Asia’s very first bus with green rooftops!

On 5^th May 2019, ‘Garden on the Move’ initiative was launched by GWS Living Art at the inaugural Singapore Garden Festival (SGF) Horticultural Show. This initiative sees Asia’s very first green roof bus in an effort to study the effects of green roofs on moving vehicles.

The ‘Garden on the Move’ initiative was started by GWS more than 2 years ago. Prior to this initiative, green roofs were primarily static systems. This immovability limited the ways in which our green roof systems could be implemented. Our founder, Zac Toh, sought to innovate and challenge the ways in which nature can be integrated into our urban landscape. This desire led to a 2 year journey of designing, prototyping, testing as well as close collaboration with stakeholders in order to bring our green bus concept to fruition. We are grateful to have received support from various organizations, including Temasek Foundation, Moove Media, National Parks Boards (Nparks) and Singapore Green Building Council (SGBC). This project was also made possible with the help of Dr Terrence Tan from National University of Singapore, who acted as an advisor for the study. Dr Tan will continue to aid us with the research findings throughout the 3 month study.

Past studies on immovable green roofs reflected a positive correlation between the roof surface temperatures when fitted with green roofs and air conditioning’s energy savings within the buildings. In one study done by GWS alongside Kasetsart University in Thailand, GWS’s Gaiamat green roof system was found to have reduced the roof surface temperature by as much as 30 degrees Celsius. Ambient room interior temperature also dropped by 3-4 degrees Celsius when installed on industrial buildings. We are confident that this study will also yield valuable results and give us more insights into the effects of green roofs on reducing heat transmissions.

A total of 10 buses were used in our ‘Garden on the Move’ initiative. All buses will be fitted with GWS’s green roof systems as part of a three-months study to confirm if green roofs can effectively reduce heat transmissions in public buses. For this study, data loggers were installed on strategic locations within and outside of the buses. Data will be collected every 10 minutes and overall change in temperature monitored. At the end of the study, the data will be tabulated and used to determine if green roofs can lead to reduction in fuel consumption for the air-conditioning in these green roofed buses.

‘Garden on the Move’ mobile green roofs are adapted from GWS existing Gaiamat Green Roof design. The Gaiamat is a lightweight green mat that weighs up to 2-3 times lighter than conventional green roof systems. This reduces loading on the bus while also allowing for easier installation and maintenance to be carried out. The Gaiamat green roof system is also a soilless system. Instead of soil, layers consisting of natural fibers act as a soil substitute for the plants. The lack of soil means fewer pests and dirt, ensuring the green buses can move around safety during travel.

Two main plant species were grown on our green roof buses, namely Cyanotis Cristata and Cyanotis Axillaris. These two species were chosen for hardiness and adaptability to grow under a wide range of soil conditions, characteristics which are crucial in order for them to survive under full sun and with little maintenance. Additionally, the Cyanotis Cristata species is known to turn from green to reddish when exposed to strong sun, adding a little reddish hue in the mat of green.

GWS Living Art is grateful to have the opportunity to embark on this project. Regardless of the results of this trial, it is our sincere hope to raise awareness about the benefits and beauty of urban greenery. We plan to continue innovating and discover new ways to include nature in our urban landscape. In the meantime, do take the time to head down and have a look at Asia’s very first green roof buses for yourself!

GWS Living Art Founder with Nparks, Temasek and Singapore Building Council

GWS Living Art Founder with Singapore Green Building Council