Feasibility study of Preventing Snow Accumulations on Roofs using Airflows

Abstract

This thesis is intended to contribute to research in cold climate engineering. Further it intends to provide a principle solution for structural and avalanche safety due to snowfall on roofs. We have conducted a feasibility study of preventing snow from accumulating on roofs using airflows. This includes empirical, numerical and experimental methods.

Snow loads on roofs makes great impact on structural safety and is the cause of annual injuries due to snow removal. Studies have shown that incidents related to snow clearing activities occurs more frequent in winter seasons with heavy snowfall (Bylund, Johansson & Albertsson, 2016, p. 107). At the same time, several climate projections predict that the annual rainfall will increase significantly, along with increased global temperature. However, for several places in cold climate regions, the rise in temperature will not be enough for the rain to stay liquified. The consequences of increased snowfall can be severe, especially for lightweight structures or structures built according to outdated standards. Regardless of the climate changes, risks for humans associated with snow loads on roofs is present. To assess the risks for human and assets a PHA is conducted and supported by risk matrices and bow-tie method.

The experiments are based on empiricism and CFD simulations of airflows. To generate airflows, a compressor was used as source and pneumatic hoses from Festo was applied. The falling snow seemed to behave as intended - to a certain extent - by the influence of airflows. Due to challenges related to the experiments, we were not able to efficiently prevent snow from accumulating at the surface. However, from the results and discussion it emerges potentials for achieving the purpose. If the design chosen in this study is applicable and how it can be improved is concluded in the last chapter, followed by suggestions for further work.