The ACT government was warned about fire safety risks potentially affecting a "significant" number of territory buildings almost two years before the issue flared-up at a Forrest apartment complex.
In late November 2017, residents of the Bentley Suites complex in Forrest were told of alleged building code breaches related to the fire resistance of structural steel beams in the apartment's car park.
Engineers found many beams would be resistant to fire for just 10 to 15 minutes, rather than the 120 minutes required by the building code at the time, according to a letter sent to residents on November 27, 2017.
Peak industry body Engineers Australia wrote to government planning officials in February 2016 to express concerns about building regulations in the territory, and the specific use of steel beams and columns with inadequate fire ratings.
Although the letter from Engineers Australia did not single out particular buildings, it said a number of residential units could be affected as well as aged care facilities.
"This raises serious concerns about the level of risk posed to residents of units and aged care facilities, in the event a fire occurs," the letter read.
Engineers Australia said the fire safety issue stemmed from the use of cement-filled steel columns over the past 10 to 15 years.
"A significant proportion of units and other building developments in the ACT have been constructed using very small - 100mm or less - cement-filled steel columns and small - 150mm or 200mm - steel beams, purporting to be suitably fire rated," they wrote.
"However, in many instances we have seen no evidence to support the rating for a particular project."
Engineers Australia ACT general manager Keely Quinn said engineers had a number of concerns about the regulation of the building industry in the ACT.
"The main regulatory issues relate to fire issues [passive fire ratings], having competent people signing off on documents and record keeping when things are being built," she said.
"A lot of structural problems take 10 to 15 years to reveal themselves," she added.
"In 10 years will we have a long row of medium and high-density housing with safety issues? The ACT government needs to make sure everything is compliant and safe."
Passive fire protection refers to structures that are engineered to stop the spread of fire, such as fire-resistant beams, walls or doors.
Active fire protection refers to systems such as sprinklers or extinguishers that actively work to combat a fire.
The ACT planning directorate did not say whether it was aware of concerns about widespread fire safety breaches, or what it would do to address such concerns.
"All building plans are required to comply with the Building Act, Building Code of Australia and are approved by qualified building certifiers," a spokeswoman said.
"Where a building exceeds 500 square metres or involves alternative solutions to comply with fire safety requirements ... the proposed plans are referred to ACT Fire and Rescue for comment."
Each year Access Canberra audited a minimum of 10 per cent of each licensed building certifier's work, the spokeswoman said.
"Additionally, investigations are also carried out when complaints are lodged specifically on the work of a building certifier."
Access Canberra has previously said it would be looking into the Bentley Suites situation, although it had not received any complaints about the apartment complex.
In their 2016 letter, Engineers Australia called for better performance monitoring and a registration scheme for professional engineers in order to help stamp out fire rating issues.
"Engineers Australia believes that an effective response to this problem requires...provision of credible and documented evidence to support any 'alternative solutions'."
An ACT engineer, who asked not to be named, said the fire-rating issues could potentially be a bigger problem than concerns about flammable aluminium cladding raised in the wake of the Grenfell Tower disaster.
"In my view it's a bigger problem than flammable cladding and potentially much more dangerous," the engineer said.