Hydraulic Impact Hammers with Wet Dust Suppression

Hydraulic impact hammers with wet dust suppression use water spray nozzles to reduce airborne dust while breaking rocks and concrete.

Description:

Hydraulic impact hammers or hydraulic breakers use a piston driven tool to repeatedly strike and break concrete or rocks. Hydraulic impact hammers are mounted on excavators, loaders, skid steers, backhoes and other carriers and generate a large amount of dust which may contain high levels of crystalline silica and creates a hazard for everyone in the vicinity. Hydraulic impact hammers with wet dust suppression are available and reduce airborne dust and silica during breaking. These systems consist of one or more spray nozzles mounted on the hammer and a source of pressurized water.
 
Atlas Copco hydraulic breaker without wet dust suppression

 

Allied Construction Products / Sandvik Hydraulic Impact Hammers with Water Jet System
  • The water jet system, standard on the City Pro models in the G series and available as an option on some other models, is integrated into the hammer’s housing and used to control dust during breaking.
  • Cost: contact Allied Construction Products for a quote.
  • Activated by the operator or automatically in conjunction with the impact hammer
  • Hydraulically driven water pump is powered by either the hammer supply circuit or from another high pressure (up to 3,050 pounds per square inch) hydraulic source from the carrier
  • Water spray nozzles: 2
  • Water flow rate: up to 7.9 gallons per minute
  • Water pressure: up to 150 pounds per square inch
  • Sound pressure level: Likely to exceed 90 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average) for the operator and nearby workers
 
Manufacturer supplied data for hydraulic impact hammers with water jet system
Model
Suitable Carrier Weight, pounds
Blow Rate, blows per minute
Breaker Hydraulic Oil Flow Rate, gallons per minute
Distance Required to Reduce Sound Pressure Level to 85 dBA, feet
BR3088/G88 City Pro
60,000 to 88,000
300 to 625
42 to 60 at 2,180 psi*
56 to 82
BR3890/G90 City Pro
77,000 to 121,000
300 to 480
55 to 82 at 2,320 psi*
59 to 79
BR4511/G110 City Pro
88,000 to 154,000
300 to 700
58 to 92 at 2,390 psi*
59 to 79
*psi is pounds per square inch
 
 
 
Atlas Copco SB (solid body) breakers with wet dust suppression
  • Used for breaking concrete, asphalt or stone during road construction, landscaping, building renovation, demolition and trenching
  • Operating hydraulic pressure for breaker: 1,450 to 2,176 pounds per square inch
  • Connection to water source: ¼” hydraulic hose with a 37 degree flare/JIC connection
  • Water pressure: 58 pounds per square inch
  • Breakers are equipped with a connection for wet dust suppression but water spray nozzles must be purchased and installed
  • Damping and solid body design result in reduced vibration and noise levels
 
Model
Cost
Suitable Carrier Weight, pounds
Blow Rate, blows per minute
Breaker Hydraulic Oil Flow Rate, gallons per minute
Number of Water Spray Nozzles
Water Flow Rate, gallons per minute
Sound Pressure Level, dBA*
SB 152
$7,700
4,200 to 9,900
780 to 1,920
6.6 to 11.9
1
up to 1.3
86
SB 202
$8,835
6,200 to 13,200
840 to 1,800
9.2 to 17.4
1
up to 1.3
90
SB 302
$12,075
9,900 to 19,800
600 to 1,380
13.2 to 21.1
1
up to 2.4
91
SB 452
$16,960
14,300 to 28,000
540 to 1,260
14.5 to 26.4
2
up to 2.4
94
SB 552
$21,200
19,800 to 33,000
660 to 1,140
17.2 to 30.4
2
up to 2.4
98
*measured at a distance of 10 meters (32.8 feet) in accordance with EN ISO 3744 and likely to exceed 90 dBA, OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average, for operators and nearby workers
 
 
 

 

Risks Addressed:

Breaking concrete and rock is a high dust activity that in the absence of controls would place workers at risk of lung disease, cancer, chronic obstructive pulmonary disease (COPD), lung scarring and silicosis with prolonged exposure. Silicosis is an incurable, sometimes fatal disease. Such disease is well documented in the Vermont granite quarries and stone cutting sheds, and in construction operations. The NIOSH-recommended exposure limit (REL) for silica is 0.05 mg/m3 as a time-weighted average concentration for up to a 10-hour workday during a 40-hour workweek.  This is one-fourth of the OSHA standard, but still twice the ACGIH-recommended threshold limit value (TLV) of 0.025 mg/m3.

How Risks are Reduced:

One or two water spray nozzles are located on the body of the hammer and aimed toward the bit or tool, the site of dust generation. When airborne dust and silica particles are sprayed with water mist they combine and, due to their increased weight, settle to the ground. The spray also wets the work surface before it is broken, thereby reducing the amount of dust generated. These systems control dust and silica near the source, reducing concentrations in the worker's breathing zone and his or her exposure.

Using water will visibly suppress dust, but the extent that it reduces the small, respirable particles is unclear, without additional testing. Although exposure will not be reduced to zero, substantial reduction is expected. This is dependent on the amount of water used, the number and location of the spray nozzles, the water spray pattern, frequency and duration with which the water spray system is used, how effectively it prevents suspension of particles in the air, the nature and amount of work and the extent to which workers are exposed to resuspended dust after it dries. While there are 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 dust controls for use with jackhammers, NIOSH found that a “low-flow, water-spray control reduced dust exposures by 70%–90%” and “may reduce exposure to dust for jackhammer operators and other workers near the work area.” 

The manufacturer Sandvik states that its Water Jet System for hydraulic impact hammers “suppresses dust effectively in any application.”

Effects on Productivity:

When used with hydraulic impact hammers, wet dust suppression systems are expected to increase productivity. Wet dust suppression systems reduce the amount of dust produced and eliminate large amounts of airborne dust, consequently, they provide a cleaner, more efficient means of breaking concrete and rocks.
 
Improved visibility can improve quality and productivity. Dust suppression may reduce site cleanup times. Dust suppression avoids exposing other workers, members of the public, adjacent property, cars and building occupants, which can be associated with increased liability or 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 hammer use is intermittent, a water spray dust control may be adequate to reduce the need to wear a respirator and 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. 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 diesel and particularly gasoline-powered equipment poses the risk of carbon monoxide exposure, especially 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. Equipment should not be left idling to cut down on carbon monoxide and to conserve fuel.
 
Hydraulic impact hammers consistently generate sound levels that are greater than 90 decibels, the OSHA Permissible Exposure Limit (PEL), and hazardous. Hearing protection should be worn when using hydraulic hammers unless an industrial hygienist has conducted noise monitoring and indicated that hearing protection is not required.
 
Some city ordinances (e.g. Boston) may consider visible dust generated in urban construction operations to be a public nuisance.
 
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:

Michael R. Cooper and Bruce Lippy - The Lippy Group, LLC

Hazards Addressed:

  • Excavation & Demolition
    • Chip, break and recycle concrete
    • Deconstruct building foundations
    • Deconstruct superstructures

Availability

Allied Construction Products / Sandvik Water Jet System for Hydraulic Impact Hammers
To obtain information, visit http://www.alliedcp.com or contact 1-216-431-2600 sales@alliedcp.com

Atlas Copco SB (solid body) breakers with wet dust suppression
To obtain information, visit http://www.atlascopco.us or contact 1-800-732-6762 accmt.acconnect@us.atlascopco.com

Return on Investment

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