most reliable single heuristic in solar-control design, and it follows directly from the thermodynamics established in Lecture 5. External shading is the strongest thermal performer because it absorbs and rejects solar energy outside the building envelope; internal shading is the weakest because it can only manage energy that has already entered; mid-pane (between the glazing leaves of a sealed or ventilated cavity) sits between, closer to external performance when the cavity is ventilated to outside and closer to internal when it is not. In effective-SHGC terms the ordering is consistent across fabric types: for a given fabric on clear double glazing, external mounting typically yields an effective SHGC in the 0.10–0.20 band, mid-pane in a ventilated cavity perhaps 0.20–0.35, and internal mounting 0.40–0.55. Because the XA fenestration energy calculation consumes effective SHGC directly, moving a device from inside to outside is frequently the cheapest single intervention that brings a facade's fenestration total back within the allowance — far cheaper than re-glazing or reducing window size. That is the compliance reason external shading dominates SA specification on demanding north and west elevations.
In depth
The ranking must, however, be qualified by South African practice realities, which is why position is a design decision and not merely a calculation. Wind loading on the Highveld and in exposed coastal sites is significant; external devices must be engineered for the local wind speed, and lightweight retractable screens may need wind sensors that retract them above a threshold — a control feature that also has to be reflected honestly in any rational model, because a screen that retracts in wind is not shading at that moment. Dust in the interior and pollen in spring foul external tracks and fabrics, raising maintenance frequency; specifications should call up cleanable fabrics and accessible cassettes. Coastal corrosion, especially in Zone 5 (Durban) and the Western Cape's marine atmosphere, demands marine-grade fixings and hardware, or the external device degrades fast. Security drives a preference for shading that does not create a climbing aid or a concealment point at ground level, nudging ground-floor solutions toward fixed architectural shading (overhangs, brise-soleil) rather than retractable fabric.
Maintenance access on multi-storey facades is a genuine cost that internal shading avoids entirely — one of the few honest arguments for internal devices. The market response to these objections is the rise of concealed and cassette external systems: external roller screens and venetians housed in weather-sealed cassettes integrated into the facade or window head, which deliver near-external thermal performance while protecting the mechanism from dust, wind and corrosion and presenting a clean architectural line. For the specifier, the decision logic is therefore two-stage: first establish that external is the position the XA numbers want; then select an external system robust enough for the site's wind, dust, corrosion and access realities — and where ground-floor security or maintenance genuinely precludes external fabric, default to fixed architectural shading rather than retreating to a thermally weak internal device. Internal shading is reserved for its honest role: glare and privacy control behind an external or glazing-based thermal layer, never as the primary solar-control instrument on a demanding elevation.
Lesson 09 · 7 min
Glass and Cloth: Specifying the Assembly to a Declared Standard
A rational design is only as good as its inputs, and inputs must be traceable. This lecture is about specifying the glazing-plus-shading assembly so that every number in the submission has a declared source.
The integrity of an XA submission, deemed-to-satisfy or rational, depends on traceable component data, and the specifier's craft is to write a specification in which every performance number cited in the energy calculation is anchored to a declared, standard-referenced source. On the glazing side, four properties govern: the solar heat gain coefficient (SHGC), the fraction of solar energy admitted; the visible light transmittance (VLT or tau-v), the fraction of daylight admitted, which couples to the glare and daylight duties of Lecture 10; the U-value (thermal transmittance, W/m²K), which feeds the conductance term in the fenestration calculation; and the glazing build itself (single, double, low-e coated, laminated, tinted). These are declared by glass manufacturers to recognised optical standards (the EN 410 family for solar and light properties, EN 673 for U-value, with equivalent ISO methods), and South African glass suppliers publish them on product data sheets. The relevant SANS glazing standards govern the glass as a building component rather than its optics: SANS 10400-N (Glazing) sets the deemed-to-satisfy rules for glazing design including wind-load and structural requirements, and SANS 613 covers impact-resistant (safety) glazing for human-impact safety — both must be satisfied independently of XA, and a thermally excellent glazing choice that fails the safety or structural glazing rules is not specifiable.
In depth
On the shading side, the fabric and device properties that drive performance are: the openness factor (OF), the percentage of open area in a screen weave, which trades daylight and view against solar and glare control; the fabric's solar reflectance and solar transmittance, which together with absorptance determine how much energy the fabric rejects, absorbs and passes; the visible openness and colour, which drive glare; and, crucially, the device's contribution to the combined effective SHGC of the assembly. A light-coloured, low-openness external fabric maximises solar rejection; a higher-openness fabric preserves view and daylight at the cost of more solar and glare transmission. The combined-SHGC declaration is the single most important shading input, and it must state the glazing it was combined with, the device position, and the calculation method (the EN 13363 / EN ISO 52022 combined-transmittance methods are the accepted basis), because an effective SHGC quoted without its glazing pairing and position is meaningless. Writing the specification clause is where this becomes operational.
A robust clause names the property, the value, the standard and the position: for example, External roller screen, light-coloured, openness factor not exceeding 5%, combined with the specified clear double glazing to achieve an effective SHGC not exceeding 0.15 declared per EN ISO 52022 for external mounting; fabric solar reflectance not less than 0.65; device and fixings to be marine-grade where within 2 km of the coast. Such a clause ties the device modelled by the competent person to the device procured on site, closing the drift gap that causes most compliance failures. The discipline generalises: never cite a number in the energy calculation that the specification cannot reproduce against a declared standard, and never accept a manufacturer's effective-SHGC claim that does not state the glazing, the position and the method behind it.
Lesson 10 · 6 min
The Other Duties: Glare, Daylight and SANS 10400-O
Solving the thermal problem with a cave fails the building a different way. Shading carries simultaneous duties — admit useful daylight, control glare, and preserve view — and these are governed alongside XA by SANS 10400-O (Lighting and ventilation), which sets minimum natural-lighting provisions, and by occupant-comfort expectations imported from the daylight and glare literature.
Shading is never a single-duty component, and a specification optimised only for the XA thermal number routinely fails the building on daylight, glare or view — duties governed in South Africa by SANS 10400-O (Lighting and ventilation) and by the occupant-comfort expectations that good practice imports from the international daylight and glare standards. SANS 10400-O sets the deemed-to-satisfy requirements for natural lighting and natural ventilation: habitable rooms must receive natural light through glazing of a minimum area expressed as a percentage of the floor area served (commonly cited as a minimum aggregate glazing area for natural light, with a separate ventilation-opening requirement), and rooms relying on natural ventilation must have openable area to a stated minimum. The tension with XA is direct and must be managed deliberately: XA caps and penalises glazing area to control solar energy, while SANS 10400-O sets a floor on glazing area to guarantee daylight and ventilation. A design that aggressively minimises glazing to ease the XA calculation can drop below the SANS 10400-O natural-light minimum and fail the building from the other side; conversely a heavily glazed daylight-rich design must shade to survive XA.
In depth
Shading sits exactly in the middle of this tension, and the openness factor is the control variable. A low-openness, light-coloured external screen maximises solar and glare rejection but, if too dense, can suppress daylight below useful levels and obscure the view, driving occupants to switch on electric lighting at noon — a daylighting failure even where SANS 10400-O's bare glazing-area minimum is technically met, because the effective transmitted daylight has been throttled. A higher-openness fabric preserves daylight and view but admits more solar energy and more glare. Glare itself, while not numerically prescribed by SANS 10400-O, is a real occupant-comfort and productivity duty that the international literature quantifies through Daylight Glare Probability (DGP) bands and through fabric glare classes (the EN 14501 0-to-4 scale), and a defensible high-end SA specification will reference these even though XA does not, because a facade that overheats occupants visually fails its users as surely as one that overheats them thermally.
The resolution strategy is to recognise that thermal, daylight and glare duties pull in different directions and to either hold all three in one assembly where the elevation permits, or to zone the duties. Holding all three in one fabric is feasible on moderate elevations: a light external screen at an openness factor around 3-5% can reject most solar energy and control glare while still transmitting workable daylight and preserving a filtered view. On demanding west and north elevations where one fabric cannot satisfy all three, the professional answer is to zone: put the thermal duty on an external layer (a screen or louvre tuned for solar rejection and sized by sun-path geometry) and a lighter internal layer for fine glare and privacy control, so each layer does the job it is best at. The unifying principle is that shading must be specified against all of its duties at once — XA thermal, SANS 10400-O daylight and ventilation, and occupant glare comfort — and that the cheapest way to satisfy them together is almost always to move the thermal duty outside and reserve the inside layer for visual comfort, which is the same conclusion the thermal physics reached, now confirmed from the daylight side.
Lesson 11 · 8 min
Worked Compliance: A Johannesburg Office Facade
Theory meets a real submission. We take a G1 office building in Johannesburg (Zone 1, cold interior) with an ambitious glazed north and west elevation that fails the deemed-to-satisfy fenestration cap on first pass, and we work it to compliance step by step.
This lecture runs a complete compliance exercise so the specifier can see every number in sequence on a realistic project. The building is a four-storey G1 office (SANS 10400-A occupancy class G1, offices) in central Johannesburg: Zone 1, cold interior, latitude approximately 26° south. Per storey net floor area is 600 m², and the architect has proposed a glazed north facade of 110 m² per storey and a glazed west facade of 70 m² per storey, both clear double glazing at SHGC 0.72, U-value 2.8 W/m²K. Step one, establish the baseline: the deemed-to-satisfy glazing allowance is 15% of net floor area, 90 m² per storey; the proposed total glazing is 180 m², exactly double the cap. The scheme cannot use the simplest DtS interpretation, and the fenestration energy total — area times SHGC times conductance, weighted for orientation — is well over the allowance, driven hardest by the unshaded north glazing (which takes the most solar energy at this latitude) and the west glazing (which takes intense low-angle afternoon sun that elevates the cooling load and glare). Step two, diagnose where it breaks: the north glazing dominates the solar-gain term because of its area and orientation, while the west glazing, though smaller, contributes disproportionate peak cooling load and glare because the afternoon sun strikes it near-horizontally.
In depth
The conductance term is secondary here because the double glazing's U-value is moderate; the binding constraint is solar heat gain, which is the good news, because solar heat gain is exactly what shading attacks. Step three, design the shading by zone and orientation. North elevation: fixed horizontal overhangs sized by the Johannesburg sun-path (Lecture 6) — at this latitude the summer noon sun is near overhead and the winter noon altitude is about 40°, so an overhang with a projection factor around 0.5 shades the north glass through the high-sun months while admitting valuable winter solar gain, which is a genuine asset in Zone 1's heating-significant climate. The overhang reduces the north glazing's effective SHGC for the cooling season substantially. West elevation: horizontal overhangs cannot catch the near-horizontal afternoon sun, so the design uses automated external screens (light-coloured, openness factor 3%, marine-grade not required inland but engineered for Highveld wind with a wind-retract sensor) that deploy above a set solar irradiance, taking the west glazing's effective SHGC from 0.72 down to roughly 0.12 when deployed. Step four, re-run the numbers.
With the overhangs and external screens modelled at their true effective SHGC, the fenestration solar-gain total falls dramatically; combined with the orientation weighting (north is penalised most, so shading it yields the largest reduction), the design now has two legitimate outcomes. If the shaded effective-SHGC values bring the fenestration energy total within the allowance, the design can pass on the XA fenestration provisions despite exceeding the 15% area cap, because the standard tests fenestration energy, not area alone. If it remains marginally over — likely given the doubled glazing area — the project moves to a SANS 204 rational design (Lecture 7), where the notional building is built at the DtS limits and the proposed building, with its explicitly modelled overhangs and automated screens, is shown to have equal or lower theoretical energy demand. The west screens' automated control is modelled with its deployment logic, earning full credit as an engineered system. The deliverable to the local authority records the zone, the classification, the glazing schedule with declared SHGC and U-values, the shading geometry and effective-SHGC declarations with their source standard, and — for the rational route — the notional-versus-proposed energy comparison. The lesson the worked example teaches is the course in miniature: area is where the conversation starts, solar heat gain is what actually binds, orientation decides where shading pays best (north hardest in the southern hemisphere), and external and automated shading are the instruments that convert an over-cap facade into a compliant one with a defensible paper trail.
Lesson 12 · 6 min
Automation and Credit: When Operable Shading Counts
Operable shading raises a hard question: when does a device you can open and close actually count in the calculation? The principle South African rational design shares with international practice is that automated shading with a defined control logic is creditable because it is modellable and repeatable, while occupant-operated shading that depends on someone remembering to close a blind is not. This lecture sets out how to model automated external screens and venetians in a SANS 204 rational design — deployment setpoints, wind-retract behaviour, and honest with-and-without reporting — and the specifier's rule that no compliance pass should ever rest on an occupant's daily diligence.
Operable shading occupies a grey zone in every compliance regime, and the South African rational route resolves it on the same principle that governs the strongest international precedents: a device may be credited in the energy calculation to the extent that its operation is defined, repeatable and modellable, rather than dependent on unpredictable human behaviour. A fixed external overhang is creditable absolutely, because it is always there. An automated external screen that deploys above a set solar irradiance is creditable because its behaviour is a deterministic function of measurable conditions that the energy model can represent hour by hour. An occupant-operated internal blind that a person may or may not close is, by contrast, the weakest possible input, because the model cannot honestly assume diligence that real occupants do not reliably provide — which is precisely why internal occupant-operated blinds are treated so skeptically and, in the strictest interpretations, excluded. Modelling automated shading in a SANS 204 rational design requires the control logic to be declared and represented faithfully.
In depth
The deployment setpoint — for example, deploy when solar irradiance on the facade exceeds a stated W/m² threshold — is modelled so the device contributes its low deployed effective SHGC only when it is actually deployed and its higher retracted effective SHGC at other times. Wind-retract behaviour must be modelled honestly: a lightweight external screen engineered to retract above a Highveld wind threshold is not shading during high-wind periods, and a rational model that assumes it is deployed through a windy summer afternoon overstates its benefit; the competent person must either model the retraction or demonstrate that the wind events do not coincide materially with peak solar load. The discipline of with-and-without reporting — presenting the energy result both with the automated shading active and with it removed — is the integrity test that lets a reviewer see exactly how load-bearing the device is, and a robust submission includes it so the local authority can judge the dependency. The specifier's rule generalises across all of this: never let a compliance pass depend on an occupant remembering to close a blind. A design whose pass evaporates if the occupant forgets is a latent defect with the competent person's signature on it.
The robust strategy is layered, exactly as in the worked Johannesburg example: secure as much of the pass as possible on fixed measures — orientation, glazing choice, fixed overhangs, reveal depth — and then let automated shading convert a marginal result into a comfortable one, rather than carrying the entire pass alone. Integration with an intelligent building management system (IBMS) strengthens the case: a screen driven by a building-wide control system with logged setpoints and irradiance sensors produces an auditable operational record, and an automated facade tied to the IBMS is far easier to defend than a standalone motorised blind. The documentation that makes automated credit defensible therefore comprises the declared control logic, the deployment and retraction setpoints, the with-and-without energy comparison, the device geometry and effective-SHGC source, and — where present — the IBMS integration that proves the logic will actually run. With those in hand, automated shading is not a compliance liability but the most powerful single lever a rational design can pull on a demanding elevation.
Lesson 13 · 6 min
The Paper Trail: Documentation, Competent Persons and the OC
A compliant design you cannot document is a non-compliant design. The local authority never sees your physics; it sees your submission.
Energy compliance in South Africa is realised not in the model but in the documentation the local authority receives, and the specifier who treats documentation as an afterthought loses on submission what was won in design. The legal endpoint is the occupancy certificate: under the National Building Regulations and Building Standards Act 103 of 1977, a local authority may not lawfully issue an occupancy certificate unless the building complies with the National Building Regulations, and SANS 10400-XA compliance is part of that requirement. This makes the XA documentation a precondition for legal occupation, not a courtesy. The package differs by route. For the deemed-to-satisfy route, the submission demonstrates that the fenestration meets the area cap and the conductance and solar-heat-gain limits for the zone — typically a fenestration calculation sheet showing each glazing element's area, orientation, SHGC and U-value, the shading credits applied, and the totals against the allowance, supported by the glazing and shading schedules with declared properties.
In depth
For the rational-design route, the package is the SANS 204 rational-design report: the building classification and climatic zone, the notional (reference) building defined at the DtS limits, the proposed building modelled with its real glazing and shading, the theoretical energy comparison showing the proposed building equal to or below the notional, the modelling assumptions (weather data, occupancy, internal gains, HVAC), and the competent-person certification. Who may sign is a statutory matter. A rational design must be prepared and certified by a competent person — a professional registered with a recognised statutory council (the Engineering Council of South Africa under the Engineering Profession Act 46 of 2000, or the South African Council for the Architectural Profession under the Architectural Profession Act 44 of 2000) and competent in the relevant field — who accepts legal responsibility for the design. An unregistered drafter or a supplier's brochure cannot substitute for this certification; submissions relying on uncertified rational claims are rejected as a matter of course. The most common rejection causes are predictable and avoidable.
The first is drift between the model and the specification: shading devices or glazing properties in the energy calculation that do not match, by name and dimension and value, the items in the architectural specification and drawings — a reviewer who finds a 600 mm overhang in the model and a 400 mm overhang on the section will reject the package. The second is untraceable shading and glazing values: an effective SHGC quoted with no glazing pairing, no device position and no source standard, or a manufacturer claim with no declared method behind it. The third is route confusion: a submission that asserts rational compliance without the notional-building comparison, or that mixes DtS credits into a rational argument incoherently. Building a package that survives the first review is therefore a discipline of consistency and traceability: every number in the calculation reproduces against a declared standard; every device in the model appears by name and dimension in the specification; the route is stated and followed cleanly; and the competent person who signs has actually checked that the documented building is the building that was modelled. The paper trail exists to make drift visible to the reviewer before it becomes a defect in the built facade — and to convert a correct design into a granted occupancy certificate.
Lesson 14 · 6 min
Decision Path and the Road Ahead: SANS Mastery
We compress the whole course into a single decision path a specifier can carry onto any project, then look at where the standards are heading. Four moves resolve almost any SA shading-compliance question: establish the zone and classification; run the deemed-to-satisfy fenestration check to find where it breaks; design shading by orientation and sun-path to drive down the effective SHGC; and, if the prescriptive route still will not hold, carry it into a SANS 204 rational design with full credit for external and automated devices.
The entire course reduces to a four-move decision path and a professional posture, and a specifier who internalises both can triage any South African shading-compliance question with confidence. Move one: establish the zone and the classification. Fix the climatic zone (one of the six, Lecture 4) from the site location, because the zone sets the conductance and solar-heat-gain limits, and fix the SANS 10400-A occupancy class, because it sets which provisions and floor-area bases apply. Everything downstream depends on getting these two data right first. Move two: run the deemed-to-satisfy fenestration check to find where it breaks. Compare total glazing against the 15% net-floor-area cap, and compute the fenestration energy total — area times SHGC times conductance, weighted for orientation — against the zone allowance.
In depth
If everything passes, the design is deemed to comply and no modelling is needed. If it fails, identify precisely which term binds: area, conductance, or — most often — solar heat gain, because that diagnosis tells you whether shading can solve it (it usually can, since shading attacks solar heat gain directly). Move three: design shading by orientation and sun-path to drive down the effective SHGC. Shade the north elevation hardest, because in the southern hemisphere it takes the most solar energy and is the easiest to shade with fixed overhangs sized to block summer and admit winter sun; use vertical or operable devices on east and west where overhangs cannot catch the low-angle sun; and put the thermal duty outside, because external mounting drives the effective SHGC down three-to-nine times more than internal, which is exactly what the fenestration calculation rewards. Re-run the numbers with the shaded effective SHGC. Move four: if the prescriptive route still will not hold — typically because glazing area greatly exceeds the cap — carry the design into a SANS 204 rational design, building the notional reference building at the DtS limits and proving the proposed building, with its explicitly modelled external and automated shading, achieves equal or lower theoretical energy demand.
Document everything to survive review: declared glazing and shading properties, device geometry matching the specification, and competent-person certification. That path resolves the compliance question; the posture resolves the professional one. Standards move, and the energy-regulation trajectory in South Africa is one-directional toward stringency: the 2011-to-2021 tightening of XA will be followed by further revision, and the broader market is pulling in the same direction through voluntary instruments — Green Star SA (the Green Building Council of South Africa's rating tool, which credits solar control and daylighting) and EDGE (the IFC's resource-efficiency certification, increasingly required by lenders and developers), both of which reward exactly the shading strategies XA compliance already demands. The specifier who masters XA is therefore also positioned for the green-rating market. The closing discipline is citation hygiene: quote the standard, the edition and the clause, date-stamp every compliance citation, and verify against the purchased standard before publishing any limit or value, because the figure that is correct under SANS 10400-XA:2021 may change in the next edition. Rules move; the professional's edge is to design to the physics, document to the standard, and verify before signing — that posture outlasts any single edition of the regulations.
Assessment · self-check
Ten application-based questions
Each question tests a project decision, not recall. Choose an answer, then reveal the worked explanation. Pass mark 70% (7 of 10).
Question 1
A single-storey H4 dwelling house has a net floor area of 200 m² and a proposed total glazing area of 42 m². Under the SANS 10400-XA:2021 deemed-to-satisfy fenestration provision, what is the position?
ACompliant — 42 m² is below the 25% deemed-to-satisfy glazing allowance
BAutomatically non-compliant — glazing above the cap is prohibited outright
CCompliant — the cap applies only to non-residential occupancy classes
DOver the 15% deemed-to-satisfy baseline (30 m²); the design must reduce effective solar heat gain through shading and high-performance glazing to bring the fenestration energy total within the allowance, or move to a rational design
Reveal answer & explanation
Correct: D. Lecture 3 — the DtS baseline glazing allowance is 15% of net floor area, here 30 m², so 42 m² is 12 m² over. Exceeding the cap is not an outright failure: the design can recover by reducing effective SHGC with shading and high-performance glass so the fenestration energy total falls within the allowance, or by moving to a SANS 204 rational design. The 25% figure and the residential-only claim are distractors.
Question 2
An architect wants 80% more north-facing glazing than the prescriptive cap allows, using a deep external overhang and automated screens to compensate. Which compliance route lets the shading earn full credit for the extra glazing?
AThe deemed-to-satisfy route, because external shading is fully credited in the prescriptive tables
BNeither route — glazing over the cap can never comply
CThe SANS 204 rational-design route, where a competent person models the actual shading against a notional deemed-to-satisfy reference building and proves equal or lower theoretical energy demand
DThe SANS 10400-O daylight route, which overrides the XA glazing cap
Reveal answer & explanation
Correct: C. Lecture 2 and 7 — the rational-design route under SANS 204 is where external and automated shading earn full credit. The competent person builds a notional building at the DtS limits, models the proposed building with its real shading, and shows the proposed building's theoretical energy demand is equal to or less than the notional building's. The DtS tables cannot fully reward operable external devices; SANS 10400-O governs daylight, not the XA energy cap.
Question 3
A specifier must shade the north elevation of a Johannesburg (Zone 1) office and the same client's Durban (Zone 5) office. Why must the shading strategies differ?
AThey need not differ — XA applies one national fenestration limit regardless of location
BZone 1 (cold interior) has significant winter heating demand, so shading should block summer sun while preserving winter solar gain; Zone 5 (sub-tropical coastal) has negligible heating and high humidity, so aggressive year-round solar rejection is the priority
CDurban is colder than Johannesburg, so Durban needs more winter gain preserved
DOnly Zone 1 requires shading; coastal zones are exempt from fenestration limits
Reveal answer & explanation
Correct: B. Lecture 4 — the six climatic zones carry different conductance and SHGC limits and different design logic. Zone 1 (cold interior, Johannesburg) wants summer rejection but winter gain preserved, favouring sun-path-sized overhangs; Zone 5 (sub-tropical coastal, Durban) has little heating demand and high humidity, so year-round solar rejection and ventilation dominate and there is no winter gain to protect. Durban is warmer, not colder, than Johannesburg, and no coastal zone is exempt.
Question 4
An identical light-coloured roller-screen fabric is offered for a clear double-glazed unit (glazing SHGC 0.75). Mounted internally the assembly's effective SHGC is about 0.45; the client asks what external mounting achieves and why it matters for XA.
AAbout 0.45 also — position does not change effective SHGC, only appearance
BAbout 0.60 — external fabrics perform worse because they are exposed to sun
CAbout 0.10–0.15 — external mounting rejects solar energy before it crosses the glass, roughly 3–9 times more effective, and the XA fenestration calculation consumes effective SHGC directly so the lower value most reliably brings the facade within the allowance
DEffective SHGC is irrelevant to XA, which uses only the glazing U-value
Reveal answer & explanation
Correct: C. Lecture 5 and 8 — an external device absorbs and rejects solar energy outside the envelope, so the same fabric yields a far lower effective SHGC externally (roughly 0.10–0.15) than internally (roughly 0.45), a 3–9x advantage. Because the XA fenestration energy calculation consumes effective SHGC directly, moving the device outside is the single most reliable move to bring a facade within the allowance. Position is decisive; U-value alone does not determine compliance.
Question 5
Designing a fixed horizontal overhang for a north-facing window at Johannesburg's latitude (about 26° south), the specifier wants summer shade but winter solar gain. What geometric fact makes this achievable?
AThe summer noon sun is very high (near overhead, about 87° altitude) while the winter noon sun is low (about 40°), so an overhang sized for the high summer sun automatically admits the low winter sun beneath it
BThe sun is in the southern sky in South Africa, so south overhangs work best
CSolar altitude is constant year-round at this latitude, so one overhang depth suits all seasons
DWinter sun is higher than summer sun in the southern hemisphere, so the overhang blocks winter and admits summer sun
Reveal answer & explanation
Correct: A. Lecture 6 — in the southern hemisphere the sun tracks the northern sky, so north elevations take the most sun and are the easiest to shade with horizontal overhangs. At Johannesburg's latitude the summer noon altitude is near 87° and the winter noon altitude about 40°; an overhang sized for the high summer sun admits the low winter sun beneath it, delivering free winter gain valued in Zone 1. The other options reverse the hemisphere geometry.
Question 6
In a SANS 204 rational design, the competent person models a 'notional building'. What is its correct definition?
AThe actual proposed building modelled with all its real shading devices
BA geometrically identical reference building with envelope and fenestration set exactly at the deemed-to-satisfy limits, used as the energy benchmark the proposed building must equal or beat
CAny nearby existing building of similar size used for comparison
DA theoretical building with zero glazing used to establish the minimum possible energy demand
Reveal answer & explanation
Correct: B. Lecture 7 and 13 — the notional (reference) building is geometrically identical to the proposed building but with envelope and fenestration properties set at the deemed-to-satisfy limits (glazing at the cap, conductance and SHGC at the zone limits). The rational design proves the proposed building's theoretical energy demand is equal to or less than this notional benchmark. The proposed building is the actual design; the notional is the regulatory reference, not a neighbouring or zero-glazing building.
Question 7
A submission credits an internal occupant-operated blind, assuming occupants draw it every summer afternoon, to achieve its energy pass. How should a competent person treat this in a SANS 204 rational design?
AAccept it — internal blinds carry the same credit as external devices
BAccept it provided the blind achieves a good glare class
CTreat it as the weakest possible input and not let the pass depend on it — operable shading is creditable only where its operation is defined, repeatable and modellable (e.g. automated with a setpoint), never on assumed daily occupant diligence
DReject the entire submission outright with no remedy available
Reveal answer & explanation
Correct: C. Lecture 12 — the principle is that a device is creditable to the extent its operation is defined, repeatable and modellable. An automated external screen on an irradiance setpoint qualifies; an occupant-operated internal blind dependent on daily diligence is the weakest input, and a pass must never rest on it. The remedy is to secure the pass on fixed and automated measures, not to assume occupant behaviour. It is not rejected outright — it is redesigned.
Question 8
A specification cites an effective SHGC of 0.15 for a shading assembly but states no glazing pairing, device position or calculation method. Why is this a likely rejection cause?
AIt is not a problem — effective SHGC is a property of the fabric alone
B0.15 is too low to be physically possible for any assembly
CThe value should have been expressed as a U-value instead
DEffective SHGC is meaningless without its glazing pairing, device position and source method; an untraceable value cannot be reproduced against a declared standard and reviewers reject it as undocumented drift
Reveal answer & explanation
Correct: D. Lecture 9 and 13 — combined effective SHGC is a property of the whole assembly: glazing, device position and calculation method (the EN 13363 / EN ISO 52022 combined-transmittance basis). A value quoted without those is untraceable and cannot be reproduced, and untraceable shading values are among the most common rejection causes, alongside drift between model and specification. 0.15 is entirely achievable for external shading; the defect is documentation, not the number.
Question 9
A designer minimises glazing aggressively to ease the XA fenestration calculation, dropping below the natural-light minimum for habitable rooms. Which standard does this breach, and what does it illustrate?
AIt breaches SANS 613 safety glazing, illustrating an impact-resistance failure
BIt breaches SANS 10400-O (Lighting and ventilation), which sets a floor on glazing area for natural light — illustrating that XA caps glazing for energy while SANS 10400-O sets a minimum for daylight, and shading sits in the tension between them
CIt breaches nothing — less glazing always improves overall compliance
DIt breaches SANS 10400-N structural glazing wind-load rules
Reveal answer & explanation
Correct: B. Lecture 10 — SANS 10400-O (Lighting and ventilation) sets a minimum glazing area for natural light and a minimum openable area for ventilation, a floor that pulls against XA's energy-driven cap on glazing. A design that over-minimises glazing to pass XA can fail SANS 10400-O. Shading resolves the tension by allowing daylight-rich glazing to survive XA. SANS 613 (safety) and SANS 10400-N (structural glazing) govern different duties.
Question 10
Who may prepare and certify a SANS 204 rational design for XA compliance, and why does it matter for the occupancy certificate?
AAny drafter or the glazing supplier, since the data come from product sheets
BA competent person registered with a recognised statutory council (e.g. ECSA under the Engineering Profession Act or SACAP under the Architectural Profession Act) who accepts legal responsibility — because a local authority may not issue an occupancy certificate unless XA compliance is properly certified
COnly an employee of the local authority's building-control department
DThe contractor on site, once the shading is installed
Reveal answer & explanation
Correct: B. Lecture 13 — a rational design must be prepared and certified by a competent person registered with a recognised statutory council (ECSA under the Engineering Profession Act 46 of 2000, or SACAP under the Architectural Profession Act 44 of 2000) and competent in the field, accepting legal responsibility. This matters because the National Building Regulations make the occupancy certificate conditional on demonstrated compliance; an uncertified or unregistered submission is rejected, blocking lawful occupation. Suppliers, contractors and unregistered drafters cannot certify it.