Manual stacking station |
After curing, the plates are stacked either by hand or
by machine so that
positive and negative plates alternate with an insulating separator in
between. The major source of lead exposure in the stacking process is from oxide from
the plates which can become easily airborne.
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| Stacking |
Figure 1. Ventilated scrap barrel
Figure 2. Contaminated clothing
Figure 3. Central vacuum drop station
Figure 4. Hand stacking |
Potential Sources of Exposure
- Exposure to lead dust may occur from
improperly handling plates in unsealed envelopes.
- Tamping plates in unventilated areas, such as the rack, creates a puff of dust.
- Lead oxide that accumulates on equipment, racks, and floors may become airborne.
- Clearing stacking equipment jam-ups.
- Exposure to lead may increase when scrap plates
are handled improperly, such as throwing in unventilated pail.
- Leaning against equipment may increase clothing
contamination.
- Exposure to lead may increase from emptying clean-out trays improperly, by dumping in unventilated area.
- Lead dust may escape from the stacking machine if the hinged panels are not closed.
Possible Engineering
Controls
- Use downdraft or slot ventilation at
workstations.
- Provide a grating or a perforated plate tamping
stand.
Stacking
Table Single Exhaust
Booth Hood
Slant Stacking Station (Industrial)
- Use a ventilated scrap barrel (Figure
1).
- Use a central vacuum drop.
- Consider adding duct cleanout openings so that large particles will drop out and not plug the
lines.
- Provide exhaust ventilated storage
rack.
Plate Storage Rack Hood
- Place pallets of plates on a rotating
base.
- Use local exhaust ventilation with machines that use shuttles for moving
plates.
- These
machines may have higher airborne levels due to abrasion of the
plates.
- Use a laminar
flow (supplied-air) island over operators
workstation.
- Provide a plastic or glass, see-through plate between the stackers breathing zone and the
plates. Enclose the process, if possible, to minimize the ventilation requirements.
- Provide rubber mats or grated walking
surfaces.
Possible Work Practice
Controls
- Tamp, break, or
separate plates only in ventilated work
areas.
- Handle groups of plates with the hands
only rather than leaning them against the stomach, chest, or
chin.
- Wear an apron (Figure 2).
- Maximize the distance between the operators breathing and the plates by not stacking assembled groups more than three
high.
- Place, do not throw, defective plates into scrap barrel.
Scrap Handling Barrel/Drum Exhaust Hood
- Cover drums with a plastic bag before removing them from the area.
- Keep access doors to ventilated enclosures closed, except when access in needed.
- Provide adequate PPE, a change of clothes, and shower
rooms (see OSHA Lead Requirements for PPE, Housekeeping, and Hygiene Facilities).
- Maintenance:
- Ensure that local exhaust ventilation is working
properly.
- Prevent cross drafts.
- Housekeeping:
- Vacuum work station and adjacent areas to prevent accumulation of oxide
dust.
- Vacuum off each row of plates before
using.
- Use dust suppression techniques, such as keeping floors wet, using
dust suppression compounds, or
vacuuming.
- Vacuum clean-out trays (Figure 3) or dump in ventilated areas; do not dump them into unventilated barrels.
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