OEM filter media is not designed to mitigate against respirable dust
Picture of contaminated HVAC evaporator with dust
Fine dust contamination is the main reason for air conditioning-HVAC system underperformance and premature failures. Dust wears out electrical components quickly while dust accumulation inside the system restricts air flow increasing entire system heat load.
This is due in part to the inefficacy of OEM filters and the harsh and dusty conditions at mine, quarry and construction sites
The design of the original HVAC system by the manufacturer is intended to deliver cooling capacity overall and may not be designed to perform in extreme dusty environments or to be effective at removing smaller fine dusts.
The OEM filters are normally intended to filter out coarse dust but not hazardous respirable particulate.
For instance, if HEPA filters were to be retro-fitted to an original system, the end result is a system that may not be capable to cool down the cabin from higher air restriction of HEPA filters. The best practice is to use a multitude of controls combined with an environmental cabin (tight against particulate) that is precisely designed with fresh air pressurisation with HEPA filters to control respirable dust.
The Breathe-Safe design is a custom system that regulates the correct volume of fresh air delivered to the air conditioning- HVAC system. Thus, minimise the amount of hot ambient air being blown into the cabin – reducing heat load on the HVAC. The system can effectively keep the operator comfortable even in very hot and humid conditions.
The worst scenario is an air conditioning-HVAC system that is not effective at cooling the working environment leading to unsafe practices such as the operator opening a window for ventilation risking high exposures and allowing the cabin to be contaminated with respirable dust. This situation is hazardous because once respirable dust is inside the cabin; it will continue to be recirculated by the air conditioning system.
HVAC evaporator with Breathe-Safe fresh air pressuriser system Caterpillar 330DL (HEPA filtration)
This Breathe-Safe system has been installed with HEPA primary and HEPA return air filter for equipment working at a cement shed with 1800 hours of operation. It has kept the cabin clean and it has kept the internal HVAC compoments clean and dust free.