NIOSH- Report- RESPA- "should be considered for all HVAC Systems on surface mining equipment"

Published Wednesday 11 Feb, 2009 by Peter Woodford

This report (download below), is based upon recent testing by CDC’s National Institute for Occupational Safety and Health (NIOSH) of LSM Technologies / Sy- Klone's "world first" patented RESPA™ HVAC Precleaner  / Filtration Technology as technology that "should be considered for all new and retrofit systems in surface mining equipment so as increase the Protection Factor (PF) for Operators Health.

The comprehensive NIOSH Report (also can be download below), is based upon recent testing (also refer to our News Item dd 14th Oct 2008) by CDC’s National Institute for Occupational Safety and Health (NIOSH) of Sy- Klone's "world first" patented RESPA™ HVAC Precleaner  / Filtration Technology as technology that "should be considered for all new and retrofit systems in surface mining equipment so as increase the Protection Factor (PF) for Operators Health.

Crystalline silica — also known as silicon dioxide (SiO2) — is the basic component of sand, quartz and granite rock and is found in varying proportions in aggregates, sand, mortar, concrete and stone, and is also in the air and the soil. Processes which may give rise to airborne concentrations of crystalline silica dust include hard rock mining, excavation, tunneling and earthworks, construction, foundry operations, ceramics production, stone works, refractory brick production, abrasive blasting, agricultural ploughing and harvesting, and the production of asphalt, agricultural chemicals, abrasives, glass and paint. If the dust given off from working with these materials is fine enough to be breathed into the lungs, it is termed “respirable”. See the NOHSC 2005 Media Release on revised standards / sources of silica. 

Extract from the Report states:

Enclosed cabs have been used on surface mining equipment for many years to protect equipment operators from health and safety hazards.  The surface mining and quarrying process is a highly mechanised process that generates large quantities of respirable dust.  

NIOSH has performed a number of different field studies, as well as a comprehensive laboratory study evaluating various factors and parameters regarding enclosed cabs. 

NIOSH has recently completed a cooperative research effort with Sy-Klone International and Vulcan Materials Company to evaluate the effectiveness of a newly designed uni-directional filtration and pressurisation system that brings all the clean filtered air in at the roof of the cab and extracts all recirculated air near the floor.  This design provides the highest air quality to the equipment operator.  Testing on this new system showed an almost 10-fold reduction in respirable dust inside the enclosed cab. 

The uni-directional design is easy to incorporate and should be considered for all new and retrofit systems in surface mining equipment

This issue came to light from a study performed in 1996 and 1997 which showed an alarming prevalence of silicosis in the surface coal mining industry. This study was undertaken at eight different surface coal mining operations in central Pennsylvania and was performed by the Mine Safety and Health Administration, the Pennsylvania Department of Health, the Department of Health Evaluation Sciences of the Pennsylvania State University College of Medicine, and the CDC’s National Institute for Occupational Safety and Health (NIOSH). This was a voluntary program that screened 1,236 miners for lung diseases and determined that 6.7 percent of these workers were classified with at least category 1/0 silicosis. In an anomaly that was noted in one particular county (Clearfield), 16 percent of the 213 participants were classified with silicosis [1].

This investigation noted that a number of young miners with relatively few years of mining experience were developing silicosis from using surface drills with enclosed cabs that were not providing an acceptable level of protection.  Further, although surface drills provided the highest risk of overexposure, operators of other types of mechanised equipment such as bulldozers, loaders, and haul trucks were also being overexposed to crystalline silica and respirable dust.

Results of this field study on a uni-directional cab filtration and pressurisation system showed that:

  • The system to be very effective at reducing respirable dust levels inside the enclosed cab of a pneumatic drill, thus providing the drill operator a more comfortable and safer work environment.
  • During baseline testing respirable dust concentrations inside the enclosed cab ranged from an average of 0.43 to 0.95 mg/m3 for the three days of testing.
  • There were three post-test evaluations. In the third and final post-evaluation, the average respirable dust concentration ranged from 0.09 to 0.14 mg/m3 for the two days of testing.
  • This comparison indicates the improved air quality inside the enclosed cab with the filtration system and ultimately, the improved protection to the drill operator.

Subsequently the RESPA HVAC System meets the Australian NOSHC (National Occupational Safety Health Commissions) requirements for Respirable Silica of 0.1mg / M3 TWA (Time Weighted Average)- see the amended NOHSC report below

TWA = The average airborne concentration of a particular substance when calculated over a normal eight-hour working day, for a five-day working week.

Also the particle size must be < 7.0 micron and so one needs to use  MERV 17 Filters (click here see Merv Rating Table) to achieve such filtration levels.

This testing was focused on Operator health- however other beneficial aspects of the LSM Technologies / Sy- Klone RESPA™ HVAC Precleaner Technology are:

  • Maintains Designed Cabin Pressurisation: As the RESPA unit is motor driven then it still operates and pre- cleans even when the HVAC is off. By maintaining the optimum designed cabin pressure, means that the cabin seals maintain their integrity. 
  • Extends Filter Life: The HVAC Filter life is dramatically extended, no blowing out of filters / pads and so labour costs / productivity interruptions are reduced. Also as the RESPA unit has its own filter, then it can replace the existing HVAC filter system or will ensure that the filter / reticulation filter of the existing HVAC is maintained at optimum and with extended service life.
  • Cooling / Heating Coils: Maintenance of coils is virtually eliminated and so service life is extended.
  • Increases Operator Comfort: Clean air means that the HVAC system maintains efficient cooling / heating.
  • Enhances OH&S: Reducing  / eliminating the entry of contaminated air into the cabin decreases odours and enhances health aspects for the Operator.
  • Cabin Cleanliness: Increases the cleanliness of the cabin and protects mechanical / electrical components.
  • Filtration: The RESPA has three (3) filters available- click here to see details.
  • Mounting:  The RESPA SD Unit can be installed on a variety of different  types of machines, typically roof or hood mounted with only five (5) bolts.
  • Cab Pressuriser: Replaces the existing Filter and Pressuriser on HVAC Systems.

For more detailed information see:

Also refer to the Safe Work Australia (was NOHSC National Occupational Health & Safety Commission). 

If you require further information. please contact us.