Lloyd Layman’s Theory: Its Time Has Come and Gone
Departments
Gene Carlson’s Volunteers Corner
Lloyd Layman is known as the father of the tactics scheme used either entirely or in part by most fire departments in North America. In addition, his concepts on fire extinguishment revolutionized water application in fire suppression.
Chief Layman began his work during World War II when he was commandant of the United States Coast Guard Fire Fighting School at Baltimore, Md He later adapted what he had learned about the indirect application of water to structural fire fighting while chief of the Parkersburg, W Va., Fire Department. His theory, termed the theory of indirect application and atmospheric displacement, assumed that “the cooling action of water, applied in the form of finely divided particles at the upper level within a highly heated confined space, is not limited to the immediate area”
From Layman’s exeriments the popular indirect method of attack was born. It soon became the popular way to handle a structural fire: stretch a small line up to the window and begin discharging water into the superheated atmosphere at the ceiling level This was not a difficult procedure to sell in the late 1940s when little self-contained breathing apparatus was available and the level of protective clothing was far from that available today.
Misunderstood: Many people did not accurately understand Chief Layman’s theory. His contention was that a fog stream could be introduced at one location for confined fires with a very high heat buildup, but mult pie fog streams would be necessary at several locations with unfavorable conditions of confinement to quickly extinguish the fire.
Fire departments soon paid little attention to the necessity of confinement of the fire and immediately initiated an indirect attack through the most convenient opening. With this misapplication of the principle, disastrous results can occur Since the attack is to start at the area of major involvement, if the fire is not confined internally, for example by a closed door to the room, the heated products of combustion and smoke along with the fire can be driven throughout the structure. This is especially true if there is a reduced water application rate due to the use of small streams.
With the susceptibility of building structural members and contents to heat damage, this would be an unsatisfactory attack. It could also seriously limit the rescue of anyone ahead of the fire if these superheated, toxic gases were driven into their location.
Getting inside: Today Chief Layman’s theory is dead. Progressive, well-trained fire departments realize that more efficient fire fighting can be done by getting inside the building ahead of the fire and cutting it off from other rooms or sections. The spread of the fire must be positively confined – merely hoping that it is confined when the attack is initiated is not sufficient. Internal exposures can be protected and heat damage reduced by an inside attack coordinated with good ventilation practices that enables the fire, heat and smoke to be driven out of the building, not in.
Since the smoke is removed by venting, there is much better stream application due to the improved visibility. Since there is no longer a. fire fighter using a window (with steam or heat blowing out) for an indirect attack, one can see where to direct the 30-degree fog stream for the best results.
There is less water used since the nozzle can be shut down as soon as the fire darkens. The attack team can move in quickly and extinguish remaining spot fires with intermittent use of the partially opened nozzle. And a rapidly initiated interior attack enhances rescue —by placing a line between the fire and those in need, by driving toxic gases out and by maintaining good visibility for the search team.
Need protective clothing: In order to perform an efficient interior attack, fire fighters need to use their protective clothing properly: earlaps down, collars and boots up, adequate gloves on and positive-pressure self-contained breathing apparatus in use. They must place the first lines to cut off the fire and keep it from spreading. This requires crawling in and not using the nozzle until the fire is seen, then using a combination of direct and indirect attack to quickly knock down the fire. Ventilation of exterior openings or the roof must be coordinated with the attack.
In many fire departments the procedure for positioning the attack is to meet the fire head-on. Many fire fighters believe that if fire is coming out of a window or door they must go in that opening with an attack line. In most cases this is not a good attack position because it only serves to push the convection currents and smoke farther into the structure.
A much better course of action is for the officer in charge to make a size-up of the avenues of fire spread and place lines to cut off this spread. As stated above, in Layman’s original theory the attack in unconfined fires should be made from more than one location. With the present manpower situation this is normally not possible. Thus, the first line must be placed to achieve the most effective property and life protection. Also remember that a nozzle discharged on smoke does not put out fire and can upset the thermal balance, delaying extinguishment.
Application rate: For fast knockdown of a fire, the rate of application of water must be adequate to absorb the heat being generated. As the fire area becomes larger, the attack line must have greater capacity. Large fire areas or potential fire areas will require a 2-inch or 2 1/2-inch line as a minimum. The line should be used long enough to blacken down the fire, but then shut off and used as necessary for the remaining pockets of fire.
A ventilation-coordinated interior attack by properly protected fire fighters will reduce the fire, heat, smoke and water damage at your next alarm. Although an indirect application of water to a highly heated ceiling area brings rapid steam generation for extinguishment, this exterior attack proposed by Layman may not lead to confining and limiting damage. Interior fire fighting pays dividends in many ways but especially through a reduction in fire losses.
