Shading Device Requirements for Energy Compliance

What This Requirement Covers

This requirement governs the use of external shading devices to control solar heat gain through glazing as part of building energy efficiency under the National Construction Code (NCC) and the ABCB Housing Provisions. Shading devices are used to reduce summer cooling loads and, where appropriate, allow beneficial winter solar gains. The provisions set how shading is measured, counted in an energy compliance calculation, and what performance or dimensional criteria fixed projections and external shading devices must meet.

These rules apply to new and altered buildings required to demonstrate compliance with the NCC energy efficiency provisions. They are relevant to designers, certifiers, builders and homeowners for both residential work covered by NCC Volume Two/ABCB Housing Provisions and commercial or multi-residential work covered by NCC Volume One. The requirement ensures consistent treatment of projections, screens and adjustable shading in the NCC energy compliance methods.

Key Requirements

1. Shading is treated in the NCC energy calculation by a shading multiplier (solar admittance factor) that depends on the type of shading and the projection geometry P, G and H as shown in Figure S37C7, as specified in NCC 2022 Volume One, S37C7.
2. For permanent external projections (verandah, eaves, fixed canopy, balcony, shading hood or similar) that extend horizontally each side of the glazing by distance P, the shading multiplier is read from Table S37C7a (northern, eastern, western aspects) or Table S37C7b (southern aspect) according to the building’s climate zone, P/H ratio and G/H ratio, as specified in NCC 2022 Volume One, S37C7.
3. Geometry definitions (as shown in Figure S37C7):
4. P - horizontal projection distance of the shading device measured from the glazing face
5. H - height of glazing or story height used in the P/H ratio
6. G - vertical distance from the top of lower glazing to top of the upper shading projection where applicable
7. For external shading devices such as shutters, blinds, vertical or horizontal building screens with blades, battens or slats the shading multiplier is 0.35, provided the device:
8. is capable of restricting at least 80% of summer solar radiation, and
9. if adjustable, will operate automatically in response to solar radiation, as required in NCC 2022 Volume One, S37C7(b).
10. The ABCB Housing Provisions (NCC Volume Two related provisions in the Housing Provisions Standard) set equivalent dimensional and performance requirements for houses and associated Class 1/10 work, including:
11. Shading may be provided by an external permanent projection that extends horizontally both sides of glazing for a distance greater than or equal to the projection P in Figure 13.3.2b, in accordance with ABCB Housing Provisions Standard 2022, 13.3.3.
12. Alternatively shading may be provided by an external shading device that is capable of restricting at least 80% of summer solar radiation and, if adjustable, is operated readily by occupants, in accordance with ABCB Housing Provisions Standard 2022, 13.3.3(b).
13. The Housing Provisions include explanatory limits such as: where G exceeds 500 mm the value of P must be halved for some sizing conditions (see ABCB Housing Provisions Standard 2022 guidance text and clause NT 13.3.3 references).
14. Shading provided by gutters counts only when they are attached to a legitimate shading projection (verandah, eaves, canopy, etc.), per ABCB Housing Provisions Standard 2022 explanatory information.
15. Adjustable shading devices should be readily operated without ladders/rigging and may be considered when located adjacent or attached to the building (free-standing lattice screens permitted if compliant), as noted in ABCB Housing Provisions Standard 2022, 13.3.4.

Applicable building classes and standards

1. Applies to residential classes under Volume Two (typically Class 1 and 10 associated work) via the ABCB Housing Provisions and to multi-residential/commercial classes under Volume One (typically Class 2-9) via S37C7 shading provisions.
2. Where structural fixings or projections are involved, relevant Australian Standards may apply for design and construction, for example AS 1684 (timber framing for verandahs and projections), AS 4100 (steel structures) or AS 3700 (masonry) depending on the shading device construction. These standards govern structural integrity, connectors, and wind loading design - consult the specific standard for design details.

Residential vs Commercial

1. Residential (Class 1/10, ABCB Housing Provisions):
2. Shading provisions are given in the ABCB Housing Provisions Standard (e.g., 13.3.2-13.3.4) which provide dimensional rules for projections (P/H ratios), performance tests (80% summer radiation reduction) and practical explanatory requirements (gutters, free-standing screens, operability of adjustable shading).
3. The Housing Provisions present simpler, prescriptive methods aimed at typical houses and associated work and explicitly allow verandahs, eaves, balconies or external screens to be used as shading when they meet the P/H and G/H dimensional guidance (see ABCB Housing Provisions Standard 2022, 13.3.3).
4. Commercial / Multi-residential (Class 2-9, NCC Volume One):
5. Shading is considered in the energy compliance calculation through the shading multiplier approach in NCC 2022 Volume One, S37C7 and accompanying Tables S37C7a and S37C7b. The multiplier depends upon climate zone, orientation and measured P/H and G/H ratios.
6. For engineered or complex facades, externally applied shading that meets the 80% summer radiation reduction may be treated as equivalent to a permanent projection with the fixed multiplier 0.35 if adjustable and automatically operated as required in S37C7(b).

Exceptions and Exemptions

1. Devices that do not meet the dimensional projection or 80% solar reduction criteria cannot be credited with the stated shading multiplier and must be treated as unshaded in energy calculations.
2. Gutters alone do not qualify as shading unless attached to an approved projection such as an eave or veranda (ABCB Housing Provisions Standard 2022 explanatory information).
3. Where G exceeds 500 mm, the Housing Provisions state that the effective value of P must be halved for sizing guidance in specific clauses (see ABCB Housing Provisions Standard 2022, NT 13.3.3 note).
4. Alternate compliance paths are available under the NCC energy provisions - if shading cannot practically meet the projection or performance targets, designers may use other energy efficiency measures (improved glazing performance, thermal mass, insulation, HVAC efficiency, or dynamic modelling) to demonstrate overall compliance using the NCC’s Deemed-to-Satisfy or Verification Method pathways. Relevant clause references: energy efficiency sections in NCC Volume One and Volume Two energy provisions and the ABCB Housing Provisions.

State and Territory Variations

1. The NCC is national, but each state and territory may have schedules or amendments in the NCC Schedules (Schedules 4-12 in NCC 2022 Volume One) that alter or add to national provisions. Designers must check the relevant state schedule for modifications affecting energy provisions or shading in that jurisdiction.
2. The ABCB Housing Provisions document includes jurisdiction-specific explanatory notes (for example references such as NT 13.3.3 in the Northern Territory guidance). These notes illustrate how some jurisdictions apply the standard wording or add clarifying statements for local climates.
3. Examples to check for local differences:
4. Queensland, NSW, Victoria and Western Australia have state schedules or energy efficiency initiatives that can affect how energy calculations are accepted by local regulators - always verify against the relevant state schedule in NCC 2022 Volume One (Schedules 4-12) and any local planning or building authority guidance.
5. If in doubt, check the state schedule in NCC 2022 Volume One and the state or territory amendments to the ABCB Housing Provisions for precise local requirements.

Practical Compliance Tips

1. Always document P, H and G measurements on drawings and in the energy compliance report using the dimension definitions from Figure S37C7 in NCC 2022 Volume One so the assessor can reproduce shading multipliers from Tables S37C7a/S37C7b.
2. When specifying external screens or slatted devices, require a certified shading performance statement showing the device restricts at least 80% of summer solar radiation (or specify the device be included in the energy model with a multiplier of 0.35 only if that performance is demonstrated), as required by NCC 2022 Volume One, S37C7(b) and ABCB Housing Provisions 13.3.3(b).
3. For residential projects rely on the ABCB Housing Provisions dimensional method where possible - it is simpler and often accepted by certifiers for Class 1 work. Include details showing compliance with the P/H and G/H rules and note any halving of P when G > 500 mm where applicable.
4. Design adjustable shading to be readily operable from safe occupant positions - avoid designs that require ladders or specialist access, to meet the ABCB Housing Provisions operability expectation (see ABCB Housing Provisions Standard 2022, 13.3.4).
5. Coordinate structural and wind-load design of fixed projections with the applicable standards (AS 1684, AS 4100, AS 3700) and include fastener details on drawings to satisfy building surveyors and certifiers.
6. Check orientation and climate zone early in design. P/H ratios that work well for a north-facing living room may be inappropriate for east/west glazing. Use the correct table (S37C7a for north/east/west, S37C7b for south) from NCC 2022 Volume One, S37C7.
7. If using alternative compliance paths or custom façade systems, provide energy modelling that clearly explains assumptions about shading, or obtain a specialist report verifying shading performance to avoid rejection at approval.

References cited inline: NCC 2022 Volume One, S37C7 and Tables S37C7a/S37C7b; ABCB Housing Provisions Standard 2022, Clauses 13.3.2-13.3.4 and NT 13.3.3 explanatory notes; Figure S37C7 measurement diagram. Structural references where applicable: AS 1684, AS 4100, AS 3700.

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