HEPA fresh air pressurisation (High Efficiency Particulate Arrestance)
Breathe-Safe clean air technology has been development for a cabin/enclosure. Which is a fresh air pressuriser where HEPA filters are used to trap and separate respirable particles at the submicron range.
This technology includes HEPA media which has been tested and certified to EN1822 Euro standard for an absolute minimum efficiency at 0.3-micron diameter at 99.97%.
HEPA filters are manufactured to this strict standard are then used in wide range of industries with stringent applications such as ‘clean rooms’ for example.
Figure 1. Protection factor by filter efficiency. (NIOSH- Dust Handbook)
HEPA filters are extremely efficient at capturing respirable particulates so it should be noted that HEPA media is somewhat restrictive for air to pass through when compared to standard filters.
Breathe safe has delivered a custom design combination with a silent pressurising fan and long life brushless motor with technology to filter the correct amount of fresh air.
The display-controller adjusts internal pressure constantly while delivering filtered fresh air to the air-conditioning (HVAC) system. The system will alert operator if falling pressure is detected and it can alert mine management as well if remote monitoring is enabled.
Remote monitoring is designed to collect data of internal pressure over time and other events like a window that has been left opened. This is a valuable tool for operator training and/or for maintenance personnel to detect a pressure leak inside the cabin. The same data can be used to develop maintenance schedule with data that will demonstrate when filter media is approaching a predetermined capacity.
Effective clean air technology involves utilising different separation stages and these include:
A Pre-cleaner (Extends the lifecycle if filter by ejecting coarse particles)
A HEPA primary filter (Respirable dust control)
A HEPA return air filter (Respirable dust control: contamination from clothes and boots)
Breathe-Safe submits that fresh air HEPA pressurisation systems are designed to control respirable dust at mineral processing sites and are the most effective. They are also effective in other industries that can be sources of fugitive airborne respirable dusts. Such as ports, railways and tunnels.