With LED lighting becoming the mainstream in todays recessed lighting industry, and with the need to make the building envelope and thermal envelope as consistent as possible, the barrier standard (AS/NZS 5110) was implemented (Called up by AS/NZS 3000 the wiring rules) and now luminaire fittings without a cover are required to have IC ratings (AS/NZS 60598.2.2).
The different standardised solutions specified in AS 3000, which can be implemented to will achieve a similar result for household safety, yet different results for energy efficiency of heating and cooling.
Taking into Consideration LED’s can have such a long lamp life and they are composed of electronic components, it is actually very important to understand what temperatures they get to, especially if they are IC rated and have a heat sink fin design, which is not the best design under insulation.
If you are looking at owning or you currently own IC-4 (IC-F) rated fittings, and there are some great products out there but, be careful about lamp life. HOLD onto your receipt, because there is a chance of premature failure regardless of Warrantee. These fittings are not required to be tested for LED life longevity under insulation, and can over heat and fail prematurely. An IC-4 rating is a safety standard only. Although a NATA accredited test laboratory (Such as LEDLab) would perform an In-Situ test of such a product actually covered with insulation, this is not a mandatory test. If correctly performed this test will give a close approximation of LED lifetime. However even government subsidy schemes such as I-PART and VEET do not require NATA endorsed In-Situ reports and reports from overseas are accepted even if performed at 25 degrees uncovered.
So when you consider IC Rated Downlights there is still a good reason why you could benefit significantly using a barrier on top of an IC rated fitting. The LED chip will run cooler and the fitting will last longer.
IC-4 (IC-F) Rated Downlights VS Barrier Standard
Luminaire Barriers: Extend the building envelope
IC-4 & IC-F Rated fittings: Become the building envelope
All of these standards do not include the control gear, and it must be considered when installing these fittings.
CA90 Downlight Fitting: Fitting can be abutted to its sides with insulation only.
IC-4 (IC-F) Downlight Fitting: Largest hole on a fitting must be less than 1mm in width,but what happens to control gear?
IP-65 Downlight Fitting: Highly protected against dust and water. Ingress protection.
IC Downlight Fitting: Fitting can be abutted and covered with insulation, but what happens to control gear?
IC-F (IC-4) Downlight Fitting (NZ): Fitting is a completely sealed unit and can be abutted and covered with insulation, again, what happens to control gear?
These fittings really need to be installed under insulation, and they should be designed without fins to enable efficient dissipation of heat in insulation. Fins in a heat sink do not help when submerged inside insulation.
The Benefits of the two solutions
What ends up happening…
Barrier Standard fitting combination
- A good quality air tight barrier insulates extreme temperatures in the roof from the luminaire more reliably. Roof area temperatures in Australia can go as high as 60˚C for significant periods of time.
- It includes an R-value in the barrier itself.
- Keeps insulation away from a LED Luminaire allowing an area to breathe in, improving lamp life longevity.
- Can provide a Tested and reproducible sound proofing and fire rating if required in the building.
- Provides an ability to keep heat producing control gear outside of the barrier and away from insulation, improves control gear longevity.
- Significantly Reduces the chance of vermin living on top of insulation hotspots where they may lower the life of the luminaire, from compacting insulation and or excretion. This was a common occurrence with Halogen Lighting in Australia.
- Install-able from below the ceiling.
Things to look out for:
- Make sure the downlight cover includes an R-Value. Steel and plastic do not insulate at all, and they contribute to thermal bridging. Heat sinks are great conductors.
- Ensure the barrier conforms as a combination barrier with a LED
- Quick and easy installation.
- Insulation consistency is maintained but can be problematic, because the insulation will sit up off of the plasterboard, and hot attic air can move in between the gap.
- The heat sink is exposed outside of the building envelope directly into insulation. The insulation after time usually sags around the luminaire and reduces exposed cooling plasterboard exposed to the living area for an efficient means of dissipating heat downwards.
- Install-able from below the ceiling.
Things to look out for:
- Be wary of what temperature IC-4/IC-F/IC testing was undertaken with, because most roof cavities in Australia can reach extremely high temperatures. 25˚C Ambient testing is not reflective of some roof cavities that can reach up to 60˚C very consistently.
- Newer LED downlights do not stand as high, so insulation does not lift up so much. This means that there is less air for the LED to breath with, and less uninsulated plaster for the fitting to use to dissipate heat downwards into the living area.
- No matter how much a luminaire manufacturer tells you an LED is designed to run under insulation, if they can run cooler they will last a lot longer. Heat sink fins do not help LEDS to dissipate heat under insulation. a flat surface with a larger surface area is more beneficial.
- Luminaires that are designed to operate under insulation directly abutted and covered, should not have fins on the heatsink, but should be conducting straight into insulation batts with an entirely flat piece of aluminium as opposed to using convection. Hold onto to your receipt to ensure you can replace the fitting should it fail.
- AS3000 has some requirements for transformers. Make sure the Control gear can also be covered in insulation, most of the time it CANNOT!
- If the control equipment needs to be clear of insulation, mount them on structural timbers or look at using an insulative barrier that can allow installation of the control gear up and out of the way of insulation.
- Having a gap under the insulation, where the LED is completely open underneith, will highly likely become a nesting ground for vermin during cooler times of the year, where they will excrete and move around at night potentially causing damage to the luminaire.
- The LED can be exposed to hotspots depending on how the insulation forms on and around the LED.
- The amount of exposed plasterboard where heat can radiate downwards is not garaunteed, especially with some of the more flat LED’s that do not protrude so much.
- Lamp longevity testing is NOT required to be done under insulation, IC-4 rating a fitting is only a safety thing. Hold onto your receipt when covering these fittings with insulation.
Electronic luminaire or control gear failures operating inside elevated temperature environments.
These failure rates can depend on how efficient a given device is capable of moving heat away from the electronic components, control gear and LED itself. But it helps understand just how critical it is to keep these devices as cool as possible to ensure a much longer lamp life.
25˚C represents no change in lamp life, and most IC-rating tests are conducted using this temperature. Any exposure that a fitting like this might get from the loft area which can go to 65˚C will have the following effect on an LED.
- 45˚C Operating temperature can reduce LED/Control gear life expectancy by 7. 50000 hour service life could become 7000 hour.*
- 65˚C Operating temperature can reduce LED/Control gear life expectancy by 40. 50000 hour service life could become 1500 hour.*
*As a contrast, a high quality MR16 Halogen globe should last up to 5000 hours.
If you are buying/using an IC rated fitting that has only been tested at 25˚C Ambient, and you aren’t using an insulative barrier with it, make sure you hold onto your receipt!
Its important to keep LED’s as cool as possible. Protecting the LED from roof area temperatures while also allowing it to breath so that it can dissipate its own heat is a tight balancing act.
Both solutions, provide a significant energy efficiency benefit as opposed to old Halogen oven technology recessed lighting which can contribute significantly to draughts and insulation inconsistencies while also being a fire hazard with old filament lighting technologies.
So when you consider IC Rated downlights VS The Barrier Standard. There are still good reasons why you could benefit significantly using a barrier on top of an IC rated fitting. So they don’t necessarily need to be competing standards.
Be aware!!! In order to ensure an LED with a AS/NZS 5110 barrier or IC Rated LED fitting is installed as efficiently as possible for heating and cooling, its important to put insulation around the luminaire/barrier afterwards. So make sure your professional tradesman who installs an energy efficient barrier or an IC rated fitting, finishes the job and covers the downlights after fit off. Be aware of the limitation of control gear, most of the time they need to be away from insulation. Read the documentation, and hold onto your receipts if you are completely submerging your IC rated downlight with insulation.