Hot-work fires: devastating but preventable

WHEN SIMULTANEOUSLY delivering good and bad news, I find it better to deal with the bad first. So, here it is: Contractors appear to be responsible for a majority of hot work-related fires and explosions which result in multimillion-dollar disasters at commercial and industrial facilities. The good news is that some very simple steps can prevent contractors' (and their clients') worst nightmares,

WHEN SIMULTANEOUSLY delivering good and bad news, I find it better to deal with the bad first. So, here it is: Contractors appear to be responsible for a majority of hot work-related fires and explosions — which result in multimillion-dollar disasters — at commercial and industrial facilities.

The good news is that some very simple steps can prevent contractors' (and their clients') worst nightmares, thereby preserving the reputation and integrity of their business operations.

For the past year, engineers and researchers at commercial and industrial property insurer FM Global have been analyzing the various threats associated with hot-work procedures (for example, welding, cutting, grinding, brazing and torch-applied roofing). Additionally, the FM Approvals laboratory has been testing products and studying methods that can prevent those threats from happening when they are partnered with a solid hotwork management program.

The study found that hot work-related disasters reported to FM Global averaged nearly $2 million per incident; since 1993, cutting or welding torches caused three of every four such incidents. Another disturbing trend: The risk of fire at commercial and industrial facilities can more than double when outside contractors perform unsupervised hot work. During the past two decades, contractors have accounted for nearly 75% of hot-work blazes at FM Global-insured properties.

In most cases, hot-work fires occur when companies, their employees or contractors fail to follow proper hotwork safety guidelines. Those who perform the hot work aren't necessarily irresponsible; they simply are human and are bound to make mistakes, or they aren't aware of the hazards or the steps that can prevent property loss. Sometimes, they're lulled into a false sense of security, especially at facilities where hot work is conducted routinely.

Sparks and molten slag from cutting and welding can, of course, easily ignite combustible materials located below or near hot-work areas. But hotwork hazards aren't always so obvious, even to seasoned professionals. Hotwork residue can fly or roll long distances, igniting combustible materials, such as insulation, wood particles or flammable liquid vapors. Sparks also can settle in areas not easily seen smoldering undetected for hours before finally igniting a blaze. Examples include the tops of high ledges or inside vents, recessed walls, floor openings or ceiling openings.

Combustible material isn't even always visible. Cutting into metal walls, for example, can ignite the insides of walls or anything close by. Flammable deposits, such as vapor or invisible gas, can spark a fire or explosion. Poorly maintained hot-work equipment, such as hoses or connections that leak gas, is another prime culprit.

Before starting any hot-work job, contractors and their clients should discuss the planned project completely, including what the clients' hot-work management policies and regulations are. A signed contract should include language stipulating that contractors adhere to the company's hot-work policies.

Contractors also can take their own steps toward prevention. The first is something that we call "the hot-work 35-ft. rule" — clearing combustible material from any area within 35 ft. of the hot work. Other crucial steps include:

  • Shielding combustible flooring with wet sand, FM Approved hot-work blankets/pads or sheet metal;
  • Cleaning up the area, especially of oily deposits and trash;
  • Covering or shielding any storage (or other combustibles that cannot be moved) with the aforementioned hotwork blankets or welding curtains;
  • Blocking off any duct openings to prevent sparks from traveling to other areas or to ignite deposits/ linings within the ductwork;
  • Covering or filling any openings in exposed walls, flooring and ceiling with noncombustible materials or FM Approved fire-stop material;
  • Relocating any movable combustible material;
  • Cleaning dust and deposits outside and inside enclosures and ducts;
  • Providing the hot-work blanket under the work area if hot work is being performed at elevated locations such as building frames, ceilings or the undersides of roofs;
  • Closing all doors and fire doors;
  • Checking for significant gaps under doors or along their sides to prevent sparks from getting through and igniting combustible material outside the hot work area.

Another alternative is to designate an area devoted exclusively to hot work, assuming the items being worked on can be moved into this area. Then, isolate the area from the rest of the facility with noncombustible screens or partitions. And never ever let that area be used for temporary storage.

Welding pads, welding blankets and welding curtains that meet FM Approvals' Approval Standard 4950 (a testing standard for hot-work protection products) are now entering the market to help prevent disasters.

Devastating hot-work fires are preventable. But prevention requires twoway communication between contractors and facility managers, diligent adherence to safety precautions and proper use of quality products.

Mark Blank is chief engineering technical specialist for FM Global. He is the author of the FM Global Property Loss Prevention Data Sheet No. 10-3 (Hot Work Management) and is a member of the National Fire Protection Association.