Cab Filtration System for Heavy Equipment

Cab filtration and a pressurization system added to heavy equipment removes silica dust and dust from the air supplied to the cab. 

Description:

Heavy equipment operation generates a large amount of dust which may contain crystalline silica and creates a hazard for the operator.

Adding a cab filtration and a pressurization system to a heavy equipment may be an effective method to reduce operator exposure to dust and silica and is an important dust control option to consider. These after-market control systems use a cyclonic, or inertial, separator followed by one or more filters to remove particles from the air supplied to the equipment cab. Some systems feature a second filter that cleans the cabin air that is recirculated. The filtration efficiency and protection provided by a system depends on the integrity of the cabin and the filtration system as well as filter efficiency.

 It is important to distinguish between:

  • Filter efficiency – manufacturer’s rating of the actual filter
  • Pressurizer efficiency – manufacturer’s rating of the pressurizer/filtration unit
  • System efficiency – rating of complete enclosure including pressurizer/filtration unit and HVAC system
If properly designed, installed, maintained and used, cab filtration systems may significantly reduce dust exposures to operators. This may reduce exposures enough that a respiratory protection program isn’t required. Extended operation may exceed the OSHA Permissible Exposure Limit, even with the use of cabin air filtration, however.
 
Sy-Klone International Respa-SDX System
  • An air cleaner and cabin pressurizer system that can be added to the cabin ventilation system of heavy equipment. The cabin must be enclosed and sealed.
  • Cost: $2,200 to $3,000
  • Two air filtration units, one for outdoor air (cyclonic/inertial precleaner and a filter) and one for recirculated air (filter)
  • Cyclonic/inertial precleaner
    • Removes greater than 90 percent of particles larger than 5 microns
  • Filter options:
    • Minimum Efficiency Reporting Value (MERV) 8: removes greater than 70 percent of 3 to 10 micron particles
    • MERV 16: removes greater than 95 percent of 0.3 to 10 micron particles
      • Replacement cost: $140
    • HEPA: removes 99.97 percent of 0.3 micron (the most penetrating) particles
      • Replacement cost: $260
  • Pressure monitor: alarms when cab pressure falls below 0.2 inches of water
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Sy-Klone International Respa-SD System
  • An air cleaner and cabin pressurizer system that can be added to the cabin HVAC system of heavy equipment. The cabin must be enclosed and sealed.
  • Cost: $1,000 to $1,500
  • One air filtration unit for outdoor air (cyclonic/inertial precleaner and a filter)
  • Cyclonic/inertial precleaner
    • Removes greater than 90 percent of particles larger than 5 microns
  • Filter options:
    • MERV 8: removes greater than 70 percent of 3 to 10 micron particles
    • MERV 16: removes greater than 95 percent of 0.3 to 10 micron particles
      • Replacement cost: $140
    • HEPA: removes 99.97 percent of 0.3 micron (the most penetrating) particles
      • Replacement cost: $260
  • Pressure monitor: alarms when cab pressure falls below 0.2 inches of water
 
Clean Air Filter, Co. FPS50 and FPS950 Series Filtration and Pressurization Systems
  • Air cleaner and cabin pressurizer systems that can be added to the cabin HVAC system of heavy equipment
  • Removes greater than 95 percent of 0.3 micrometer particles
  • Heavy duty powder coated metal construction
  • The patented Clean Air Filter systems feature a 3 in 1 design:
    • Paper media: for removal of large particulates
    • Activated carbon: for removal of gases/organic vapors
    • Final filter: for removal of small particulates (0.3 microns)
  • Power source: 12 or 24 volts DC or 110 volts AC (FPS950 unit available in 110 volts AC only)
  • Centrifugal/inertial precleaner
  • Differential pressure gauge to ensure pressurization
  • Every FPS 50 series pressurizer is factory tested for integrity, utilizing CAF’s patent pending test procedure
  • Options:
    • Stage II Housing with additional 0.3 micron final filter (FPS-S205P)
    • Motorized pre-cleaners available in 12 and 24 DC volts are an additional $550 each
    • Recirculation filter
 
Models
Filter
Pressurizer Average Filtration Efficiency for 0.3 micrometer particles*
Approximate Air Flow Rate, cubic feet per minute
Cost**
Filter Replacement Cost
FPS5012
CAF07R
96.74%
50
$1,320
$140
FPS5012
CAF47R
99.77%
50
$1,320
$162
FPS5012 with Stage II Final Filter
CAF47R
 
FPS-S205P
>99.99%
45
$1,630
$162
 
$122
FPS9502
CAF950R
99.98%
143
$2,395
$216
 
* Pressurizer efficiency is a measure of the pressurizer/filtration unit performance, not the filtration efficiency of a complete system, consisting of a pressurization/filtration unit and a cabin. The manufacturer can provide actual test data for each pressurizer/filtration model upon request.
** Price depends on options (filters and precleaners) selected.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Clean Air Filter FPS-50 Filtration and Pressurization System
 
 
 
 
 
 
 
 
 
 
 
 
 
Clean Air Filter FPS-50 with Stage II Housing and Final Filter
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Clean Air Filter FPS-9502 Filtration and Pressurization System

 


Risks Addressed:

Operating heavy equipment is a high dust activity that in the absence of controls would place operators at risk of lung disease, cancer, chronic obstructive pulmonary disease (COPD), lung scarring, silicosis, renal disease and autoimmune disorders, such as lupus and rheumatoid arthritis, 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-half of the OSHA standard when the dust is pure silica, but still twice the ACGIH-recommended threshold limit value (TLV) of 0.025 mg/m3.  A study on an older enclosed cab used at surface coal mine noted respirable dust in the cab almost 13 times the NIOSH REL (Cecala et al. 2004).


How Risks are Reduced:

 

Cab filtration systems use inertial separators followed by filters to remove particulate, including silica, before they enter the equipment cabin. In addition, some systems are equipped with a second filter to clean the cabin air prior to recirculation, further reducing concentrations in the cab and operator exposure.

 

 

Using filtration and pressurization systems will reduce the concentration of particulate, including silica, in the cabin, but the extent that it reduces the small, respirable particles will vary.  The extent of the reduction is dependent on the efficiency of the filters used, the integrity of the cabin, the use of a recirculation filter, the presence of dust or silica sources inside the cabin and the nature and amount of work. Although exposure is not reduced to zero, data from manufacturers and researchers indicate exposure to dust and respirable silica can be significantly reduced through the use of filtration and pressurization systems.

 


Effects on Productivity:

Cab filtration systems can have either positive or negative effects on productivity, but definitely improve the quality of the work by removing large amounts of airborne dust, which allows a cleaner environment for operators. 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 work is intermittent, use of cab filtration systems should be adequate to reduce the need to wear a respirator, and the need for an employer respiratory protection program.


Additional Considerations:

Cabs on new equipment or retrofit kits can be designed to conform with ISO 10263 standards which provides for positive cab pressure of at least 0.2 inches of water (50 Pascals), a minimum of 25 CFM of filtered intake air into the cab, and typically 200 to 300 CFM filtered recirculating air within the cab.  This requires that cabs be tightly sealed and have both filtered recirculating air and air conditioning (typically 20,000 BTU).  See the MSHA report on “Effectiveness of Cabs for Dust and Silica Control on mobile Mining Equipment” Garcia,J.J. et.al.  MSHA.

There are additional conditions and practices that can improve the performance of filtration and pressurization systems and reduce dust and silica concentrations in equipment cab:
  • The enclosed cabin must be leak-tested and sealed.
  • Door and window gaskets can be replaced and cracks and holes sealed to improve cabin integrity.
  • Doors and windows should be kept closed at all times.
  • Cab floors should be kept clean of dust and debris. Some studies indicate that the use of floor sweep compounds may help reduce airborne dust originating from cabin floors.
  • The performance of electrostatic filters decreases after a few months. This type of filter should be replaced on a fixed schedule; not on one based on hours used.
  • When feasible, filtration and pressurization systems should recirculate and filter cabin air.
  • Radiator-type floor heaters with fans have been found to significantly increase airborne dust concentrations in the cab by stirring up dust from the floor and the operator’s clothes and boots. This type of heater should not be used; if there is no other option then they should be positioned near the top of the cab.
 
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.
 
Heavy equipment frequently generates sound levels that are greater than 90 decibels, the OSHA Permissible Exposure Limit (PEL), and hazardous. Hearing protection should be worn when using rock drills 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.
 
After market versions of cab filtration devices will not be addressed in the heavy equipment manufacturer's scheduled maintenance, which generally directs service mechanics.  Without proper maintence, such as filter replacement, performance can decline rapidly.

Service of these devices often requires access to the roof of the cab.  Safe access may require the addition of appropriately placed steps and hand-grabs or other fall prevention design considerations, particularly in icy or wet conditions.  Falls from  the cab roof can result in serious injury.

For more information, NIOSH has a mining publication on Reducing Hazardous Dust in Enclosed Operator Cabs During Construction


Contributors:

Bruce Lippy, PhD, CIH - CPWR - The Center for Construction Research and Training
Michael R. Cooper - Aria Environmental, Inc.


Hazards Addressed:

Availability

Sy-Klone International
To obtain information, visit RESPA Kits & Adaptation or contact 1-904-448-6563 sales@sy-klone.com

Clean Air Filter, Co. FPS-50 and FPS950 Series Filtration and Pressurization Systems
To obtain information, visit http://www.cleanairfilter.com or contact 1-712-748-3642 caf@cleanairfilter.com

NIOSH Workplace Solutions Sheet
The National Institute of Safety and Health (NIOSH) has published a series of “Workplace Solutions”, which are easy-to-understand recommendations from NIOSH research results. Related to this Construction Solution, please find more information on: Reducing Hazardous Dust in Enclosed Operator Cabs During Construction

Return on Investment

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