Hand-arm vibration testing according to the ISO5349

Introduction

Hand-arm vibration is vibration transmitted by the use of vibrating hand-held power tools, such as pneumatic jack hammers, drills or electrical tools such as grinders. The nature of these tools involves vibration which is transmitted to the hands and arms of the person working with the tool.

LMS Test XPress ISO5349 hand-arm-1.jpg

Regular exposure to hand-arm vibration causes following health effects: reduced grip strength, pain in arms and shoulders, vibration-induced white finger syndrome, carpal tunnel syndrome.

Those can further lead to e.g. sleep disturbance and inability to do fine work. The longer a person uses a vibrating tool, and the faster the tool vibrates, the greater the risk of health effects.

Industries and applications concerned

Measuring the hand-arm vibration levels is a legal duty imposed by e.g. the european vibration directive 2002/44/EC and needs to be done by the manufacturers of the power tools - to label their tool - as well as by the

end user - to limit the daily exposure.

Following industries are concerned with hand-arm vibration: construction and maintenance of buildings, roads and railways, heavy manufacturing, foundries, shipbuilding, forestry, mines and quarries, public utilities (e.g. water, gas, electricity, telecommunications)

Following products are concerned with hand-arm vibration: chainsaws, concrete breakers, cut-off saws, hammer drills, hand-held grinders, impact wrenches, jigsaws, needle scalers, pedestal grinders, polishers, power hammers and chisel, power lawn mowers, powered sanders, scramblers, trimmers / brush cutters.

Measurement approach

LMS Test XPress ISO5349 hand-arm-6.jpg

Hand-transmitted vibration is measured at the contact surface from the hand with the tool. Since one cannot assume that the tool has a dominant axis, the measurement needs to be taken in three orthogonal axes followed by the vector summation of the individual axes. To avoid the effect of “mass loading” on the result, it is important that the transducer’s mass is not too big compared to the object under test.

The typical measurement process of vibration exposure implies the following steps:

Measurement of the time signals of all acceleration channels. In case only one hand grip is measured this means 3 acceleration channels (X, Y, Z direction), in case the two hand method is used this means 6 acceleration channels (X1, Y1, Z1 and X2, Y2, Z2).
The time signals are weighted with the Wh time domain filters as specified in the ISO2631 standard.
The X, Y and Z directions are recombined to get the vector sum.
For all directions and for the vector sum, the weighted RMS values are calculated.
The report in MS Excel copies all values and generates a Results sheet showing the measurement name, data and time, the weighted RMS values for the X, Y and Z direction and the weighted RMS value for the vector sum.
In addition, one can enter the daily exposure time in order to calculate the 8 hour vibration exposure values A(8).
If the work is such that the total daily vibration exposure consists of several tasks with different vibration magnitudes, then the A(8) can be calculated based on: A(8) =√ (1 / T0) Σa2hviTi.

The LMS Test.Xpress solution for whole-body vibration testing

The LMS Test.Xpress system consists of a measurement front-end (LMS SCADAS Mobile SCM01 or SCM05) and the LMS Test.Xpress analyzer software.

The LMS Test.Xpress Human Body Vibration Filters applies the ISO2631 time domain filters to the incoming vibration signals. Those filters are available both online as well as offline in case of post processing raw data.

The number of channels can go from 4 to 40, thus allowing:

Measurement of all directions from the triax sensor in one run
Measurement of multiple handle grips in one run (2 hands)
Combination of hand-arm ISO5349 with whole-body ISO2631 measurements
Measure extra channels (speed, temperature, noise, …)
Later in-depth analysis of the measurement as all time signals are saved

At the end of the measurement, an ISO report in MS Excel shows the results for the hand-arm vibration and also allows to calculate the A(8) daily exposure values.

The whole measurement and reporting is controlled by use of a simple toolbar, and as all critical settings are blocked by a password there is no risk for errors or unwanted changes.

Supported standards for hand-arm vibration

The LMS Test.Xpress system supports the following handarm vibration standards:

ISO 5349 Hand transmitted vibrations
ISO 8662-1 Hand-held portable power tools: measurement of vibrations at the handle
ISO 8662-2 Chipping hammers and riveting hammers
ISO 8662-3 Rock drills and rotary hammers
ISO 8662-4 Grinders
ISO 8662-5 Pavement breakers and hammers for construction work
ISO 8662-6 Impact drills
ISO 8662-7 Wrenches, screwdrivers and nut runners with impact, impulse or ratchet action
ISO 8662-8 Polishers and rotary, orbital, or random orbital sanders
ISO 8662-9 Rammers
ISO 8662-10 Nibblers and shears
ISO/DIS 8662-11 Fastener driving tools
ISO 8662-12 Saws & files with reciprocating action and saws with oscillating or rotating action
ISO 8662-13 Die grinders
ISO 8662-14 Stone-working tools and needle scalers

	主页 \| 登录 \| 语种 \| 联系我们 \| 全球LMS分支机构一览 \| 搜索