As fire protection engineers and consultants, we have seen some pretty interesting (and dangerous) things! When contractors are on project sites day after day, working with the same types of equipment again and again, it can become easy to allow the mind to slip into auto-pilot, which then opens the door for some potentially harmful mishaps. Here are a few examples of incidents that we have seen that can happen to anyone!

Getting Lucky

During one of our fire protection consultant’s last site visits, he encountered a scary event during the final preparations for an electric fire pump test. When our consultant arrived on site to witness the test, the electrician was completing the electrical connection to the electric driver and buttoned up the motor junction box. The pump vendor energized the controller, and then pressed the start button. There was an immediate and very loud bang as one of the motor conductors grounded out against the motor junction box! The controller tripped and killed the power, which protected the microprocessor. The electrician added more electrical tape to further insulate the junction of the conductors, and the motor started and ran without incident. The pump vendor mentioned that in similar events, he has seen the junction box cover be blown clear across the pump room! In the incident we witnessed, we were lucky that it just resulted in a very loud, and very scary noise!

On another occasion, one of our fire protection engineers was standing behind a contractor, looking over his shoulder, as the contractor was working on the controller for an electric motor-driven fire pump. Suddenly, a small electric arc flash occurred inside the motor controller. Fortunately no one was injured, but this was a close call.

Chain Reaction

A few months ago, one of our fire protection consultants witnessed a nearly tragic series of events. He was at a job site to witness the underground flushing and a fire pump acceptance test. One employee of the sprinkler contractor was preparing the sprinkler risers for flushing, while another prepared the fire pump suction piping to flush through the test header. When they opened the valve, hardly any water came out. So, they opened the bypass, and only got a trickle.

Meanwhile, back in the pump room, water was running across the floor and coming in under the walls! And, in the warehouse, an open 8-inch pipe was flowing thousands of gallons of water into the building. It covered nearly 100,000 square feet in a couple of minutes and continued to flow out of the building through various door openings for several hours.

When the water was turned off, the relief port of the backflow preventer continued to discharge water full bore. Once opened, a large piece of concrete was found stuck in the primary check valve. The underground foreman reached in the check valve to free the debris when the check valve snapped closed on his hand! The only thing that saved his fingers was the crescent wrench he was poking the debris with. Our consultant was able to find a long pry bar to help free the foreman’s hand.

The underground foreman then dismantled the valve, cleared the debris, and reassembled the valve. Or, so he thought. When he opened the city valve, there was a deafening bang that sounded like a gun. The top of the backflow preventer shot sky high, 30 feet at least! Thankfully, it landed without hurting anyone.

On another occasion, also inside a fire pump room during an acceptance test, one of our consultants was struck on the knee by a pipe end cap that blew off because it was improperly installed. Fortunately, the injury to the knee was only bruising and not more serious.

These are just a few reminders that sometimes, good intentions can lead to accidents with the potential of serious injury. It’s easy to become complacent and it’s important to take your time to dot every “i” and cross every “t”, and to make sure that job sites and work processes are safe.

Tell us….What types of mishaps have you seen on the job?