Apparatus Architect: How Tools, Equipment & Compartments Figure into the Most Efficient Design of Heavy Rescue Rigs

Fire departments operate a variety of special service vehicles to support fireground, technical rescue and hazmat operations. Depending on the community demographics and the hazards that are in the response district, the size of the special service apparatus, the equipment cache and the department’s staffing models affect the service delivery for these assets.

There’s different terminology for these special service vehicles depending on past practices and, in some cases, as new technical rescue resources are brought on board. Most commonly, these rigs, regardless of size and operational mode, are referred to as rescues or rescue squads. Whatever the local terminology dictates, these units enhance the department’s capability to carry equipment resources that are beyond the capabilities of engine and ladder company units. Although not every department requires this type of apparatus—along with the enhanced training that’s required to operate the equipment—resource planning should be accomplished to have this level of expertise available, even if organized on a regional level.

Larger not always better

Because of federal funding that became available after 9/11, many departments developed technical rescue teams that include vehicles and equipment that were made available with a subsequent increase in the number of heavy rescues of all sizes, including semitrailer units. Departments that have previous experience with operating heavy rescues have an advantage based on their experience with the equipment that must be carried to meet the mission and how the overall size of the vehicle affects the capability to safely access the response area and position for optimal use at the incident scene.

Historically, the apparatus industry developed some standard body designs based on the length and height of the rescue body for both walk-around and walk-in heavy rescues. Because of the amount of equipment that’s desired to be carried, along with the weight and staffing levels for these special service units, tandem-axle rescue apparatus have become more prevalent. Although this “bigger is always better” philosophy works in some cases, the larger apparatus still might not provide the appropriate size and compartment configuration to meet a department’s needs without careful planning.

More than ever, apparatus committees must evaluate the service needs of their first-due area and temper this with some practical application of situational awareness to provide for a well-designed apparatus. With many communities introducing traffic circles in lieu of signal-controlled intersections, the maneuverability of the apparatus, including the angle of approach and departure, is an important consideration during the design process.

Equipment measurements

NFPA 1901: Standard for Automotive Fire Apparatus addresses heavy rescue and squad vehicles in Chapter 10 and provides for an equipment weight capacity of 10,000 lbs. for vehicles that have a gross vehicle weight rating of more than 60,001 lbs. This payload allowance is a minimum, which requires a department’s apparatus committee to determine its requirements for tool and equipment storage along with a detailed inventory of the equipment, including dimensions and weights for each item. This information must be shared with the prospective apparatus manufacturers to determine the appropriate front- and rear-axle ratings that are required to accommodate this equipment. It might be helpful to have the prospective manufacturers provide the members of the apparatus committee with shipping weights for completed vehicles, which would indicate the front- and rear-axle weights on the vehicle, prior to mounting of the department’s equipment. These weight tickets are invaluable to the process of assessing the available payload that can be carried on the apparatus and to determining whether the proposed chassis components are adequate to safely carry personnel and the desired tool and equipment payload.

The size and configuration of technical rescue equipment are critical, because the manufacturers’ standard compartment dimensions might not account for the space that’s required for slide-tray and tool-board clearance with equipment that’s mounted on these devices. Some specifications state overall compartment dimensions in inches for the height, width and depth of each area. These numbers might not take into consideration the loss of height because of headers, the roll-door shutter or the clear door opening of hinged doors. Likewise, the depth of each compartment both on the interior and exterior should be verified with the door in the closed position.

Tool layout

After the particular compartment dimensions are established, you can begin to lay out your tools and equipment within each compartment for an initial run. Many manufacturers and equipment-mounting companies can provide a computer-aided design (CAD) drawing for each area that’s within the compartment body. These CAD drawings can be of great assistance to determine ahead of time that your proposed tool/equipment and compartment layout will work once the body fabrication is completed.

Another technique that can be accomplished in the fire station is to mark out each surface area (e.g., adjustable shelf, tray or wall) on the apparatus bay floor with tape and locate the desired equipment within the space. Documentation of this work should include digital images and a listing of the appliances and equipment for each location.

Weight analysis

Prior to contract, the department should require bidders to provide a detailed weight analysis on the apparatus to include all of the fixed and portable equipment that would be supplied by the department. Projected weight should be verified at the final inspection. If sufficient equipment weights aren’t available, sand or shot bags should be loaded onto the apparatus to simulate the missing equipment.

Prior to final acceptance, the completed and fully equipped vehicle should be weighed, including personnel, on a certified scale to validate the rig’s in-service weight.

Plan accordingly

Designing a new heavy rescue/squad is a detailed and time-consuming process. It requires the apparatus committee to review the department’s staffing and deployment practices as well as to confirm the required tools and equipment that will meet the operational needs of the department for the planned life cycle of the apparatus. Heavy rescues that are cross-staffed by multiple companies often provide different specialized technical rescue missions compared with units that are staffed constantly and operate to perform multiple missions, including truck company functions, vehicle extrication and support functions on the fireground. In either case, the personnel who operate the rigs must be trained to provide the appropriate level of services to meet the defined mission of the unit.

There are many influences on the design of heavy rescues, compartment configuration and interior body layout that, ultimately, determine which style of rescue body is the appropriate one for a department. The time spent upfront in researching equipment needs, visiting other departments to gain from their experiences and defining the mission for the apparatus will pay off with a well-designed apparatus. Plan accordingly. You only get one chance to make the correct choice.