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October 13, 2021

Increased Fire Risk for Buildings Under Construction

A very recent article in the Chicago times got me thinking about the increased loss and risks associated with fires in buildings, especially those under construction.

The article, called “How the Great Fire changed Chicago Architecture” covers the fire that decimated the city in 1871 and the rebirth and reinvention of the Windy City over the 25 years following the fire

Some interesting facts, most from the article:

  • The fire killed 300 people, left 100,000 homeless and destroyed over 2,000 acres of land
  • Millions of tons of rubble from the fire were dumped into Lake Michigan. The resulting  landfill would be reshaped into Grant Park and portions of Burnham Park, just south of current day Roosevelt Road.
  • Chicago Tribune Publisher Joseph Medill ran for mayor under the Union-Fireproof Party. Since the election was a month after the fire and still very fresh on the voters minds, he won nearly 73% of the vote. 
  • Most commercial buildings and other structures within the 2,100-acre fire zone were rebuilt in fire resistant materials such as brick, stone and a significant use of terracotta cladding.
  • Ironically, brick and stone buildings were also lost or ruined in the fire. The blaze was hot enough to loosen mortar or melt iron frames and cast iron storefronts, causing many  buildings to collapse.
  • Masonry buildings with wooden roofs were also vulnerable.
  • Chicago, particularly its downtown, eventually became a new city of early skyscrapers and fireproof buildings but those things didn’t happen overnight as the myth portrays. The city’s first real skyscraper, the 10-story, steel-framed Home Insurance Building at Adams and LaSalle streets didn’t come along until 1885, almost a decade and a half after the fire.

Fire is a major risk to buildings under construction.

According to the National Fire Protection Association (NFPA)

  • Local fire departments responded to an estimated average of 3,840 fires in structures under construction and 2,580 fires in structures under major renovation per year in 2013-2017.
  • Three of every four fires in structures under construction involved residential properties.
  • Lighting equipment was the leading cause of fires in structures under major renovation.
  • The fires in structures under construction caused an average of four civilian deaths, 49 civilian injuries, and $304 million in direct property damage annually, while those in structures under major renovation caused averages of eight civilian deaths, 52 civilian injuries, and $104 million in direct property damage annually.

Most common Factors:

  • Electrical failure or malfunction  15%
  • Abandoned and discarded material  14%
  • Heat source too close to combustibles 14%
  • Welding 7%
  • Misuse of materials 7%
  • Equipment unattended 7%
  • Housekeeping 5%

This report from the NFPA goes into great detail related to construction fire occurrences.


Arson is also a chief concern when it comes to fires in buildings under construction, as well as for fires in buildings being renovated or demolished. According to a recent NFPA report, “Fires in Structures Under Construction, Undergoing Major Renovation, or Being Demolished,” the majority of fires in buildings being demolished from 2010 to 2014 were caused by arson, 42 percent on average. 

For fires in both buildings under construction and being renovated, the percentage of those that were intentional was still very significant, 13 percent. 

The fact is that many sites are left unwatched or unsupervised during the evenings.  News stories suggest the motives for torching a building under construction can also be political, especially frustration over gentrification, a phenomenon that has been on the rise over the United States over the past 20 years.

To address the concern, NFPA 241, Safeguarding Construction, Alteration, and Demolition Operations, includes a section on keeping construction sites safe from arson. It outlines measures to take such as hiring guards, putting up fences, and securing entrances. This might mean 24/7 monitoring.

Why are construction sites more vulnerable?

The primary reason is the lack of fire protection systems like sprinklers and firewalls, along with an abundance of potential fuel sources, can make an arsonist’s job quite easy at construction sites and increase general risk overall.

Structure fires in buildings under construction come with a unique set of circumstances that require an equally unique set of tactics and strategies. Because these buildings are just starting their useful lives, many of the construction and fire protection features previously mentioned that can help  control incidents, such as sprinkler systems, standpipe systems and hydrants, may not be in place. In addition, if the construction process is still in the early stages when the fire occurs, you may be presented with what’s basically an exposed standing lumberyard.

When a building is under construction, drywall might not be installed yet. This lack of protection with sheetrock allows a fire to spread quickly into wooden truss areas or wooden support structures, leading to premature failure.

Other dangers associated with rapid fire spread occur when tracks of homes or other wood frame commercial projects are in different stages of completion and are closely spaced. The fire can then spread to exposures quickly, meaning that the fire departments may face several well-involved buildings on arrival. These circumstances require proper strategies and tactics and may involve response from several fire stations. 

Fire departments recognize when they need to go into a high-flow attack, and leave the small hand lines on the truck. First- and second-due to arrive fire companies must establish a continuous water supply and start high-flow attacks to knock down large volumes of fire or cut off the extension of that fire from moving into other uninvolved buildings or parts of a large building.

Other challenges may be limited access to an area where concrete forms are being built and rebar rods are exposed, making deployment of lines much more difficult and increasing trip hazards. There are all sorts of other trip hazards as well, including but not limited to piles of lumber and trash, high stacks of new  building materials, and lots of holes and uneven ground.

Other dangers encountered on the same site could include paint and other flammable or combustible liquids used in the building process. Scaffolding around the site could collapse because of flame impingement or fall from forceful hose streams pushing them over.

Because these buildings are unoccupied, the biggest life safety issue is usually the members of the fire departments and other first responders but there still needs to be a search of the building because vagrants or construction workers could be trapped inside. A thorough risk assessment is key.

Top 10 Tips For Fire Prevention On Site

  • Do not build fires for any reason
  • Keep the site clear and clean
  • Frequently check the on-site offices for heaters and other hazards
  • Check temporary lights frequently
  • No smoking
  • Provide extinguishers and make certain they are the correct type for the hazard
  • Get rid of waste
  • Get and follow Hot Works Permits
  • Make fire checks routine
  • Have a plan in case of fire

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We are the first to merge our construction management expertise with blockchain technology to create the world’s most revolutionary technology bringing risk management and visibility to your projects.

Through verifiable collaboration, we eliminate risk, disputes, save time and create a healthier and happier global construction industry.

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