Environmental Agricultural Tractor Cab Filter Efficiency and Field Evaluation

Heitbrink, William A.; Moyer, Ernest S.; Jensen, Paul; Watkins, Daniel S.; Martin, Stephen B.

doi:10.1080/15428110308984832

Cited by 10 publications

(8 citation statements)

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“…Also, new and used HEPA filters and prefilter media used on the Nelson cab were evaluated in the laboratory at face velocities between 2-15 cm/sec. (15) The HEPA filters were shown to have efficiencies of >99.97% for aerosol particles in the most penetrating particle size range of 0.1-0.3 µm at the face velocities used.…”

Section: Methodsmentioning

confidence: 99%

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Test for the Integrity of Environmental Tractor Cab Filtration Systems

Moyer

Heitbrink

Jensen

2005

Journal of Occupational and Environmental Hygiene

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Cab filtration systems can be used to protect vehicle operators from hazardous air contaminants. In a cab filtration system, a fan draws air through filters and pressurizes the cab with this filtered air. This article describes the application of a low-cost, optical particle counter to evaluate the performance of tractor cab filtration systems. The tractors were equipped with environmental enclosures to protect the operators from pesticide exposures that occur during air blast spraying in orchards. Prior to testing, all environmental tractor cabs underwent a complete maintenance overhaul followed by a careful inspection by the manufacturer's field representative. As part of this maintenance effort, 13 tractors with cab filtration systems were tested in an enclosure. A Met One model 227B two-channel optical particle counter was used to measure the aerosol concentration outside and inside the cab. Ambient aerosol and/or aerosol generated by burning incense sticks were used to challenge the stationary cab filtration system in an enclosure. The ratio of the outside to inside concentration (Co/Ci) is the exposure reduction attained by the cab system. Alternatively, the inside concentration divided by the outside concentration times 100 (Ci/Co x 100) gives the percent penetration. All 13 tractors were tested for leak sites. Leak sites were identified and sealed. This process was repeated until each cab showed an exposure reduction ratio Co/Ci of at least 50 (aerosol penetration into the cab Ci/Co x 100 was less than 2%) at the 0.3-0.5 microm particle size interval.

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Section: Methodsmentioning

confidence: 99%

“…In a previous study, similar cabs were evaluated for aerosol penetration according to the ASAE S525 method. (15,16) …”

Section: Field Testing Proceduresmentioning

confidence: 96%

Test for the Integrity of Environmental Tractor Cab Filtration Systems

Moyer

Heitbrink

Jensen

2005

Journal of Occupational and Environmental Hygiene

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“…Recent studies have found that manufacturing mistakes, bowed flanges, and deteriorated gasket material caused increased penetration into the cabin filtration systems. (10,11) This situation suggests that tests are needed to evaluate aerosol FIGURE 1. Schematic description of cabin filtration system penetration into cabins as part of maintenance and quality control programs so that each cabin filtration system provides the expected exposure reduction.…”

Section: Introductionmentioning

confidence: 96%

Aerosol Generation by Blower Motors as a Bias in Assessing Aerosol Penetration into Cabin Filtration Systems

Heitbrink

Collingwood

2005

Journal of Occupational and Environmental Hygiene

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In cabin filtration systems, blower motors pressurize a vehicle cabin with clean filtered air and recirculate air through an air-conditioning evaporator coil and a heater core. The exposure reduction offered by these cabins is evaluated by optical particle counters that measure size-dependent aerosol concentration inside and outside the cabin. The ratio of the inside-to-outside concentration is termed penetration. Blower motors use stationary carbon brushes to transmit an electrical current through a rotating armature that abrades the carbon brushes. This creates airborne dust that may affect experimental evaluations of aerosol penetration. To evaluate the magnitude of these dust emissions, blower motors were placed in a test chamber and operated at 12 and 13.5 volts DC. A vacuum cleaner drew 76 m3/hour (45 cfm) of air through HEPA filters, the test chamber, and through a 5 cm diameter pipe. An optical particle counter drew air through an isokinetic sampling probe and measured the size-dependent particle concentrations from 0.3 to 15 microm. The concentration of blower motor aerosol was between 2 x 10(5) and 1.8 x 10(6) particles/m3. Aerosol penetration into three stationary vehicles, two pesticide application vehicles and one tractor were measured at two conditions: low concentration (outside in the winter) and high concentration (inside repair shops and burning incense sticks used as a supplemental aerosol source). For particles smaller than 1 microm, the in-cabin concentrations can be explained by the blower motor emissions. For particles larger than 1 microm, other aerosol sources, such as resuspended dirt, are present. Aerosol generated by the operation of the blower motor and by other sources can bias the exposure reduction measured by optical particle counters.

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“…This field study identified and sealed several tractor cab filtration system leaks around a high-efficiency particulate air (HEPA) filter, which effectively reduced particle penetration into the cab from 11% to less than 1%. (4) Another study measured 0.3-0.5 μm particles inside and outside a stationary unoccupied cab parked inside a temporary enclosure filled with incense smoke contaminants. In this procedure a two-channel particle counting instrument sampled alternate positions inside and outside an unoccupied cab using equal lengths of sample hoses to these locations.…”

Section: Introductionmentioning

confidence: 99%

“…(3) Alternative particle counting cab field test procedures have been examined by NIOSH with submicron particles (0.3-0.5 μm) and have been used to quantify and improve agricultural tractor cab protection performance for pesticide spray applications. (4,5) One procedure used two optical particle counters alternated between the inside and outside locations of the tractor cab during four mobile test replicates, similar to the ASAE consensus standard test except that 0.3-0.4 μm particle sizes were used as the test medium. This field study identified and sealed several tractor cab filtration system leaks around a high-efficiency particulate air (HEPA) filter, which effectively reduced particle penetration into the cab from 11% to less than 1%.…”

Section: Introductionmentioning

confidence: 99%

Field Assessment of Enclosed Cab Filtration System Performance Using Particle Counting Measurements

Organiscak

Cecala

Noll

2013

Journal of Occupational and Environmental Hygiene

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Enclosed cab filtration systems are typically used on mobile mining equipment to reduce miners' exposure to airborne dust generated during mining operations. The National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) has recently worked with a mining equipment manufacturer to examine a new cab filtration system design for underground industrial minerals equipment. This cab filtration system uses a combination of three particulate filters to reduce equipment operators' exposure to dust and diesel particulates present in underground industrial mineral mines. NIOSH initially examined this cab filtration system using a two-instrument particle counting method at the equipment company's manufacturing shop facility to assess several alternative filters. This cab filtration system design was further studied on several pieces of equipment during a two-to seven-month period at two underground limestone mines. The two-instrument particle counting method was used outside the underground mine at the end of the production shifts to regularly test the cabs' long-term protection factor performance with particulates present in the ambient air. This particle counting method showed that three of the four cabs achieved protection factors greater than 1,000 during the field studies. The fourth cab did not perform at this level because it had a damaged filter in the system. The particle counting measurements of submicron particles present in the ambient air were shown to be a timely and useful quantification method in assessing cab performance during these field studies.

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Environmental Agricultural Tractor Cab Filter Efficiency and Field Evaluation

Cited by 10 publications

References 0 publications

Test for the Integrity of Environmental Tractor Cab Filtration Systems

Test for the Integrity of Environmental Tractor Cab Filtration Systems

Aerosol Generation by Blower Motors as a Bias in Assessing Aerosol Penetration into Cabin Filtration Systems

Field Assessment of Enclosed Cab Filtration System Performance Using Particle Counting Measurements

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