Gone are the days of using only a wrecking ball and crane for demolition work. Today, demolition crews employ more controlled methods of demolition, such as dismantling a structure in a manner that allows crews to control where the debris falls and leaving portions of the structure intact for renovation. In addition, controlled demolition often involves using more traditional construction equipment, including compact excavators, to break up, sort through and haul away demolition debris.
"The size, the swing, the reach, and the versatility of compact excavators are perfect for demolition duty," said Bill Parker, Terex Construction product manager. "And despite their smaller size, compact excavators really do have the power to take on demolition work."
Other compact machine options often aren't as productive as compact excavators on demolition sites. For example, skid steers have the power and versatility to tackle demolition work but have limited reach, and loaders with a wider tail swing can't maneuver as easily inside a building.
Compact excavators also save on tedious manual labor. They get the job done faster and more efficiently than hand labor would, saving time and money for the contractors and physical stress on the crews.
Whether a compact excavator is being used to demolish a home, an office or retail building, a casino, a hospital, a road, a bridge, or a parking garage (to name just a few), excavators are designed to grapple, shear, hammer, break, cut, compact, and scoop up construction debris on demolition sites. Attachments enable compact excavators to perform many different jobs around a demolition site.
Compact excavator attachments are designed to tackle all types of structural debris, such as steel, brick, wood, concrete, glass and drywall. Common attachments for demolition are hydraulic thumbs, grapples and hammers (or breakers). Other attachments that also find a lot of use on these sites are cutting wheels, compactors and shears.
And, compact excavators aren't just used for the actual demolition work. These machines also play a large role in handling the debris during the cleanup process, such as segmenting recyclable items from the construction materials, and loading the material into trucks to be hauled away. Buckets are essential attachments for this stage of work.
"But no matter what attachment an operator wants to use on a demolition project," says Parker, "the key to productivity is to make sure the machine's hydraulic flow is matched to the attachment, and that it is easy for operators to change out and operate the attachment." For instance, quick coupler systems make it fast and easy to change attachments. And, auxiliary hydraulics offer flexibility in adding attachments.
Parker further explained that each manufacturer designs its compact excavators differently to meet customer demands. "Terex® excavators, for example, are engineered with an auxiliary hydraulic circuit that has an open return and are plumbed out to the dipper stick. This provides customers with immediate dual function capability — no switching back and forth."
Changing job site requirements have dictated how the designs and engineering of compact excavators have evolved. Today, most compact excavator manufacturers incorporate features into their designs that keep these machines safe and productive in the harsh environments of demolition sites.
For example, a Roll Over Protective Structure/Falling Object Protective Structure (ROPS/FOPS) system is standard in the cab design from most compact excavator manufacturers, but if a compact excavator is going to be used for demolition tasks, the unit should have an enclosed cab with steel grating or polycarbonate polymer windows to prevent falling objects from piercing the cab and causing potential harm to the operator. In addition to the protection that the machine's design offers, the Occupational Safety and Health Administration (OSHA) requires all operators to wear a hard hat and safety glasses while operating a compact excavator in a demolition zone.
The cab should also be designed with a pressurized ventilation system to minimize the exposure to potentially hazardous dust during demolition operations. Additional protective guarding is recommended on the engine compartment. "The dust created during demolition can also cause damage to the engine and the machine's other vital organs," Parker said.
The hydraulic hoses and boom cylinders also need to be protected during operation on demolition projects. Each manufacturer has its own rationale for designing the placement of the cylinders and hoses under, in or on top of the boom. "Terex, for example, positions the boom cylinder on top of the boom to protect from impact with loads," Parker said. "We also invert the cylinder so that the seal is facing down, which prevents dirt buildup and protects the cylinder from the elements."
When the machine is working in a confined environment — for example, inside a building doing parallel-to-wall operations — a zero tail swing design, along with an offset boom with built-in swing, provides excellent operator visibility and machine maneuverability. Using zero tail swing machines should result in less damage to peripheral structures and to the machines during operation because the movement of the machine is contained within the tracks.
A compact excavator's narrow profile and light footprint are also critical for indoor work. For example, on building renovation projects, smaller excavators can get in where larger machines can't, and replace hours of manual labor as crews gut a building's existing interior and prepare the space for remodeling. Smaller units are designed to fit through standard-sized doorways and are light enough to be loaded onto freight elevators and moved from floor to floor. With their smaller design, compact excavators excel at working on multiple levels of a building, as well as in basements, orchestra pits in stadiums and theaters, subway tunnels, and underground parking garages.
Other features that come in handy on indoor demolition sites are variable-width track systems for easier access through narrow openings, as well as built-in lift points that allow the units to be placed in basements or craned to upper floors.
"Also, it is important to have catalytic converters or scrubbers on your compact excavator when operating in areas where diesel exhaust needs to be restricted. These converters not only reduce engine emissions but also the noise," Parker said. A few manufacturers offer electric units for use in areas with zero tolerance for emissions, like grocery stores, hospitals and shopping malls.
"To keep a compact excavator up and running in the demolition zone, operators need to do a visual inspection of the machine everyday," Parker said. Operators need to make sure that the hydraulic hoses are not scored or pinched, and that the protective guarding is intact. Also, greasing the machine everyday before start-up is recommended, as well as thoroughly cleaning the machine at the end of the day to make sure that dust contaminants and corrosive substances don't affect the performance of the machine.
It is also important to check the attachments for wear and tear. "It is a good idea to hard face the implements you are using," Parker said. "And check to make sure the hammer is properly charged, and the tool inside the hammer has not been weakened or otherwise compromised."
Another key to productive operation is that operators must always follow the manufacturer's recommended guidelines for safe operation — it is especially important to follow all weight requirements for the compact excavators and the attachments. Stability is critical for safe, productive operation.
As the trend grows to renovate older buildings for new uses — such as loft apartments, boutique retailers and new office space — controlled demolition and compact excavators are gaining in popularity on demolition job sites.
"Compact excavators are ideal for use on any demolition site where space restrictions don't allow larger, more traditional demolition machines to be used, as well as where manual labor would be time-consuming and cost-prohibitive," Parker said.
Feature provided by Terex Construction Americas, Southaven, MS.