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ISO 28927-10:2011 — Hand-Held Portable Power Tools — Vibration Emission Test for Percussive Drills, Hammers and Breakers
A comprehensive technical guide to vibration emission testing of percussive drills, hammers and breakers according to ISO 28927-10
Introduction to ISO 28927-10
ISO 28927-10:2011 specifies a laboratory test method for measuring vibration emission from hand-held percussive drills, hammers, and breakers. These tools are widely used in construction, demolition, mining, and quarrying industries, and they typically generate high levels of hand-arm vibration that pose significant health risks to operators. The standard provides a standardized testing framework enabling manufacturers to produce comparable vibration emission declarations and allowing users to make informed choices about tool selection for workplace risk assessment.
Percussive tools such as breakers and rotary hammers frequently generate vibration magnitudes exceeding 20 m/s² — well above the EU daily exposure action value of 2.5 m/s² A(8). Understanding ISO 28927-10 test procedures is essential for designing tools that minimize operator health risks while maintaining productivity.
The standard applies to machines powered by electric, pneumatic, or hydraulic sources, including rotary hammers with impact mechanism, combination hammers, demolition hammers, and concrete breakers. It supplements the general requirements of ISO 28927-1 and provides specific test conditions tailored to the percussive nature of these tools.
Test Conditions and Measurement Methodology
Operating Conditions
ISO 28927-10 defines specific operating conditions for each tool type within its scope. For rotary hammers, the test involves drilling into standardized concrete blocks of defined compressive strength (typically C25/30 grade). For demolition hammers and breakers, testing is performed on a concrete test bed or equivalent structure. The standard specifies feed force, drilling depth, and tool orientation to ensure reproducible results. For pneumatic tools, the supply pressure and air consumption are specified to ensure consistent power delivery during testing.
| Tool Category | Test Workpiece | Key Test Parameters | Typical Vibration Range |
|---|---|---|---|
| Rotary hammers (small) | C25/30 concrete block | Feed force 100-150 N, drilling depth 50 mm | 8-15 m/s² |
| Combination hammers | C25/30 concrete block | Feed force 150-200 N, drilling depth 100 mm | 10-20 m/s² |
| Demolition hammers | Concrete test bed (300 mm thick) | Tool weight 10-30 kg, chisel/point tool | 15-30 m/s² |
| Breakers (large) | Concrete test bed (500 mm thick) | Tool weight 30-60 kg, moil point | 20-35 m/s² |
A critical factor in percussive tool vibration testing is the concrete block condition. ISO 28927-10 requires that concrete blocks be cured for at least 28 days and have a specified moisture content. Using improperly cured or excessively dry concrete can change vibration magnitudes by up to 5 m/s², invalidating the test results.
Vibration Measurement Points
The standard specifies measurement locations on both the main handle and auxiliary handle (if fitted). For tools with a D-handle or anti-vibration handle system, the measurement position is on the handle at the operator grip location. Tri-axial accelerometers are used to capture vibration in all three orthogonal axes. The frequency range covers 5 Hz to 1500 Hz with Wh frequency weighting per ISO 5349-1.
Engineering Design for Reduced Percussive Vibration
Reducing vibration in percussive tools presents unique engineering challenges because the impact mechanism inherently generates high-magnitude, broadband vibration. Key design strategies include: active vibration isolation systems using pneumatic or hydraulic dampers between the impact mechanism and the handle, tuned mass dampers tuned to the fundamental impact frequency (typically 20-50 Hz for breakers), and optimized tool bit geometry to improve energy transfer to the workpiece and reduce recoil.
Modern breaker designs employ variable-speed impact mechanisms that adjust impact energy and frequency based on material hardness. These systems can reduce operator vibration by 40-60% compared to fixed-speed designs. For rotary hammers, the use of a decoupled drive train where the rotary motion and impact mechanisms are separately sprung from the housing has proven highly effective.
The most significant single design improvement for reducing percussive tool vibration is the implementation of a spring-suspended handle system with a natural frequency below 15 Hz. When properly tuned, such systems can reduce transmitted vibration by 50-70% at the fundamental impact frequency, dramatically lowering the declared vibration emission value.
Frequently Asked Questions
Q1: Why do percussive tools have much higher vibration than rotary tools?
The impact mechanism in percussive tools generates high-peak-force impulses at rates of 10-50 Hz, producing broadband vibration with significant energy content across the entire hand-arm frequency range. In contrast, rotary tools generate primarily sinusoidal vibration at rotational frequencies, which can be more effectively isolated.
The impact mechanism in percussive tools generates high-peak-force impulses at rates of 10-50 Hz, producing broadband vibration with significant energy content across the entire hand-arm frequency range. In contrast, rotary tools generate primarily sinusoidal vibration at rotational frequencies, which can be more effectively isolated.
Q2: How does concrete curing affect test results?
The compressive strength and moisture content of concrete significantly affect the energy transfer from tool to workpiece. Harder concrete increases rebound energy and vibration. ISO 28927-10 specifies C25/30 concrete cured for 28 days to ensure reproducible results across different testing laboratories.
The compressive strength and moisture content of concrete significantly affect the energy transfer from tool to workpiece. Harder concrete increases rebound energy and vibration. ISO 28927-10 specifies C25/30 concrete cured for 28 days to ensure reproducible results across different testing laboratories.
Q3: Can anti-vibration gloves be used to meet regulatory limits?
While anti-vibration gloves can provide some attenuation (typically 10-30% depending on frequency), they are not considered a primary risk control measure under most regulatory frameworks. ISO 28927-1 vibration declarations assume bare-hand operation, and the preferred approach is to select tools with inherently lower vibration designed and tested per ISO 28927-10.
While anti-vibration gloves can provide some attenuation (typically 10-30% depending on frequency), they are not considered a primary risk control measure under most regulatory frameworks. ISO 28927-1 vibration declarations assume bare-hand operation, and the preferred approach is to select tools with inherently lower vibration designed and tested per ISO 28927-10.
An important factor in percussive tool vibration testing is the operator grip force applied during the test. ISO 28927-10 specifies that the operator should apply a grip force typical for the tool type, but individual operator technique can still influence results. To minimize operator-related variability, the standard recommends using a mechanical feed device where feasible, particularly for tools with consistent operating positions. For tools that must be hand-held, the standard provides guidance on operator training and the number of replicate measurements needed to achieve statistically reliable results.
When comparing vibration data between different percussive tools, engineers must consider that the declared vibration values represent laboratory conditions with standardized workpieces. Actual field vibration depends on the material being worked, the tool bit condition, and the operator technique. ISO 28927-10 provides the basis for comparative evaluation, but workplace-specific factors should be considered in risk assessments.
An additional consideration in percussive tool testing is the effect of tool bit condition on vibration. Worn or improperly sharpened bits require greater percussive force to achieve the same material removal rate, which increases vibration emission. ISO 28927-10 requires the use of standardized bits in good condition to ensure reproducible test conditions. In practice, operators should use sharp, well-maintained bits and replace them at regular intervals to minimize vibration exposure. The standard also recommends that vibration testing be conducted with the tool operating at its rated air pressure or voltage, as both under- and over-pressure conditions can alter the tool operating characteristics and vibration output.
