Background According to a report by the Tokyo Fire Department, 114 children under 5 years of age fell from balconies or windows from 2011 to 2015.

Objectives To evaluate actual balcony situations and collect photographic data for the development of a new monitoring system.

Methods We conducted an online survey to ask the public questions about 1) the size of their balcony, 2) what kind of objects are on the balcony, 3) how they mainly use their balcony, 4) their child’s age and sex, and 5) the floor number on which the balcony is located. We also collected a photograph of their balcony.

Findings One hundred and fifteen people participated in the present study. Approximately half of the respondents live in houses, and the other half live in apartments. The average balcony width was 496.7 cm (min=150 cm, max=1,500 cm), the average depth was 130.4 cm (min=65 cm, max=400 cm), and the average height was 118.5 cm (min=78 max=400). Compressor units, laundry poles, drying racks, and planters are major objects that are commonly located on the balcony, and slippers, brooms, dustpans, glass fish tanks, and tricycles are among the less common but important objects to be aware of in terms of fall prevention. Over 65% of respondents said that they used their balcony to hang laundry, and 67% of respondents reported that their balcony was located on the second floor. Although approximately 90% of respondents said that they knew of numerous incidents of falls from balconies, only 27% of respondents actually took preventive actions.

Conclusion Based on the results of this survey, we developed a new monitoring system using a RGB-D camera that has the ability to calculate fall risk based on shape evaluation of objects present on the balcony.