SkyCity convention centre fire started accidentally by workers fitting roof - report

Wednesday, 22 April 2020

Smoke pours into the damaged SkyCity convention centre from above before a flare up takes hold of the collapsed ceiling on Thursday. (First published in October, 2019)

The SkyCity convention centre fire was accidentally started when a waterproof membrane being fitted to the roof was 'momentarily exposed' to a worker's gas torch, a investigation has found.

But a contractor working on the roof disagrees with the findings and is calling on Fire and Emergency NZ (Fenz) to retract the report.

The blaze erupted on the roof of the under-construction NZ International Convention Centre Fire on October 22, 2019.

Flames rage on the roof two days into the fire, as firefighters in an aerial appliance continued to battle the blaze.

It slowly consumed the roof, caused widespread disruption in central Auckland and took days to fully extinguish.

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Fire and Emergency NZ Te Hiku region manager Ron Devlin in central Auckland as the fire burned on.

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Fenz said in a statement on Wednesday the cause of the blaze was deemed accidental.

Fenz Te Hiku region manager Ron Devlin said it was inadvertently started while workers were applying waterproofing membrane, known as cap sheet, on the roof.

The cardboard inner of the cap sheet roll was 'momentarily exposed' to the flame from a worker's gas torch, which then began to smoulder, Devlin said.

Firefighters battle the blaze on the roof of the unfinished SkyCity convention centre.

'After smouldering unnoticed inside the roll, an intense fire developed that burnt through the top layer of the cap sheet, and then spread across the level seven roof membrane.'

Speculation was rife at the time an inexperienced contractor sparked the blaze by leaving on their blowtorch then going for lunch.

Devlin quashed any suggestion that had happened.

'Our investigators found all gas bottles around the origin of the fires were turned off for the lunch break. There were no inexperienced contractors working in the area at the time.'

An independent peer review agreed with the investigation's findings, Devlin said.

He said: 'I want to take this opportunity to thank our people who worked hard on this fire.

'We understand the convention centre fire had a severe impact on Auckland, and we appreciate the patience the city showed while we extinguished it.'

But contractor MPM Waterproofing said in a statement on Wednesday it had reviewed the investigation report and believed it contained several factual inaccuracies.

'As with the initial suggestions as to the cause of the fire already referred to, MPM Waterproofing has voiced its concern to FENZ about the content of the report and the accuracy of the conclusions made in it.

'MPM Waterproofing takes the view that it would be appropriate for Fenz to retract the report while further consideration is given to MPM Waterproofing's concerns and the matter is the subject of further investigation.'

The company continued to analyse the report with help from its legal advisor and was preparing to 'outline more fully the reasons for its concerns', the statement said.

In response, Devlin said many of MPM's concerns were brought to Fenz's attention during the investigation.

Crews spent long shifts in aerial appliances trying to bring the fire under control.

'We believe they've been appropriately considered, along with all the other relevant evidence and commentary.

'While other parties are free to express their own views about the cause and origin of the fire, we are confident about the conclusions we have reached.'

Firefighters rest after a shift spent battling the blaze.

Fletcher Construction chief executive Peter Reidy, whose company is building the centre, welcomed the report.

The company's own investigators reached a similar conclusion to FENZ, that the fire stared with the inadvertent ignition of the cardboard centre of a roll of waterproofing membrane, he said.

'It should be noted that this is an extremely common product with a common application process across the industry.

'The subcontractors working on the roof of the [convention centre] had 40 years' experience between them, were employed by one of the two largest specialist roofing membrane installers in Auckland and the firm was approved by the product manufacturer.'

Following the fire, Fletcher Construction undertook a review of torch-on roofing membrane processes across its sites and ran workshops with frontline workers, Reidy said.

Fire crews begin the process of securing the facade of the Sky City Convention Centre.

SkyCity chief executive Graeme Stephens said the company was reviewing the findings, it remained committed to the project and looked forward to work re-starting on the site.

CAUSE AND EFFECT

The application process for waterproofing membrane (cap sheet) requires it to be pre-heated to enable it to stick to the surface of another layer of membrane already fixed to the roof.

Under the two layers of membrane is a layer of plywood, itself fixed to the timber framing.

Beneath the plywood was 100mm of thermal insulation sitting atop layers of Durra Panels, used as noise insulation.

Footage examined by the investigators showed contractors were rolling out the cap sheet on the roof of the convention centre until 12.36pm, before they left the area at 12.39pm, according to Fenz's summary.

For 38 minutes, the cardboard centre of the roll smouldered.

It then burst into flames and ignited the entire roll of membrane, producing a self-sustaining fire.

That version of events was consistent with tests and a recreation conducted by Fenz, the summary said.

Strong gusting winds fanned the flames in their slow spread across the roof.

The fire has been deemed accidental.