As an initial starting point, NFPA 1904 (1991 edition) recommends that truck ... (
NFPA 1931), selection is often a combination of personal preference and ...
Ground Ladders Part I By John Mittendorf Although ground ladder operations can be one of the most effective and versatile fire fighting tools that are often used to support and enhance efficient fireground operations, reduced staffing levels have often reduced their implementation to a consideration after more important operations (i.e., fire attack, ventilation, search and rescue, forcible entry, etc.) are completed. However, in the science of firefighting, effective fireground operations are often dependent on the timely and adequate placement of ladders to facilitate other fireground operations. The importance of ladders at structure fires cannot be overemphasized.
LADDER SELECTION Ladder selection consists of two interrelated considerations as follows: Initial Purchase Before any ladder is spotted and placed to a structure (objective), the needs of a particular area and type of ladders necessary for appropriate applications must be thoroughly analyzed and wisely purchased. Remember, the initial purchase of ground ladders (which normally coincides with the purchase of new apparatus) will often effect fireground operations (and considerations) 15 to 20 years later. With this thought in mind, let's briefly consider compliment, type, and construction: •
Compliment
As an initial starting point, NFPA 1904 (1991 edition) recommends that truck companies carry a minimum of 115-feet of ground ladders. This basic compliment will provide the ability to access attics from the interior of structures, enhance ventilation-overhaul operations on peaked roofs, and provide access to the roofs of two and some three story buildings (with a minimum of two ladders to the roofs of two story buildings. However, note this compliment is marginal when applied to three story buildings. Therefore, the needs of an area (served by a truck company) may alter or add to the basic NFPA compliment. As an example, consider the following two examples: 1. Sixteen-foot straight ladders require less personnel and are easier to implement than 24-foot extension ladders to the roofs of most single-story, single-family dwellings (remember, there are more single family dwelling type structures than any other structure). Again, the presence of numerous single-family dwellings might require the addition of a 16-foot straight ladder in addition to a 24-foot extension ladder.
2. Four story structures that are not accessible by an aerial device may require a 40 to 50-foot extension ladder in addition to a 24 and 35-foot extension ladder. •
Type of Ladders
When comparing extension ladders to straight ladders: 1. An extension ladder can be adjusted to a specific length and also be used as a replacement for shorter ladders (i.e., a 35-foot ladder can replace 28, 24, 20, and 16-foot ladders). 2. Extension ladders can require additional personnel to compensate for the additional weight and necessity of extension operations as compared to straight ladders of comparable length (i.e., a 24-foot metal extension ladder weighs 110 to 142 lbs and requires 2 personnel for implementation. A 24-foot metal straight ladder weighs 62-76 lbs and can be raised by one person. Straight ladders are normally lighter than extension ladders and can require less personnel (and time) for implementation. 3. More straight ladders must be purchased to equal the adjustable length combinations of an extension ladder. Additional ladders will also require more space on apparatus. 4. Minimal space constraints can place an emphasis on purchasing several extension ladders to provide the capability of additional shorter ladders. However, the addition of selected straight ladders (in addition to extension ladders) can increase flexibility and require less personnel for implementation. •
Construction
Currently, ground ladders are constructed from wood, metal, and fiberglass. The most common ladders are constructed from aluminum. The next most common ladders are constructed from wood, and the least common ladders are constructed from fiberglass. These ladders are summarized as follows: Metal 1. 2. 3. 4.
Good conductor of heat, cold, and electricity. Least expensive and easily repairable. Extensive choice of sizes and configurations. Can suddenly fail when exposed to heat or flame over 200-degrees (loss of annealing).
Wood 1. 2. 3. 4.
Higher cost than aluminum or fiberglass. Can be exposed to heat and flame and retain strength. Good durability. May require refinishing of damaged finish, depending on frequency of use.
Fiberglass 1. 2. 3. 4. 5.
Not a willing conductor of electricity, heat, and cold. Moderate cost. May chip and crack with impact forces. May suddenly crack and fail when overloaded. Can burn when exposed to flame.
As aluminum, wood, and fiberglass ladders are constructed to meet the same standards (NFPA 1931), selection is often a combination of personal preference and tradition. Characteristics Now, let's combine the aforementioned considerations with the distinct characteristics of cost, weight, maintenance, and safety that should also be considered before selecting a ground ladder: Cost Wood ladders are the most expensive and aluminum ladders are the least expensive (i.e., for a 20-foot extension ladder, wood is approximately $1,600, fiberglass is approximately $750, and aluminum is approximately $680). Weight The common perception that aluminum ladders are lighter in weight than currently available wood (tapered truss) and fiberglass ladders should be re-evaluated when reviewing the following chart that has been assembled from manufacturers' catalogs: Ladders
Wood
Metal
Fiberglass
16' straight
52#
56#
37#
20' straight
65#
65#
50#
12' extension 34#
29-48#
45-69#
24' extension 110#
75-142#
99-133#
10' roof
30#
24-40#
30#
16' roof
48#
44-56#
42-46#
Maintenance The maintenance of any ladder is affected by frequency of use and adherence to NFPA 1932, which recommends all ground ladders be visually inspected at least once each month, after each usage, and: • •
To restore the surface finish, an occasional application of a good automotive paste wax shall be used on aluminum and fiberglass ladders The varnish finish shall be inspected at least every six months and redone at least annually, or sooner, if damage to the finish is noted, to preserve the wood and varnish finish of wooden ladders.
Therefore, as the frequency of use increases, so does the necessary maintenance of any ladder, regardless of construction. In any case, most ground ladders do not receive adequate maintenance regardless of the type of ladder and frequency of use. Safety When selecting a ladder, safety considerations should be carefully evaluated. Therefore, when comparing metal, wood, and fiberglass ladders, remember that metal is a willing conductor of electricity, whereas wood and fiberglass are not. Consider the following facts: 1. According to the Federal Emergency Management Agency (FEMA), nine firefighters were killed between 1977 and 1988 due to electrocution involving metal ground ladders (not including the number of non-fatal injuries attributed to these ladders). 2. According to the United States Consumer Products Safety Commission (CPSC): • •
•
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Commission accident data consistently identifies metal ground ladders as a product commonly associated with electrocutions. When accurate depth perception is required, the human visual system is limited in its ability in estimating the clearance distance from ladders to power lines as viewed against the sky. When an object (power line) is seen against the sky, the human eye only sees a dark line against the sky. Unless a person is close enough to see some details on an objects surface, it is almost impossible to accurately estimate its distance. Therefore, visual judgment cannot be depended on solely for estimating critical clearance distances of objects in the sky (such as power lines and ground ladders). Since people are task oriented; they will tend to move an extension ladder while it is still extended to avoid interrupting the task sequence. Therefore, this condition increases the possibility of contacting power lines with an extension ladder. Most electrocutions associated with metal ladders involved extension ladders. The average electrical service lines (120/240-volts) to a single-family dwelling are commonly insulated with a material rated at 600 volts. However, age and exposure to the extremes of weather contribute to brittleness and cracking of the
insulation material which degrade dielectric strength and the ability to prevent electrocution. Therefore, power line coverings are not designed, or, in the case of service drop lines, not adequately maintained to be a reliable protection against an abrasive contact by a ladder. In the private sector, the telecommunications industry has significantly reduced electrocution hazards by simply requiring exclusive use of either wood or fiberglass ladders (both of which are inherently non conductive), and the National Electrical Safety Code prohibits the use of metal ladders or metal longitudinal supports along wooden ladders in the vicinity of electrical conductors. Interestingly, the United States fire service may be the only agency in the United States that allows the use of metal ladders with virtually no restrictions. Therefore, in the interest of safety and the fact that metal ladders are not the lightest ladder, why are metal ladders utilized in the fire service? Answer: Cost!
Ground Ladders Part 2 Before we continue with Part 2 of "Ground Ladders," let's briefly re-address a common subject — metal ground ladders vs. wooden ground ladders. I am frequently asked, "Why do some fire departments still use wooden ladders on the fireground?" Interestingly, the question is normally asked within the parameters of "Why don't those fire departments update their fireground operations and step into the 21st Century?" Metal ground ladders have typically benefited from three perceptions among firefighters as follows: • • •
Metal ground ladders are cheaper than their wood counterparts. This is a true statement. Metal ground ladders require less maintenance than wood ladders. This statement is not true if NFPA 1932 is adhered to. Metal ground ladders are lighter than tapered truss wood ladders. In reviewing manufacturer's advertising brochures, this statement is also false.
Therefore, why do some modern fire departments (i.e., Los Angeles City, San Francisco, Bellevue, Washington, etc.) specifically use wood ladders? The answer is (in capital letters) SAFETY! Most firefighters are unaware that FEMA statistics indicate that metal ladders cost the U.S. Fire Service approximately one firefighter per year! However, it is also noteworthy that personnel who have utilized both types of ladders will readily agree that tapered truss wood ladders climb with less flex, are easier to use in cold weather, "shoes" will stay planted easier and longer, and are easier to carry due to rounded edges of the beams. Therefore, the current use of metal ground ladders is not based on ease of implementation and safety, it is based on tradition and cost.
There are many guidelines used in selecting and placing ground ladders into operation. The following is a review of basic considerations: Timely and effective ladder placement should be an initial priority for two basic reasons: • •
It lays the groundwork for a timely, coordinated attack on a structure fire. Normally, it is the only time at a structure fire that an officer has the entire company together and can effectively control and coordinate ladder placement prior to committing company personnel to other fireground operations.
Ladders left on apparatus are not effective on the fireground. In fact, this basic rule can be expanded to include all types of equipment as follows, "Equipment left on apparatus parked in the street is not usable on the fireground"! The largest ladder that requires the most personnel should be raised first. Always use the proper type and length of ladder. If the length or placement is incorrect, replace the ladder or correct the problem. Do not let an inconvenience become a fireground compromise or potential safety consideration for the balance of an incident. When lifting ladders from apparatus or the ground, use the muscles of the legs, arms, and shoulders. Coordination of effort between team members is essential for smooth operations. Ground ladders should be properly spotted, shifted, or moved into the correct position for raising prior to being raised due to the following considerations : • •
Ground ladders are most easily and safely maneuvered while on the ground. Once a ground ladder is in a vertical position, additional movement increases the chances of losing stability, striking wires and other similar obstacles.
When carrying a ladder to an objective and it is necessary to change direction of travel but it is unnecessary or undesirable to turn a ladder end for end, a simple pivot to reverse direction of ladder personnel can be used. Normally, the operations necessary to lower ladders are the reverse of those used in raising. Be sure the appropriate area is clear before lowering. Check overhead and ground obstructions. If more than one person is responsible for lowering the ladder, the base person is responsible for the safety of the operation. Avoid the tendency to work too fast when lowering a ladder. Do your ladder SOP's clearly designate a "base person"? Straight ladders are normally lighter and require less time to place into operation than extension ladders. Extension ladders offer a variable height factor. Straight ladders with rungs set in the main beams should be raised with the rungs away from a building, and extension ladders should be raised as follows:
• •
With the fly away (or on the outside of the main section) from an objective for metal and fiberglass extension ladders. With the fly between the objective and the main section for truss wood extension ladders with rungs set in the main beams.
On extension ladders, the fly section should be strapped to the main section (before climbing) by placing a strap around the bottom rung of the fly section and the adjacent rung of the main section. The base of an extension ladder may be shifted toward a building or to either side after it is lowered into an objective. Do not move the base away from an objective unless the sections are strapped together. When shifting large extension ladders (prior to strapping the fly), one member shall capture the halyard on the front side of the ladder to prevent the dogs from accidentally unlocking, resulting in a premature release of the fly section. Some extension ladders can be separated to make two straight ladders. However, it is not practical on ladders with a halyard. If deciding between different lengths (20- or 24-foot, 24- or 35-foot, etc.) for laddering an objective, choose the longer ladder for the following reasons: • • •
The ladder will reach the objective (length). The ladder will be heavier and wider. This improves stability and is easier to climb (strength and access). Additional extension of the ladder above an objective (visibility).
Ground ladders that need multiple personnel for implementation require a specific person of a ladder team to be responsible for communications (timing and placement of ladder) between team members. This is usually handled by the base person unless otherwise specified. The two basic methods of raising ground ladders are the flat and beam raises. Overhead obstructions, limited space and other similar considerations will dictate the type of raise that should be used. The required working height of a ladder can be estimated as follows: • • •
Habitational occupancies are approximately 9-feet from floor to floor. Commercial occupancies are approximately 10-feet from floor to floor. The average windowsill height above a floor is approximately 3-feet, allow 4-feet for window height, and any extension above an objective must be added to determine the approximate length of ladder.
The proper climbing angle for a ladder is approximately 70-degrees. This angle allows personnel to climb a ladder in an erect posture while comfortably placing their hands on the rungs of a ladder. To quickly achieve 70-degrees, the base of a ground ladder is normally placed one-fourth of the working height (vertical distance from grade level to objective) from the base of a building. When ascending a ladder, look toward the rungs just above the head. Climb with hands grasping the center of the rungs, body erect, shoulders at an arm length from the ladder, knees in-line with the body, balls of the feet on the rungs. The legs carry the weight and the arms maintain balance and stability. Do not reach up to pull with the arms. Ascend briskly but smoothly, feet and hands working together, taking every rung with the feet and every other rung with the hands. Descending, look toward the rungs just below the head. Grasp each rung alternating hands. The feet and hands should contact appropriate rungs at the same time to develop a rhythm that is essential to smooth and safe climbing. Ladders placed for climbing should be positioned with the base of a ladder resting evenly on both shoes. If a ladder footing is sloped, the unsupported down-slope shoe can be supported with a wedge (i.e., apparatus chock block) to level the ladder and provide "4point contact." If possible, a ladder should be placed to the windward side of an objective. This will keep personnel on the upwind side of any contaminants. There should be a minimum of two ladders to a building. At least two ladders should be placed to a roof, preferably at opposite ends or at least two sides of a fire so there will be more than one way off a roof. On large structures, all four corners of a fire building should be laddered.
Ground Ladders Part 3 This article will conclude our three-part series on ground ladders. Ladder the strong areas of a building or roof. Always consider the strong areas of construction and the area that will be traversed. Areas such as pilasters, hips, valleys, and ridges offer excellent areas to place a ladder. Remember that one of the best areas to place a ladder is to a corner of a building. The corners of a building are considered a prime location for ladders for the following reasons: •
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No horizontal openings. Windows, doors, and vents are not usually found in corners. Placing a ladder over a horizontal opening is inviting the possibility of a burned ladder and losing a means of egress. Strength. Structural stability is enhanced where two walls and a roof are tied together.
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Location. When ventilation operations are completed, the location of a ladder can be easily determined by looking at the corners. This is an asset at night, in smoky conditions, or when immediate egress is necessary. Access. By laddering the corners of a structure, the entrance to a building is generally avoided. Therefore, hose lines that are being deployed through doorways, etc., are not competing for space with ladder operations. Hip roofs. Hips converge at corners. Therefore, when laddering the corner of a structure with a hip roof, personnel will step off a ladder and onto a hip.
Place initial ladders away or opposite from the location of a fire. This procedure allows personnel to start and return to the strongest area (unburned) of a building. Ladders should extend above a roof or parapet wall enough distance so they are readily visible. Ladders placed in windows and on fire escape balconies should only extend onefoot above the sill or rail to prevent blocking access and egress. When placing a ladder to a window, three options should be evaluated: •
•
•
If the tip of a ladder is placed just below a window sill, the ladder will not block the window opening for personnel who need to enter or exit through the window. Although this operation enhances egress-ingress through a window opening, it should be remembered that personnel inside the building will not be able to identify the window with the ladder. This placement is normally preferred for most window operations. If a ladder is not supported at all four corners (i.e., ladder footing is sloped, resulting in a loss of four-point contact), the ladder should be placed on the downhill side of a window sill with the tip of the ladder just over the sill and beam touching the downhill side of the window frame. These two factors will prevent a ladder from moving away from the supporting window frame as it is being climbed. If a ladder is placed to the side and above a window sill, it can enhance ingressegress through a window opening. However, as personnel transfer their weight from the ladder to the window sill, the ladder can be inadvertently pushed away from the window, creating a dangerous condition for personnel. Additionally, personnel inside the building will not be able to identify the window with the ladder. In no case should a ladder with less than 4-point contact be placed to the side and above a widow sill.
When necessary, ground ladders should be secured to objectives through the use of: • •
Ladder straps which can be strapped directly to building features (fire escape balconies, pipes, etc.), or ladder straps and hay hooks. A rope between the bottom rung and a building feature (pipe, etc.). This will keep the base of a ladder from moving outward.
When climbing a ladder, at least one hand should grasp the ladder to provide security and stability. Tools can be carried by straps, slings, or moved with drop cords. If necessary, a hand carrying a tool can provide security and balance by positioning the hand and tool behind a ladder beam with the wrist cocked against a beam. While working from a ladder, personnel should not overextend their horizontal reach. Overextension can suddenly overbalance or twist a ladder and cause a ladder to slide against an objective. If necessary, reposition the ladder or lock-in to the ladder. This will limit the reach of personnel. Stability and safety are the key considerations. Before stepping off a ladder, ensure the stability of the landing area. Although a roof may look normal, fire may have weakened the underside of a roof so it is not capable of supporting additional weight. Stability can be tested by sounding with a rubbish hook, pike pole, axe, or other similar tool. Once ladders have been spotted to an objective and ascended by personnel, never remove the ladder(s) unless personnel who have used the ladder are aware of its removal. Some structures have tall parapets. If a parapet is of excessive height (over 5-feet) and it is necessary to place a ladder to the parapet to access the roof, a roof ladder should be placed adjacent to the ladder at the top of the parapet to facilitate access and egress from the roof to the top of the fascia (and ladder). Hooks should be opened and placed over the parapet to assist footing for personnel using the ladder. When laddering fire escapes, the top of a ladder should extend a maximum of one-foot above railings. Ladders should be spotted adjacent to fire-escape ladder handrails and strapped to minimize side loads while personnel are climbing the ladder. Avoid laddering to areas that may interfere with the use of fire-escape drop ladders. Consider releasing drop ladders for use by occupants and to keep drop ladders from prematurely releasing during an incident. Roof ladders should be used on all pitched or sloped roofs where footing is precarious. Remember that pitched-sloped roofs are always steeper in reality than when viewed from the ground. Roof ladders used for roof ventilation operations should be placed on a roof where ventilation operations are anticipated. Therefore, initially position a ground ladder (if possible) near or next to the section of roof to be ventilated (and on the windward side of the anticipated ventilation operation). This will facilitate placement of a roof ladder on the appropriate section of roof. This results in a straight path to the ventilation area, personnel will be working on the windward section of roof, and a quick route back to the ground. To complement the use of ground ladders, consider the use of aerial ladders on any structure equal to or larger that a two-story dwelling.
When appropriate, first-in truck officers (or other appropriate personnel) should relay additional ladder requirements to incoming companies (such as the need for additional ladders, proper location, etc.). Drop bags can be effectively utilized in concert with ground ladders to hoist or lower tools and hose lines during above ground operations. When it is not possible to secure the top of a ladder from which a hose stream must be used, the ladder should be used at a flatter-than-normal angle. The base should also be secured.
Portions of this article are reprinted from Truck Company Operations by John Mittendorf. © Copyright Firenuggets.com 2002 •
