Effectiveness of dust control systems tested for use during masonry restoration the sequel
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Effectiveness of Dust Control Systems Tested for use During Masonry Restoration – The Sequel. RT 232 - Implementing Engineering Controls in Construction - Needs, Challenges, and Effectiveness June 4th, 2014. Michael R. Cooper, CIH, CSP, MPH [email protected]

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Effectiveness of Dust Control Systems Tested for use During Masonry Restoration – The Sequel

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Effectiveness of dust control systems tested for use during masonry restoration the sequel

Effectiveness of Dust Control Systems Tested for use During Masonry Restoration – The Sequel

RT 232 - Implementing Engineering Controls in Construction - Needs, Challenges, and Effectiveness

June 4th, 2014

Michael R. Cooper, CIH, CSP, MPH

[email protected]


Effectiveness of dust control systems tested for use during masonry restoration the sequel

The local exhaust ventilation system evaluations being described are part of a four-year NIOSH-funded project to reduce exposures in construction


To reduce silica exposures during tuckpointing lev systems must be

To reduce silica exposures during tuckpointing, LEV systems must be:


Our partnership identified tuckpointing lev systems to evaluate

Our partnership identified tuckpointing LEV systems to evaluate


Effectiveness of dust control systems tested for use during masonry restoration the sequel

The partnership rated the following as the most important criteria when selecting systems for further evaluation:

  • Impact on productivity

  • Durability

  • User acceptance/compatibility with existing work practices

  • Blade visibility


Effectiveness of dust control systems tested for use during masonry restoration the sequel

While considering these criteria, the partnership selected tuckpointing LEV systems for further evaluation

  • Impact on productivity

  • Durability

  • User acceptance/compatibility with existing work practices

  • Blade visibility


The partnership selected from the grinders identified as most prominent in construction

The partnership selected from the grinders identified as most prominent in construction


The partnership selected from seven tuckpointing shrouds

The partnership selected from seven tuckpointing shrouds

ICS Dust Director

Hilti Tuck Point Dust Removal Hood

Joe Due Blades and Equipment Dust Mizer

Bosch Tuckpointing Shroud

Dustless Technologies CutBuddie II

Arbortech AS170 Brick and Mortar Saw

Danish Tool North America Tuckpointing Router Bit and Shroud


The partnership selected from 14 vacuums

The partnership selected from 14 vacuums

ICS Vacuums (4 models)

Hilti VC 40U Vacuum

Little Red Ruwac WNS 2220

Bosch Airsweep™ 13 Gallon Wet/Dry Vacuum Cleaner with Power Broker

Tiger-Vac AS-400 HEPA

Dustless Technologies HEPA Vac

Dustcontrol Vacuums (3 models)

Ermator Vacuums (2 models)


Four high ranking systems were tested with and without lev in a controlled setting

Four high ranking systems were tested, with and without LEV, in a controlled setting

  • Metabo grinder, ICS Dust Director shroud with Dustcontrol 2900 vacuum

  • Bosch grinder, ICS Dust Director shroud with Dustcontrol 2900 vacuum

  • Boschgrinders, ICS Dust Director shroud with Ermator S26 vacuum

  • Hilti grinder, Hilti shroud with Hilti vacuum


Test conditions and data collected were consistent between evaluations

Test conditions and data collected were consistent between evaluations

  • Used type S mortar after 28+ days curing

  • Used filter (HEPA or 99.9%) recommended by manufacturer

  • Conducted at least five trials per tool/control combination

  • Randomized trial order to minimize bias

  • Sampled for 16 to 26-minute with LEV, approximately half as long without LEV

  • Sampled respirable silica sampling with BGI GK2.69 cyclone at 4.2 lpm

  • Measured static pressure to monitor flow rate

  • Documented mass of dust collected by LEV

  • Documented linear feet of joints cut per minute


Effectiveness of dust control systems tested for use during masonry restoration the sequel

Using the Metabo grinder with the Dust Director shroud and DustControl vacuum reduced respirable silica exposures by 95.6%


Using this lev system reduced exposures by 95 6

Using this LEV system reduced exposures by 95.6%

6.3

130 times REL

0.28

5.5 times REL

0.05


Effectiveness of dust control systems tested for use during masonry restoration the sequel

Using the Bosch grinder with the Dust Director shroud and DustControl vacuum reduced respirable silica exposures by 98.7%


Using this lev system reduced respirable silica exposures by 98 7

Using this LEV system reduced respirable silica exposures by 98.7%

7.2

140 times REL

1.8 times REL

0.09

0.05


Effectiveness of dust control systems tested for use during masonry restoration the sequel

Using the Bosch grinder with the Dust Director shroud and Ermator vacuum reduced respirable silica exposures by 97.6%


The ermator s26 is rated to provide sufficient air flow to support two grinders

The Ermator S26 is rated to provide sufficient air flow to support two grinders


Using this lev system reduced respirable silica exposures by 98 71

Using this LEV system reduced respirable silica exposures by 98.7%

35

690 times REL

0.82

16 times REL

0.05


Using the complete hilti tuckpointing lev system reduced respirable silica exposures by 96 6

Using the complete Hilti tuckpointing LEV system reduced respirable silica exposures by 96.6%


Using this lev system reduced exposures by 96 6

Using this LEV system reduced exposures by 96.6%

11

220 times REL

0.38

7.5 times REL

0.05


In addition we performed limited evaluations with a new grinder shroud from ermator

In addition, we performed limited evaluations with a new grinder shroud from Ermator


Test conditions and data collected were consistent between evaluations1

Test conditions and data collected were consistent between evaluations

  • Used type S mortar after 28+ days curing

  • Used HEPA filter as recommended by manufacturer

  • Conducted at least three trials per tool/control combination

  • Randomized trial order to minimize bias

  • Sampled for 24 minutes with LEV and 10 minutes without LEV

  • Sampled respirable silica sampling with BGI GK2.69 cyclone at 4.2 lpm

  • Measured static pressure to monitor flow rate

  • Documented mass of dust collected by LEV


Effectiveness of dust control systems tested for use during masonry restoration the sequel

Using the Bosch grinder with the Ermator shroud and Ermator S13 vacuum reduced respirable silica exposures by 96.1%


Using this lev system reduced exposures by 96 1

Using this LEV system reduced exposures by 96.1%

5.9

120 times REL

0.23

0.05


Effectiveness of dust control systems tested for use during masonry restoration the sequel

Using Bosch grinders with the Ermator shrouds and Ermator S26 vacuum reduced respirable silica exposures by 97.8%


Using this lev system reduced exposures by 97 8

Using this LEV system reduced exposures by 97.8%

8.1

160 times REL

3.6 times REL

0.18

0.05


Effectiveness of dust control systems tested for use during masonry restoration the sequel

The highest flow rates at the tool were 79 percent of the manufacturers’ specifications for the vacuums tested


The average flow rates after use were 68 to 75 percent of our desired flow rate

The average flow rates after use were 68 to 75 percent of our desired flow rate


The average flow rates returned to 85 to 102 percent of our desired flow rate after filter cleaning

The average flow rates returned to 85 to 102 percent of our desired flow rate after filter cleaning


The available tuckpointing lev systems can be effective but there are challenges

The available tuckpointing LEV systems can be effective but there are challenges


Acceptance and effectiveness varies with the user

Acceptance and effectiveness varies with the user


Moving the grinder toward the point of dust capture is required

Moving the grinder toward the point of dust capture is required

Dust Capture


Blade visibility and ability to cut both directions is important

Blade visibility and ability to cut both directions is important

Dust Capture


Air flow rate at the tool must be maintained

Air flow rate at the tool must be maintained


Average exposure reduction was 97 percent but additional controls may be needed

Average exposure reduction was 97 percent but additional controls may be needed

Respirable Silica (mg/m3)

10 X NIOSH REL

NIOSH REL


Questions

Questions?

Michael R. Cooper, CIH, CSP, MPH [email protected]


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