Managing fume and dust emissions in the workplace

IN THE UK, exposure levels to potentially harmful airborne contaminants are stipulated in the COSHH (Control of Substances Hazardous to Health) regulations and expressed as workplace exposure limits (WELs). These limits are presented in the Health & Safety Executive’s EH40 guidance as time weighted averages for either 15 minutes or eight hours, in both ppm (parts per million) and mg/m³ (milligrams per meter cubed). 

In a 24/7 operating environment, filtration technology plays a vital role in helping to keep production lines moving, maintaining quality and contributing to effective workplace atmosphere management. As a result, there is an increased reliance on automation and the role that operational data can play in enhancing productivity.  

The context for filtration technology for manufacturers is best seen through the prism of WELs. Safety Data Sheets need to be understood and reflected in system configuration, along with any chemical changes that might occur during the process. As a company, BOFA works closely with industry to help businesses choose the most appropriate system for their process by determining:

1. The type, volume, size and velocity of particles being emitted
2. The type of production machinery being used
3. Whether the process is enclosed or not
4. The duration of the process - 24/7 for example
5. Whether there are thermal risks associated with higher temperatures. 

Once armed with this information, data-driven airflow analysis can help set the control parameters that contribute to optimal filtration. Typically, a BOFA system will incorporate pre-filtration, a main High Efficiency Particulate Air (HEPA) filter and a layer of activated carbon to filter vapours and gases. 

The objective is two-fold: firstly, to contribute to a safe working environment; and secondly, to enhance productivity by keeping equipment free from dust to avoid unplanned downtime, which could be costly in high volume sectors such as laser marking and coding.

There are also challenges that go beyond managing fume and dust emissions, particularly where extraction systems are linked to processes at risk of thermal events. This might be where interaction between say a laser and material being worked emits a combustible dust with the potential to be drawn into the filtration system. Under these circumstances, managers should specify a system benefiting from fire-resistant materials for casings and filters, thermal cut-out protection and technology such as BOFA’s Spark Arrestor 2 and FireBOX to mitigate the risk of burning particulate entering the extraction system.

The precise design of each system will require in-depth analysis of many different variables to ensure correct mitigation of risk.
Design options include captor hoods, which use a capture velocity across the source of the emissions; receptor hoods, which use the movement of particles / vapour towards the device to capture them; partial enclosures, which extract contaminants typically for hand grinding and finishing; and full or partial enclosures matched to the needs of automated processes such as laser coding or PCB manufacture. 

System control is another key determinant for optimal productivity and safe operating conditions and this is available through technology such as BOFA’s Intelligent Operating System (iQ). The latest iteration of this system – iQ2 - features a host of functionality enhancements and innovations, leveraging the value of extended onboard data logs and real-time system condition visualisation, plus a colour touchscreen user interface, smart alarm configuration and remote system upgrades.

This application of data enhances the ability of manufacturers to plan a timely exchange of filters in step with production schedules, using volume-based data rather than periods of time.

Joshua Evans is applications engineer and head of BOFA Academy at BOFA International

For more information:

www.bofainternational.com

Tel: 01202 699444