“Up to two hours does not mean that a fire-stopping product is automatically suitable for 60- or 90-minute wall systems. Always check the fire-test report, tested wall construction and required FRL.“
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.
Under the National Construction Code (NCC), prescriptive fire ratings are typically assigned to fire-separating elements as part of a building’s passive fire protection measures. These measures help limit the spread of fire, provide additional time for occupants to evacuate and support firefighting efforts.
Fire-resistant plasterboard systems are commonly used to create fire-separating elements. These systems typically consist of steel studs and tracks lined with one or more layers of specially formulated pink fire-resistant plasterboard, often 13 mm or 16 mm thick. They are commonly referred to as lightweight fire-rated construction.
But how do these fire ratings work? What building services can pass through lightweight walls, shafts and ceilings, and what fire testing is required to achieve a particular Fire Resistance Level (FRL)?
How is fire testing conducted?
In Australia, the NCC uses the FRL to define the fire-resistance requirements for fire-separating elements. To achieve an FRL, the complete as-built system is subjected to the Standard Fire Test defined in AS 1530.4:2014.
For vertical walls and shaft wall systems, testing is typically conducted using full-size 3 m × 3 m specimens. Horizontal floor and ceiling systems are generally tested using full-size 4 m × 3 m specimens.
However, fire-separating elements are rarely left completely blank in real buildings. They commonly contain doors, shutters, glazing, control or movement joints, and openings that allow building services to pass from one side to the other.
Australian fire-resistant plasterboard wall systems
Several manufacturers supply fire-resistant plasterboard systems in Australia. Typical wall constructions include:
- 60 minutes: One layer of 13 mm board on either side of a steel stud.
- 90 minutes: One layer of 16 mm board on either side of a steel stud.
- 120 minutes: Two layers of 13 mm or 16 mm board on either side of a steel stud.
Individual systems may vary, so always consult the manufacturer or distributor and confirm the tested construction before specifying or installing a system.
Fire stopping and sealing of service openings
Suppose a fire-stopping product is successfully tested in a two-hour plasterboard wall and achieves an FRL of -/120/120. Does that automatically mean the same product can be installed in a 60- or 90-minute wall and achieve -/60/60 or -/90/90?
The answer is that we do not automatically know. A fire test applies to the wall construction that was tested. Further fire testing or appropriate supporting evidence may be required before the same fire-stopping system can be used with a different wall construction.
This is where contractors can be caught out—sometimes after construction is almost complete. A product promoted as having been tested “for up to two hours” may not have appropriate evidence for every 60-, 90- or 120-minute plasterboard wall system.
This is just a snippet of the full article. To read the entire article, download the pdf today.
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