Understanding hydraulic hammer characteristics and proper application matching is essential for maximizing productivity and equipment lifespan. This comprehensive guide covers the key specifications, selection criteria, and uses of hydraulic breakers across different industries.
What is a Hydraulic Hammer?
A hydraulic hammer (also called hydraulic breaker or rock breaker) is a percussion attachment that connects to excavators, backhoes, and skid steers. It uses the carrier machine's hydraulic system to deliver high-impact blows for breaking rock, concrete, and other hard materials.
Basic Operating Principle
The tool operates by using pressurized hydraulic fluid to drive a piston back and forth inside a cylinder. When the piston strikes the chisel or working tool, it transfers kinetic energy to break apart material. The effectiveness comes from delivering repeated impacts at high frequency while maintaining consistent force.
Development History
Hydraulic breakers emerged in the 1960s, evolving from earlier pneumatic hammers to become standard equipment on construction sites worldwide.
Key Characteristics and Specifications
Impact Energy
Impact energy is the most critical specification for hydraulic hammers, measured in joules (J) or foot-pounds (ft-lbs). However, comparing breakers based on power ratings in product literature is challenging because when specifications don't indicate an AEM-certified rating or are categorized as a foot-pound "class," the figures are essentially manufacturer estimates and lack a concrete basis for comparison.
Understanding Impact Energy Classifications:
Small hydraulic breakers have up to 1,200 ft-lbs (1,627 Joules) and are typically used in concrete and light duty work. Medium hydraulic breakers range from 1,200-4,000 ft-lbs (1,627-5,423 Joules) and are used in both concrete and rock applications. Large hydraulic breakers exceed 4,000 ft-lbs (5,423 Joules) and are typically used in rock and large scale concrete demolition projects.
Operating Frequency
Modern hydraulic breakers feature impact rates ranging from 500-1,200 blows per minute, though some smaller models can reach higher frequencies. The frequency affects how quickly material fractures—higher frequencies generally work better for concrete demolition, while lower frequencies with higher energy suit hard rock applications.
Hydraulic Requirements
Hydraulic breakers require specific flow rates and pressures to operate correctly:
- Flow Rate: Measured in liters per minute (L/min) or gallons per minute (GPM)
- Operating Pressure: Typically ranges from 100-220 bar (1,450-3,190 psi) depending on the breaker size
If the maximum flow on an excavator is 100 GPM total, the maximum flow requirement by the breaker should not exceed 50 GPM. If the flow required is 60 GPM, you must use a bigger excavator or reduce the size of the breaker.
Weight Classes and Carrier Matching
Matching Formula and Guidelines
Proper weight matching between the hydraulic hammer and carrier machine is critical for safe and efficient operation.
If you measure by the weight ratio, the hydraulic hammer should weigh only 10% of the carrier weight. For example, a 20-metric-ton excavator weighing around 44,092 pounds would need a hammer weighing less than 4,409 pounds.
Each breaker has a 'Recommended Carrier Weight' range assigned. If the operating weight of the carrier falls within this range, the carrier will safely handle this model of breaker.
Weight Class Categories
Mini/Compact Class
Small hydraulic breakers are often placed on skid steers, small mini excavators, or walk-behind excavators. These hammers have a shorter stroke and lighter strike piston, enabling them to cycle as quickly as 1,800 blows per minute, with impact power between 200 and 1,000 ft-lbs.
Example specifications:
- TMG-HB90S for 45-100 HP skid steers delivers 1,030 J impact energy with 500-800 BPM
- TMG-HB90Q for 6-9 ton excavators/backhoes provides 1,030 J impact energy with 500-900 BPM
Medium Class
Medium hydraulic breakers typically range from 1,500 to 5,000 ft-lbs of impact power and are carried on large mini excavators and backhoes of around 8 tons, up to 20-25 ton crawler excavators. These hammers typically handle most concrete demolition and are suitable for major trenching, underground utility work, and breaking large boulders.
Large and Demolition Class
Large-scale hydraulic hammers with impact power from 6,000 to 25,000 ft-lbs are used for primary breaking or breaking large oversized rocks in quarries and mining. The carrier must be a full-sized crawler or excavator weighing at least 25 tons, with the largest severe duty breakers requiring carriers between 50 and 140 tons.
Consequences of Improper Matching
Oversized Hammers:
An oversized breaker transmits energy in two directions: both toward the material and resonating through the carrier. This produces wasted energy and can damage the carrier.
Undersized Hammers:
If the hammer is too small, excessive down-pressure will cause the frame to twist, damage mounting adapters and produce weldment cracks.
Primary Applications by Industry
Construction and Demolition
Hydraulic breakers excel at demolition work including:
- Breaking concrete foundations and slabs
- Removing asphalt pavement
- Demolishing building structures
- Breaking reinforced concrete
For urban demolition, precision is essential—breakers can selectively break specific sections without damaging adjacent structures.
Mining and Quarrying
In mining operations, hydraulic hammers handle:
- Secondary rock breaking (oversized boulders)
- Trenching in hard rock
- Breaking frozen material in winter
- Scaling loose rock from pit walls
Mining applications demand higher impact energy and enhanced sealing for abrasive environments.
Road Construction and Maintenance
Road crews rely on breakers for:
- Removing old pavement sections
- Breaking compacted base material
- Excavating utility trenches in paved areas
- Ripping frozen ground
For all-day road work, fuel efficiency and operator comfort become important considerations.
Utility and Pipeline Work
Hydraulic breaker hammers are essential in mining, demolitions, excavations, and quarries as they chip away large boulders and concrete structures. They are adaptable and sustainable, fitting every construction need.
When installing underground utilities, hydraulic hammers break through rock layers that would stop conventional digging equipment. The ability to work in confined spaces makes compact models valuable for urban utility work.
Selection Criteria
Material Considerations
Match the hammer's impact energy to the material hardness:
- Soft materials (asphalt, soft concrete): Lower energy, higher frequency
- Medium materials (standard concrete, limestone): Medium energy
- Hard materials (granite, basalt, reinforced concrete): Higher energy, lower frequency
Hydraulic Compatibility
Matching the right hydraulic breaker to a job is a balancing act of considerations including the machine's operating weight, hydraulic flow characteristics (operating pressure, hydraulic flow rate, auxiliary flow rate), overall lift capacity, and boom design geometry.
Always verify:
- Auxiliary hydraulic flow rate (L/min or GPM)
- System pressure (bar or PSI)
- Carrier's lift capacity at full extension
- Boom type (standard, heavy-duty, or long-reach)
Work Environment Factors
Consider:
- Confined spaces: Require compact models
- Noise-sensitive areas: May need models with sound suppression features
- Underwater work: Special sealed models available
- Production requirements: Calculate daily volume needs
Maintenance Requirements
Nitrogen Accumulator System
Many medium and large hydraulic breakers include a nitrogen accumulator—a critical component that stores energy and cushions the hammer's recoil on the carrier.
Nitrogen Pressure Requirements:
The accumulator's optimum working pressure varies according to the hydraulic breaker model and external conditions. Usually, the pressure should be around 1.4-1.6 MPa (approximately 14-16 kg or about 14-16 bar).
Consequences of Incorrect Pressure:
If there is not enough nitrogen, the pressure in the accumulator decreases and striking will be less powerful. If too much nitrogen is added, the hydraulic oil pressure can't push the cylinder rod upward to compress nitrogen, and the accumulator cannot store energy.
Low impact power is the most obvious symptom when nitrogen charge is low. The breaker will feel weak and struggle to break material it would normally handle easily. The large hydraulic hoses connecting the carrier to the breaker will visibly jump or shudder during operation.
Inspection Frequency:
A hydraulic breaker accumulator should be checked for nitrogen pressure every 3 to 6 months, depending on operating conditions. For light to medium-duty work, inspection every 6 months is usually sufficient. For heavy-duty work in quarrying, mining, and road construction, inspection every 3 months is recommended.
Maintenance Schedule
Daily Checks:
Daily maintenance includes checking hydraulic oil level and condition, inspecting chisel for cracks or excessive wear, checking for hydraulic fluid leaks, and ensuring all pins and fasteners are secure.
Weekly Tasks:
Weekly maintenance should include tightening bolts to correct torque values, inspecting chisel and holder for deformation, cleaning the breaker body, checking hydraulic hose fittings for leaks, inspecting seals visually, and verifying accumulator or nitrogen pressure where applicable.
Monthly Service:
Monthly service includes withdrawing and inspecting the chisel for tip wear, checking piston surface for scoring, inspecting liners and valve assembly, checking wear bush clearance, inspecting seal kits, and verifying hydraulic oil condition.
Chisel Maintenance
Hydraulic breaker manufacturers provide minimum tool lengths to protect the breaker. Each time the hammer breaks through material, it dives forward. If the tool is too short, the dive can result in wear to the outer casing when it hits the material. The shorter the demolition tool, the more wear-inducing heat and vibration are transferred to the breaker itself.
Replace worn chisels promptly—a severely worn chisel significantly reduces breaking efficiency and can damage internal components.
Operating Best Practices
Proper Operating Technique
Positioning and Pressure:
- Position the chisel perpendicular (approximately 90 degrees) to the material surface
- Allow hammer weight plus slight boom pressure—avoid excessive forcing
- Keep carrier level when possible to reduce side loading
Firing and Material Contact:
- Maintain steady contact during operation
- If no progress occurs after 15-20 seconds, reposition
- Never continue firing in the same spot indefinitely
Avoiding Blank Firing
"Blank firing" occurs when the chisel isn't in contact with material but the operator continues firing. This causes the piston's energy to have nowhere to go, resulting in direct metal-to-metal impact and severe internal stress.
If the hydraulic hammer is operated when the accumulator is low, it lacks power and has no way to absorb spikes in the hydraulic system, which can result in damage to the excavator and hydraulic breaker. If your breaker is leaking, stop immediately—not only will the oil wash away the chisel paste protecting the demolition tool and bushings, but it indicates the striking piston is no longer riding on its seals and is scraping against the cylinder wall.
Modern premium breakers include auto-stop systems that detect blank firing and shut down within a fraction of a second to prevent damage.
Safety Considerations
- Wear appropriate personal protective equipment, including hearing protection
- Ensure all guards and protective covers are in place
- The carrier must be heavy enough to safely carry the hammer at all angles and extensions of the boom and stick without tipping or causing excessive diving when the hammer breaks through material
- Never operate equipment beyond its rated capacity
Advantages Over Alternative Methods
Compared to Pneumatic Hammers
Hydraulic breaker hammers use the hydraulic power of the carrier, which is generally more energy-efficient than pneumatic or mechanical systems, resulting in lower fuel consumption and reduced emissions.
Hydraulic breaker hammers can be easily attached to and detached from the carrier, making it convenient for operators to switch between different tools and tasks.
Flexibility and Control
Unlike chemical rock splitting agents or controlled blasting, hydraulic hammers offer immediate start-stop capability, can work in populated areas, and allow operators to adjust their approach based on changing material conditions. There's no waiting for chemical reactions or dealing with explosive permits.
Industry Standards and Technology Trends
Measurement Standards
The AEM (Association of Equipment Manufacturers) developed a standardized testing system for impact energy ratings. However, only a few breaker companies continue to promote standardized impact energy ratings, leaving buyers encountering power specifications from different manufacturers that seem to use the same unit of measurement but are actually comparing apples to oranges.
When comparing breakers, look for AEM-certified ratings or understand that "foot-pound class" designations may be manufacturer estimates rather than standardized measurements.
Modern Design Features
Modern hydraulic breaker hammers feature high-impact energy delivery, robust construction from durable materials, variable frequency and energy control allowing operators to customize performance, and noise reduction designs suitable for urban environments.
Accumulator-Free Designs
Currently, hydraulic breaker industries are developing towards non-accumulator devices. Brands from Europe, America and Japan have cancelled the accumulator. The hydraulic breaker without accumulator represents advanced technical performance—with simple structure, fewer failures, convenient maintenance, and lower cost, while maintaining comparable impact energy.
Conclusion
Hydraulic hammers combine power, versatility, and efficiency for breaking hard materials across construction, mining, demolition, and utility industries. Success with these tools depends on understanding key characteristics:
- Impact Energy: Must match material hardness and project requirements
- Weight Matching: Hammer weight should be properly proportioned to carrier capacity
- Hydraulic Compatibility: Both flow rate and pressure must meet breaker specifications
- Regular Maintenance: Particularly nitrogen pressure checks and chisel condition
- Proper Operation: Correct technique prevents damage and maximizes productivity
The breaker must be sized properly for both the work it will do and the carrier on which it will be mounted. This is the most critical factor in choosing the breaker size.
By selecting equipment that matches your application, maintaining it according to manufacturer guidelines, and operating it correctly, hydraulic hammers deliver reliable performance and long service life across demanding job sites.
Additional Resources
For specific model selection and technical support:
- Consult manufacturer compatibility charts for your carrier make and model
- Contact equipment dealers for application-specific recommendations
- Review manufacturer service manuals for detailed maintenance procedures
- Consider rental options for short-term projects or to test different specifications
Disclaimer: This guide provides general information based on industry standards and manufacturer specifications. Always consult equipment manufacturers, dealers, and your machine's operating manual for specific recommendations for your application. Specifications and requirements may vary by manufacturer, model, and region.