Comparison of heat stress reduction provided by rain umbrellas and sunshade parasols

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K02140
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 08030:Family and consumer sciences, and culture and living-related
• Research Institution: Daido University
• Principal Investigator: Watanabe Shinichi 大同大学, 工学部, 教授 (00340175)
• Co-Investigator(Kenkyū-buntansha): 岩井 将行 東京電機大学, 未来科学部, 教授 (30458971)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 日傘 / 雨傘 / 暑熱緩和 / UTCI / WBGT

Outline of Final Research Achievements

In this study, we clarified the thermal stress reduction of rain umbrellas and sunshade parasols based on measurements of the thermal environmental parameters. The white parasol had the largest UTCI reduction by 3.7 °C, followed by the black parasol by 2.2 °C and the black rain umbrella by 2.1 °C. Meanwhile, no reduction in UTCI was observed for the white umbrella. The WBGT reduction was also greatest for the white parasol, with a value of 1.3 °C.
The heat stress reduction provided by the parasol was greatest for the head level under the parasol and decreased closer to the ground. The heat stress reduction on the head provided by the parasols was greater for shorter children than for taller adults. The larger the parasols, the greater the reduction in heat stress in the torso and legs. However, the heat stress reductions on the head provided by different sized parasols were approximately the same regardless of the parasol size.

Free Research Field

建築環境工学

Academic Significance and Societal Importance of the Research Achievements

雨傘および日傘の日射透過率および下向き長波長増加率を明らかにし、日射および熱放射を総合化した平均放射温度MRTで各傘の放射特性を示したことは学術的に意義が大きい。また、雨傘および日傘による暑熱緩和効果を体感温度UTCIおよび暑さ指数WBGTで示し、白日傘が最も暑熱緩和効果が大きいことを示した。一方、白色の雨傘の暑熱緩和効果は認められないことを示した。これは、白色の雨傘では日傘の代用にはならないことを示したものであり、社会的な意義は大きい。