Fire Rated Wall Systems

The recent fire onsite at Hobsonville Point highlights the importance of using non-combustible claddings and proven fire rated wall systems in the appropriate areas.

Hobsonville Point is a master planned community in the northwest of Auckland, comprising more than 3,000 residential buildings of various types. Universal Homes has commissioned a medium density housing development on the corner of Hobsonville Road and Squadron Drive. Currently under construction, the three-storey townhouses are specified with high quality materials, which meet NZBC fire safety requirements, including RAB™ Board, HomeRAB™ Pre-Cladding, and Oblique™ Weatherboard.

On the 1st of September 2017, a large fire broke out in the complex at the intersection of Hobsonville Point Rd and Squadron Dr. At the time of the fire, the property at Lot 8 was still under construction, with HomeRAB™ Pre-Cladding installed on the external walls.

The boundary walls of the adjacent Lots 7 and 9 had been specified as James Hardie JHETGR30 - a 30-minute fire-rated external wall system using Oblique™ Weatherboard as the external cladding, with 6mm RAB™ Board direct fixed to framing. Given that the fire had been burning for at least one hour before FENZ made an entry into the building, the cladding performed remarkably well.

Thanks to the fire rated wall system, the fire was well contained within Lot 8 and the external Oblique™ Weatherboard on the adjacent units were not extensively damaged by the fire. Moreover, the HomeRAB™ Pre-cladding used in Lot 8 was not consumed by fire, nor did it contribute to the spread of fire, keeping damage to a minimum, and exceeding the fire safety requirements.

Fire resistant

The new fire safety requirements regarding stopping the external fire spread on exterior of buildings which are over 7m height have been applicable from 31st of May 2017. The new requirements apply to commercial and multi-unit residential buildings like this one and requires non-combustible materials used on the exterior of buildings.

Universal Homes Construction Manager, Grant Coutts, says the fire highlights the importance of using non-combustible claddings and proven fire rated wall systems in appropriate areas. “While the incident was unfortunate, it has given Universal Homes complete confidence that the high performance products and systems we use perform as designed.”

All of Hardie™ cladding products and rigid air barriers are classified non-combustible materials, and therefore meet the new requirements. However, timber products without a fire retardant will usually not meet the requirements. With increasing density of residential developments in Auckland, having confidence that the non combustible claddings used in the appropriate applications will perform as specified is critical.

“James Hardie products are the logical choice for Universal Homes, with high performance backed by great service and support,” Coutts says.