Equipment
Truck Tech: February 2012

The sky is the limit – or so they say. The beginning of 2012 means a new year of planning for any fire department – a fresh start and, for maintenance divisions, the scheduling of preventive maintenance programs for the fleet. Aerial maintenance can be done at any time of the year. Because there is so much to cover, I’ll start with some basics, beginning on the apparatus bay floor with the crew assigned to these pieces of equipment.

Aerial ladders were first invented in the late 19th century in response to the need for longer ladders to help firefighters reach the upper storeys of tall buildings. The first aerial ladders were made from wood and were raised by a system of hand cranks and moved by horse-drawn teams. Modern aerial ladders are made from strong materials, such as aircraft-grade aluminum or steel, and can be quickly raised by means of hydraulics or electric motors.

Most ladders are constructed by combining two or more sections of reinforced ladder so that that they nest within each other when retracted. These ladders are more strongly constructed than standard ladders, and the sections will often have a box-like profile when viewed from the side, with diagonal cross bracing that may resemble bridge or roof trusses. An aerial ladder is designed to be self-supporting until it reaches its target, and some are capable of remaining freestanding, even with the weight of one or more firefighters.

There are many categories of aerials: extendable straight ladders, waterway-equipped ladders, platform-equipped ladders, tillers, tele-squirts, tele-booms, snorkels, articulating arms . . . the list goes on.

Modern aerial ladders are made from strong materials, such as aircraft-grade aluminum or steel, and can be quickly raised by means of hydraulics or electric motors.
Modern aerial ladders are made from strong materials, such as aircraft-grade aluminum or steel, and can be quickly raised by means of hydraulics or electric motors.
Initiate all PTO-controlled equipment in sequence (based on the builder’s instructions) before the aerial is fully engaged to make sure it is in working order.
Interlock systems and bed zone warning lighting must be tested during aerial truck checks. Photos by Chris Dennis

Regardless of the type of equipment you have, you want it to last, so preventive maintenance is important. If a piece of equipment is deemed unsafe then it must be removed from service until it can be repaired, tested or recertified, and returned to service. The firefighter’s job is to save lives and save property, and if the equipment is not looked after, the safety of firefighters and those they protect will be jeopardized.

If you do not have a truck-check schedule in place, this should be done first. The 2001 and 2012 versions of NFPA 1911 (Standard for the Inspection, Maintenance, Testing, and Retirement of In-Service Fire Apparatus, 2007 edition) are a good start.

The size of your department, and whether it is full time, volunteer or composite, may determine how often the equipment is checked. In my department, truck checks are done weekly. All original equipment manufacturer recommendations are followed, based on which manufacturer built the truck and using NFPA 1911 as a guideline. Post-trip inspections are done on everything, after any response, no matter how big or small. The Vaughan Fire & Rescue Service mechanical division and training division designs and creates training programs to educate our firefighters as aerial operators and on their roles in preventive maintenance on their apparatuses.

OK, let’s get to work. Our first inspection at the fire station will be on all operational systems. These systems are to be tested by a trained, qualified person. Each fire-truck builder designs a program to check all systems. (I am talking about an NFPA-compliant-built piece of equipment. The standard means that the apparatus will be constructed and built with certain features that are standard on all NFPA-compliant fire trucks.) The trained firefighter should position the truck and deploy the aerial. The aerial safety warning systems, interlock systems, stabilization, bed zones, creep controls, monitor and master stream functions, emergency lighting, scene lighting, rope-rescue attachments and remote-control functions, among other things, should be checked.

The trained firefighter begins the inspection with the truck on level ground with enough room to fully extend the stabilizers. The park brake is applied and two sets of wheel chocks are in place at the steer tires (be sure the wheel chocks are in good shape and are not something the dog chewed). Large, missing or bent pieces of rubber or metal material compromise the job the wheel chocks are to perform, so replace them if they are damaged.

Check visually, then walk around the truck to be sure no one is touching the apparatus or anywhere near it, and that the platoon chief or a civilian you cannot see hasn’t pulled up alongside it. When the stabilizers are deployed, people, places or things can be hurt or damaged.

Be sure you observe what is overhead. Hydro wires or any other obstruction in a controlled area should be out of the operational test zone. Deploy the steps or ladder (whichever feature is on your truck that provides access to the upper turntable control console) and be sure that this equipment is secure and is not damaged.

Look up and visually inspect the ladder from the ground, checking for burn marks, scratches, dents or bends. Doing this will help to prevent serious injury and any of these imperfections can be quickly repaired. If the ladder has come in contact with enough force against a stationary object, a beam or a rung could be bent, which decreases the structural integrity of the ladder. If so, the ladder should be taken out of service and immediately assessed by a qualified mechanic.

Check and note the level and condition of the aerial hydraulic oil level. A milky colour means there’s water in the oil; if the oil is black in colour there’s dirt in it. If the oil filler cap to the hydraulic tank is missing, the oil can be contaminated by any number of things. All of these problems can mean costly repairs if they are not detected early. Each manufacturer recommends a hydraulic oil filter replacement as well as hydraulic oil replacement at specific intervals. It is recommended to follow these guidelines to make your equipment (and warranty) last longer. Be sure not to cross-contaminate oils if you have to add hydraulic oil.

The next step is to start the engine (using the engage-aerial-hydraulic function, usually found in the cab).

This may be accomplished using multiplexed switches, simple rocker switches or a power take off (PTO) shift lever. Next, engage aerial electrics, again by engaging a switch in the cab. These switches must turn on and off smoothly. Ensure that all manufacturers’ safety labels are in place and secure. If any other PTO-controlled equipment is to be initiated, ensure this is done in the correct sequence (based on the builder’s instructions) before the aerial is fully engaged. It would be a shame to get everything up and running and then have to go back and turn on another PTO function and possibly have to disengage the aerial mode.

With the engine running and the aerial hydraulics engaged, look under the truck for obvious signs of hydraulic leaks. Pressure in the system will quickly cause the hydraulic oil to leak if there are problems. No leaks? Great. Turn on all aerial-related electric, emergency and scene lighting. Walk around the truck again to be sure all the lights work and that they are all secure and are not falling off. Lights mounted on the tips of aerials – rear-mount or mid-mount – are easy targets for tree branches and other items overhead. If you notice a light hanging off, report the deficiency and either remove it or have it corrected to avoid a safety hazard. If the stabilizers are equipped with lighting that turns on only when aerial electrics are engaged, be sure they work, that they are not water contaminated and that the lenses are not broken.

With the aerial on level ground and all circle checks complete, it is time to deploy the ground stabilizers. I will use our truck as an example for this exercise. It has a 17-metre steel ladder and two stabilizers mounted at the rear left- and right-hand sides. The controls are mounted at the rear of the truck. With all systems running, both visual and audible warning systems should be working. Remove the ground pads from their secure mounting spot and position them out to where the stabilizer will be in full extension. If equipped with a ground-level indicator, check for position and the slope. If the ground-level indicator is damaged, report, repair or replace. Rather than a visual inspection, this will help you to determine that the truck is level once the stabilizers are out and down. If your truck is equipped with an aerial stabilizer short set or plant illumination bulbs and beepers, all these items should be working. There are lockouts built in for the operator’s protection that must be checked. How do you know that you are safe if a system lockout does not work and allows you to do something with the aerial that should not be done out of sequence? Follow the manufacturer’s guidelines on this item to be sure your truck is safe to operate.

The sequence of lockouts should work.

It is important to make sure that all bulbs are lit and go out when they are suppose too. I have seen on more than one occasion a short set done to verify that the warnings are working but the bulb has stayed lit, indicating that it is OK, when it actually does not turn off. Know the operation and sequence of your equipment and you will know what should be on and off at certain times.

Being complacent on the job can cause injuries. Treat every inspection as if it were the first one ever done and that your life and the lives of others are on the line.

Using the electronic paddles or hydraulic control levers, slowly move the stabilizers, one at a time, out and/or down, being sure the ground pad and the surface you are working on is solid. Let go of the lever or paddle and be sure it bounces back to its neutral position on its own, and that the hydraulic function you were doing has stopped. Keeping these areas clean and well lubricated prevents sticking. Send the stabilizers to full extension until they stop. Check for hydraulic leaks in the stabilizer storage area. If equipped, check the ground lighting (a burned-out 50-cent bulb in the daylight is nothing, but at night it’s a big deal). Extend the down stabilizers to the ground pads. Begin to extend and level the truck as per manufacturer’s guidelines. Once the truck is level and all safety interlocks are in place, remove and inspect the plant extension cylinder locking pin for cracks or poor welds, and put it into its hole. The truck is now secure.

Wearing correct PPE, climb to the turntable control console or move to the aerial control panel if it is mounted on the side of the truck. If it is on the side, be sure to slide out the foot tray and use it. If the foot tray does not come out easily, or the bearings are rusted and broken, have the tray repaired. This tray is your safety should you ever be in contact with live hydro wires. If it did not slide out, and you and your crew were called into action with your aerial and an overhead-wire incident happened, you would not be insulated from the ground.

Be sure all occupant side railings and man-saver bars are in place and working. Inspect all controls for sticking and check that hydraulic gauges and lighting on the console work.

If the truck is equipped with a communication system, make sure it works at the control console and at the tip of the aerial.

Before raising the ladder, check the monitor and nozzle functions. At some point, try flowing water through the waterway and nozzle. This will determine leaks and the speed of the nozzle and whether flow patterns change while under water pressure. If any of these fail when testing with flowing water, a deficiency must be reported.

Take a walk up the ladder to make sure rungs are not bent. The other rungs can be checked once the aerial is fully extended. If the ladder is steel, be sure rung covers are secure, that there are no tears, that the ladder is not misshapen from heat or corrosion, and that the rungs are not bent. If equipped with rung lighting, inspect all lights. Making your way to the tip, be sure all tip controls work and are free. It is important that this area stays clean and lubricated, especially in the winter.

Once back at the control console, engage the aerial hydraulic button and raise the ladder, being cognizant of your surroundings. Run the aerial as you have been trained: up, down, in, out, full left, full right. With the stabilizers fully extended and deployed down, a short set or short-jack condition should not occur. If it does, something is wrong. With another crew member, create a short-jack condition and operate the aerial on that side to determine (as per the manufacturer) that the interlocks are working.

If the truck is equipped with body armour (a feature that does not allow a rotating aerial to come in contact with a cab or body), be sure it is working.

Visually inspect cables, guides and rollers – don’t touch, just look and report.

Check egress at the ladder tip. Check for hydraulic lift cylinder leaks and hydraulic cable extension and retraction cylinders for leaks or obvious signs of chipping or dents in the chrome cylinder. A dent or chip can cut packing and cause an oil leak.

When bringing the ladder back to its resting place, be sure all bed-zone functions are lit and working and that any and all overrides are working.

If the monitor and nozzle have a stow zone, be sure it works. If all is well, bring the ladder to its nested position or to bed. Once the ladder is down, be sure to hydraulic bed it by holding the down lever and watching the hydraulic pressure gauge climb to the manufacturer’s set pressure. This happens instantly when the lever is applied, and when the process is completed, the hydraulic helps to lock the ladder in place.

You can now make your way back down and retract the stabilizer system. Turn off all aerial functions in the cab. Double-check all shut-down procedures, report any and all findings and, if all is well, you are in service and have just performed a large part of aerial operational preventive maintenance.

Next time, we will get into the mechanics of the aerial, including cables, sheaves and swivels, and we will touch on platforms.

Remember: rubber side down, my friends.

Chris Dennis is the chief mechanical officer for Vaughan Fire & Rescue Service in Ontario. He can be reached at Chris.Dennis@vaughan.ca