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Considerations for Specific Operations

Because there are operational differences in exposure risks between beryllium metal and beryllium-containing alloys, the industry has categorized operations into low inhalation concern and operations having a likely inhalation hazard. The following table provides a summary of the processes used in beryllium metal processing (beryllium-containing alloys are treated later in this section), and groups them according to the inhalation hazard. It should be noted that most of the processes are only conducted outside the European Economic Area under strictly controlled conditions applying risk management measures as described in the table thereafter, and are given here to develop a comprehensive picture on operations performed in the beryllium industry.

The following exposure control measures must be considered for particle producing operations involving beryllium metal:

Machining Copper Beryllium Alloys

Drilling, Boring, Milling, Turning, Tapping, Reaming, Sawing, etc.

Copper beryllium is a ductile metal that machines easily, generally producing large chips and turnings. Processes that generate large particles are usually performed in an open shop environment with no special ventilation or housekeeping practices required. Machining processes that do generate small particles must be controlled with appropriate work practices and engineering controls. Best has prepared a Safety Bulletin “Safety Practices for Machining Copper Beryllium Alloys“. Additionally, a more detailed guide for machining copper beryllium alloys for use by end users is offered in “Guide to Machining Copper Beryllium“.


Benching

Sanding, grinding, buffing, lapping and polishing

These machining processes are capable of generating small particles. These processes must be controlled with appropriate work practices and engineering controls. BeST has prepared a Safety Bulletin “Safety Practices for Sanding, Grinding, Buffing, Lapping and Polishing Copper Beryllium Alloys” for use by end users. BeST has also prepared a case study report on benching operations (see “Case Study Benching CuBe Alloys“).


Stamping Copper Beryllium Alloys

Copper beryllium alloys are stamped into a variety of shapes, sizes and designs for use in electrical and electronic equipment. The manufacturing operations commonly associated with precision stamping can safely process copper beryllium alloys. The latest scientific evidence indicates that airborne beryllium exposure levels experienced at precision stamping operations are not sufficient to adversely affect health. Special controls are not required during the precision stamping, die repair, and inert atmosphere heat treating of copper beryllium alloys. Best has prepared a Safety Bulletin “Safety Practices for Precision Stamping Copper Beryllium Alloys” for use by end users. BeST also has developed a case study report on stamping (see “Case Study Precision Stamping CuBe Alloys“).


Welding (A Special Case)

Welding or cutting (with a gas flame or electric arc) indoors, outdoors, or in confined spaces, involving beryllium-containing base or filler metals must be done using local exhaust ventilation and airline respirators unless atmospheric tests under the most adverse conditions have established that the workers’ exposure is within the acceptable concentrations. In all cases, workers in the immediate vicinity of the welding or cutting operations shall be protected as necessary by local exhaust ventilation or airline respirators. BeST has prepared a Beryllium Safety Bulletin for safety practices for welding on copper beryllium alloys (see “Safety Practices for Welding Copper Beryllium“).

Casting and Alloying

Safe foundry practices must be employed when working with beryllium alloys. Furnace ventilation is required to capture fume and particulate generated during melting operations. The configuration and extent of ventilation must be designed for the specific application. One type of melting furnace, for example, may by its very design create little air contamination, while another may require more sophisticated engineering controls. Implicit in all foundry operations are the difficulties of handling molten metal and drosses plus the cutoff and finishing operations that are usually involved.  BeST developed an overview of safety practices for copper beryllium foundry operations.

The importance of controlling airborne beryllium contaminant from drosses in an alloy foundry cannot be overlooked. Chemical analysis has shown that drosses frequently carry higher concentrations of beryllium than the alloys originally melted. Dross, moreover, is easily airborne, a characteristic which intensifies the need for appropriate management and control.  


Ram Electrical Discharge Machining (EDM)

Ram EDM uses spark erosion to remove metal. When sufficient voltage is applied, the dielectric oil ionizes and controlled sparks melt and vaporize the work piece. As the metal melts and vaporizes, metal fumes are emitted. To control visible fuming and potential exposures, a properly designed ventilation system is recommended when conducting EDM on beryllium-containing alloys. BeST has developed a case study report on an EDM operation.


Computer Numerically Controlled (CNC) Lathe on Copper Beryllium Alloys

A CNC Lathe involves digitally automated machining of a rotating part mounted onto a chuck. CNC Lathe operations are generally performed in enclosed machining centers with a flooding of machining fluids. These machining centers allow for a variety of complex machining operations such as boring, turning, cutting, drilling and routing. The water soluble machining fluids are used to lubricate and cool the cut and to flush away the resulting swarf. This containment and flooding of swarf in the enclosed machining centers minimizes the release of particulate. BeST has developed a case study report on a CNC operation (see “Case Study CNC Lathe on CuBe Alloys“).

Wet Methods

  • Machining operations are usually performed under a liquid coolant flood which assists in reducing airborne particle dispersion.  However, the process may also require complete hooded containment and local exhaust ventilation (see exhaust ventilation section below).
  • Care must be given to lubricant containment which prevents splashing onto floor areas, external structures or operators’ clothing.
  • Coolant splash which does deposit outside the ventilated enclosure  should be cleaned up immediately.  Splashed coolant must not be allowed  to dry because it may carry with it particulate containing beryllium  which can later become airborne. Cycling of liquid machining  lubricant/coolant containing finely divided beryllium in suspension can  result in the particle concentration building to a point where beryllium  may become airborne during use.   The coolant reservoir should be  enclosed and ventilated.  A coolant filtering system is recommended.

Exhaust Ventilation

  • Local exhaust ventilation with full enclosure hooding must be used on all beryllium metal machining operations capable of producing airborne beryllium dust, mist or fume.  The type of ventilation required depends on the characteristics of particle generation.  Particulate generation can be highly variable as determined by feed rate, feed speed, size and speed of the tooling, tool sharpness, coolant flow, configu­ration of the part being machined, etc. The hooding should completely enclose the “point of operation” area without interfering with the travel of machining tooling.  The enclosure should have no openings which would allow direct release of airborne particulate outside the enclosure.  Any opening within the normal range of direct particle/coolant scatter should be baffled or convoluted in design to prevent a direct release outside the enclosure. 

Enclosure doors should be interlocked to the machine controls.  If the doors are opened, the machine should stop automatically.  Ventilation systems should be interlocked to the machines in a manner which requires the ventilation to be operating before or concurrent to the start-up of the machines. 

  • Dry machining of beryllium requires a close capture, high velocity, low volume ventilation system.  High velocity/low volume ventilation pick-ups must be located as close to the point of particu­late release as possible and be positioned “in-line” with the direc­tion of particle generation.  Where necessary, custom fabricated ventilation duct inlets should be provided to opti­mize capture of chips and particulate released by particle producing processes.  In addition to having a close capture ventilation system, a secondary total enclosure may be necessary when dry machining beryllium.
  • The particles generated when using powered grinders or roto tools can be very difficult to control due to the random nature of particle generation.   The use of powered grinders and roto tools must be controlled in a ventilated partial or complete enclosure designed to draw particles away from the operator.  Alternative methods to powered grinders such as wet filing or wet hand sanding should be used where possible.
  • Dry hand sanding or filing of beryllium must either be performed inside a ventilated enclosure or performed completely wetted or submerged.  Parts and other contact materials must be cleaned before removing from the ventilated enclosure or immediately after wet processing.  Compressed air must not be used to clean parts.  Residue on tooling and contact materials must not be permitted to dry and should be cleaned and/or double bagged in a moist condition to prevent airborne exposure during subsequent handling.
  • Disruption of the airflow in the area of a local exhaust inlet, such as by a man cooling fan, should be avoided.  The discharge of air from an air cleaning system into the work place air is not recommended due to the potential for exposure in case there is a failure of the filtration system.  The system should be discharged outside and away from building makeup air inlets.

Tooling

  • During machining of beryllium products, the tooling may become contaminated to a point where subsequent conditioning and sharpening activities may need special controls and work practices.  Tooling used to machine beryllium should be dedicated to the activity or should be cleaned prior to use in other areas or on other materials.
  • All tooling should be cleaned immediately after removal from a machine by wet cleaning methods to ensure no loose particulate remains on the tooling.  Consideration for a potential exposure to airborne beryllium must be given when tooling is to be sharpened. Emissions from sharpening can be best controlled by utilizing appropriate close capture ventilation or by machining under a coolant flood of sufficient flow to control airborne particulate. If tooling is sent out for sharpening, the service provider should be provided a copy of the SDS and warned in writing of the potential for exposure to beryllium.


Workplace Exposure Characterization

  • Air samples should be taken for all operations where a potential for beryllium exposure exists.

Respiratory Protection

  • Whenever possible, appropriate work practices, use of local exhaust ventilation or other engineering controls are the preferred methods for controlling exposure to airborne particles.  When these methods are ineffective or are being developed and potential exposures are above the occupational limits, approved respirators must be used.  Pressure-demand airline respirators are required when performing jobs where a potential for high exposure exists, such as changing filters in a baghouse air cleaning device.


Protective Clothing and Personal Hygiene

  • Work clothing and/or disposable over garments must be worn if the job or work activity includes the potential for contamination of personal clothing (gloves, shirts, pants, and boots) with beryllium dust, mist, fume or powders.
  • Work practices and procedures should be developed to prevent beryllium particles from coming in contact with worker’s skin or hair.  Workers who may come in contact with beryllium particles must be provided with appropriate hand, skin and hair washing facilities. These clothing requirements help keep beryllium-containing particles from being spread to non-production areas or from being taken home by the worker. Used disposable clothing should be containerized and disposed of in a manner which prevents airborne exposure during subsequent handling activities. Contaminated work clothing and overgarments must be managed in such a manner to prevent secondary airborne exposure to family or laundry personnel handling soiled work clothing.  Never use compressed air to clean work clothing.

Housekeeping

  • Beryllium processing equipment and associated support systems (e.g. dust collectors, heat treat furnaces, coolant trays and reservoirs) should be cleaned on a regular basis to prevent the accumulation of any beryllium-containing materials.
  • Floors and walls should be cleaned frequently so no visible accumulation of dirt or debris is apparent.
  • Brooms must not be used in the beryllium work area.  They can cause air­borne exposures as a result of the sweeping action.  The use of compressed air or brooms for cleaning dust must be prohibited because such activity can result in unnecessary airborne dust exposure.
  • Wet cleaning and HEPA vacuuming are effective methods for cleaning machining and support equipment.  Portable vacuums should be of a type equipped with High Efficiency Particulate Air (HEPA) rated filters.
  • After machining, parts should be HEPA vacuumed or rinsed with coolant.  Parts should be wet wiped clean.  Rags or towels used to dry or wipe parts clean should not be allowed to dry and must be maintained in a closed container.  Used rags and towels should be containerized and disposed of in a manner which prevents airborne exposure during subsequently handling activities.  The use of reusable rags is not recommended.

Maintenance

  • Under certain conditions the repair or maintenance of equipment can generate airborne particles.  Under these circumstances, protecting workers can require the use of specific work practices or procedures involving the combined use of ventilation, wet vacuum cleaning methods, respiratory protection, decontamination, special protective clothing, and when necessary, restricted work zones.
  • Beryllium-contaminated equipment should be thoroughly cleaned prior to performing service and maintenance.
  • Beryllium-containing residue may deposit on the internal surfaces of ventilation enclosures and equipment structures.  The residue must be removed, kept wet or otherwise controlled during maintenance and service activities to minimize airborne generation or particles.
  • Detailed procedures for safely maintaining the process equipment and ventilation systems should be developed.
  • All operators and maintenance personnel need to be trained in the established procedures prior to performing maintenance or service activities.  The procedure should detail the use of wet methods or vacuuming, ventilation and appropriate personal protective equipment required to prevent exposure to airborne particles.

Recycling

  • Beryllium scrap should be kept segregated from other metals because of its higher value as a recyclable material.

Disposal

  • Beryllium scrap, chips, and powder are normally recycled as by-products and are not classified a waste.  If being disposed, the outer container must be labelled with the appropriate label and hazard warning label(s) and shipped under a uniform hazardous waste manifest to an approved hazardous waste management facility.

Within the European Economic Area, copper beryllium and nickel beryllium alloysare mostly stamped into a variety of shapes, sizes and designs for use in electrical and electronic equipment.  The manufacturing operations commonly associated with precision stamping can safely process beryllium-containing alloys.  The latest scientific evidence indicates that airborne beryllium exposure levels experienced at precision stamping operations are not sufficient to adversely affect health.  Special controls are not required during the precision stamping, die repair and inert atmosphere heat treating of copper beryllium alloys.  The following two tables provide a summary of those for copper beryllium and nickel beryllium alloy processes: