Shutdown & Out

Know how to combat the effects of mask shutdown

Imagine donning your facepiece and entering the fire area to conduct a search for a confirmed report of people trapped. You’re crawling on your knees, navigating the structure by hugging the left wall for orientation. The structure is filled with black, hot, acrid smoke, and the visibility is zero. Your heart pounds. You know you’ll have a limited time to conduct your search, and the survival of those trapped depends on you locating them—fast.

The fire is located in a rear room on the first floor of a two-story, wood-frame, private home. The engine has stretched the line and is awaiting water so they can enter the building and proceed with fire attack.

Photo Michelle French

After a few moments of searching, you locate the stairway and navigate your way to the second floor. You arrive at the top of the stairway and, without warning, the facepiece of your mask squeezes tight to your face and you quickly realize that you’re not receiving air. It’s starting to get hotter, but you can hear the engine applying water on the fire.

Do you panic? Hopefully not. Although you likely feel uncomfortable, if you’ve trained on mask emergencies—which I’m sure everyone has—you should have no problem getting air to your facepiece.
           
Mask Shutdown
So what happened? You’re positive you checked your mask prior to the start of the tour, and it was working properly. Why did you stop receiving air after operating for some time? The answer: mask shutdown. Mask shutdown occurs when the cylinder valve is not fully opened. If the cylinder valve is not completely open, you’ll initially receive air and then you may or may not continue to receive a free flow of air.

Step 1: Rotate the purge valve; air should start to flow into the facepiece.
Step 2: Notify your officer or the incident commander (IC) that you’re leaving the fire building due to a malfunctioning mask.
Step 3: Make sure you leave with the area with another firefighter to ensure you can exit the building safely.
Step 4: After exiting the building, notify the IC that you’re safely outside.

Mask shutdown is a rare occurrence, but for some reason, it usually happens at a bad time. I experienced this problem while trying to escape from imminent flashover very early in my career. Lucky for me, I found an area of refuge until the brothers could locate me and assist me out of the building. I didn’t receive any serious injuries, but the incident opened my eyes to the dangers involved in this profession.

Mask Usage Tips

• Always fully open the cylinder valve, both when checking your mask and prior to operation.
• Never enter a contaminated area with a malfunctioning mask.
• If activating the purge valve for a mask emergency, immediately notify your officer or the IC, and leave the fire area.
• When exiting the fire area, always leave with another firefighter.
• Inhalation of smoke can decrease lung capacity and may inhibit your ability to exert enough force to activate the air flow to the facepiece. This is why you should always don your facepiece prior to entering the fire area.
• Activation of the vibralert alarm does not indicate that the cylinder valve is completely open.
• Failure to fully open the cylinder valve will restrict air flow and may cause mask shutdown.
• Exposure to two to three breaths of carbon monoxide (CO) can cause unconsciousness and possibly death. CO causes disorientation and inhibits one’s ability to make sound decisions. It can also cause a feeling of calmness that can prevent you from accurately assessing the risks around you.

Stay Safe
The mask may be the most important tool a firefighter uses and, as such, we must conduct mask-related training on a regular basis. The procedures described in this article may help to avert serious injury or death.

Chief Fred LaFemina is a 23-year veteran of the New York City Fire Department (FDNY), presently serving as a battalion commander for Rescue Operations Battalion #1. He has been with Special Operations for more than 19 years and is the task force leader for New York’s Task Force 1 Urban Search and Rescue team. He is also the operations chief on the USAR IST White Team. LaFemina has written many articles on fire operations and technical rescue and lectures throughout the country. He is a technical editor of FireRescue.