Everyday human beings interact with some sort of machinery, making contact with vibration inevitable. Unfortunately, continuous exposure to mechanical vibration can lead to serious injury. The effect on the human body is dependent upon the magnitude of
vibration, the frequency content, and the duration of exposure.
Understanding Hand-Arm Vibration
Hand-Arm Vibration is defined as the vibration workers experience when using tools such as chain saws, jackhammers, grinders, drills, etc. Excessive Hand-Arm Vibration can lead to what is commonly referred to as Hand-Arm Vibration Syndrome (HAVS).
What is Hand-Arm Vibration Syndrome (HAVS)?
Hand-Arm Vibration Syndrome is a general term used to broadly describe the physical damage to the hands, fingers, and related structures resulting from chronic exposure to excessive vibration (also known as Vibration White Finger or VWF).
Physical Damage Includes:
- Vascular (damage to the blood vessels, i.e. Vibration White Finger Disease)
- Neuropathic (damage to the nerves/nervous system)
- Carpal Tunnel Syndrome
Determining HAVS Risk
Some questions that can be used to help determine areas for HAVS concern:
A) Are power tools being used and is there a medical diagnosis of injury?
B) Are workers reporting tingling or a "pins and needles" feeling in their fingers?
C) Has a case of HAVS been documented?
HAVS Exposure Limits
Vibration exposure limits have been established through European Directive 2002-/44/-EC and the American Conference of Industrial Hygienists (ACGIH). Limits
for maximum exposure which are called the Threshold Limit Value (TLV) and action levels are shown below.
|ACGIH Threshold Limit Values (TLVs)
|Total Daily Exposure Duration
|Maximum value of the frequency weighted acceleration
|4 to less than 8 hours
|2 to less than 4 hours
|1 to less than 2 hours
|Less than 1 hour
|EU Directive 2002-/44/-EC Limit and Action Levels
|Daily Exposure Duration
|Daily Action Level
Measuring Hand-Arm Vibration Exposure
It is possible to measure and report the vibration levels produced by handheld equipment using products such as the Larson Davis Human Vibration Meter Model HVM200. The
HVM200 provides all the functionality needed
to measure human exposure to vibration
Standards, Regulations & Directives
In Europe, Directive 202/44/EC has been implemented to define "exposure limits" and "exposure action values". This specifies an employer's obligations with regard to determining and assessing risks. Also, Machinery Directive 98/37/EC requires anyone providing
power tools or machinery for use in Europe must provide vibration exposure data.
In the US, OHSA has not regulated specific requirements for vibration standards. However, the American Conference of Governmental Industrial Hygienists (ACGIH) has developed Threshold Limit Values (TLV's) for vibration exposure and advises that these
values be applied in conjunction with other protective measures. As mentioned above, any manufacturer providing equipment to Europe must comply with the Machinery Directive.
Some of the ISO standards related to Hand-arm vibration are listed below:
|Standard for instruments measuring human response to vibration
|General requirements for measuring human exposure to hand-transmitted vibration
|Practical guidelines for measuring human exposure to hand-transmitted vibration at the workplace
|Measurement and evaluation of gloves
|Vibration of portable, hand-held tools used in forestry and gardening
|angle and vertical grinders
|Wrenches, nut runners and screwdrivers
|Polishers and rotary, orbital and random orbital sanders
|Drills and impact drills
|Nibblers and shears
|Saws, polishing and filing machines with reciprocating action and small saws with oscillating or rotating action
|Scaling hammers and needle scalers
|Percussive drills, hammers and breakers