Ductwork Fire Dangers

BY MICHAEL N. CIAMPO

Over the course of the years on this job, you’ll run into many odd jobs, to say the least. Between the type of fire, building construction, alterations, and modifications, you might be behind the eight ball prior to even arriving. Pulling up to any establishment with a commercial kitchen and vent hood with ductwork that’s caked in grease is surely one of those situations. Knowing your rig’s entire inventory, from power tools to various types of fire extinguishers, is of utmost importance when you’re operating at such jobs. Keep in mind that most of us have to follow specific building codes and regulations, but the federal government doesn’t always have to be 100-percent compliant, so be on your toes when responding to one of these occupancies, and don’t expect the building to follow all the rules that typical construction and occupancies have to follow.

Responding to a federal office building for an automatic fire alarm is somewhat of a common response for many units. Many of us might be sizing up that someone burned some food in the office microwave and it set off the smoke detector or the fire alarm company forgot to take the system offline while maintenance was being performed. Normally, we arrive and head to the building’s fire alarm panel to find security waiting to give us an update, but there will be times when they’re waiting for us on the sidewalk as we pull in. Whether it’s to tell us it was set off in error or there’s a problem inside, we should still get off the rig and investigate. There have been times that something occurred such as a construction worker created a small fire and extinguished it and security would just like to keep us out of the way. Plus, it’s our job to ensure the system is reset, online, and operational once the alarm has been transmitted.

As we pulled into this federal building, security personnel informed the officer that smoke was issuing from the ductwork up on the maintenance and attic floor; we followed them into the building. There were separate elevators for maintenance to use, which offered access to this isolated area. Security still had personnel on the floor who radioed information back to our chaperone that the smoke was still issuing moderately from the duct but there were no signs of fire. The officer was asking the guard if maintenance was on scene and up in the attic waiting for us.

As we arrived, we noticed the standpipe connection was just outside this elevator lobby, in the stairwell, and the engine began to check it out for serviceability. We met the maintenance personnel and immediately asked them if the duct issuing smoke was a grease duct or from a heater/air-conditioning (AC) unit and feeding specific floors or spaces. They said it was an AC duct, but they had been to the roof and checked the units and none were malfunctioning, on fire, or had motors overheating. 

We began our trek through this solid concrete attic with eight-foot-high ceilings and no windows; the nasty taste of smoke began to reach us, and it became a bit heavier than just a haze. The maintenance workers pointed to the direction of the smoking duct and said it was about 40 feet down after we make a right-hand turn. Masking up to avoid the pungent odor of the smoke, we headed in that direction as they went back to fresh air and the safety of the lobby.

We proceeded down the hallway; the smoke began to get a bit heavier, but we still had good visibility below the thermal layers. The ductwork’s construction was mostly solid, but some smoke was pushing around the seams. Farther down, we noticed a smaller air vent register/grating had flames beginning to issue from it.

As the engine hooked up to the standpipe outlet and advanced the line, the duct’s grate was pulled down, and burning dust and lint particles began to emit from the opening. As the line approached, it was flaked out and then charged. We hoped that the water stream would penetrate into the duct and extinguish the dust fire inside. 

The nozzle firefighter opened the line and directed it toward the flames and opening. Within seconds of the water hitting the duct, a lightning bolt followed the stream back to the nozzle and threw the firefighter off his feet and backward onto the floor. Arcing and flashes of different colors were now over our heads, and things suddenly went from “We’re in control” to “What the heck was that?” All eyes focused on removing the injured member; a few firefighters immediately grabbed him and dragged him past the turn in the hallway to better access his injuries. His gloves and the soles of his boots were smoking, and he was semiconscious; we knew we needed to get him to the hospital. Luckily, in the attic hallways, we came upon a rolling desk chair and were able to take his air pack off and begin pushing him to the elevator and, once in the lobby, to an awaiting ambulance.

After the fire was extinguished with dry chemical extinguishers, fire investigators were requested to find out what exactly was going on inside the ductwork. The investigation found that electrical wires were snaked through the ducts and their casing must have been cut into and scraped off when pulled and exposed to some sharp metal inside the duct. Some wires were welded together and their protective casing burned off where the water was introduced and in other areas. Unfortunately for us, we weren’t aware of this practice inside this occupancy; but, as a “probie,” it is one that will stick with me throughout my career when operating around ductwork.


MICHAEL N. CIAMPO is a 33-year veteran of the fire service and a lieutenant in the Fire Department of New York. Previously, he served with the District of Columbia Fire Department. He has a bachelor’s degree in fire science from John Jay College of Criminal Justice in New York City. He is the lead instructor for the FDIC Truck Essentials H.O.T. program. He wrote the Ladders and Ventilation chapters for Fire Engineering’s Handbook for Firefighter I and II (Fire Engineering, 2009) and the Bread and Butter Portable Ladders DVD and is featured in “Training Minutes” truck company videos on www.FireEngineering.com.

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