LETTERS TO THE EDITOR
Safe ladder positions
I find your magazine very informative and accurate. However, in the January 1990 issue I noticed an error that I had seen once before. In the article “Safe Firefighting Practices,” Vincent Dunn says that when you suspect a building collapse, you should position an aerial ladder’s nozzle tip a distance from the building equal to the height of the building above the nozzle tip. This same statement was made in an article on building collapse that I read in Fire Engineering two years ago.
In addition to the rule for aerial equipment, a rule for ground personnel and equipment was also stated. This rule said that ground personnel should be positioned as far from a building (one suspected of imminent collapse) as the building is high. The rationale for this rule is that in the worst possible case the entire wall can fall over in one piece. If this happens, it will crush everything in an area as wide and as long as the wall is high and wide. This rule works well to ensure that ground personnel are outside the collapse area. However, the rule for aerial equipment is incorrect and will provide a false sense of security.
The aerial rule defines a danger zone that is the shape of a triangle. In effect, by this rule, the aerial may not cross an imaginary line that connects the top of the building and boundary for ground personnel. Assuming the same worst-case condition as was applied for ground personnel, the top of the wall will follow a circular path as shown in Figure 1. Figure 1 also shows the danger zone as described by the rule. Clearly, an aerial that strictly follows Dunn’s rule is in danger of being struck by the falling wall. For a building that is 30 feet high the aerial could be struck by as much as the top 8 feet of the wall. The danger zone described in the article is incorrect: Its limits should be the path of the falling building as shown in the figure, not the height of the building above the nozzle tip.
Unfortunately this is not enough to judge the safety of the aerial. By Dunn’s rule, an aerial that has its nozzle tip above the top of the building should be safe, but as Figure 2 shows, a falling wall could strike the aerial somewhere in the middle. It is important to make sure that the entire aerial is ouside the danger zone as described by the arc of the falling wall. This may not be so easy to do.
One way to ensure that the aerial is outside the danger zone would be to specify the angle of the ladder. This angle would be a function of the height of the building and the distance that the truck is from the building. In general, the farther the truck is from the building, the flatter the ladder could lay.
Defining the ladder angle may not be an easy task. However, some method for ensuring the safety of aerial equipment must be developed. Dunn’s rule is easy to implement, but we must understand the inherent dangers involved; the rule does not safeguard against a worst-case collapse. Even in more common collapse situations, Dunn’s rule may prove to be inadequate. At this point the fire service must establish an adequate level of safety and an easy-to-use method to implement it.
Michael von KannewurfF
Middlebury, Connecticut
Forming a rope rescue team
The Emergicare Rescue Team, a division of Township Fire Department, Inc., is in search of information and recommendations from fire departments that have aerial and rope rescue teams. We are in the process of forming a team to perform both rescues and recoveries.
Our rescue group covers a fivetownship area and provides mutualaid responses to surrounding areas. We have experienced only a few instances that required rope rescue techniques but feel that developing and training a rope rescue team will be a great asset. We will be looking to provide a quick and efficient service to victims of trauma, trapped victims, and other instances that require rope rescue techniques. Our geographical and structural features will include some tall buildings, silos, towers, grain bins and lags, miscellaneous structures, and steep land inclines.
The team will consist of approximately 16 to 24 members. If there are any departments that have experience in the area of rope rescue and rappeling and could provide us with information on equipment, training ideas, innovative ideas for equipment made or used, and other essential advice, please contact:
Michael C. Miller
Township Fire Dept. Inc.
SI0370 Cty Rd. HH/I
Eleva, WI 54738
(715) 878-4914
In advance I thank you for your help and cooperation.
Michael C. Miller
Crew Chief
Firefighting equipment needed
I’m fire chief for the Amble Fire Department, a small rural volunteer department located in Montcalm County, Michigan, about 50 miles northeast of Grand Rapids.
We’re in need of various equipment such as hose, hand tools, nozzles, pagers, and so on. Due to recent repair costs to our tanker and grass truck and trying to keep our pumper going until it can be replaced later this summer, my township can’t afford to get the equipment we need to do a better job of firefighting.
I know that financial hardships are an everyday ongoing battle for fire departments all over. So I’m asking if any fire department has some surplus equipment that it can donate to our department. Any help would be greatly appreciated; please call 616-7624304.
I’ve been fire chief since April 1987, and I’ve been reading and receiving your magazine since that time also. I find that it is an excellent magazine and I’ve learned a lot from the informative articles you’ve had. Please keep up the good work.
Tom Lewis
Fire Chief
Amble Fire Department
Howard City, Michigan
