The board of the Glasgow School of Art is unfit to manage the future of the famous Mackintosh building, which was gutted by fire in June, after ignoring repeated warnings of fire risk before a previous blaze in 2014, Holyrood’s culture committee has heard.

Malcolm Fraser, one of Scotland’s leading architects, accused the school of prioritising “flashy new buildings” ahead of “the jewel at the heart of its estate”, in a combative hearing of evidence from invited experts on Thursday morning. Representatives of the art school are expected to contribute to a subsequent hearing.

While Glasgow city council has faced ongoing criticism of its handling of the aftermath of the second fire, this evidence session marked the most direct public criticism of “systemic failures” on the part of the art school’s management.

On Sunday, the GSA chair, Muriel Gray, in her first substantial interview since the second fire, insisted that the board of governors was unanimous in its desire to rebuild the school as Mackintosh intended it, estimating that the project would take 4 to 7 years and cost around £100m, which would be made up by insurance cover and a major private fundraising drive.

But this was dismissed by representatives of the local residents and businesses still excluded from their homes and premises by the safety cordon imposed by Glasgow council’s building control as the painstaking work to stabilise the remaining structure of the devastated building continues.

Gill Hutchison, the owner of Biggars music and spokesperson for Sauchiehall Street Inner Cordon Businesses, described Gray’s comments as “tone-deaf and cavalier”.

She told the Guardian: “The building has burned twice on their watch. If a management fails so catastrophically twice over in their curatorship of something so highly valued and adored, then surely that should have consequences for those responsible for those failings? I fear there is a smokescreen of maudlin emotion covering up systemic failings which need to be closely scrutinised.”

Hutchison also expressed disappointment that representatives of the local community had not been invited to speak at Thursday’s hearing.

The first fire, in May 2014, which destroyed the world-renowned Mackintosh library in the east wing of the building, was sparked by a projector igniting some expanding foam used by a student for a degree show exhibit. It is widely understood that the fire accelerated as quickly as it did because flames were funnelled through the old heating system, which used wooden ducting to take warm air from a boiler room in the basement to the rest of the building.

Roger Billcliffe, who has been a strident critic of the GSA’s conduct following the first fire, told the culture committee that the building had been “a firetrap waiting to happen”.

Calling for the fire service report into the 2014 fire to be released in its unredacted form, the author of a number of definitive books on Charles Rennie Mackintosh said that the school should be “relieved of responsibility” for the building, arguing that the public “did not know if lessons had been learnt” from the first fire.

Eileen Reed, who worked at the art school as head of widening participation until November 2014, confirmed that there was no clarity following the first fire about whether the art school management was undertaking an internal investigation.

She said that she understood there had been “multiple failing of health and safety”, a list of which was passed to the art school director, Tom Inns, at the time. “What’s gone wrong here is that at the very least there should have been an immediate internal investigation into how we ended up in the situation that the risk for the most vulnerable building in Glasgow and possibly Scotland was not properly calculated.”

Fraser, who emphasised repeatedly the difficulty of drawing any conclusions about the second blaze while the fire service investigation was ongoing, made an argument for better statutory oversight of historic buildings but argued that risk management had improved following the first fire.

Asked whether the art school board was fit to manage the rebuilding of the Mackintosh building, the director of the Charles Rennie Mackintosh Society, Stuart Robertson, said that the project should be put in the hands of an expert panel or trust.

Noting that the GSA came bottom of satisfaction rankings in this year’s national student survey, Robertson emphasised the need to re-focus on education: “Since 2014, the re-building of the library did detract from their core business, diverted resources, attention and focus from what they are there to do. I don’t see how the current set-up is fit for purpose.”