And when someone calls 911 to report a fire, one of the instructions a good dispatcher will give is “close the door.” The examples are abundant. Hotels are required to have automatic door closures on all guest room doors. The National Fire Protection Association (NFPA) has developed NFPA 105, Standard for the Installation of Smoke Door Assemblies and Other Opening Protectives. The standard addresses the installation, maintenance, and testing of smoke door assemblies and smoke dampers that are used as a means to restrict the smoke movement through openings. The New York Times published an article on November 12, 2012, titled, “A Closed Door: The Best Ally in a Home Fire.” Its source of information was taken from FDNY fire educational material.
|1 A firefighter deploys an air curtain at a live burn at an acquired structure. Air curtains are sheets of flame-retardant fabric mounted to a spreader bar that firefighters can rapidly install in a door opening. (Photos by author.)|
OK, the point is made-close the door! Yet historically, when the fire department arrives, one of the first tasks has been to vent or open up. Does the fire behave differently if the fire department opens the door and creates other openings as opposed to the occupant leaving the building open? Other than a time lapse, of course not. Study after study is showing that ventilation is important, but not until hose crews have applied water or are in position to apply water. As I stated in an earlier column and based on scientific research, never delay applying water-even if it means attacking from the exterior.
|2 Air curtains are advantageous as exterior doors because they provide fire department personnel with a means of keeping a door opening closed without disrupting hose movement. They do not deter a sudden escape by firefighters like a permanent door. In addition, they also provide an indication of air flow direction.|
This all leads to the main point of this month’s column-using portable doors or air curtains. Portable doors or air curtains are sheets of flame-retardant fabric mounted to a spreader bar that firefighters can rapidly install in a door opening. They are advantageous as exterior doors because they provide fire departments with a means of keeping a door opening closed without disrupting hose movement. They do not deter a sudden escape by firefighters like a permanent door. In addition, they also provide an indication of air flow direction. They are also beneficial for interior operations. Many homes have openings from one area of the house to another without a door. Most ranch-style houses have a hallway that, in effect, opens the house from one end to the other. A portable air curtain is an excellent tool for compartmentalizing fire and smoke.
Air curtains are inexpensive and require minimal compartment space and maintenance. As the fire service learns more and more about controlling smoke and fire movement, the air curtain could well become standard equipment on every engine and ladder. At least two manufacturers are already marketing air curtains. SuperVac has patented its air curtain, called the SmokeBlockAid. Tempest calls its air curtain the PathMaster.
It was interesting and encouraging that all the fire science (behavior) courses at FDIC 2014 were packed and overflowing. I arrived at one of the courses ten minutes early and could not get in because the room was already at full capacity. Obviously, the fire service is paying attention to all the research the National Institute of Standards and Technology (NIST), Underwriters Laboratories (UL), Alcohol, Tobacco and Firearms (ATF), and Kill the Flashover (KTF) are conducting.
One presentation, by Adam St. John, a fire research engineer with the ATF Fire Research Laboratory, showed that every fire has a flow path and they are buoyance-driven. He said that the more we vent, the bigger the fire becomes until we add water. He showed that the air flow paths of a fire often travel at eight to 10 miles per hour. He stressed that this is faster than firefighters can crawl or run while wearing PPE. He was able to prove, just as the other testing agencies, that fire cannot be pushed by hose streams. This definitely opposes what has been taught in the fire service for the past few decades. He also stated that fire departments should isolate the fire and smoke as much as possible, remembering that smoke is fuel. Translated-close the door! This underscores the need for the fire service to adopt the use of portable air curtains.
In retrospect, the fire service may have outsmarted itself when it comes to understanding fire behavior and the quickest and safest ways to suppress fire. Portable air curtains are safety devices both for the general public and for firefighters.
ROBERT TUTTEROW retired as safety coordinator for the Charlotte (NC) Fire Department and is a member of the Fire Apparatus & Emergency Equipment editorial advisory board. His 34-year career includes 10 as a volunteer. He has been very active in the National Fire Protection Association through service on the Fire Service Section Executive Board and technical committees involved with safety, apparatus, and personal protective equipment. He is a founding member and president of the Fire Industry Equipment Research Organization (F.I.E.R.O.).