Solution Summary: Quieter Vacuum Extraction Trucks
Quieter vacuum extraction trucks are vehicle mounted vacuums designed to limit noise exposure while removing liquid or semi-solid waste.
Description:
Quieter vacuum extraction trucks use engineering controls to limit noise exposure. An improved design of the vacuum pump (blower) and lower amounts of engine power needed to run the blowers reduce noise. The vehicles remove semi-solid or liquid waste with suction generated by a blower that often requires the engine to operate at a higher speed, producing high levels of noise from exhaust airflow. Through the use of exhaust silencers and lower engine speed, the noise generated by the truck is reduced.
Through the use of specially designed exhaust silencers and lower engine speed, the noise produced by these vacuum extraction trucks is mitigated and exposures are reduced. Sound pressure levels on the construction site, however, may still be above the OSHA Permissible Exposure Limit and workers may need to wear hearing protection for more than intermittent visits.
Guzzler NX Vacuum Truck
- Airflow Rate: 5,300-5,500 cubic feet per minute (cfm)
- Airflow Rate at Maximum Static Pressure: 2,900 cfm
- Maximum Static Pressure: 28 inches of mercury
- Capacity: 3,600 gallons
- Cyclonic separator
- Filtration: 10, 5, or 1 micron bags
- Hose Diameter: 8 inches
- Hose Length: 10 foot section of hose (approximately $700)
- Application: wet/dry
- Engine: diesel
- Vehicle Weight (empty): 44,820 pounds
- Noise Control Methods: silencers and injection cooled blower allowing lower engine RPM
- Exterior Sound Power Level: 88.9 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
VACMASTERS Vacuum Trucks
| Model | Capacity (gallons) | Gross Vehicle Weight (pounds) |
| System 4000 | 450 or 800 | 25,500 |
| System 3000 | 300 | 19,000 |
- Airflow Rate at Maximum Static Pressure: 1,000 cubic feet per minute
- Maximum Static Pressure: 15 inches of mercury
- Filtration: final filter is 10 microns
- Hose Diameter: 4 inches
- Hose Length: 25 or 33 feet
- Application: wet/dry
- Engine: diesel
- Noise Control Methods: silencers and enclosures
- Exterior Sound Pressure Level based: 94 dBA (OSHA’s Permissible Exposure Limit for an 8-hour time-weighted average is 90 dBA)
GapVax Vacuum Trucks
GapVax offers an optional enclosure option of the blower, intake, and exhaust to minimize noise on the HV-57 model.
| Model | Airflow Rate (cubic feet per minute) | Maximum Static Pressure (inches of mercury) | Capacity (gallons) | Gross Vehicle Weight (pounds) | Sound Pressure Level (dBA) |
| MC Series | 4,500 (free flowing) | 15 | 1,000 – 2,000 | 50,000 – 65,000 | >90 |
| HV-57 | 5,300 (free flowing) | 28 | 3,500 | 64,000 | 86 |
- Cyclonic separators
- Filtration: final 600 micron stainless steel screen
- Hose Diameter: 8 inches
- Hose Length: 26 feet
- Application: wet/dry
- Engine: diesel
- Noise Control Methods: silencers, quieter blower
Risks Addressed:
Manufacturers often report sound levels exceeding 90 dBA for vacuum extraction trucks. Over time, exposure to noise levels at or above 85 decibels can lead to permanent hearing loss. The NIOSH Recommended Exposure Limit (REL) for occupational noise is 85 decibels on an A-weighted scale as an 8-hour time weighted average (U.S. Department of Health and Human Services, 1998). OSHA limits noise exposure to 90 decibels, also on an A-weighted scale and as an 8-hour time weighted average (U.S. Department of Labor). A-weighting is an adjustment that gives lower frequencies less weight or significance than higher frequencies. An A-weighted sound level more closely resembles the human ear’s response to noise.
The American Conference of Governmental Industrial Hygienists (ACGIH) assigned noise a Threshold Limit Value (TLV) of 85 dBA as an 8-hour time weighted average. Exposure to 88 dBA is limited to 4 hour, exposure to 91 dBA is limited to 2 hours, exposure to 94 dBA is limited to 1 hour and so on. (ACGIH, 2013).
Noise exposure has also been associated with temporary hearing loss, perception of noisiness and masking, increased stress, fatigue, disturbance of sleep, decreased concentration and decreased mental performance (Osada, 1988). Noise-induced hearing loss starts in the higher frequencies (3,000 to 6,000 Hz) and slowly develops from chronic exposure to excessive sound. Sound must exert a shearing force on the hair cells lining in order to be perceived, and if the force is too strong, cell damage and cell death can occur (Berger et al., 2003).
Vacuum trucks create very loud environments due to the vacuum blower. The noise is low in frequency and continuous while work is being done. The trucks have generated complaints from adjacent property owners and bystanders in the vicinity of these machines. The excess noise has also been reported to vibrate nearby buildings causing distress and distraction to anyone occupying the structures (Thalheimer, 2000).
How Risks are Reduced:
Quieter vacuum extraction trucks use engineering controls to limit noise exposure. An improved design of the vacuum pump (blower) and lower amounts of engine power needed to run the blowers reduce noise. The vehicles remove semi-solid or liquid waste with suction generated by a blower, which often requires the engine to operate at a higher speed, producing high levels of noise from exhaust airflow. Through the use of exhaust silencers and lower engine speed, measured in revolutions per minute, noise generated by the equipment is reduced.
While there is little published sampling data on these specific vehicles, evidence indicates exposure to noise can be significantly reduced through the use of quieter vacuum extraction trucks. Using noise control techniques on vacuum trucks will reduce workers’ exposure to hazardous levels of noise and reduce environmental or community noise. The extent that it reduces noise exposure is expected to be significant. The extent of the reduction is dependent on the type of blower used, the method of noise reduction, the vehicle the blower is mounted to, the amount of airflow through the system and proximity to the vehicle.
The Central Artery/Tunnel project in Boston used Guzzler vacuum extraction trucks to reduce accidental utility disruptions. The machines generated levels of noise and vibration that were a nuisance to neighbors and action was taken to reduce the impact. The manufacturer and contractor retrofitted a vacuum extraction truck with silencers. The silencers on the Guzzler reduced low frequency noise by 10-15 dBA and resulted in less frequent complaints from neighboring buildings (Thalheimer, 2000).
Industrial hygienists use sound level meters or noise dosimeters to determine noise levels and recommend the use of quieter techniques to prevent hearing loss and reduce the risk of accidents. Proper maintenance and retrofitting of existing equipment can decrease excess sound as well (Suter, 2002).
VACMASTERS states that its SYSTEM 4000’s “high efficiency absorption chamber silencer and enclosed power head minimize noise levels helping you to be a good neighbor.”
Guzzler claims that its new NX vacuum truck produces 88.9 dBA while in operation.
Effects on Productivity:
Lower noise levels are expected to reduce stress and fatigue, and increase the concentration and mental performance of workers. Improved worker health, comfort and concentration may lead to greater productivity. Reduced sound levels can also lower the risk of accidents as communication among workers is easier and more effective. The number of time-consuming complaints received by the vehicle owner may be reduced, thereby increasing productivity.
Additional Considerations:
Data from OSHA and the Bureau of Labor Statistics indicate that 60 to 80 deaths each year result from vehicles backing over workers. The danger is greater in industries that use larger vehicles, such as trucking, highway construction, and sanitation. There are many ways to reduce the risk of backovers. First, the need to back vehicles should be reduced to the extent possible. When backing is necessary, traffic control plans should be used to keep vehicle and people on foot separated. Vehicles can be equipped with backup alarms, cameras, and proximity sensing devices and drivers should use spotters. Workers on foot should be required to wear high-visibility clothing when they will be near moving vehicles. Drivers, spotters, and pedestrians should receive general and site-specific training on preventing backovers.
The use of diesel-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.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:
Andrew Kingston
Michael R. Cooper
Bruce Lippy
Availability
GapVax Vacuum Trucks
To obtain information, visit http://www.gapvax.com
or contact 1-888-442-7829
VACMASTERS Vacuum Trucks
To obtain information, visit http://vacmasters.com
or contact 1-800-466-7825
Guzzler NX Vacuum Truck
To obtain information, visit http://www.guzzler.com
or contact 1-815-672-3171
