Recent changes to Section J6 of the National Construction Code are causing a stir within the industry, with many arguing they’ll have a negative impact and leave us with bland, sterile building spaces. Jacob Harris caught up with Peter McLean to find out more.

The Australian Building Codes Board (ABCB) is introducing changes to Section J6 of the National Construction Code (NCC) that, according to many in the industry, will fundamentally change the way decorative (or non-general) lighting is designed and installed in Australian buildings. Section J6 of the NCC deals with the minimum standards for energy-efficient lighting design and the 2019 version, which comes into effect in July 2019, applies an overall reduction of the limits and separates allowances for general and decorative lighting.

According to the ABCB’s NCC Energy Efficiency Provisions Volume One Handbook, the intent of Section J6 is to enable artificial lighting and electric power to be used in a responsible manner, in order to avoid excessive energy use. Lighting used in buildings consumes high levels of electric power and so it follows that
there are significant gains to be had by introducing requirements for more efficient power usage.

“Lighting is often installed far in excess of the lighting needed for the task or inefficient fittings are used; the intent of these provisions is to limit these occurrences. For example, ambient lighting installed for aesthetic or mood purposes is not generally required for safety or operational purposes so there are opportunities to save energy by restricting excessive usage. Shops, in particular, tend to have very high lighting levels to attract customers,” the handbook states.

While a reduction in the limits is not a problem perse, it appears the importance of the above-mentioned ‘ambient lighting’, its overall impact on building spaces and the level at which it can be considered ‘excessive’ are at the core of the industry’s concerns. Peter McLean is a lighting consultant at Lighting Art & Science and was also a consultant to the ABCB to draft the original J6 together with the guide. He also wrote the original industry impact statement and did the  calculations to justify the limits that were specified.

“This is the second set of reductions since the inception of the J6, and it is the largest. There is some justification in the reduction of the limits as the extensive take up of LED technology makes the limits easier to comply with. However, the major problem is that the new levels are too low. It is possible to achieve the required lighting levels within the energy limits, but not in all applications and not while maintaining the principles of good lighting,” says Peter.

An example of this is applications where uniformity of illuminance and low wattage LEDs are required. The losses in an LED driver are relatively constant through a variety of wattage ranges. For example, the losses of an LED fitting are around 3W, regardless of whether the fitting is 1W or 24W. So in spaces where uniform, low lighting is required, the energy consumption is considerably higher due to the use of a higher number of low wattage LEDs.

“One 24W fitting has a circuit load of around 27W, whereas the equivalent illumination level with 24 1W fittings would be 96W. With areas that require a lower illumination level it is not possible to light the space with higher wattage fittings and achieve a reasonable uniformity and low wattage fittings rapidly use up the energy allowance,” says Peter.

Although the light levels are achievable in spaces with relatively high illumination levels, flat ceilings and light coloured walls, the new restrictions will inhibit the use of decorative lighting in many non-standard applications. Lighting heritage buildings, repurposed buildings such as warehouses, and architecturally  interesting buildings where standard lighting applications won’t suffice will become difficult under the new restrictions.

Visual comfort may also suffer under the new J6 due to an inability to sufficiently apply glare-reducing lighting techniques.

“The method for ensuring visual comfort by reducing sky glare and luminaire glare is to increase the illumination of a space in relation to the background.  alternatively, lighting of the walls improves the visual performance and can avoid an increase in the general illuminance; however, there is no surplus in the allowances.”

Another important function of lighting is to create visual interest. This will also become more difficult under the new J6.

“Lighting is not only used for performing a task. It is also used to create a mood or atmosphere and can draw attention to specific parts of the visual space or architecture. Lighting can also be used to make a space appear differently so that the ceiling looks higher or lower, larger or smaller, shorter or longer. Again there is no additional allowance to provide this,” says Peter.

While there is no direct limit on decorative lighting in the new J6, there is little allowance left over from functional lighting requirements. This will potentially have a negative impact on building design in the future.

“It could affect building designs as there are many building forms that will be difficult to achieve the lighting requirements within the limits. It will tend to make architecture very boring.”

According to the J6, lighting is estimated to be responsible for 26% of the electricity used in an office building. Lighting inefficiencies also have a compounding effect in warmer climates because the extra electrical load for lighting translates to waste heat that increases the load on air-conditioning systems.

While of course it is important to eliminate inefficiencies and the excessive use of power in general, the value of a varied, interesting and aesthetically pleasing built environment is also not to be taken for granted. Like architecture, lighting helps to shape the spaces we live and work in and is a fundamental part not only of the functional operation of buildings but of their aesthetic enjoyment. Hopefully the new J6 leaves room for a balance between efficient power usage and the principles of good lighting.