Design of an enclosed and automated sand rainer system to reduce respirable silica dust exposure
Design of an enclosed and automated sand rainer system to reduce respirable silica dust exposure
Sand raining is widely used in physical modelling to prepare uniform sand samples; however, the process can generate airborne respirable crystalline silica (RCS), presenting a significant occupational health risk in laboratory environments. Increasing regulatory scrutiny and tightening exposure limits have highlighted the limitations of reliance on personal protective equipment (PPE) and administrative controls alone. This paper presents the safety-in-designdriven development of a purpose-built enclosure and automated hopper system for an Acutronic sand rainer to reduce operator exposure during sand raining operations. Early hazard identification, informed by material safety data and observations of sand rainer use, identified dust generation during sand flow control and sand spread beyond the raining zone as key exposure pathways. The engineering solution integrates three complementary control measures: (i) a fully enclosed raining volume, (ii) a negative-pressure mechanical extraction system incorporating HEPA Class H filtration to prevent airborne particles escaping the enclosure, and (iii) an automated pneumatically actuated hopper door operated remotely from outside the enclosure. Electrical interlocks link the hopper actuation, enclosure doors, and filtration system, with fail-safe logic ensuring automatic hopper closure under unsafe or loss-of-signal conditions. The enclosure was designed and constructed around a pre-assembled sand rainer commissioned at the University of Melbourne. Operational experience indicates a qualitative reduction in visible dust, improved control of sand spread, and reduced operator proximity during high-exposure tasks. The paper outlines key design considerations for implementing engineering controls to mitigate silica risks in physical modelling laboratories.
Yifa Wang; Steve Beard; Shiao Huey Chow; Mark Jason Cassidy
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 1: New facilities, new equipment, and measuring techniques
https://doi.org/10.53243/ICPMG2026-462