Adams, Aerials

Aerial or Platform?

Issue 10 and Volume 23.

BILL ADAMS

Asking about preference for an aerial ladder or an aerial platform is a loaded question. There are too many unknowns to formulate an appropriate answer. One could say it depends on the weather and terrain, which is a military axiom—a catch-all phrase sometimes used to justify a decision. Preference should only be contingent on determining the environment where the device will be used, defining the specific and secondary tasks to be accomplished, evaluating where it will be housed, acknowledging the staffing available to operate it, and understanding the financial constraints when purchasing one. My analysis is limited to rear-mount appliances, showing no partiality for steel vs. aluminum construction or for cost. Nor will I espouse whether the device should be equipped with a pump.

Elevated Master Stream

I am not in favor of firefighters being “on top” of any aerial device directing a stream; however, if the intended use is primarily or regularly as an elevated master stream, I prefer the platform. It is safer. My first choice would be to invest in a drone to observe an elevated stream’s direction and effectiveness. It is inexpensive, and it keeps firefighters out of harm’s way.

National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus, Chapter 19: Aerial Devices, sentence 19.2.9.1 says two folding steps shall be provided for an aerial ladder pipe-monitor operator, each with a minimum of 35 square inches. Or, per sentence 19.2.9.2, a single step with a minimum of 200 square inches can be provided. An elevating platform must have a minimum standing area of 14 square feet (more than 2,000 square inches) per sentence 19.7.6.1. Which would you rather stand on for an hour? Having prepiped breathing air is another advantage of a platform.

When an aerial ladder is equipped with a prepiped monitor, Section 19.6 says it must have a minimum 1,000-gallon-per-minute (gpm) capacity. Section 19.11 says platforms of 110 feet or less in rated height shall be equipped with a water delivery system with one or more monitors capable of flowing 1,000 gpm.

NFPA 1901 criteria are minimum requirements. Aerial device manufacturers may exceed the NFPA flow requirements, and many do. In many instances, especially with aerial ladders, high flow rates may affect a device’s rated weight capacity and possibly minimize the allowable operating envelope when flowing water. Read the fine print when specifying one. Purchasers should consider determining a desired flow rate before evaluating devices on the market.

Equipment Hauler

It is easier and safer to transport saws and multiple hand tools in a platform than it is to manually carry them up an aerial. Depending on the amount of equipment to bring to the roof of, say, a seven-story building, firefighters may have to make multiple trips up and down the stick. Safety oriented old-timers believe in “one hand for me and one hand for thee.” The steeper the angle of the aerial, the harder it is to climb—with one hand. Aerials have limited room to mount tools on the fly section. Platforms, by nature of their design, have more room.

Threading the Needle

Ladder company (aka truck company) operators in older urban areas with multiple overhead wires can attest to the difficulty in maneuvering a platform through a maze of overhead wires to reach an objective. Photographs abound on the Internet of working fires in cities like Providence, Rhode Island, and Boston, Massachusetts, where aerial devices are positioned where I consider to be “too close for comfort” to electric wires. One manufacturer’s platform “bucket” is a hair over eight feet in width by just over four feet in height. The height does not account for a firefighter operator in the bucket peering over the rail to observe obstructions. It is possible a platform, because of its design and size, can’t physically or safely reach its target.

Threading the needle is also applicable to structures surrounded by trees and telephone poles. Thirty-plus years ago, I had the opportunity to fly a platform during an aerial vs. platform evaluation on multiple homes in a residential response district with numerous trees, poles, and overhead wires. The platform was not chosen.

Hydraulic Ventilation

Mentioning hydraulic ventilation may cause apparatus manufacturers and training officers to lose their prime and go into full vapor lock. I do not advocate hydraulic ventilation and admittedly have not personally seen it done in quite a while. I have seen it done in the past with both Maxim and LaFrance steel aerials. Justification, whether reasonable or not, can be desperate times require desperate measures. Limited staffing and an immediate necessity for ventilation may influence a decision to pop a window or two with an aerial ladder—easily done with a single firefighter flying a stick and virtually impossible with a platform with a sole operator on the turntable. Damaging the stick and its accoutrements, voiding warranties, and incurring the wrath of irate white coats are not addressed.

Heavy or Light Duty?

NFPA 1901 does not address “light” duty or “heavy” duty aerial devices. Those terms are used by apparatus manufacturers’ marketing and salespeople to describe and enhance the value of their own product. There is nothing illegal, immoral, or deceptive in doing so. I caution purchasers not to specify something that does not exist and cannot be evaluated when writing apparatus specifications. Use care when evaluating manufacturers’ advertising and claims. NFPA 1901 Sentence 19.3.1 states that aerial ladders must have a minimum 250-pound rated capacity under specific conditions. Sentence 19.3.3 states that rated capacities in excess of the minimum must also be in 250-pound increments. NFPA 1901 sentence 19.8.1 rating requirements for platforms are 750 pounds with no water in a delivery system and, per sentence 19.8.2, 500 pounds with water in it but not flowing. And, as previously mentioned, ratings are subject to specific conditions delineated in the standard.

Purchasers should be aware that manufacturers may and do advertise ratings and capacities in excess of NFPA 1901 with their own stipulations for device positioning, flows, and number of personnel on the device. There is nothing wrong in doing so. Some manufacturers are better at marketing their product than others. Some are forthright in describing their product. Lisa Barwick, director of business development, Aerial Products for Pierce Manufacturing, says, “Pierce uses the NFPA requirement, which states, ‘The rated capacity of the aerial ladder shall be a minimum load of 250 lb ….’ as Medium Duty. Pierce defines anything with a 500-lb tip load or above as Heavy Duty.”

There are some general rule-of-thumb differences when comparing a minimum 100-foot rear-mounted stick and a minimum 100-foot rear-mounted platform when both have similar components such as tandem axles, pump, tank, cab size, and compartmentation. These are approximate and can vary from manufacturer to manufacturer and between like devices with different weight ratings.

Wheelbases for platforms could be from one to two feet longer than aerials. Platforms could weigh 15 percent or more than aerials (check bridges and firehouse floor ratings!). Platforms generally require higher front and rear gross axle weight ratings. The base sections of aerials with higher weight ratings are higher and wider than lower rated aerials. The internal width of the fly sections of higher rated aerials can be 15 percent wider than the lower rated devices. The internal width of the fly section of a platform can be 25 percent wider than a higher rated aerial. Overall height with prepiped water is about the same: around 11 feet 7 inches. Jack spreads on platforms are generally wider than on aerials.

Aerial advocates believe anything that can be done with a platform can be done with an aerial, albeit the platform is safer and easier for the firefighter. They also say the stick has a lower initial cost and less overall maintenance in the future. The dilemma for apparatus purchasing committees is to evaluate the number and scope of alarms and weigh firefighter safety (or comfort) vs. additional cost.

BILL ADAMS is a member of the Fire Apparatus & Emergency Equipment Editorial Advisory Board, a former fire apparatus salesman, and a past chief of the East Rochester (NY) Fire Department. He has 50 years of experience in the volunteer fire service.