Bucket Shroud with Vacuum Dust Control

A bucket shroud clipped on to a mixing bucket captures airborne silica and other dust at the mixing source.

Description:

Airborne dust generated when bags of dry mortar, grout, cement, or joint compound are emptied into a bucket may contain high levels of crystalline silica and create a hazard for everyone in the vicinity.  A bucket shroud that snaps onto the mixing bucket and attaches to a vacuum with a disposable filter (a high efficiency particulate air - HEPA-filter is recommended when practical) can keep this dust from becoming airborne.  The shroud evenly distributes the vacuum's suction so that as the materials is poured the dust is captured and transported through the hose into the vacuum's bag or reservoir.

Beaton Innovations Wale Tale bucket shroud:

The Beaton Innovations Wale Tale bucket shroud is an example of a commercially available bucket shroud that along with a compatible vacuum can be used to capture dust before it become airborne.  The WaleTale has a vacuum port diameter of 2.5 inches and clips on to the rim of a 5, 3-1/2 or 1 gallon mixing bucket.  The dust is drawn into a 2.5 inches opening on the shroud, through the hose and into the vacuum.  The WaleTale is compatible with several different vacuums including those listed below and approved by the manufacturer:

Bosch Airsweep 13 Gallong Wet/Dry Vacuum with Power Broker

CS Unitec Vacuum CS 1225

Dustcontrol DC 3800c

Bosch Vacuum Specifications:
o    Hose Port Inside Diameter: 2-1/4 inches
o    Air flow rate (maximum): 130 cubic feet per minute
o    Vacuum suction pressure: 9.76 inches (248 millibars)
o    Dust capacity: 13.3 gallons (gross)
o    Weight: 45.7 pounds
o    Filter cleaning: Pulse-Clean™ electromagnetic filter cleaning
o    Airsweep™ HEPA Vacuum Filters (Model VAC019) may be used
o    Power requirements: 120 volts, 11 amps
o    Click the link for more details on the Bosch Airsweep 13 Gallon Wet/Dry Vacuum with Power Broker
o    Optional Airsweep™ Vacuum Hose Adapters can be used to connect 35mm hoses to the vacuums with ports for 1-1/4, 1-1/2 and to 2-1/2 hoses.  Click the link for more details: 2-1/2 inch Vacuum Hose Adapter

CS Unitec Vacuum Specifications:
o    Air flow rate (maximum): 130 cubic feet per minute
o    Maximum static pressure: 98 inches of water
o    Dust capacity: 6.6 gallons
o    Weight: 24.3 pounds
o    Electromagnetic Pulse Cleaning System maintains maximum airflow and suction with automatic filter vibration.
o    Vacuum hose is 2 inches in diameter and 15 feet long and comes with an adapter for connection to the 1.5-inch outside diameter vacuum port
o    Wet vacuuming capability with sensor for automatic shut-off to protect motor and filters
o    Click the link for more details on the CS 1225 H HEPA Vacuum and related products, including the larger CS1500 H with a 13 gallon capacity, and the CS 2000 - Water Recycling and Slurry Containment Vacuum: CS 1225 and Other Models

Dustcontrol, Inc. Single Phase Dust Extractors 3800c:
o    Cyclonic pre-separator- this system collects the majority of particles before they reach the filter, and reduces the amount of dust that collects on the filter
o    Filtration: a fine filter, rated to remove 99.9 percent of particles, followed by a HEPA filter, rated to remove 99.95 percent of 0.3 micron particles (the most penetrating size
o    Features a “reverse air pulse cleaning system”
o    Vacuum hose inlet diameter: 2 inches
o    Sound Pressure Level: 68 to 75 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
o    Click here to learn more about the DC 3800c and other models, and see additional details in the table below.


Risks Addressed:

Inhaling silica dust may cause silicosis or lung scarring with prolonged exposure.  Silicosis is an incurable, sometimes fatal, disease.  Exposure to silica also causes lung cancer and other lung diseases including chronic obstructive pulmonary disease (COPD) and tuberculosis, and has been linked to renal disease and rheumatoid arthritis.  A report by OSHA noted that "silica dust can be generated when materials such as ceramics, concrete, masonry, rock and sand are mixed, blasted, chipped, cut, crushed, drilled, dumped, ground, mixed or driven upon." (OSHA Controlling Silica Exposure in Construction - 2009).


How Risks are Reduced:

When a vacuum system is used to capture silica and other dust at or very near the source, dust concentrations in the worker’s breathing zone and exposures are reduced.  In some cases, particularly where work is intermittent or in an area with general ventilation, use of dust collectors may be adequate to reduce the need to wear a respirator, and the need for an employer’s respiratory protection program.

The manufacturer states that the WaleTale "eliminates dust from mixing mortar and grout in buckets... [and] will not allow dust to escape the top of the bucket."  In addition, studies of the use of vacuums with other tools during much higher dust generating tasks have been found to be effective in reducing exposures.
 
There have not been independent published studies measuring the exposure of construction dust and silica exposure while using a bucket shroud with a vacuum dust control.  However, with concrete cutting generating more quartz level than mixing concrete (Silica Dust Exposures During Selected Construction Activities, Flanagan), health and safety experts believe that workers can have a more substantial reduction in dust exposure - if not equal - when using a bucket shroud with an effective vacuum dust control.
 
For example:  A 2009 study, “Engineering Control Technologies to Reduce Occupational Silica Exposures in Masonry Cutting and Tuckpointing”, found respirable silica levels were reduced by 96% with the use of the vacuum while cutting block.   Average exposure with use of the control was 0.11 mg/m3 or just over the OSHA Permissible Exposure Limit (PEL) of 0.1 mg/m3 and roughly two times the NIOSH Recommended Exposure Limit (REL) of 0.05 mg/m3.  Respirable silica levels were reduced by 91% when cutting brick with an average exposure of 0.08 mg/m3, which is below the PEL but over the NIOSH REL.  The results were based on data collected in 2006 using the Bosch saw and an earlier version of the Bosch vacuum described earlier.

NIOSH found similar results in a separate 2007 study, “In Depth Survey of Dust Control Technology for Cutting Concrete Block and Tuckpointing Brick,” which was based on data collected in 2004.  This study found respirable silica exposures were reduced by 95% when cutting block, and noted that dust levels were reduced by maintaining the saw's blade depth to the minimum necessary to make the cut.

Effects on Productivity:

Vacuum dust control systems create a cleaner work environment, and may reduce time spent cleaning up the work site and thereby improve productivity.


Contributors:

Jean Christophe Le, MPH. - CPWR - The Center for Construction Research and Training.


Hazards Addressed:

Availability

CS Unitec 1225
To obtain information, visit http://www.csunitec.com or contact 1-800-700-5919 info@csunitec.com

Dustcontrol, Inc. Dust Extractors
To obtain information, visit http://www.dustcontrolusa.com/newsite/ or contact 1-910-395-1808 sales@dustcontrolusa.com

Bosch Airsweep
To obtain information, visit http://www.boschtools.com or contact 1-877-267-2499 http://www.boschtools.com/Service/ContactUs/Pages/default.aspx

Beaton Innovations Wale Tale
To obtain information, visit http://waletale.net/ or contact 1-607-207-5890 joelbeaton@mac.com

Return on Investment

To calculate the return on investment (ROI) for your specific application, please visit our Return on Investment Calculator. While a specific ROI example has not been developed for this particular solution, the ROI Calculator provides a useful tool and guidance on how to generate your own on investment analysis.