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Heavy steel fabrication (including shipyards)

Table 1: Alternative processes to avoid/reduce use of vibrating equipment

This table identifies alternative methods for specified high risk activities or processes; and links to further information and case studies.

A PDF version of table 1 is also available. It includes example vibration magnitudes and the corresponding times to reach the exposure action and limit values.

Activity or process Alternative methods Further information (links)

Manual cutting of steel plate and re-working to correct component profile using:

angle grinders

straight grinders

chipping hammers(rarely)

Nibbling machine (hand-fed type)

Expect to see accurate pre-prep, cutting components to correct size, with a minimum of “green” . “Measure twice, cut once.” Significant exposures from rework using grinders etc. should be challenged.

Select suitable modern, precision processes for cutting out, as appropriate:

  • CNC oxy-fuel flame cutting
  • CNC machining
  • laser profiling (up to approx 5 mm plate thickness)
  • abrasive water jet cutting (up to 150 mm thickness) – cold process with no heat distortion
  • submerged plasma cutting
  • submerged spark erosion (electrical discharge machining)

Note: improving accuracy and minimising manual reworking is also usually cost-effective.

 

 

 


Machining
Laser cutting


 


Plasma cutting

Weld preparation and finishing using tools as above
  • Apply bevelled edges for welding while cutting out to avoid unnecessary grinding
  • Use single sided welding (with a suitable backing material) to avoid routine back gouging associated with double sided welding (resulting distortion can be managed with “strongbacks”, heat line straightening, etc.)

Noise reduction in the ship repair industry – research report 1992


Control of noise in heavy fabrication SIM 03/1001/14

Removing fairing aids, lifting lugs, etc. using grinders

Design fairing and lifting processes to avoid temporary welded aids which must be removed by grinding.

  • Use magnetic, vacuum or screw clamps and anchors instead of welded fairing aids
  • Bolt fairing aids to welded studs which require less grinding to remove
  • Design welded lifting lugs that can be left in place
  • Use lifting clamps instead of welded lifting lugs
  • Use bolted lugs or shackles instead of welded lifting lugs


Noise reduction in the ship repair industry – research report 1992

Surface preparation using:

needle scalers

scaling hammers (piston type)

deck planers, leaf-type scalers, peening tools

Cleaning steel surfaces and preparing for painting. Use of scaling tools should be minimised (small and awkward areas only) and modern vibration-reduced tools should be used.

 

Where reasonably practicable an appropriate alternative process should be used, for example:

  • shot blasting
  • abrasive vacuum blasting
  • ultra high pressure water jetting
  • dry ice pellet blasting (non-abrasive, “clean” method)
  • ice blasting (wet)

Noise reduction in the ship repair industry – research report 1992


Control of noise in heavy fabrication SIM 03/1001/14

 

Example: abrasive blasters


Note 1: Changes of process to eliminate or reduce vibration may introduce other hazards to safety or health or safety (e.g. chemical, fume, spatter, noise, dust) which must be addressed and managed.
Note 2: For shipyards, HSE policy since 1998 has been to serve an Improvement Notice for action plan/control where no progress has been made; Prohibition Notice for old design chipping or scaling tools used for more than 1 hour.

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Table 2: Management of HAV risks where use of vibrating equipment is unavoidable

A PDF version of table 2 is also available.

Issue Expectation References and related guidance
Selection of work equipment

Tool selection can make a substantial difference to the vibration level but the tool must be suitable for the task and used correctly.

Employers should demonstrate a sound procurement policy for power tools and hand-guided machines, showing they have considered the following:

  • There is no reasonably practicable alternative method with no (or less) vibration exposure (see Table 1)
  • Equipment is generally suitable for the job (safety, size, power, efficiency, ergonomics, cost, user acceptability, etc.)
  • Reduced vibration designs are selected provided the tools are otherwise suitable (e.g. grinders with automatic spindle balancing)
  • Declared vibration emission is not high compared with competing machines of similar capacity to do the job
  • Information on likely vibration emission in use (e.g. from manufacturer, hire company, databases)
  • Available information from the manufacturer or elsewhere on control of vibration risks through:
    • maintenance (e.g. servicing grinders, sharpening drills and chisels)
    • selection of consumables (abrasive discs, chisels, drills, etc.)
    • correct operation and operator training (see below)
    • maximum daily trigger times or maximum daily work done with the tool

Selecting equipment

Employers’ leaflet on HAV

Limiting daily exposure time

Restricting exposure time (“finger-on-trigger” time) may be required to bring exposures below the ELV, even after all reasonably practicable measures to reduce vibration levels are in place.

Maximum times can be determined using the exposure points system or supplier’s “traffic lights” tool categories, but these should be derived from sound “real use” vibration emission values.

Note: Employers tend to ask “How long can we use this tool?” The exposure must be reduced to the lowest level that is reasonably practicable (Reg 6(2)), so the ELV should not be used as a target, if a lower exposure is reasonably practicable.

Reduce the period of exposure


Exposure points system and ready reckoner

Other risk controls

Control of HAVS risk by means other than reducing vibration exposure:

  • Ergonomic aids such as tensioners or balancers to support weight of tool and reduce forces applied by operator
  • Suitable workplace temperature or provision of warm clothing and gloves
  • Regular breaks from work involving vibration and encourage operators to exercise fingers

Gloves and warm clothing

Other measures

 


Employees’ leaflet on HAV

Information, instruction and training

Employees at risk from vibration should have received information on:

  • the risks from HAV and how to help reduce them (see above)
  • the importance of correct operation and maintenance of equipment
  • arrangements for health surveillance and their duty to cooperate.

Look for evidence that tools are being used correctly, as recommended by the manufacturer. This may require operators to receive specified training – are operators and their supervisors aware of the need? For example, percussive tools with suspension systems designed to absorb vibration must be used correctly, and with appropriate force, or the potential reduction in vibration will not be achieved.

Employees’ leaflet on HAV



Information and training

Health surveillance

Required where the EAV is likely to be exceeded. Expect to see, as a minimum:

  • use of a periodic health screening questionnaire – ideally annually and for new employees
  • arrangements for referral of relevant cases to an occupational health provider with HAVS expertise for diagnosis and on-going monitoring
  • arrangements to receive medical advice on management of affected employees
  • arrangements for RIDDOR reporting of HAVS cases
  • arrangements to receive anonymised information to demonstrate effectiveness of controls

Employers’ leaflet on HAV

Health surveillance guidance

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2012-11-21