Solution Summary: Walk-Behind Stone Polishers with Wet Dust Suppression
Description:
Polishing stone and concrete creates fine dust that workers can inhale. Concrete and many common stones, such as granite, can be composed primarily of crystalline silica, which if inhaled can cause lung disease and cancer. Using water to suppress the dust may be easier than using local exhaust ventilation in some circumstances and is an important dust control option to consider.
Wet methods can extend tool life, improve visibility and reduce dust exposure. These particular brands and models of polishers, however, have not been evaluated to determine the amount of dust generated or the effectiveness of the dust suppression systems.
Intertool DS 302 12-inch planetary floor polisher with wet dust suppression
- Used to polish or grind floors, steps, tight areas and under toe kicks
- Cost: $3,895 - $3,995
- Motor: 2 horsepower Baldor premium efficiency, Super-E, TEFC
- Power requirements: 115 volts, 20 amps or 230 volts, 10 amps
- Polishing diameter: 12 inches, achieved with three 5-inch planetary discs
- Disc speed: 250 to 2,500 RPM
- Weight: 200 pounds (including 50 pound weight)
- Alternative dust control methods: 1-inch port for use with a vacuum
- Sound pressure level: not available but likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
Intertool DS 605 24-inch planetary floor polisher with wet dust suppression
- Used to polish or grind floors, steps, tight areas and under toe kicks
- Cost: $8,450 - $8,500
- Motor: 5 horsepower Baldor premium efficiency, Super-E, TEFC
- Power requirements: 230 volts, 20 amps
- Polishing diameter: 24 inches, achieved with two 12-inch planetary platforms, each with three 5-inch discs
- Disc speed: 300 to 3,000 RPM
- Weight: 250 pounds
- Alternative dust control methods: 2-inch port for use with a vacuum
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Sound pressure level: not available but likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
CONTRx Systems ProPolisher II with wet dust suppression
- Used to polish or finish concrete floors
- Cost: $7,214 to $8,472
- Motor: 5 horsepower, TEFC
- Power requirements: 230 volts, 1 phase, 19.5 amps
- Polishing width: 23 inches, achieved with two counter rotating disc assemblies, each with three 3-inch discs
- Disc speed: 385 RPM
- Weight: 330 pounds
- Alternative dust control methods: port for use with a vacuum
- Sound pressure level: not available but likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
CONTRx Systems ProPolisher IV with wet dust suppression
- Used to polish or finish concrete floors
- Cost: $14,943 to $15,143
- Motor: 10 horse power, TEFC
- Power requirements: 230 volts, 3-phase, 23 amps or 460 volts, 3-phase, 11.5 amps
- Polishing width: 38 inches, achieved with four counter rotating disc assemblies, each with three 3-inch discs
- Disc speed: 385 RPM
- Weight: 582 pounds
- Alternative dust control methods: port for use with a vacuum
- Sound pressure level: not available but likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
Husqvarna PG 530, PG 680 and PG 820 polishers with wet dust suppression
- Designed to grind and polish marble, terrazzo, granite and concrete
- Planetary polisher features three disc assemblies
- Alternative dust control methods: port for use with a vacuum, accepts 3-inch hose
- Sound pressure level: not available but likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
Models
|
Costs
|
Power Requirements, volts, phase, amps
|
Horsepower
|
Polishing Width, inches (millimeters)
|
Individual Disc Diameter, inches (millimeters)
|
Disc Speed, RPM
|
Weight, pounds
|
PG 530
|
$15,950 to $18,895
|
220-240, 1, 16
|
5
|
21 (530)
|
9.5 (240)
|
200-710
|
480
|
PG 680
|
$23,950 to $30,863
|
380-480, 3, 32
|
17
|
27 (680)
|
9.5 (240)
|
600-1,200
|
850
|
PG 820
|
$25,950 to $32,333
|
380-480, 3, 32
|
17
|
32 (820)
|
10.5 (270)
|
250-1,100
|
970
|
(Photo courtesy of Husqvarna AB Construction Division)
Risks Addressed:
Polishing concrete or stone containing crystalline silica such as granite is a high dust activity that in the absence of controls would place workers at risk of lung disease and cancer. Such disease is well documented in the Vermont granite quarries and stone cutting sheds, and in construction operations.
Polishing stone containing crystalline silica can generate high levels of silica dust that may cause silicosis or lung scarring with prolonged exposure. Silicosis is an incurable, sometimes fatal disease. The NIOSH-recommended exposure limit is 0.05 mg/m3 as a time-weighted average concentration for up to a 10-hour workday during a 40-hour workweek. Silica has also been associated with lung cancer.
How Risks are Reduced:
Water is delivered to the polishing pad and wets dust created by abrasive polishing of concrete or stone. Silica in the masonry material is only hazardous if it is inhaled and is not hazardous for skin contact. As long as the dust does not become airborne, the hazard is reduced. The extent to which this is effective in meeting recommended exposure limits has not been evaluated.
Using water will visibly suppress dust, but the extent that it reduces the small, respirable particles is unclear, without testing. Although exposure is not reduced to zero, substantial reduction is expected. This is dependent on the amount of water used, how effectively it prevents suspension of particles in the air, rotational speed of the polisher and the extent to which workers are exposed to resuspended dust after it dries. While there is no published sampling data on these specific tools, evidence indicates exposure to respirable silica can be significantly reduced through the use of wet methods. In a study of granite processing facilities, Wickman and Middendorf stated that “the workplace controls, which are typically wet methods, implemented in the granite industry have been generally effective in reducing employees' exposures to below the OSHA PEL.” They recommended that “use of these controls should be implemented and enforced in other workplaces, such as rock drilling and abrasive cutting of concrete, where silica exposures remain problematic.” In a survey of silica exposure during fabrication of granite countertops, Simcox et al. concluded “wet processes significantly reduced worker exposure to respirable crystalline silica and, in all cases, to below the state of Washington’s PEL of 0.1 mg/m3.”
Effects on Productivity:
Using wet dust suppression with walk-behind stone polishers is expected to improve productivity by increasing visibility, reducing work site cleanup, reducing worker cleanup, and increasing the useful life of the polishing pads which reduces costs and time spent changing pads. Dust suppression also avoids exposing other workers, members of the public, adjacent property, cars and building occupants, which can increase liability and time-consuming disputes. Improved worker comfort is a result of reduced airborne dust which may in turn result in less fatigue for the worker and greater productivity. In some cases, particularly where polisher use is intermittent, wet dust suppression may be adequate to reduce the need to wear a respirator and the need for an employer respiratory protection program.
Additional Considerations:
The use of water controls may result in wet and slippery ground and walking surfaces. During cold weather this may lead to the formation of ice and an increased risk of slips, trips and falls. Polishing debris that is not bagged and removed from the work area while wet may become airborne once dried, posing an inhalation hazard to anyone in the area. Maintaining a work area free of debris and excess water will reduce the risk of these hazards.
The use of water as a dust control increases the risk of shock when electricity is used in the same area. Electrical cords and extensions must be rated for the tool's power requirements, be regularly inspected, and used in combination with ground fault interrupt circuits.
The use of gasoline-powered generators and compressors poses the risk of carbon monoxide exposure, particularly in areas where airflow is reduced. Steps to control exposure are important because the gas is invisible, odorless and tasteless. Small, inexpensive personal monitors can be worn by the operator to warn of unacceptable exposures.
Stone polishers may generate sound levels that are greater than 90 decibels, the OSHA Permissible Exposure Limit (PEL), and hazardous. Hearing protection should be worn when using stone polishers unless an industrial hygienist has conducted noise monitoring and indicated that hearing protection is not required. As is the case with any construction equipment, users should follow manufacturer safety recommendations and comply with any applicable local, state or federal regulations.
Availability
CONTRx Systems ProPolisher II and IV with wet dust suppression
To obtain information, visit http://contrxsystems.com
or contact 1-800-638-3326 info@contrxsystems.com
Husqvarna Portasaw PG 530, 680 and 820 polisher with wet dust suppression
To obtain information, visit http://www.husqvarna.com/us/construction
or contact 1-800-700-5919
Intertool DS 302 12-inch and 605 24-inch planetary floor polisher with wet dust suppression
To obtain information, visit http://www.inter-tool.com
or contact 1-800-926-9244 mm@leitchco.com