My Internship Project
By Colin V.
This summer I have been an Environmental Health and Safety intern at Seacast, an investment casting foundry in Seattle and Marysville, Washington. My main summer project was to help design and implement a new fume collection system for plasma cutting. When an operator uses a plasma torch to cut metal, combustible metal dust and other fumes are generated. Of primary concern is Hexavalent Chromium, also known as Hex Chrome. Hex chrome is a sub-micron particulate that can have adverse health effects at low levels of exposure. The PEL set by OSHA is just 0.5 µg/m^3 as an 8-hour time-weighted average. Adverse health effects that can arise from hex chrome exposure include eye irritation or damage, skin ulcers, respiratory irritation and asthma, and lung cancer. The operator wears a Powered Air Purifying Respirator (PAPR) that provides a filtered air supply to a welding helmet. Implementing a fume collection system would reduce operator exposure and the potential exposure to other workers.
To collect these fumes, I have helped design a system that would use a wet dust collector to quench and collect flammable metal dust, followed by a HEPA filter bank on the end of the ventilation duct would capture any sub-micron particles that pass through the dust collector. In order to design this unit, I have been working with several Seacast employees: the Corporate EHS Manager, the Seattle operations manager, an aerospace engineer, and the foundry manager. To help visualize the setup of the system, I spent part of a day learning how to use a basic CAD program. This allowed me to create 3D mock-ups of the complete system in different arrangements. Using the CAD program made a huge difference in creating a visualization for others to understand, especially when compared to hand-drawn sketches.
The design process is almost entirely complete. Now we are in the process of submitting a Notice of Construction to Puget Sound Clean Air Agency. With the current backlog of projects awaiting approval, we found out that it could take up to 4 months for our project to be approved. Since I have to return to school, it is unlikely that I will be able to fully implement the dust collection system and conduct air sampling. However, all of my design and process notes up to this point will likely be used by the team to implement the collection system upon approval.