Making a lighting impression
By David Crossley, Technical Manager, Lighting Council Australia
Monday, 15 July, 2019
Implementing impressive, interesting and welcoming lighting installations may become more of a challenge for designers and installers under the new energy efficiency provisions (ie, Part J6) of Volume one of the National Construction Code (NCC) 2019. However, there are a number of aspects of the new code that can be used to allow for higher levels of lighting power to be utilised for impressive indirect and architectural lighting designs.
Designers like to be able to use a wide range of lighting effects such as wall wash, cove lighting, uplighting, narrow beam and other types to create spaces that are visually interesting, attractive, welcoming and functional. These types of lighting effects are sometimes not as efficient at delivering light to a work surface or floor as wide beam downlights and troffers. However, they are certainly more attractive and usually lower glare.
Lighting Council Australia and the International Association of Lighting Designers recently ran a series of educational seminars on changes to NCC 2019 and the following tips were highlighted during these events.
Designers should not forget that two conformance paths are available to comply with the requirements of the NCC. One is the performance solution path and the other is the deemed-to-satisfy path.
A performance solution for lighting may use various strategies to achieve compliance. For example, a designer may be able to demonstrate that a particular building management system can achieve overall lower energy usage compared with the deemed-to-satisfy provisions even though the watts per square metre used by lighting may be more than the deemed-to-satisfy provisions. Alternatively, trading increased energy savings in other building service areas (ie, through the installation of a more efficient HVAC system) would allow for more energy to be used for lighting.
From a practical perspective, unless the complete building design is being handled by the one design company or a deal agreed with the building owner and other designers early in the project, a performance solution may not be easy to negotiate.
It is likely that most designs will be completed under the deemed-to-satisfy provisions of NCC 2019. In this case it is important to remember that Part J of NCC 2019 will only be mandatory to apply after 1 May 2020. Up until that date, either Part J6 of NCC 2016 or Part J6 of NCC 2019 can be used. This delayed implementation will allow for new tools such as the Australian Building Code Board Lighting Calculator to be redeveloped and designers to become familiar with the new provisions.
The NCC 2016 track lighting provisions were overly onerous and proved to be a disincentive to including track lighting in designs even though track systems are a practical way to light areas that change over time. The new NCC 2019 provisions treat the lighting installed on track systems like any other lighting. That is, the lighting installed on track systems when the installation is certified is the lighting that is assessed. This is a reasonable approach.
Steve Brown of the International Association of Lighting Designers demonstrated that it is possible for impressive foyer lighting designs including large ‘green walls’ (ie, interior gardens) to be installed, in part due to the exemption for green wall lighting power. Other types of exempt lighting include that used for fixed display cases, signage, emergency and exit, light heaters, art or sporting performances, museum or art exhibitions, specialist process lighting and plant growth. Steve also highlighted it is best to use the ABCB lighting calculator spreadsheet as this is endorsed by the ABCB.
Sim Steele of Steensen-Varming highlighted that if art is displayed within any commercial space then the lighting power used to illuminate that art is exempt. Such display lighting must be controlled separately from general lighting. Sim also asked the question, “What is art?”
Tim Hanson of GLG highlighted that table J6.2a would be more appropriately titled ‘Baseline illumination power density’ instead of ‘Maximum illumination power density’ as additional allowances are able to increase the figures obtained from this table.
Tim also demonstrated through a wide number of examples that designers should always try to utilise the room-aspect-ratio adjustment factor because many common room shapes are able to take advantage of significant lighting power allowance increases via this method.
NCC 2019 has reduced the amount of power able to be used by different spaces within commercial buildings by between 20% and 88%. Some space types such as auditoriums, retail, cafes/restaurants/bars/hotels, lobby areas and corridors have included additional lighting power allowances to enable designers to implement indirect or architectural lighting designs in those spaces. So, the interpretation and classification of a particular space could mean higher power allowances depending on the classification.
Some spaces are multifunction and could be classified in a number of different ways. For example, if food or drink will be served in a space then that space is eligible to use 14 W/m2 as a baseline allowance. Also, open plan areas may contain a number of different classifications depending on how each part of the floor plan will be used.
All presentations highlighted the significant additional allowances that are able to be used to increase the baseline power allowance. As well as the room-aspect-ratio allowance two controls factors can be used (eg, motion detection, dimming, daylight sensing and dynamic lighting control). Also, two allowances can be used for lighting colour quality. High colour rendering index lighting (ie, equal to or greater than CRI 90) would allow an additional 11% power. Lower colour temperature lighting (ie, equal to or less than 3500K) would allow an additional 25% power to be used for lighting.
So, a maximum of five additional adjustment factors can apply and increase the baseline power allowance for a particular space.
NCC 2019 also includes a number of additional requirements for switching and fire stairs so the new requirements should be read thoroughly. For example, lighting in fire stairs/ passageways/ramps must be controlled by a motion detector.
Sensibly, the exterior lighting requirements can be satisfied by simply installing LED lighting.
Separate to the requirements of the National Construction Code it is interesting to note the outcomes of research recently conducted by renowned Nancy Clanton regarding office worker satisfaction with lighting. The highest satisfaction ratings were obtained using daylighting (where available), the use of up-blinds that brought light into spaces up near ceilings, relatively low levels of general lighting (ie, around 160 lux) and task lighting able to be adjusted by the user. The task lighting should be able to be adjusted up to relatively high illuminance levels. In many cases in the study, workers would adjust their work surface lighting levels up as high as 800 lux or higher. We suggest that such practices are likely to increase alertness and productivity.
Also, the link here back to the NCC is that sophisticated task lighting standalone luminaires are becoming available (ie, including in-built sensors, dimming and split up/down lighting) and plug-in task lighting luminaires are outside of the NCC restrictions.
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