Solution Summary: Walk-Behind Masonry Saws with Wet Dust Suppression
Description:
Cutting concrete and other masonry materials generates a large amount of dust that may contain high levels of crystalline silica and create a hazard for everyone in the vicinity. Increasingly, nano-enabled masonry products are being used in construction that can also expose workers to inhaling engineered nanomaterials when the products are being cut.Concrete that contains nano-size titanium dioxide is an example. Wet suppression is a control option for dust generated while cutting masonry materials with walk-behind masonry saws. These controls use a pump or line pressure to deliver water to the saw blade where it combines with particles and reduces airborne dust levels. Without dust controls, user and bystander exposures are almost certain to exceed OSHA limits for total dust (15mg/m3) and exceeded limits for crystalline silica.
If properly designed and used, exposures can be reduced 50 to 95%. If use is brief and intermittent, this may reduce exposures enough that a respiratory protection program isn’t required. Continuous use may exceed the OSHA Permissible Exposure Limit, even with the use of wet dust suppression, however.
EDCO, Inc. 14-inch down-cut walk-behind concrete/asphalt saws with water connection
- Used for short-run slab cutting, contraction joints, patch repairs in asphalt, traffic loop installation and trenching
- Cost: $2,054 (optional water tank is an additional $221)
- Blade diameter: 14 inches
- Maximum cutting depth: 4 ¾ inches
- Sound pressure level: greater than 85 dBA and likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
Models
|
Power Requirements
|
Horsepower
|
Unloaded Blade Speed, RPM
|
Weight, pounds
|
SK-14-9H
|
gasoline
|
9
|
3,600
|
190
|
SK-14-11H
|
gasoline
|
11
|
3,600
|
190
|
SK-14-13H
|
gasoline
|
13
|
3,600
|
190
|
- Used for short-run slab cutting, contraction joints, patch repairs in asphalt, traffic loop installation and trenching
- Blade diameter: 18 inches
- Maximum cutting depth: 6 ¾ inches
- Sound pressure level: greater than 85 dBA and likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
Models
|
Costs*
|
Power Requirements
|
Horsepower
|
Unloaded Blade Speed, RPM
|
Weight, pounds
|
DS-18-13H
|
$2,549
|
gasoline
|
13
|
3,000
|
254
|
DS-18-5B
|
$2,549
|
230 volts, single phase, 19.5 amps
|
5
|
2,880
|
280
|
DS-18-5B
|
$2,549
|
230 volts, three phase, 12 amps or 460 volts, three phase, 6 amps
|
5
|
2,880
|
280
|
- Used for Highway, road and bridge deck repair, utility installation and traffic loop installation
- Maximum blade diameter: 20 inches (16 inches for SS-20-13H)
- Maximum cutting depth: 6 ¾ inches
- Sound pressure level: Greater than 92 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
Models
|
Costs
|
Power Requirements
|
Horsepower
|
Blade Speed, RPM
|
Weight, pounds
|
SS-20-20H
|
$6,153
|
gasoline
|
20
|
2,760
|
458
|
SS-20-13H
|
$5,330
|
gasoline
|
13
|
3,600
|
438
|
SS-20-7.5B
|
$5,531
|
230 volts, three phase, 17.4 amps or 460 volts, three phase, 8.7 amps
|
7.5
|
2,835
|
465
|
SS-20-10B
|
$5,703
|
230 volts, three phase, 23 amps or 460 volts, three phase, 11.5 amps
|
10
|
2,835
|
478
|
SS-20-25P
|
$9,993
|
propane
|
25
|
2,760
|
498
|
- Used for Highway, road and bridge deck repair, utility installation airport construction and traffic loop installation
- Maximum blade diameter: 26 inches (blade guards that will accommodate 14 to 30 inch blades are available)
- Maximum cutting depth: 10-1/2 inches
- Sound pressure level: Greater than 92 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
Models
|
Costs
|
Power Requirements
|
Horsepower
|
Blade Speed, RPM
|
Weight, pounds
|
SS-26-38K
|
$12,350
|
gasoline
|
38
|
2,091
|
1,040
|
SS-26-15L
|
$13,430
|
460 volts, three phase, 17.5 amps
|
15
|
1,725
|
970
|
SS-26-31D
|
$23,899
|
diesel
|
31
|
2,129
|
1,225
|
- Used for Highway, road and bridge deck repair, utility installation airport construction and traffic loop installation
- Maximum blade diameter: 36 inches (blade guards for smaller blades are available)
- Maximum cutting depth: 15 inches
- Sound pressure level: Greater than 92 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
Models
|
Costs
|
Power Requirements
|
Horsepower
|
Blade Speed, RPM
|
Weight, pounds
|
SS-36-61D
|
$26,970
|
diesel
|
61
|
1,675
|
1,588
|
SS-36-61PC*
|
$28,071
|
diesel
|
61
|
2,358
|
1,775
|
- Used for small to medium concrete cutting jobs
- Blade diameter: 14 inches (12-inch blade is optional)
- Maximum cutting depth: 5-1/2 inches (with a 14-inch blade)
- 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
|
Horsepower
|
Blade Speed, RPM
|
Weight, pounds
|
CX-3 H
|
$1,554
|
gasoline
|
6.5
|
3,600
|
119
|
CX-3 R
|
$1,222
|
gasoline
|
6
|
3,600
|
117
|
- Used for small to medium concrete cutting jobs
- 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
|
Horsepower
|
Maximum Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
Weight, pounds
|
MK-9136 H
|
$2,691
|
Gasoline
|
11
|
16
|
5-5/8
|
3,600
|
238
|
MK-9514 E1
|
$2,995
|
230 volts, single phase
|
5
|
14
|
4-5/8
|
3,450
|
245
|
MK-9514 E3
|
$2,782
|
230 volts, three phase, or 460 volts, three phase
|
5
|
14
|
4-5/8
|
3,450
|
255
|
- Used for cutting concrete
- Power: 35 horsepower gasoline
- Weight: 1,150 pounds
- 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
|
Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
MK-4024
|
$16,000
|
24
|
9-1/2
|
1,900
|
MK-4030
|
$17,118
|
30
|
12-1/2
|
1,900
|
MK-4036
|
$17,118
|
36
|
15
|
1,650
|
- Used for cutting concrete
- Power: 30 horsepower diesel
- Weight: 1,190 pounds
- 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
|
Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
MK-4024D
|
$17,036
|
24
|
9-1/2
|
1,800
|
MK-4030D
|
$17,663
|
30
|
12-1/2
|
1,800
|
MK-4036D
|
$17,663
|
36
|
15
|
1,500
|
- Used for cutting concrete
- Power: 48 horsepower gasoline
- Weight: 1,120 pounds
- 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
|
Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
MK-4024HY
|
$22,380
|
24
|
9-1/2
|
1,900
|
MK-4030HY
|
$22,589
|
30
|
12-1/2
|
1,900
|
MK-4036HY
|
$22,767
|
36
|
15
|
1,650
|
- Used for cutting concrete
- Power: 44 horsepower diesel
- Weight: 1,080 pounds
- 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
|
Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
MK-4024KB
|
$22,380
|
24
|
9-1/2
|
1,800
|
MK-4030KB
|
22,589
|
30
|
12-1/2
|
1,800
|
MK-4036KB
|
$22,767
|
36
|
15
|
1,550
|
- Used for concrete cutting
- 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
|
Horsepower
|
Maximum Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
Weight, pounds
|
MK-3024V
|
$9,795
|
gasoline
|
35
|
24
|
9-1/2
|
1,900
|
650
|
MK-3024K
|
$10,395
|
gasoline
|
38
|
24
|
9-1/2
|
1,900
|
650
|
MK-3030V
|
$9,865
|
gasoline
|
35
|
30
|
12-1/2
|
1,900
|
650
|
MK-3030K
|
$10,465
|
gasoline
|
38
|
30
|
12-1/2
|
1,900
|
650
|
MK-3024B
|
$13,220
|
230 volts, three phase,
|
20
|
24
|
9-1/2
|
2,020
|
700
|
$13,100
|
460 volts, three phase
|
||||||
MK-3030B
|
$13,920
|
230 volts, three phase
|
20
|
30
|
12-1/2
|
2,020
|
705
|
$13,200
|
460 volts, three phase
|
- Used for cutting concrete
- Water supply: ¾-inch hose connection (water tank is available)
- 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
|
Horsepower
|
Maximum Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
Weight, pounds
|
MK-1613H
|
$2,700
|
Gasoline
|
11
|
18
|
6-5/8
|
2,600
|
223
|
MK-1609H
|
$2,499
|
Gasoline
|
7
|
16
|
5-5/8
|
3,600
|
210
|
MK-1610B
|
$3,290
|
230 volts, three phase, or 460 volts, three phase
|
10
|
18
|
6-5/8
|
NA
|
275
|
- Used for cutting concrete
- Water supply: ¾-inch hose connection (water tank and pump are available)
- 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
|
Horsepower
|
Maximum Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
Weight, pounds
|
MK-2013HE
|
$4,039
|
gasoline
|
11
|
16
|
5-5/8
|
3,400
|
290
|
MK-2013HSP
|
$3,705
|
gasoline
|
11
|
16
|
5-5/8
|
3,400
|
310
|
MK-2020HSP
|
$5,427
|
gasoline
|
18
|
20
|
7-5/8
|
2,850
|
392
|
MK-2024HSP
|
$5,557
|
gasoline
|
18
|
20
|
7-5/8
|
2,850
|
398
|
MK-2020KSP
|
$6,402
|
propane
|
20
|
20
|
7-5/8
|
2,863
|
417
|
- Used for joint sawing, floor sawing, trenching, road repair and other cutting applications
- Cost: $3,360
- Blade diameter: Up to 20 inches
- Blade speed: 2,900 RPM
- Maximum cutting depth: 7 inches
- Weight: 107 pounds
- Water supply: ¾-inch hose connection
- Alternative dust control: port for use with vacuum
- Sound pressure level: Not available but likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average)
- Used to cut concrete or asphalt floors, driveways, highways, streets and runways
- Fuel: diesel
- Engine horsepower: 84
- Water supply: ¾-inch hose connection (water pump kit is available)
- Sound pressure level: 95 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
(Photo courtesy of Husqvarna AB Construction Division)
Models
|
Costs*
|
Maximum Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Shaft Speed, RPM
|
Weight, pounds*
|
FS 8400 D 26
|
$29,531
|
26
|
10-1/2
|
1,800
|
2,000
|
FS 8400 D 30
|
$29,705
|
30
|
12-1/2
|
1,600
|
2,020
|
FS 8400 D 36
|
$29,850
|
36
|
15
|
1,350
|
2,050
|
FS 8400 D 42
|
$30,110
|
42
|
17-1/2
|
1,180
|
2,080
|
FS 8400 D 48
|
$30,371
|
48
|
20
|
1,080
|
2,140
|
FS 8400 D 60
|
$41,120
|
60
|
25
|
815
|
2,390
|
- Used to cut concrete or asphalt floors, driveways, highways, streets and runways
- Fuel: diesel
- Horsepower: 66
- Water supply: ¾-inch hose connection (water pump kit is available)
- Sound pressure level: 95 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
(Photo courtesy of Husqvarna AB Construction Division)
Models
|
Costs*
|
Maximum Blade Diameter, inches
|
Maximum Cutting Depth, inches
|
Blade Speed, RPM
|
Weight, pounds*
|
FS 6600 D 20
|
$24,274
|
20
|
7-5/8
|
2,400
|
1,789
|
FS 6600 D 26
|
$24,335
|
26
|
10-1/2
|
1,800
|
1,871
|
FS 6600 D 30
|
Hilti DSH-FSC Gas Saw Floor Cart and DSH 700/900 Hand-held gas saw
- Used to cut concrete or asphalt floors, driveways, highways, streets and runways
- Fuel: diesel
- DSH-FSC Gas Saw Floor Cart: constructed from heavy duty steel with a gravity feed water container that allows the cart to be portable while still providing wet dust suppression; can be combined with the DSC 700/900 hand-held gas saws
Models |
Costs* |
Maximum Blade Diameter, inches |
Maximum Cutting Depth, inches |
Blade Speed, RPM |
Weight, pounds* |
DSH 700 |
$1,199.99 |
14 |
3.9 |
3,000 |
24.86 |
DSH 900 |
N/A |
16 |
4.9 |
3,000 |
25.74 |
STIHL TS 410/420/700/800 and Cutquik Cart Kits with water tank
- Used to cut concrete or asphalt floors, driveways, highways, streets and runways
- Fuel: diesel
- STIHL Cutquik Cart Kit: includes a water container that allows the cart to provide wet dust suppression; can be combined with the STIHL TS 410/420/700/800 hand-held gas saws; mounting kits must be purchased separately.
Models |
Costs* |
Maximum Blade Diameter, inches |
Maximum Cutting Depth, inches |
Blade Speed, RPM |
Weight, pounds* |
TS 410 |
$895.00 |
12 |
3.9 |
5,350 |
20.7 |
TS 420 |
$999.00 |
14 |
4.9 |
5,350 |
21.2 |
TS 700 |
$1,169.95 |
14 |
4.9 |
5,350 |
25.6 |
TS 800 |
$1,399.00 |
16 |
5.6 |
4,600 |
28.7 |
Wacker Neuson BFS 614, BFS 914, and BFS 1318 with water connection
- Used for cuts in asphalt or concrete
- Fuel: gasoline
Models |
Costs |
Maximum Blade Diameter, inches |
Maximum Cutting Depth, inches |
Blade Speed, RPM |
Weight, pounds |
BFS 614 |
1,399.97 |
14 |
4.9 |
4,000 |
136 |
BFS 914 |
2,199.97 |
14 |
5 |
2,200 |
183 |
BFS 1318 |
2,529.97 |
18 |
6.5 |
2,200 |
207 |
Risks Addressed:
Silica dust exposure may cause silicosis or lung scarring with prolonged exposure. Silicosis is an incurable, sometimes fatal, disease. Silica also causes lung cancer and chronic obstructive pulmonary disease (COPD). The OSHA permissible exposure limit (PEL) for respirable crystalline silica is 0.05 mg/m3 as an 8-hour time weighted average (TWA). The NIOSH-recommended exposure limit (REL) is 0.05 mg/m3 as time-weighted average concentration for up to a 10-hour workday during a 40-hour workweek.
Another less understood, but emerging hazard is engineered nanomaterials. Incredibly small particles are being added to a broad range of construction products to improve performance, but animal toxicity tests indicate a need for closer scrutiny. There is no evidence yet that engineered nanomaterials have caused harm in exposed workers. However, it is most important that exposures be limited and that precautionary approaches be used to reduce exposure and protect construction workers from the potential hazards of engineered nanomaterials. Nano-size ultrafine titanium dioxide, which can be present in nano-enabled masonry products, has been found to cause inflammation of the lungs and lung cancer in lab animals. The National Institute for Occupational Safety and Health (NIOSH) has determined that ultrafine titanium dioxide should be considered a potential occupational carcinogen. Other engineered nanomaterials that may be present in nano-enabled construction materials used in masonry work could also have the potential to cause harm when inhaled by construction workers. Cutting nano-enabled concrete roofing tiles without engineering controls can generate excessive amounts of airborne dust that if inhaled by workers could increase the risk of developing respiratory disease (West GH, et al 2016).
OSHA has no specific regulation or Permissible Exposure Limit (PEL) for any engineered nanomaterial. However, NIOSH has a recommended exposure limit (REL) for ultrafine titanium dioxide of 0.3 mg/m3 as a time-weighted average (TWA) concentration for up to 10 hours/day during a 40-hour week. The intent of the REL is to lower the risk to workers of the potential for developing lung cancer.
How Risks are Reduced:
The saw blades are partially enclosed in shrouds with water spray nozzles which are generally located near the top of the blade. When water is pumped through the nozzle, it combines with particles near the point of dust generation and, due to increased weight, the now larger particles settle to the ground. Silica and dust are only hazardous if inhaled and are not hazardous for skin contact. As long as the dust does not become airborne, the hazard is reduced.
In a review of NIOSH sampling data, Linch concluded “systems using water on the saw blade greatly reduce the amount of respirable dust generated.”
In a study of stationary masonry saws, Yereb et al. concluded “wet cutting substantially reduces worker exposures to silica dust, but does not entirely eliminate them.” Beamer et al. and Meeker et al. came to similar conclusions in their separate but similar work with stationary masonry saws.
There are no reported studies specifically evaluating the effectiveness of wet dust suppression methods in controlling construction worker exposure to engineered nanomaterials in nano-enabled masonry products when using walk-behind masonry saws. However, because wet dust suppression methods with walk-behind masonry saws have been demonstrated to be very effective in reducing exposures to respirable dust and silica, it is expected that wet cutting will also be effective in reducing worker exposure to engineered nanomaterials as well.
Effects on Productivity:
Wet dust suppression systems can have either positive or negative effects on productivity, but definitely improve the quality of the work by suppressing large amounts of airborne dust, which allows a cleaner, more efficient means of masonry cutting.
Dust suppression also reduces site cleanup times. Dust suppression 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 saw 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.
Some additional issues should be considered. Time may be required to allow masonry materials to dry after cutting and before use, which will depend on the material, the amount of water used and the application. In addition to electrical power requirements, the saw needs to be located near a source of water.
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. Cutting debris that is not 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 reduces 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, replaced when damaged, and used in combination with ground fault interrupt circuits.
The use of gasoline-powered equipment 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. Poisoning by carbon monoxide can occur quickly indoors, but working outdoors does not ensure operators won’t be overcome. Small, inexpensive personal monitors should be worn by the operator to warn of unacceptable exposures.
Walk-behind masonry saws frequently generate sound levels that are greater than 90 decibels, the OSHA Permissible Exposure Limit (PEL), and hazardous. Hearing protection should be worn when using masonry saws 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.
Contributors:
Bruce Lippy, PhD, CIH - CPWR - The Center for Construction Research and Training
Michael R. Cooper - Aria Environmental, Inc.
Bill Kojola, MS
Availability
MK Diamond CX-3, 9000, 4000, 3000, 1600, 20 series Walk-Behind concrete saws
To obtain information, visit http://www.diamondproducts.com
or contact 1-800-321-5336
EDCO, Inc. Walk-Behind 14/18-inch down-cut and Self-Propelled 20/26/24/36-inch concrete/asphalt saws
To obtain information, visit http://edcoinc.com
or contact 1-800-638-3326 info@edcoinc.com
Wacker Neuson BFS 614, BFS 914, BFS 1318 with water connection
To obtain information, visit Wacker Neuson
or contact 1-800-770-0957 sales.us@wackerneuson.com
Husqvarna Portasaw FS 8400/6600/4800/4600/4400 D, 3500 G, 3500 E flat saws; FS 500/400/309 floor saws
To obtain information, visit http://www.husqvarna.com/us/construction
or contact 1-800-700-5919
CS Unitec, Inc. CSR 150 Pneumatic Walk-Behind masonry saw with vacuum connection
To obtain information, visit http://www.csunitec.com
or contact 1-800-700-5919 info@csunitec.com