Exposure to excessive vibration can result in injuries and diseases such as vibration white finger, Raynaud's phenomenon, and carpal tunnel syndrome. In extreme cases, these injuries and diseases can lead to permanent impairment of the hands and arms.
Vibration can be explained as the back and forth motion produced by objects such as tools, machinery and equipment. It has two components:
- Frequency (or repeat rate)
- Amplitude (or displacement)
The risk of vibration induced injury depends on the average daily exposure as well as from the individual's sensitivity to vibration. An evaluation takes into account the intensity and frequency of the vibration, the duration (years) of exposure and the body part that receives the vibration energy.
Construction employees who operate powered equipment with high frequency vibration or high impact (such as chainsaws, grinders, jackhammers, impact wrenches, or sanders) for extended periods are at high risk of hand/arm vibration injuries. The adverse effect produced by exposure to vibration is called hand-arm vibration syndrome (HAVS). Employees affected by HAVS commonly report:
- Attacks of whitening (blanching) of one or more fingers when exposed to cold
- Tingling and loss of sensation in the fingers
- Loss of light touch
- Pain and cold sensations between periodic white finger attacks
- Loss of grip strength
- Bone cysts in fingers and wrists
Attacks are usually triggered by cold temperatures or contact with cold liquids or solids. Cold weather and smoking are important aggravating factors. Both increase the risk of HAVS and may precipitate an attack.
Some preventive measures include:
- Identify the jobs or occupations that require the use of powered hand tools.
- Evaluate the extent of use of the equipment, with regard to the duration and intensity of vibration.
- Determine if there are any employees showing HAVS symptoms.
- If vibration is a concern, develop a procedure for the use of tools, equipment or machinery. The procedure should include, but not be limited to, the following items:
- Tool selection (buying anti-vibration tools, choosing the proper tool for the job, etc.).
- Alternative tools and methods for certain jobs (such as hydraulic tools in place of vibratory tools).
- Information and training to employees in the proper use and handling of tools and equipment and recognizing HAVS symptoms.
- Mandatory rest periods (10 minutes or more every hour) for vibratory tool operators.
- Regular inspections and equipment maintenance.
- Selection and use of anti-vibration gloves.
- Pre-placement and periodic medical evaluations of employees exposed to vibration.
- Monitoring exposure to vibration.
As an employer, you must:
- Ensure that the exposure of an employee to hand-arm vibration is kept as low as practical and does not exceed the following exposures:
|Total daily exposure*||Acceleration|
|Less than 1 hour||12 m/s2|
|1-2 hours||8 m/s2|
|2-4 hours||6 m/s2|
|4-8 hours||4 m/s2|
While the employer is ultimately responsible for all the provisions mentioned above, the supervisor has a vital role to play in the safety of their teams. As a supervisor, you must:
- Acquaint your employees with the hazards and control measures associated with their work
- Provide the information and instruction necessary to ensure their health and safety
- Enforce company safety rules, programs, codes of practice and procedures, including ensuring employees comply with the requirements below.
As an employee, you must:
- Be aware of the risks of using powered equipment with high frequency vibration or high impact for extended periods.
- Be aware of the symptoms of the HAVS.
- Be aware of the daily exposure limits of the hand-arm vibration.
- Notify your supervisor and your joint health and safety committee if you experience symptoms of HAVs and seek medical attention.
General Regulation - Occupational Health and Safety Act
N.B. Reg. 91-191
Part V NOISE AND VIBRATION
Section 33.2 Exposure of employee to vibration
33.2 An employer shall ensure that the exposure of an employee to hand-arm vibration is kept as low as is practical and does not exceed the following exposures:
Exposure of the Hand to Vibration in either Up and Down, Sideways or Forward and Back Directions
|Total daily exposure duration*||Values of the dominant**, frequency-weighted, root mean square, component acceleration which shall not be exceeded|
|4 hours and less than 8 hours||4||0.40|
|2 hours and less than 4 hours||6||0.61|
|1 hour and less than 2 hours||8||0.81|
|less than one hour||12||1.22|
* The total time vibration enters the hand per day, whether continuously or intermittently
** Usually one axis of vibration is dominant over the two remaining axes. If one or more vibration axis exceeds the total daily exposure, then the exposure limit has been exceeded.
*** 1 g = 9.81 m/s2
[N.B. Reg. 2001-33, s. 13]