Page 37 - Summer 2006

in work, home, social, and athletic activities and in hobbies. These include:
• The tingling, numbness and loss of
tactile dexterity in the fingers and the loss of grip strength can make it difficult to handle objects (particu- larly small objects).
• There can be serious interference with work, home, social, and athlet- ic activities and hobbies that require good hand dexterity.
• Outdoor activities in cold climates that require the use of the hands may have to be avoided to prevent painful vessel spasms in the fingers or to prevent the potential for severe hand trauma because an individual may not be able to feel his/her fin- gers in extreme cold.
Exposure to work-related hand- transmitted vibration
Workers are exposed to work- related hand-transmitted vibration in many different industries throughout the U.S. Some of these industries are listed in Table 3. Typical tools that are used in these industries and that gener- ate hand-transmitted vibration are list- ed in Table 4. Vibrating tools include both hand-held vibrating tools and sta- tionary tools or machines that transmit vibration to the hands through hand- held workpieces.
Many factors affect the severity of the physiological effects of work-relat- ed hand-transmitted vibration. They include:
• The magnitude of the vibration,
• The frequency content of the vibra-
tion,
• The direction of the vibration trans-
mitted to the hand,
• The magnitudes and directions of
forces applied by the operator through his/her hands to the tool or workpiece,
• The posture of the hands, arms, and body relative to a tool or workpiece during vibration exposure (e.g., the angle and position of fingers, hands, wrists elbows, and shoulder joints),
• The areas and locations of the parts of the hands and fingers that are exposed to vibration,
• Temporal exposure patterns during a workday and work methods (e.g.,
Table 3. Industries where workers are exposed to hand-transmitted vibration
Heavy manufacturing Ship building Construction
Public utilities
Manufacturing assembly Ship repair
Mines and quarries Agriculture
Foundries Railroads Forestry
Table 4. Common industrial tools that generate hand-transmitted vibration
Road brakers
Needle guns
Chipping hammers
Nut runners
Gasoline powered chains saws, brush cutters, string trimmers, and blowers
Hand-held grinders Riveting hammers Rock drills Tampers
Pedestal grinders Bucking bars Sanders
Impact wrenches
length and frequency of at work and rest spells, whether the tool is laid aside or held idling during non-work- ing operations with a tool, etc.),
• The total exposure in years and months to work-related hand-trans- mitted vibration to date,
• The types and conditions of the vibrating machinery, hand tools, and workpieces,
• The method of working and the operator’s skill level,
• Climatic conditions and other fac- tors that affect the temperature of the hands, fingers, and body,
• Medical conditions of the operator that affect the circulation of blood in the fingers,
• Other predisposing factors in the health of the operator,
• Agents that affect the peripheral blood circulation, such as smoking,
certain medicines, or chemicals in
the work environment, and • Noise.
ISO and ANSI standards associated with work-related hand-transmit- ted vibration
Standards have been published by the International Organization for Standardization (ISO) for distribution as ISO standards and by the Acoustical Society of America (ASA) for distribu- tion as American National Standards Institute (ANSI) standards that give guidance for the measurement and assessment of work-related hand- transmitted vibration. ISO first pub-
3
lished ISO 5349 in 1986. This standard
specified methods for measuring and evaluating vibration directed into the hands from hand-held vibrating devices, tools, and workpieces. ANSI S3.34 was published by the American Institute of Physics for the Acoustical
1 Society of America the same year. This
standard was concurrently developed with ISO 5349-1986 by ANSI Working Group S3.39–Human Exposure to Mechanical Vibration and Shock. It specified methods for measuring and assessing exposure to work-related hand-transmitted vibration. ANSI Working Group S3.39 was later changed to ANSI Working Group S2.39.
The Parliament of the European Union (EU) issued the EU Human Vibration Directive-2002/44/EC in 2002. This directive specifies vibration daily exposure action values (DEAV) of 2.5 m/s2 and daily exposure limit values
2
(DELV) of 5.0 m/s . When the DEAV is
exceeded, actions should be initiated to
“ANSI S2.70 is a timely and needed revision of ANSI S3.34 that gives the United States a modern hand-transmitted vibration standard that is in agreement with ISO 5349—Parts 1 and 2 and the European Union Human Vibration Directive.”
Standards News 35