Many fire departments, rescue squads and emergency service responders are providing many more specialized services, i.e., deep resources, than a few years ago. Consequently, many modern fire, rescue and hazmat teams are adding highly specialized equipment to their response inventories.

In some cases, the delivery apparatus is changing to better meet the needs of the operating crews. For example, a trend has emerged in fire-apparatus design where smaller firefighting pump modules are losing popularity in favor of ever-increasing equipment-stowage capacity. In many areas the rise of the rescue pumper illustrates the early manifestation of this capacity-requirement trend.

Apparatus design for emergency service applications always evolves in parallel with the needs and requirements faced in the field. With the service functions provided by many emergency-response organizations becoming significantly more specialized, the subsequent equipment requirements have dictated a contemporary approach to apparatus design. Contemporary deployment options available to purchasers include designs that may at first seem non-traditional but indeed seek to maximize the operating efficiency of the response team.

Trailers and roll-off containers are two examples of such options. The ever-increasing popularity of these designs can be attributed to:

• Required payload capacity;
• Required equipment volume;
• Sustained medium- to long-term on-scene necessity;
• Deployment logistics; and
• Cost.

An important factor contributing to the interest in these types of delivery systems is the final payload and storage size required to deliver deep resources. On a typical two-axle chassis, NFPA 1901, Automotive Fire Apparatus, suggests a payload capacity up to 6,000 pounds based on a 50,000-pound gross vehicle weight rating. Where local laws may restrict the use of a 30,000-pound rear axle in a two-axle configuration, the purchaser must look at either a three-axle straight truck design or trailer configuration.

When trailers make sense

When choosing between the designs of a three-axle straight truck or tractor-and-trailer combination, equipment stowage volume often guides the buyer as he evaluates the attributes and limitations of each design. Tandem rear-axle special-service vehicles are popular in modern fire apparatus design. In many circumstances the evolution of a two-axle special service unit provides the path for consideration of a three-axle apparatus to replace it. It should be noted, however, that the relative popularity and commonality of these units is not the final design answer all purchasers accept.

Trailer-type special-service vehicles offer some advantages worth noting in your design evaluation. Within NFPA 1901, trailers are listed by type. A Type-I trailer is designed to remain connected to the tow vehicle throughout the response event. Total equipment storage volume often is cited as the fundamental advantage of this package. Designing a custom-built-trailer special-service vehicle can provide more storage space than any straight-truck configuration can meet. Maneuverability is deemed to be an advantage in a trailer design once the total equipment stowage need exceeds that which the operating crew can effectively use within the operating environment.

Type-II special-service trailers may be disconnected at the response event. The advantage of this design is that it permits the tow vehicle to be deployed as either a crew carrier or an available transportation resource based on need. The flexibility of disconnecting the special-service package from the tow vehicle permits commitment of equipment resources at a scene with an added flexibility not often available in other designs.

Note that in a Type-II trailer design, all of the subordinate power needs, system functions, water suppression (if equipped) and possible hydraulic system needs must be met with systems attached to the trailer. The tow-vehicle systems are separate from the trailer systems, so they can be operated independently and repaired more cost-effectively

Purchasers considering the use of trailer-type special-service vehicles also must consider driver training as part of the evaluation process. Organizations that do not operate trailer-type apparatus should add the cost and time of quality driver education to their analysis of this design option.

Trailers, by nature of their larger size in some cases, permit the responding organization to bring many specialized systems to the scene at once. In your evaluation this may be the goal. Or, in some cases, it may be the problem. Customized response to a very specific event or need is the domain of the roll-off container.

Roll-off container advantages

If your defined needs require highly specialized responses that are not mutually inclusive — coupled with the potential of long-term on-scene deployment with a dedicated crew — you may want to consider the design advantages of roll-off containers. Often called "pods," roll-off containers permit the delivery of function-specialized equipment and systems to a target location.

An advantage of this design in the special-services application is that it lets the responding team load the proper response pod and bring that exact configuration to the scene. In rapid-completion events, the pod may remain mounted to the host carrier vehicle. Long-term operations can be handled by dismounting the roll-off container to the ground to deploy it at the scene as long as needed. Parallel features between the Type II trailer and the roll-off container exist in that the host or tow vehicle may deliver the first equipment package and then be freed from that duty for transportation, logistics or further deployment activities.

Roll-off containers can vary widely based on needs, budgets and applications. In their simplest forms, there are pods that carry cribbing, shoring and little else to the scene. The materials are stored on shelves and racks within the pods, which are designed to economically deliver the most stored materials to the scene as possible.

Equipment pods are available in 8- to 10-foot lengths up to 24-foot large layouts. Many equipment pods can be used from the ground position as well as the loaded (stowed) position on the carrying chassis. It is important to understand that the equipment within these roll-off containers, as the name implies, must be mounted completely in accordance with the lifting, tilting and deploying to which the pods will be subjected during expected operations.

Communications, decontamination, mass-casualty and staging pods are designed to accommodate humans. These designs often feature lavatories, showers, sinks and, in many cases, kitchens for extended on-scene activities. These containers typically feature expanding sidewalls, awnings and internal flexible partition walls that allow the responding team to use the equipment in a field-customized fashion.

Pumping, foam-supply and CAFS pods are growing in popularity based on the potential need for long-term deployment in wide operating areas. In flood zones, the pump pod can be used to move large volumes of water. Some manufacturers offer specialized high-volume pumping pods that can deliver tremendous amounts of water long distances (and to high lifts as well). Industrial applications also show interest in foam and compressed-air foam pods for tank farm and chemical applications.

Before you buy

Emergency-service applications are a specialized vocation. The use of trailers and roll-off containers provides contemporary purchasers with options to deliver deep resources in either single-unit, wide-capacity modes (trailers) or highly specialized exact-need configurations (pods) based on the operational objectives of the buyer.

In commercial application, both of these designs are seen most frequently in bulk transportation and goods delivery. Such applications permit a fair amount of flexing of the trailer and pod bodywork, based on commercial-shipping accepted practices. Potential purchasers are highly advised to exercise extreme caution when considering acquiring commercial products to apply them for emergency-service duty.

The state-of-the-art equipment-loading and tool-mounting we use in the emergency-services industry is based on rigid bodywork and specific shock-absorption qualities that are required to provide users with a safe and reliable piece of operating equipment. Many manufacturers offer packages and designs that have been purpose-built to minimize this flexing and permit effective on-scene use.

In the case of pod applications, it is recommended that users be able to open all of the pod's exterior doors and that all trays and slides are operational when one corner is raised a minimum of 12 inches from the other three corners (offset test), since in the real world it may end up on a curb or median. Similarly, users must be able to operate all of the trailer's doors, latches and systems, both empty and fully loaded.

With any vehicle purchase, it is important to have a complete equipment inventory, a list of expected future equipment to be stored and spare space calculated for the total picture. Knowing your size and weight requirements makes you an informed buyer. Determining your deployment preference — all-in-one versus call-to-the-job — will help guide you to the optimal design. The flexibility of a free tow or carry vehicle may be an added benefit that your crew can leverage to serve your customers.

Keith Purdy is has been in the fire service for 23 years and is currently the vice president of sales and marketing for Plastisol Composites North America. He is the body subcommittee chairperson for the Fire Apparatus Manufacturers Association. Purdy holds associate's and bachelor's degrees in fire protection technology.