Massachusetts fire and building officials have joined those in Boston in reviewing safety and fire prevention requirements on construction sites of large wood-frame buildings, the state fire marshal said Thursday.
Fire Marshal Peter J. Ostroskey said his office, along with the two state commissions charged with overseeing state codes, is reviewing the building code and an upcoming fire code update for ways to prevent construction site fires.
Ostroskey told NBC Boston about this review in the wake of a third wood-frame building fire, early Thursday morning in Weymouth.
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"Within the context of these recent incidents, we've undertaken some additional scrutiny with respect to these incidents and what code implications there might be," he said.
The fire marshal's office does not review or enact building or fire code. But Ostroskey said his office is reviewing existing code with the state Board of Building Regulations and Standards, which oversees the Massachusetts building code, and the Board of Fire Prevention Regulations, which oversees the fire code.
"I think we have to take a look at the fires, the causes of these fires, and the significance of them with respect to the codes and how they work," he said.
Those buildings were not completed and inspected at the time of the fires. In Dorchester, the walls were up, but the sprinklers were off. In Waltham, parts of the complex were still open and without sprinkler systems.
The cause of the Weymouth fire is still under investigation, but the building was in various stages of completion.
None of the buildings were occupied at the times of the fires. No one was injured in Weymouth, and firefighters suffered minor injuries in Waltham and Dorchester.
Boston Fire Commissioner Joseph E. Finn and Inspectional Services Commissioner William Christopher in July announced that they would review the city’s regulations.
"During construction, when the building is the most vulnerable, is where Joe and our teams are going to look together for things we can improve so this situation doesn't repeat itself," Christopher said then.
The NBC Boston Investigators began digging into wood frame construction after the June Dorchester fire.
Many wood frame buildings, including the one in Dorchester, use lightweight engineered wood, which is comprised of pressed wood chips to form either a solid beam or an I-beam. Those materials are used in floor and ceiling systems to allow for larger rooms and higher ceilings.
Finn said that while the Ashmont building still smoldered behind him in June, the I-beams in the ceiling of the building began to fail shortly after his crews arrived. He immediately called them off the roof as machinery and equipment began to fall through.
"Lightweight construction has some hazards to firefighters," Ostroskey said Thursday. "Certainly they're sound practice prior to introducing a fire to the building, but those components will change the way the tactics and strategies the fire departments use."
According to studies and fire and construction experts, the I-beams in particular can fail quickly if the pressed wood chips in the middle burn, meaning people and objects can fall through floors.
But officials and experts emphasized that once the drywall is up, and smoke detectors and sprinkler systems are operational, the risks associated with those materials, and wood materials in general, drop significantly.
"Once these buildings are constructed and are in operation, they are fully closed and have working systems, they are safe buildings to occupy," Ostroskey said.
A revision to the International Building Code, which Massachusetts and most states base their codes on, allowed for larger and taller wood-frame construction. Builders like it because it is quicker and easier to work with, and cheaper than concrete and steel.
Officials determined the Dorchester fire started because an exhaust pipe from a generator in the basement was just inches from combustible materials in the wall near the ceiling. The building code requires such exhaust pipes to be at least 12 inches on all sides from combustible materials.
That building was finished, but the sprinkler system was turned off. It was due for a final inspection, when the sprinklers would have been pressurized and tested, the day after the fire.
The Waltham fire, which started early on a Sunday morning, was ruled arson. The fire marshal's office is still looking for the public's help to solve that crime. Anyone with information should call the state’s arson hotline at 800-682-9229.
The state is offering a reward of up to $5,000 for information that helps to solve the crime of arson. And the contractor, Callahan Construction, is offering up to $100,000 for information that leads to the arrest and conviction of those responsible.