“Fast forward to today, almost 30 years later, and intumescent fire dampers in Australia are now
a respected alternative to conventional mechanical curtain or blade-type fire dampers with
fusible link actuation. It’s a bit special to think that we helped pioneer the use of intumescent
grilles as fire dampers across both Australia and New Zealand. It feels like just yesterday.“
John Rakic
John Rakic is the proud Owner and Managing Director of Trafalgar Group with over 20 years of experience in the passive fire industry.
This is just a snippet of the full article. To read the entire article, download the pdf today.
There was a magical day when I met with Simon Hill, and we discussed the possibility of using the LVH44 grille as a small intumescent fire damper. The idea was to replace thick, clunky, and less cost-effective, non-fire-tested sub-ducts, which were a prescriptive design option for openings in metal ducts located in fire-rated riser shafts.
I remember those early days of fire testing, followed by pitching my innovative idea to NDY. My partner in crime back then was a young engineer, Brendan Kennedy, who is now the owner of Smoke Control in Australia.
NDY made us jump through several hoops: pressure drop data, dust and lint testing in wind tunnels at Sydney Uni, grease testing, fume cupboard chemical testing, and more. We secured our first project in Chatswood, which is where I first met a young and enthusiastic private certifier/building surveyor, Allan Harriman from BCA Logic.
We installed our product in the riser shaft as a lightweight and more cost-effective alternative to a heavy 3mm steel sub-duct. We conducted inspections over the building’s lifespan using a remote camera we developed, which we called the Lorient DamperCam.
What Is Intumescent or What Is An Intumescent Material?
For those who may not be familiar, intumescent materials are widely used in passive fire protection. The slats of an intumescent air transfer grille naturally incorporate this technology.
The dictionary definition of intumescent is as follows:
An intumescent substance is one that swells when exposed to heat, resulting in an increase in volume and a decrease in density. Intumescence refers to the swelling process. Intumescent materials are typically used in passive fire protection, where the swelling is a chemical reaction that forms a char, which continues to expand and seals off openings.
Fire Dampers
Under the National Construction Code (NCC) or Building Code of Australia (BCA), as well as the associated Australian Standards, the definition and requirements for fire dampers are clearly established.
The relevant Australian Standards include:
AS1530 Part 4 – 2014: Fire test methods (Note: New fire testing is required for ducted fire dampers)
AS/NZS1668.1: The use of ventilation and air conditioning in buildings
AS1682.1: Fire, smoke, and air dampers – Specifications
AS1668.2: Installation standards for fire dampers
AS1851: Maintenance standards for ongoing inspection and testing
Air Transfer Grilles
Air transfer grilles are fire tested just like an opening for a service penetration to Section 10 of AS1530.4 – 2014.
They will typically need a grille to meet insulation criteria of the FRL when fire testing to AS1530 Part 4 – 2014.
WHAT IS AN FRL?
An FRL, often called a fire system fire rating, is determined from a fire test to AS1530 Part 4 – 2014.
For non-load bearing elements, such as openings for service penetrations and fire dampers, the primary criteria for structural adequacy typically do not apply. However, it is essential that the opening is properly designed, often incorporating a lintel, to prevent any load transfer into the penetrations.
Integrity for a duct fire damper refers to its ability to close during a fire and restrict the leakage of hot gases below a predetermined threshold.
Insulation refers to the temperature rise criteria on the non-exposed side of the fire barrier, measured around the perimeter of the fire damper opening and on the duct itself on the non-exposed side during the fire test.
The requirement for insulation or temperature rise on ducted fire dampers is somewhat ambiguous. Historically, it has been common practice to overlook this insulation or temperature rise criteria for fire dampers, but is this approach correct?
There is currently significant discussion around this issue. Why, for example, does a fire door require 30 minutes of insulation, while a wall or penetration may require 60 or 120 minutes depending on the application, yet fire dampers are often ignored in this regard?
In Europe, fire damper assemblies are required to meet certain insulation or temperature rise criteria. Personally, I believe that a 30-minute insulation requirement makes sense.
This can be easily achieved by adding FyreWrap material for a short distance on the ductwork near the wall where the fire damper is installed, or by using a non-metallic blade or intumescent grille as part of the fire damper assembly.
A metal curtain in a roller shutter or curtrain fire damper does get very hot in a fire, very quickly.
DUCTED FIRE DAMPERS
Ducted fire dampers are now required to be fire tested in accordance with the AS1530 Part 4 – 2014. This is a new fire testing method based on ISO 10294-1.
This fire test evaluates the hot gas leakage through a fire damper after it has closed due to the heat of the fire test.
Many conventional Australian and New Zealand mechanical fire dampers, when closed, have been found to leave excessive gaps that allow hot smoke leakage. In some scenarios, this can be hazardous, even when the damper is closed correctly.
Trafalgar has recently partnered with Lorient to deliver factory-manufactured intumescent fire damper assemblies.
This is just a snippet of the full article. To read the entire article, download the pdf today.
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