Aerial Apparatus

The “old school” rule governing whether a fire district required an aerial device, or not, was based on when the portable ground ladders within a fire department would no longer reach the upper windows or the roof of buildings in the community, then an aerial device was needed.  This is a simple but yet often overlooked way of justifying your purchase, for the rule still stands true.  As sufficient as that may be, there are still other justifications to consider.  The following are a few additional consideration:

• It typically takes 3 or more firefighters to raise and place a long ground ladder. If at any given time a department has insufficient personnel to achieve this task safely and without exposure to injury, while issuing an attack and laying out hose lines, then an aerial device is needed.
• If the terrain and topography within a community make using ground ladders unsafe, an aerial device is needed. Terrain and landscape oddities may make it impossible for firefighters to gain access to two or three story structures with ground ladders. Under this condition, an aerial device is needed to perform necessary rescue or ventilating operations.
• An aerial device can significantly improve a fire district’s ISO rating, lowering a community’s property insurance premiums. This benefit will be presented in greater detail later in this buyer’s guide.
• Consideration needs to be given to the demographics of the population of your community. Increasing levels of obesity, aging, and disabled population may make it impractical to rescue a certain percentage of those you serve safely from even a second story window, without a platform apparatus.
• Communities with large square footage buildings, such as warehouses, large department stores, etc. require a safe means of delivery fire suppression from an elevated position. This can increase firefighter safety by minimizing the need for dangerous interior attacks.
• Communities with standing or running water that pose drowning hazards will benefit from increased reach capabilities that an aerial device will provide during rescue operations.
• Communities with industrial facilities where fire suppression requires high flows through a single elevated discharge will require an aerial device.
• Consider the existence of aerial apparatus in surrounding communities. A mixture of capabilities is always smart and by sharing resources, communities may make choices based on available mutual aid options.

Vertical height is an important decision when it comes to choosing an aerial device. But in communities with single family housing, the horizontal reach is just as important. Homes can be located a considerable distance from the street. Horizontal reach will determine the effectiveness of the aerial device for ventilating and rescue operations.

Landscaping and extreme slope conditions can make it unsafe for ground ladder placement.  An aerial device will provide much safer access for firefighters.

Older homes were typically constructed of heavier structural members that provide longer burn times before collapse.  Newer construction materials burn faster and may place firefighter at greater risk during interior attack operations, justifying the capability of an aerial device to provide fire suppression from an elevated master stream.

Certain types of residential architecture present a much greater challenge to accessibility using ground ladders.  Steep roofs, metal roofs, and multiple roof lines are examples where an aerial device will provide much safer access for firefighters during rescue and ventilation operations.

Hospitals and facilities serving senior citizens contain persons with special requirements which may preclude rescue using ground ladder. An aerial platform is an ideal tool in these situations to provide safe and secure rescue operations.

If your community has densely populated multi-story buildings, you will need an aerial device with wider ladder sections and higher tip loads to help evacuate large amounts of people.

Some departments require large water flows because of large scale chemical or refinery fires. Aerial units designed with larger diameter waterways and increased flows are required. The aerial device will be designed to accommodate the increased water and nozzle reaction forces.

Depending on your community’s street configurations, you may need to consider an apparatus with shorter wheelbase, tighter turning radius, and shorter rear overhang.  Tiller apparatus may be another means of dealing with tighter streets and traffic congestions.

Outrigger configuration and spread is an important consideration when you purchase an aerial device. An aerial with a short jack feature or a narrower outrigger spread may be necessary to set-up in a narrow street.

Know the apparatus leveling capabilities you will need based on the grade of the roadways you will need to set the unit. Ensure the apparatus you are selecting will allow you to setup in necessary locations. The load chart will define the slope and grade requirements of the prospective apparatus.

Understand the horsepower required to have the truck perform as your needs require. Engine and transmission choices are available to match your needs. Be aware that NFPA has top speed limitations based on gross vehicle weight.

Due to the travel height of aerial apparatus, verify that the unit can fit through all tunnels, under all the bridges, and fit into the fire station. Also be aware if the unit would ever need towed that it does not contact an overhead obstruction. The area may include low hanging tree limbs that cannot be pruned due to historical significance.

Measure your door opening. If you have a height restriction, be sure to include that in your specification. Clearly identify the maximum over-all height of the unit and state that this is a no exception item.

In some cases the height of the door is not the issue but the shape of the door is the issue. Some of the older fire stations were built with an arched doorway. The truck will fit in the center but not at the edges. Always verify that the aerial turntable control console, turntable handrails and the platform will fit through the door opening.

Unless the approach angle into your station is flat, the travel of the unit up and through the door opening could cause a clearance problem. If you believe this may be a problem, review the need for a station layout to be generated by the manufacturer or another qualified person.

The length of the unit is critical when you have limited station bay depth. The overall length of the apparatus will need to be reviewed. You may also need to verify if there is adequate room in the station to walk past the front and the rear of the unit.

Some stations will have exposed heating and plumbing in the ceiling of the apparatus bay. Depending on the building construction, exposed support beams may also be present. The location of these or any other items that protrude down from the ceiling must be identified and verification must be done to make sure an interference with the aerial device does not occur. Verify that none of the mechanical parts of the garage door opener are lower than the door when in the open position. This could create an interference with the aerial device.

The in-service weight of the completed aerial device must be compared to the capacity of the fire station floor. If the building is configured in such a way that there are rooms or crawl spaces below the apparatus bay, then you will need to identify the capacity.

If you live in a cold climate, you need to be aware of the effects of snow and ice.  Ice and snow on the apron will reduce the station door clearance.

The turning radius and tail swing required to get the unit out of the station needs to be verified. Narrow streets, sidewalks and other obstacles can provide difficulty getting in and out of the station.

An aerial ladder is the basic tool for rescue, ventilation, and extinguishment in the fire service.  It has the ability to perform all three basic functions at the basic level.  An aerial ladder will include a ladder tip capacity of 250 lbs., 500 lbs., 750 lbs or more.

Aerial ladders are generally more compact in size than aerial ladder platform units and will often be the best choice between the two types if limited space is a concern.  Also, the tip of an aerial ladder is far smaller than a platform and will enable better and more consistent access capability among trees, overhead electric lines, balcony railings, and closely spaced buildings.

An aerial ladder platform will provide expanded capacity for rescue, ventilation, and extinguishment.  It is the absolute ultimate rescue and firefighting tool.  All three basic functions can be performed at a higher level.  An aerial ladder platform will include a minimum platform capacity of 750 lbs.

Higher weight carrying capacity will enable it to rescue more people with better support from firefighters.  Where there is a higher concentration of people living or working in elevated locations, the aerial ladder platform will be the ideal choice.

The integral work platform provides a stable place from where ventilation operations can begin.  The platform will support firefighters as well as ventilation equipment and bring them under power to elevated locations.  Thus, ground ladder climbing and the associated hazards are minimized.

Water flow capacity can be brought to the highest level with an aerial ladder platform.  These can be equipped with single or dual platform mounted deck guns and can safely deliver flows in excess of 1,500 gpm.  Where large fire potential exists, or where large buildings or hazardous industrial installations are present, the aerial ladder platform offers the highest level of performance available.

If elevated fire suppression, without rescue capability, is your main criteria for your aerial apparatus, a Water Tower may be a good choice.  Water Towers range from 50 feet to 130 feet operating heights and are capable of delivering water flows in excess of 2,000 gpm.  Water Towers, particularly those with high water flow capability, are more common to the industrial fire service.

• Rear mounted aerials are generally less expensive than their mid mounted counterparts.
• Generally, the overall apparatus height will range from slightly under 11 feet to slightly over 12 feet. This being the case, it’s necessary to confirm whether any overall height restrictions exist.  These restrictions can be due to several factors.
• A low profile cab option is available that will enable packaging an aerial ladder without a telescopic waterway to an overall travel height as low as 10’ – 10”
• The low profile cab option will enable packaging an aerial ladder with a telescopic waterway to an overall travel height as low as 11’ – 4”
• The low profile cab option will enable packaging a platform to an overall travel height as low as 11’ – 6”
• Generally, rear mounted aerials are shorter in overall length than their mid mounted counterparts and fitting inside the fire station is a concern.
• Improved range of aerial operation over the front of the apparatus.
• Generally tail swing is reduced.
• Available as an aerial ladder or a platform configuration.

• A major advantage of the mid-mount arrangement is that it’s inherently low in travel height. Overall travel heights of less than 10’ can be obtained.
• Mid mounted aerials are typically comprised of four or five telescoping sections providing a shorter retracted length. This shortened retracted length provides a greater ability to maneuver the aerial in congested areas.  It also will enable the operator to place the ladder tip or platform closer to the ground or to the face of a building.
• Available as an aerial ladder or a platform configuration.
• Placement of the platform at the rear of the apparatus provides improved visibility through the windshield.

• The tractor drawn aerial is the most maneuverable type of aerial on the market today. The articulating design and the rear steering capability of the rear trailer axle enable the tractor drawn aerial to make turns around tight corners on narrow streets that are simply impossible to make with “straight” trucks.  Also, the ability to use the rear trailer steering axle to position the aerial while moving forward or in reverse is a tremendously useful capability in congested areas, on narrow streets, and in alleyways.  These factors explain why the tractor drawn aerial is still an extremely popular choice for inner city applications.
• There are other environments where the tractor drawn aerial is the best possible choice. Older communities where roadways were laid out and established by the turning radius of an oxcart or horse drawn wagon cannot be serviced with “straight” trucks.  Historical districts, trailer parks, retirement villages, and apartment / condominium / townhouse complexes are best served with tractor drawn aerial apparatus
• Another major consideration influencing the decision to select tractor drawn aerial apparatus is the greatly increased storage capability they can provide. Tractor drawn units can be packaged to include nearly twice the storage space of their rear and mid mounted counterparts.  More enclosed compartments can be provided to store more firefighting accessories and equipment.  The long trailer has space for a greater selection of portable ground ladders.  Longer ground ladders and special application ground ladders such as a 50’ two-section extension ladder or a 32’ wall ladder can only be carried on a tractor drawn unit.
• In certain rare cases, tractor drawn aerial apparatus is selected due to the requirement of the additional manpower to operate it. It’s a tactic used to preserve the number of firefighters assigned to the truck company and represents one of the few remaining sacred traditions still in existence in the modern era.

A non quint apparatus will not include a fire pump, water tank, or supply hose.  In this case the apparatus will be relied upon to provide ground ladders and a larger selection of rescue, firefighting, overhaul, and salvage equipment.

The decision to package the apparatus as a non-quint is based on the intended service for the apparatus and or operating crew.  If the apparatus and crew are intended to operate as a “truck company” where rescue, salvage, and overhaul is the primary mission, then a non-quint is the best choice.  A non- quint is also a logical choice where an organized multiple company response capability is present and available.  Most career agencies rely on the specialized and more closely defined duties and capabilities a non-quint can provide.

A quint apparatus will include a fire pump, water tank, and supply hose in addition to the aerial device.  In rare instances, the water tank may be eliminated and substituted with more hose, ground ladders, or equipment storage compartments.

The decision to package the apparatus as a quint is based on the intended service for the apparatus and or operating crew.  If the apparatus and crew are intended to operate as an “initial attack engine” where fire suppression is the primary mission, then a quint is the best choice.  A quint can be a logical choice where limited manpower is a limiting factor.  Many volunteer agencies rely on the versatile capabilities a quint can provide.

Whether specifying a quint or non-quint aerial device, additional consideration needs to be given toward ground ladder requirements.  NFPA 1901 requires a minimum of 115’ of ground ladders on an aerial fire apparatus.  If the unit is a quint, NFPA requires a minimum of 85’ of ground ladders. Due to housing and building construction, some departments may have special ladder requirements or specify an ISO ground ladder compliment. Be sure to clearly identify this in the specification. Special requirements may be necessary to fit the specified ladders.

• Single rear axle aerial apparatus inherently contain limitations but can also provide benefit if the gross weight can fall within single axle limitations. Currently the maximum rear axle rating available is 35,000 lbs.  Single axle apparatus typically provide decreased turning radius, enabling the apparatus to be more maneuverable in congested fire districts.
• A negative to single axle aerial apparatus is decreased stopping power and decreased service brake like.

• Most aerials require the use of a tandem rear axle for weight carrying capability and simply cannot be built with a single rear axle…especially platform apparatus. In certain cases, there is a need to package an aerial apparatus with more water, hose, portable ground ladders, and storage compartments.
• A tandem rear axle apparatus will include an additional set of rear brakes. The additional set of brakes will reduce the stopping distance of the vehicle, inspire greater driver confidence, improve overall driving safety, and dramatically increase the life of the service brakes.
• In areas where there are steep grades, sustained downhill grades, and hilly terrain… an apparatus with a tandem rear axle will be the better choice.
• The tandem rear axle apparatus also delivers a smoother and more stable ride with less body roll, again…inspiring greater driver confidence.