METHODS FOR SAFE AREAL DEVICE OPERATIONS

METHODS FOR SAFE AREAL DEVICE OPERATIONS

BY JOHN W. MITTENDORF

(Editor`s note: The author addressed the basics of placing aerial apparatus in “The Basics: Aerial Apparatus Placement,” in the September 1994 issue of Fire Engineering.)

You are the driver of a 100-foot ladder tower and are responding to a structure fire. On arrival at a 100- by 100-foot, three-story commercial building, you are directed to use the platform to place two firefighters on the roof for ventilation operations. While spotting for the operation, you observe a flat roof surrounded by a three-foot parapet. How would you position the apparatus and platform to accomplish your intended objective?

You, the driver of a 100-foot aerial ladder, are responding to a smell of smoke. On arrival, you are told that the smoke in the fourth-floor offices of a five-story building is coming from a defective air-conditioning unit on the roof. You are directed to place the aerial ladder to a flat roof to allow personnel to find the source of the smoke. How would you position the apparatus and aerial ladder to accomplish your intended objective?

Before positioning the apparatus and placing the platform or aerial ladder, the drivers in the scenarios described above must evaluate a combination of considerations based on SOPs, incident considerations, apparatus limitations, and driver-operator expertise. Be sure to adhere to manufacturers` recommendations regarding aerial extension at proper inclination angles; proper spotting techniques, which place the aerial in the strongest configurations (over the cab, for example); and so on.

SCENARIO 1

In Scenario 1, the apparatus should be positioned at the corner of the building away from the fire (if possible) by placing the centerline of the turntable to the junction of the two walls, which will allow personnel to (1) see at least two sides of the building, (2) reach two sides of the building with the platform, and (3) spot to a corner of a building–an area that is well-constructed and out of the potential collapse zone.

Normally, the platform should not be placed over windows or doors. Spotting to the corners will leave the front portion of the building open for other companies. Note: When spotting aerial apparatus, always watch for overhead electrical wires and the potential for placing outriggers on questionable footings (mud and drains, for example).

An additional consideration is spotting the apparatus to a corner, which would also allow the platform to operate as a potential defensive-exposure protection tool. Ideally, this objective can be accomplished in concert with proper positioning for personnel access-egress. However, proper personnel access-egress routes should take first priority.

Assuming the apparatus is proceeding past the front of the building and has been spotted to the corner away from the fire, the operator now must make the important decision of how the platform should be raised to the building: Should it be placed over the parapet-building or to the parapet-building?

Over the Parapet-Building

If the operator decides to extend the platform over the parapet-building, the platform should be extended just past the parapet and lowered as close to it as possible, which would do the following: (1) place the platform near the corner of the roof, (2) allow personnel to descend from the platform to the strongest portion of the roof, (3) minimize the distance from the platform to the roof, and (4) simplify access-egress to and from the platform.

However, this operation has resulted in an interesting dichotomy. Although the apparatus is positioned out of the collapse zone and near the strong portion of the parapet-building, roof access from the platform may require that a ladder be placed between the roof and the platform due to the ladder`s inclination angle, the distance between the parapet and the ladder`s base rails, and the height of the parapet above the roof.

When the distance from the top of a parapet or fascia to the roof is not known (when viewed from the ground), the following can assist in determining the approximate distance:

draining water off the roof with scuppers;

using rafter tie plates to indicate the locations of the rafters;

looking at the distance between attic vents and the top of a parapet-fascia;

assessing the distance from the top-floor windows to the top of a parapet-fascia–the greater the distance, the greater the possibility of a high parapet; and

looking for machinery or ventilators-vent pipes–if they can be seen, the roof is just below the top of the parapet-fascia.

The distance between an objective and the ladder`s base rails is dependent on the operator`s expertise and whether a waterway is below the ladder`s base rails. If there is no waterway, the ladder-platform can be placed as close to the objective as conditions allow. When a waterway is present, sufficient distance must be left between the exposed waterway and the objective so that the waterway is not inadvertently damaged from the potential movement of the ladder when personnel climb it. Increasing the distance between the ladder-platform and the objective potentially decreases the ease of access from the platform to the objective.

To the Parapet-Building

An alternative method would be to place the platform to the parapet-building as follows.

Place the centerline of the turntable to the junction of the two walls; the platform can be positioned just above or just on the parapet.

Note: The dictionary defines “just” as “almost at the point of” or “barely.” Applying these definitions to aerial placement, we have the following definition: “An aerial ladder that is lightly placed on an objective can increase climbing stability and operational safety considerations when being utilized by personnel.”

Place the centerline of the turntable just outside the corner or to the front wall near the corner; the platform can be positioned next to the side or front of the building with the platform floor level with the top of the parapet. When positioning the platform from the turntable, it is easier to position it to the side of a building instead of straight into a building. Determining the proper distance between the platform and objective (from the turntable) is easier when the platform is viewed from the side instead of the rear.

These two approaches allow personnel to exit the platform and reach the roof without having to position a ladder between the platform and roof (depending on the height of the parapet above the roof) and reduce the chance that the exposed waterway will inadvertently strike the building. Most platforms project forward from the aerial to allow placement without having to consider the exposed waterway.

Effective placement can be enhanced by incorporating features, such as the following, into your specifications when purchasing a platform:

Keep the preplumbed waterway close to the bottom of the base rails or rungs, particularly the fly section. Doing this will allow the ladder to be placed closer to the objective and can prevent inadvertent damage to the waterway should the ladder be placed too close to the objective.

Keep the platform simple. Make sure that personnel can easily leave and return to the platform when carrying tools and equipment, wearing full protective equipment, and that the platform is easy to work from (for ventilation operations, for example). A popular misconception is that platforms are easier to work from than aerial ladders. As a blanket statement, this is a myth, since all platforms are not identical in size, shape, and ease of access to and from the platform (this holds true also for aerial ladders).

SCENARIO 2

In this situation, the apparatus should be positioned at the building corner that offers the best access to the defective air-conditioning unit(s)–for the same reasons listed under Scenario 1. Although no fire or roof ventilation is necessary, proper spotting techniques should still be adhered to (even for false alarms) so that SOPs will be reinforced. Stated from another perspective, correct practice in nonemergency or false-alarm-type incidents allows personnel to focus on objectives during emergency incidents because the basics should be automatic.

Assuming the apparatus is proceeding past the front of the building and is spotted to the far corner, the operator raises and extends the aerial over the corner of the building. At this point, how far does the operator extend the aerial over the building, and is the ladder positioned off the objective or lowered and positioned just on the objective?

Aerial extension. When extending an aerial (or ground ladder) over an objective, forget the principle of three rungs or three feet over the objective, and focus on extending the ladder over the objective far enough so that it can be easily seen from the roof. Doing this is especially essential when an aerial is the primary escape route and it is dark or smoky. In dark or smoky conditions, a fluorescent tip and strobe light can enhance ladder identification.

Off the objective. If the aerial has a waterway below the ladder`s base rails, the ladder must be positioned far enough above the objective to keep the waterway from striking the objective during positioning and while personnel are climbing the ladder. However, doing this can keep the aerial a distance above the objective, making access to and from the aerial difficult to impossible. This condition can be avoided by considering the following:

Purchase an aerial with the waterway above the base rails or with a pinnable waterway. A pinnable waterway allows the ladder to be extended without the waterway and monitor`s extending with the fly section, allowing the aerial to be placed closer to the objective and enhancing personnel`s accessing or working from an aerial. That is also the reason aerial ladders with low or sloping handrails at the tip area are easier to work from than aerials with high handrails.

When spotting with a pinnable waterway, spot far enough away from close objectives so the ladder can be extended with the waterway pinned behind the fly. In this way, the fly can be placed as close as possible over the objective without having to be concerned about the waterway-monitor`s striking the objective.

If an aerial has a waterway below the base rails or a monitor at the outer end of the fly section, easy access to and from the aerial can be achieved by placing the turntable`s centerline just outside the corner of the objective and the extended aerial next to the building at the top of the parapet-fascia–or the turntable centerline can be placed to the front wall near the corner and the extended aerial just to the top of the objective. Note: It is easier to gauge the distance (from the turntable) between an aerial and the side of an objective than to extend an aerial straight into an objective. When evaluating the aforementioned conditions, placing an aerial to the side of an objective is preferable to placing it to an objective due to ease of placement and access to and from the aerial.

If an aerial is extended into an objective, be sure to avoid damaging the monitor by keeping it behind (or tilted backward from) the tip of the fly section as it approaches the objective.

When an aerial is positioned off an objective, the aerial is considered to be in the “unsupported” position. However, the aerial may “bounce” vertically while being climbed by personnel. Therefore, if a waterway is present below the base rails, leave enough distance between the objective and the tip of the fly to allow for this vertical movement. The extent of the vertical movement will depend on the degree of extension and strength of the aerial, but it must be considered when planning placement strategies.

On the objective. Let`s assume that an aerial has a fly section that is not limited by having a waterway below the base rails and has been extended the appropriate distance over an objective. As the aerial is lowered into the objective, can it be placed on the objective? Most fire service personnel would answer this question as follows: “Aerial ladders must be positioned about four to six inches above an objective for the following reasons:

“An aerial ladder placed on an objective can add to the potential of building collapse.

“An aerial ladder of truss construction placed on an objective will reverse the design criteria of the truss configuration and weaken the ladder.

“It is the manufacturer`s requirement.”

Although each of these considerations has some merit, an aerial positioned above an objective has the following disadvantages:

The aerial can move vertically when personnel are climbing, making the aerial unsteady and possibly result in the aerial`s bouncing on the objective.

Depending on the inclination angle, extension distance of the aerial, number of personnel on the aerial, type of aerial, and the distance from the aerial`s bottom rails to the objective, the aerial can settle and rest on the objective while personnel climb. Although this would increase the ladder`s stability for personnel, the aerial also could suddenly lift off the objective as the last person exits the fly section of the aerial, creating a potential hazard for the unsuspecting person.

As already discussed, these considerations can be minimized or eliminated by just placing the aerial on the objective.

However, what about potential building collapse, weakening of the ladder`s truss configuration, and manufacturers` recommendations when the base rails of an aerial are lightly or barely placed on an objective?

Building collapse. If an unreinforced masonry brick parapet has been exposed to fire or has several visible cracks, placing an aerial on this type of objective is not a consideration–for obvious reasons. However, if an aerial is lightly placed on a stable objective, the apparatus` hydraulic system will support the majority of the aerial`s weight, not the objective.

Truss configuration. Since most aerial ladders are constructed in a truss configuration, the ladder`s handrails are in tension and the base rails are in compression. If a truss ladder is supported on an objective, is the tension-and-compression configuration reversed, weakening the ladder? This depends on the force of the ladder on the objective. If a truss aerial ladder is forced against the objective with little regard for design criteria, the ladder easily can be damaged and can result in serious consequences, including ladder failure. However, if the ladder is lightly placed on the objective, the tension-compression configuration is minimally reversed, resulting in a supported aerial ladder. It is interesting to note that some manufacturers rate their aerials at a higher load-carrying capacity for personnel in the supported configuration than in the unsupported configuration.

When placing an aerial to an objective, the ladder should be positioned as perpendicular to the objective as possible, to allow both base rails to rest equally on the objective. In this configuration, an aerial is considered a supported ladder. Even if an aerial is correctly placed to the intersection of a corner, each base rail will rest on a wall with the intersection of the walls slightly protruding through the rungs. This concept requires operator expertise just as other types of aerial operations do. However, if an aerial is placed at an “angle” to an objective, only one base rail will rest on the objective. In this configuration, an aerial is considered an unsupported ladder and is also inherently weak due to torsional stress that can be created by ascending or descending personnel, who will weight the unsupported base rail, which can cause the following situations that must be considered:

–The unsupported base rail can be forced downward, torsionally twisting the aerial and potentially causing aerial failure. The greater the angle of the aerial to (or away from) the objective in concert with the given weight on an aerial, the more critical this consideration becomes.

–The aerial can slide against the objective toward the unsupported base rail, creating a hazardous condition for personnel and the aerial ladder. Note: Some manufacturers recommend operating their ladders in an unsupported condition since some aerial ladders are stronger in the unsupported condition than when supported on one base rail. When evaluating an unsupported aerial vs. an aerial with an unsupported base rail, consider that access on or off an unsupported aerial ladder is not perfect, but the chance of structural damage to the ladder is minimized.

Manufacturers` recommendations. The concept of positioning an aerial above an objective certainly addresses the issue of liability and unqualified apparatus operators. Yet, as we have previously discussed, aerial operations can safely be enhanced if an aerial is correctly placed on (or to) an objective when appropriate. It is imperative that all personnel operating aerial ladders and elevating platforms be intimately familiar with the strength, weaknesses, capabilities, and manufacturers` recommendations for their particular apparatus-aerial device. This may sound simplistic, but a significant percentage of aerial ladder failures result from operator error or lack of maintenance, not ladder failure.

The implementation of NFPA 1904, Standard for Aerial Ladder and Elevating Platform Fire Apparatus–1991, requires all new aerial ladders and elevating platforms have or exceed a rated capacity of 250 pounds supported at the tip, at full extension, and be able to operate in any position while carrying this load. However, NFPA 1904 should raise concerns that a large number of aerial apparatus in use were purchased before that standard was adopted and may not possess modern strength and operational capabilities. If an operator is not thoroughly familiar with the operational consideration differences of newer aerial platforms vs. “older” aerial platforms vs. the capabilities of various manufacturers` aerial platforms, a potential disaster awaits when applying the same operational considerations to all apparatus or when operating a “newer” aerial platform today and an “older” aerial platform tomorrow. As an example, let`s consider the following three general classifications for aerial ladders/platforms:

First generation: Aerials purchased before 1980 generally do not possess the operational capabilities, hydraulic-system sophistication, and metallurgical strength of newer aerials. Aerials with no rated capacity were common. These aerials generally use hydraulic fluid on one side of the hoist-lower piston, are raised under hydraulic pressure and lowered by gravity, and may have small outrigger systems.

Second generation. Aerials purchased between 1980 and 1991-1992 were developed as a result of ANSI and OSHA regulatory concerns over structural and stability safety factors. These aerials have improved hydraulic systems, strength, outrigger systems, and operational capabilities in comparison with the first-generation aerials. These aerials use hydraulic fluid on both sides of the hoist-lower pistons and are raised and lowered under hydraulic pressure (this means these aerials can easily be hydraulically forced against an objective, with an expected negative result).

Third generation: Aerials purchased after 1991-1992 to the present feature dramatically improved hydraulic systems, metallurgical strength factors, enhanced outrigger systems (improved stability), and significantly improved operational characteristics compared with the first- and second-generation aerials. These aerials can also be raised and lowered under hydraulic pressure.

Modern technology has dramatically changed apparatus and aerial devices. The key to implementing safe and effective operational considerations when using current fire apparatus is to understand and consistently implement the operational limitations of your apparatus at each incident. Regardless of the manufacturer, model, or year of your aerial device, the operator must be aware of the device`s limitations at all times. The capabilities and limitations of any aerial device depend on proper maintenance (regardless of age) and training. Departmental field training all too often enforces capabilities without covering limitations. It is these limitations that can produce problems. Are you using these tools to their fullest and safest advantage? n

I would like to thank the following for their assistance with this article: Aerial Innovations Inc.; Emergency One, Inc.; Global Fire Equipment, Inc.; Pierce Manufacturing, Inc.; and Simon Ladder Towers, Inc.

By placing an aerial device to the corner of a building (a strongly constructed area), personnel can see at least two sides of the building and the aerial device can reach two sides of the building. In addition, the front of the building is open for other companies. The aerial device is not placed over doors or windows, which often become a pathway for fire. (Photos by author.)

(Left) The floor of the platform is level with the top of the parapet, enhancing access to and from the platform. (Right) It is easier to determine the proper distance between the platform and objective when viewing from the side.

Placing a platform above an objective to clear the exposed waterway can complicate access to and from the platform.

This platform does not enhance the principle of easy access to and from the platform.

This aerial has been spotted enough distance from the building to allow the fly section to be placed to the building, keeping the pinned waterway away from the building and allowing the fly to be placed as close to the building as possible.

(Left) Placing an aerial with an exposed waterway at the fly section alongside a building enhances access to and from the aerial. (Right) To avoid damaging the monitor, keep the monitor behind or tilted backward from the fly`s tip when extending an aerial into an objective.

(Top) Lightly placing this aerial with a pinned waterway on the ridge of this dwelling has stabilized the aerial, positioned it as close as possible to the working surface (roof), and placed the waterway-monitor behind the work area. (Bottom) The advantages of a platform and aerial ladder can be effectively realized at the same incident. Note, however, that only the aerial`s right rail is supported. If personnel climb this ladder, their weight will cause the ladder to twist to the unsupported rail, placing the ladder and personnel in potential danger.

Older aerial devices do not have the operational capabilities (and outriggers) of newer apparatus.

JOHN W. MITTENDORF is a retired battalion chief and 30-year veteran of the City of Los Angeles (CA) Fire Department, where his duties included conducting apparatus operator examinations. He presents seminars on fireground operations; is the author of the books Ventilation Methods and Techniques and Facing the Promotional Interview, published by Fire Technology Services; and is a member of the Fire Engineering editorial advisory board.