Since our last installment of the Apparatus Architect covered the importance of carrying the appropriate compliment of ground ladders on aerial apparatus we thought that the equal time should be devoted to having a discussion on hose loads on engine companies. Much like the quint aerial has gained acceptance for truck company service, many departments have acquired multi-purpose rescue engine units in an effort to carry additional tools and equipment. Unfortunately, in an effort to package the necessary equipment, hydraulic rescue tools, ground ladders and hand tools results in a much higher hose bed than was initially anticipated. Some fire departments go to final inspection and do not even regonize their own truck.
A fire department recently placed into service a new pumper equipped with a 1000 gallon water tank that was designed to carry the normal compliment of engine company tools. During the design process the committee decided to specify an L-shaped water tank with the thought that this could lower the height from the ground to the bottom of the hose bed making hose line advances safer and easier to accomplish. Many apparatus manufacturers do not detail or specify this dimension on their blueprints so departments may be surprised when they measure the hose bed height during the final inspection to learn that the combination of features that they asked for resulted in a less than satisfactory arrangement.
A number of large departments including Atlanta, District of Columbia, Milwaukee and New York City have employed bulk style water tanks which resulted in the hose bed being down at the level of the chassis frame rails. With a 500 gallon water tank this enabled personnel to back stretch from the apparatus while safety standing on the rear step. While the NFPA 1901 Standard permits the use of folding steps and other devices to access the hose bed area some body configurations can result in very difficult maneuvers to gain access to the hose bed areas and can become a safety concern.
For this reason some departments have favored the use of crosslay or speedlay hose beds for preconected attack lines. Depending upon the space required for pump panel controls and equipment storage above the fire pump this configuration may provide an alternative to having all of the required attack lines loaded in the rear of the apparatus. Careful consideration must be made to insure that these hose beds are located no more than 64 to 66 inches from the ground and can be easily repacked when pulled. On many custom chassis apparatus the combination of the diesel particulate filter and other exhaust system components can impact the running board step surfaces on the right side of the vehicle. Additionally engine company units which are equipped with multiple transverse hose beds must continually train to leave sufficient space in front of the structure to allow adequate room to position the aerial apparatus.
When developing specifications for transverse hose beds details should be provided to call out the required clear height and width of each hose bed and the type of nozzle that will be used on the attack line. Some departments have been dismayed when they determine that their nozzles with pistol grip style handles do not fit into the available space. The type of crosslay cover and netting on the exterior of the hose bed can also impact how you might load your hose and the steps needed to rapidly deploy these lines. While a minor point in the overall construction of the apparatus these areas should be covered in detail during the engineering conference prior to the construction of the apparatus with the manufacturer.
Moving around to the rear of the apparatus is where there are many options for ground ladder, hard suction hose and long tool storage. All of these impact the shape and height of the water tank which ultimately impacts the hose bed area. At one time the standard water tank configuration was T shaped with some portion of the tank located over the center, rear step compartment. Over the years as more departments desired to carry electric reels and hydraulic rescue tools options were created to have higher and deeper rear compartments that would accommodate a variety of these tools. The result was the water tank became shorter and the hose bed floor was higher from the ground.
The next evolution of body design came with the development of poly water tanks that could easily be made in any configuration to accommodate ground ladders enclosed either within the body or the tank itself. Rear body compartments for hard suction hose, pile poles and other tools all require space which impact the working height in the rear hose bed. So while many of these options sound plausible in an effort to enclose all of your equipment in the end the hosebed height suffers which will now require additional body steps to access these areas.
You may have heard the expression “no two water tanks are alike” from the apparatus sales person due to the innumerable options that drive booster tank configurations. The L-shaped water tank which can provide for a lower hose bed height works well with 500 to 750 gallon size tanks. Larger capacity tanks because of overflow requirements and the height of the upper portion of the tank often do not provide the same results as the smaller size tanks. An often heard complaint of the L-shaped water tank is that when all of the supply line is loaded the top of the layout hose is about as the same height as you have on your current rigs. Most manufacturers once they are provided with the details of the type of hose and dimensions can calculate where the top of the actual hose load will be within each hose bed.
Departments that operate with having all of their attack lines loaded in the rear will require multiple 2.50 inch or larger discharges for each line in order to avoid having to rely upon a gated wye or water thief. Doing so makes good sense however each of these discharges will require a separate sleeve through the water tank which impacts the height of the water tank. You don’t have to travel far to hear stories of personnel who were injured when climbing onto an apparatus or slipped and fell off the step area during an incident. It’s one thing to get everything that you want on the apparatus and have it built by someone, it’s another to have done your homework and be assured that what you are asking to be built is safe and will enhance and improve your engine operations on every call.
When developing specifications for new pumpers take the time to measure your existing apparatus which can be used as a point of reference for any discussions. The height from the ground as well as the width and length of each bed should be determined which can then be utilized to confirm that the configuration of the new apparatus hose bed area will work out. This effort should be made prior to signing of the contract with the manufacturer with all of the critical dimensions called out including the height from the ground to the bottom of the hose bed once the vehicle is fully loaded. Perhaps you should ask that these dimensions should be noted on your blueprint.
The stepping surfaces and associated hand rail locations then may be determined based upon actual use rather than relying upon a standard placement for these components. Where possible fixed steps or access ladders should be specified for access to the top of hose bed to rack hose and for maintenance. When properly designed any attack line or leader line should be located so that personnel can stretch and advance the line without having to climb onto the apparatus using fold down or auxiliary steps. The rear step where possible should be at least 14 inches deep and provided with an aggressive non-slip surface and made at least as wide as the hose bed.
The hose bed area on any engine apparatus is the real working end of the unit and careful consideration should be made to design safety and efficiency into this often overlooked area. We often hear the expression “It didn’t look that big on the drawing” from departments during the initial phase of a final inspection. As brother Tom always says “every fire truck ever built fit on a piece of paper. Paying attention to the small details when laying out the hose bed configuration will pay big dividends when you place the new engine into service.
From Mike and Tom have a very Happy Healthy and Safe New Year.
Photos for use in Apparatus Architect-January 2014
#1. The Bay District, Maryland Fire Department Engine 91 carries 1000 feet of 3.00 inch, 1000 feet of 4.00 inch supply line together with 3.00 inch leader line and two attack lines with a 750 gallon L-shaped water tank. Note the rope lines attached to the supply line beds so that personnel do not have to climb onto the rear step.
Photo by Tom W. Shand
#2. The Hollywood, Maryland Fire Department designed their Engine 72 with a 750 gallon water tank with two 2.50 inch rear discharges and a 5.00 inch rear inlet. Note the fixed access ladder at the left side of the body.
Photo by Tom W. Shand
#3. This pumper from Tappan, New York has the ground ladders stored under the hose bed. When combined with a 500 gallon water tank the hose bed remains at a reasonable height.
Photo by Tom W. Shand
#4. Engine 32 from the Progress Fire Company in Pennsylvania is an excellent example of a low hose bed unit carrying multiple rear attack lines together with 1100 feet of 5.00 inch supply line.
Photo by Tom W. Shand
#5. The Woodstock, Virginia Fire Department operates Wagon 12 which carries split beds of 4.00 inch supply line together with three other beds for static hose and a step board gun. Note the use of fixed steps at the left side of the body for access into the hose bed
Firehouse Magazine Apparatus Architect
BY Tom W. Shand and Michael Wilbur