Is an Aluminium motorised louvre roof a lower roof in terms of C/ASx 5.7.6

Motorised or manual operated louver roofs that open when the weather is fine and close when it is wet are becoming popular for residential and commercial applications.

For commercial situations a common scenario I am encountering is a hotel or apartment building with a ground floor restaurant or cafe which has an outdoor deck. To improve the usability of the space a fabric canopy has often been used, however a more elegant looking solution is an aluminium louvre roof that can be opened and closed. Then to provide more weatherproofing plastic roll down sides are installed (obviously complying with the flammability index for suspended flexible fabrics).

The question is: When the louver roof is closed is it considered a lower roof in terms of C/ASx 5.7.6 which would require it to have sprinklers or be fire rated underneath if there was an external wall above containing sleeping or exitways within 5m horizontally or 9m vertically?

Fire rating the underside of the louvre roof is not a solution as it defeats the purpose of the louvres and fire rating the wall above is often not a palatable solution as it has many windows.

Sprinklers would be useful when the louvre is closed but not so effective when the louvre is open. The sprinklers muck up the nice clean lines of the louvres and are not an option if the building is not sprinklered.

Aluminium melts at around 660 degrees celcius and rapidly looses its strength above 150 degrees celcius so will it present more of a risk to the wall above than an open deck without any sort of roof above?

My thinking is that a significant fire would vent out the sides and deform the roof to vent out the roof before compartment temperatures were too elevated and therefore would not be too dissimilar to fire on a deck without a roof.

What are your thoughts?

Michael James

Hi Michael
According to NZBC Handbook definitions, “Roof” - “That part of a building having its upper surface exposed to the outside and at an angle of 60° or less to the horizontal”. Where pitch of the roof is between 10 to 35 degrees, (mostly likely for motorised louvre roof). The definition of “Skillion roof” comes into effect - “A pitched roof where the ceiling lining is parallel and close to the roof cladding. The roof may be mono-pitch or may consist of more than one roof plane. These roofs may have rafters exposed below the ceiling.”
As aluminium motorised louvre roof does not have cladding system, underlay, or ceiling, in my opinion it does not fit the definition of “roof” under C/ASx 5.7.6.
Tania Morgun

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The requirements of C/ASx 5.7.6 are presumably addressing building codes C3.1, C3.2, and C3.5.
So in addressing the requirements of C/ASx 5.7.6 in this situation, I would be checking that I achieve the intent of C3.1, C3.2, and C3.5.
The real question is - Is there a reasonably conceivable situation where fire spread could occur from your aluminium louvred roof over a deck to overhead walls with sleeping accommodation or exitways?
This would be a tough one to speculate on. A local louvre failure may vent enough heat to maintain some semblance of louvre integrity elsewhere. There must be examples of fires under these structures around.
Initially I would be looking around to see if there are any examples of deck fires under louvred roofs and take it from there. Not quite time to play code lawyers yet.

Robert Peart

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Determination 2017/002 ( might relate to this. It was in regards to a slatted timber deck and spread of fire to an adjacent property (being a neighboring townhouse). it relied on the carport being open and venting, although the deck was considered to be a roof.
This situation is quite common and often ignored, both for these louver roofs and for shade sail or canvas canopies.
There are also often have opening glazing so are not really open and in that case I would treat it as a room.


Thanks for everyone’s comments. Good food for thought.

From Determination 2017/002 it would appear that it has to be considered as a lower roof, and if C/ASx 5.7.6 was not being followed then an alternative solution would need to be proposed as C/VM2 refers back to the acceptable solutions.

For a hotel building where the building is under single ownership and different from the Determination because that was concerned with spread of fire to other property the relevant Building Code Clauses are:

C1 (a) safeguard people from an unacceptable risk of injury or illness caused by fire,
C3.1 Buildings must be designed and constructed so that there is a low probability of injury or illness to persons not in close proximity to a fire source.
C3.2 Buildings with a building height greater than 10 m where upper floors contain sleeping uses or other property must be designed and constructed so that there is a low probability of external vertical fire spread to upper floors in the building.
C3.5 Buildings must be designed and constructed so that fire does not spread more than 3.5 m vertically from the fire
source over the external cladding of multi-level buildings.

I have seen reports of fires under fabric canopies and they end up performing like open fires. I haven’t found anything on fires under aluminium louvres. I would imagine modelling might cost more than the roof itself.

One of the take home points from the Grenfell fire is that if you slice and dice the rules enough you can get most things to comply which doesn’t necessarily make for a safe building.

Ed Galea has some good discussion on Grenfell compliance in Linkedin here

From a sprinkler perspective we always approach it from the point of sprinkler the whole building, and what clause would permit sprinklers to be ommitted.
I would consider this to be a canopy or verandah usually, but there are also rules for recessed doors and set back walls that might be applied. The sprinkler standard has various requirements depending on dimensions and expected fire load beneath. cl 511.8
We have come across it on several projects. So far there has been a hard ceiling/soffit adjacent (with balcony above) that we have put sprinklers in that provides coverage across the louvered area.
With the louver open it obviously might be unlikely to operate the sprinklers unless the fire is near the sprinkler head. But if the heat builds to a point to operate the sprinkler head, then it will hopefully do its job of controlling the fire.
If the louver is closed then the sprinkler will be more likely be operated and do its job protecting building and occupants, although this would be subject to open sides … but then I guess it wouldnt be such a threat to the main building if heat/fire is venting.

Another option is to treat as an external exposure hazard, if the fire load deems that nececessary, with external sprinklers on exposed walls above/below as necessary. We have done this on plastic canopies where the structure cannot support the pipework.

There are obviously lots of variables that can come into it and there are various options to meet the sprinkler standard.

Hope that helps a little.