eTool : Lead: Battery Manufacturing - Oxide and Grid Processing - Grid Production and Parts Casting | Occupational Safety and Health Administration

Text Version

Typical System Layout Low Volume/High Velocity with Chart

Typical system shown with piping sizes of 2 1/8" for 7" - 72,000 rpm Disc sander(2 1/8"), 2 1/8" for chipping hammer (2 1/2"), 2 1/8" for 6" - 10,000 rpm Cup stone grinder (3"), 2 1/8" piping for 6" X 1", 10,000 rpm Wheel grinder (3 1/2"), and 2 1/8" piping for Swing Frame grinder( 2 1/2"). Fittings are in parentheses following each machine type. All lines flow into 4" piping connected to primary separator, dust collector, with recommended automatic bag cleaner, and exhauster to atmosphere.

	cfm	I.D. Plastic Hose Size
Disk sanders 3-9 inch diameter	60-175	1 - 1.5
Vibratory Pad Sander - 4" X 9"	100	1.25
Router, 1/8" to 1"	80-100	1 - 1.25
Belt Sander, 3" - 4000 cfm	70	1
Pneumatic chisel	60	1
Radial Wheel Grinder	70	1
Surface Dye Grinder, 1/4"	60	1
Cone Wheel Grinder	90	1.25
Cup Stone Grinder, 4"	100	1.25
Cup Type Brush, 6"	150	1.5
Radial Wire Brush, 6"	90	1.25
Hand Wire Brush 3" X 7"	60	1
Rip Out Knife	175	1.5
Rip Out Cast Cutter	150	1.5
Saber Saw	120	1.5
Swing Frame Grinder	380	2.25
Saw Abrasive 3"	100	1.25

System Notes:

Bell and socket, smooth - flow type tubing and fittings should be used throughout the system. When system is used for vacuum cleaning of abrasive materials, schedule Nol40 pipe and cast iron drainage fittings, or heavier, should be used in place of tubing.

From American Conference of Governmental Industrial Hygienists (ACGIH®), Figure VS-40-20, Industrial Ventilation : A Manual of Recommended Practice, 23^rd Edition. Copyright 1988. Reprinted with permission.

Text Version

Hygiene Facility

Hygiene facility floor plan:

Street
Side
Entry

(A)

Street Side Locker Room

(B)

Storage Lockers

Hand Washing Stations

(J)

Lunchroom
(K)

Vending Machines

Work Clothes Vacuum Station(I)

Plant side Entry (E)

Clean Issue

Dirty Turn-in

Restroom
(F)

Cloak Room (G)

Shoe Cleaning Machines
(H)

Laundry

Showers

(C)

Plant side Locker Room (D)

Autoshower (N)

Facility Function/Description:

The facility can be entered from the street at only one point. (A)
Street clothes are removed and clean work clothes, hardhat, and respirator are issued and donned in the street side locker room. (B)
The employee passes through a one-way turnstile in order to get to the plant-side locker room. (C)
The employee dons work boots and other safety gear in the plant-side locker room where they are stored. (D)
There is only one entry to the plant. (E)
The restroom just inside the cloak room is readily accessible during working hours. (F)
The cloak room provides a place to store coats, hardhats, gloves and respirators during break periods. (G)
During lunch break the employee first cleans his boots at the shoe cleaning machines (H), leaves coat and equipment in the cloak room (G), vacuums off his clothes at the vacuum stations (I), proceeds to the hand washing station where he thoroughly washes his hands (J), and finally enters the lunch room. (K)
At the end of the shift the procedure is as follows: the employee cleans shoes (H), removes contaminated clothing in the plant side locker room (D), stores boots, etc. in plant-side lockers, turns in dirty work clothes, hardhat and respirator to laundry (L), and proceeds to the showers. (M) He then must pass through an automatic shower (N) to return to the street-side locker room (B), where he dresses and leaves the facility. (A)

Oxide and Grid Processing » Grid Production and Parts Casting

Grid production and parts casting involves book casting, continuous casting, and strip casting. In all of these processes, lead pigs are melted down and the molten lead is poured into molds or continuously cast into grids, strips, or parts. Expanded metal grid production involves mechanical operations on the cast strip and is not a source of airborne lead dust or oxide. The major source of lead exposure in this process is from lead fumes and lead oxide which can become easily airborne.

Grid production and parts casting

Potential Sources of Exposure

View larger image of scrap pot and dross hood

Drossing the lead pot may increase lead exposure.
High levels of lead fumes are generated when a flame is put in contact with lead, such as when cutting out frozen pots.
Settled lead dust on surfaces and equipment may become airborne due to exhaust from fuel-powered fork-lifts or vehicular traffic.
High exposure to lead fumes can occur when the pig is loaded into the lead pot.
Airborne lead dust can migrate from other areas of the plant depending on the plant layout.
Separator boards may become contaminated by using lead contaminated pallets that have not been cleaned after being returned from the pasting line.
Dust may become airborne as a result of using a rotary sander for cleaning molds.
Oxide that has collected on the dross ladle may become airborne while cleaning or storing it in an area outside the hood.

Figure 2. Continuous grid casting machine

Possible Engineering Controls

View larger image of ventilated torch

Develop a system to minimize the formation of dross.
Place a local exhaust ventilation on the lead melting pot and the dross pot (Figures 1, 2, and 3).
- Lead Pot and Dross Hood
- Scrap Pot and Dross Hood
Dross with a ladle with holes in it to allow lead to drain back into the pot.
Install Laminar Flow (Supplied Air) Islands at the drossing station if exposures exceed the PEL.
Provide local slot ventilation or a ventilated torch for cutting out frozen pots.
- Ventilated Torch
Suspend plastic curtains to separate the casting areas from the traffic areas.
Isolate the lead pots from casting operations.

Figure 3. Ventilated and automated lead pot

Possible Work Practice Controls

View larger image of supplied air island

Handle dross carefully within a ventilated enclosure.
Keep the doors closed on the dross cabinets when drossing into the containers.
Keep the dross covered where air turbulence may cause powdery dross to become airborne.
Cool waste drums under exhaust ventilation.
Enclose cooled waste drums with a plastic bag prior to storage (Figure 3).
Do not add sawdust to the dross.
Keep dross from calcium and antimonial alloys separate and dry since arsine and stibine gases could be emitted.
Slide pigs into the casting pots, where feasible.
Use a long-handled push rod or mechanical system to feed the pigs into the pot.
Use separate pallets for grid storage and pasted plate storage (Figure 4).
Provide adequate PPE, change of clothes, and shower rooms (see OSHA Lead Requirements for PPE, Housekeeping, and Hygiene Facilities).
Maintenance:
- Ensure ventilation is working properly.
- Use electric powered fork lifts.
- Use an automatic conveyance system.
- Avoid using a rotary sander to clean molds.
Housekeeping:
- Use dust suppression techniques, such as, using dust suppression compounds or vacuuming.
- Keep the floor areas and work surfaces around the lead pots and lead storage areas free of oxide dust.
- Scrape metal splashes with a shovel or long-handled scraper.

Lead: Battery Manufacturing eTool

Oxide and Grid Processing » Grid Production and Parts Casting

Grid production and parts casting