A cost-effective alternative is to plumb the rear pre-connects directly off the pump at the front of the hosebed. This provides for rear pre-connected hose loads, at a lower cost, with greater hydraulic efficiently, eliminating maintenance concerns and keeping the hosebed within reach of firefighters.
These factors, together with the size of the booster tank, all have a direct impact on the height of the hosebed at the rear of the pumper. The FDNY has used 500-gallon water tanks on its apparatus for a number of years, with several engines that are remote from water supplies on Staten Island being equipped with 750-gallon tanks. These units are equipped with L-shaped tanks that provide for a lower hosebed at the rear of the body. These hosebeds are approximately 56 inches from the ground, which makes stretching attack lines both safe and easy.
Consider a standard pumper equipped with a 750-gallon booster tank with a hosebed with four bays, including a bed of 1,500 feet of large-diameter hose. Using an L-shaped water tank with a standard rear compartment can provide for a hosebed that is 62 inches from the ground. A firefighter standing on the rear step can look down into the hosebed to grab the nozzle and hose folds prior to advancing the attack line. A pumper equipped with the same 750-gallon booster tank in a T-shape design with a large rescue-style rear compartment will have a hosebed that is 78 inches from the ground. While standing on the rear step of this apparatus, you will probably have to ascend another fold-down or fixed-style step to reach the hosebed to stretch the attack line.
Now imagine a pumper equipped with a 1,000-gallon T-shape water tank with a large rear compartment and a five-inch rear suction. The hosebed on this apparatus is somewhere around 90 inches in the air and once you get onto the rear step, you have to climb two or more smaller steps to even reach the hosebed. Is it any wonder that a high number of firefighters sustain injuries while climbing on or about apparatus during the year? Who is to blame for this situation?
If you attempt to combine a lot of features into one apparatus, you will generally improve in some areas while adversely impacting others. Looking at the current trends in engine company apparatus design would lead you to believe that present-day firefighters are as tall and agile as basketball players on the fireground. Unfortunately, one of the basic missions of the engine company is compromised because we cannot safely and effectively lay a supply line and stretch attack lines without getting some of our personnel injured.
Properly designed engines should be capable of deploying their rated pump capacity through pre-connected attack lines and master stream appliances. If your department determines that a combination of crosslay and rear hosebed attack lines is beneficial, then consider locating the shorter lines, such as 150-foot or 200-foot-long lines, in the crosslays with the longer lines coming off the rear. Whenever possible, the lines should be loaded to enable one firefighter to stretch the line without having to climb all over the rig searching for the nozzle.
Attack lines that are loaded in a shoulder load or minuteman configuration allow personnel to advance the line without having to climb on the apparatus and makes it easier to deploy the line. Longer attack lines or leader lines coming off the rear are much easier to advance, particularly when the engine has pulled past the building to leave the front open for the truck or special service apparatus.
If high-capacity handlines capable of flowing 500 gpm or greater are required, then consideration should be given to using a minimum of three-inch piping and valves for these discharges. Special appliances such as hydrant valve, manifold or portable guns which are mounted at the rear should be located so that personnel can deploy them without having to climb on the apparatus. Also, they should be positioned so that these devices do not inhibit standing on the rear step when required during handline stretches or packing hosebeds.
In the next installment of "The Apparatus Architect" we will wrap up our discussions on the engine company with some examples of well-designed apparatus and how they improved department operations.