6.4.0 Thermal Comfort Strategy

The ‘Weave’

Thermal Comfort Strategy

The thermal comfort for a pedestrian in the public realm is a function of the ambient air temperature as well as heat that radiates from surrounding surfaces. Strategies for ameliorating the effects of the UHI effect have been considered during the Concept Design development for the public realm; and will continue to be studied and incorporated through Preliminary and Detailed Design stages.

Our appreciation of “thermal comfort” is our thermal perception of our surroundings that is affected by four factors: air temperature; air humidity; air velocity; and surface temperatures. In an already humid atmosphere through the summer months, we are mindful that strategies to cool the air temperature through transpiration from vegetation are offset by a resulting increase in humidity; and therefore we aim to impact 3 of the environmental factors for mitigating UHI.

• Air temperature

• Air velocity

• Surface temperatures

Air temperature affects only 6% of our perception of thermal comfort whereas the temperature of surrounding surfaces and air velocity account for 50% and 26% of thermal comfort perception, respectively.

Yas South experiences significant sea winds that conveniently address the environmental factor of air circulation and velocity. Key elements within the landscape design will therefore focus on mitigating the high temperatures of both the air and surfaces.

The specification and use of appropriate materials, whose inherent properties mitigate the effects of heating, will be carefully considered for the materials used in the public realm design of Yas South. The materials themselves will impact on the thermal comfort of visitors with regards to the levels with which they absorb and re-radiate heat at the microclimatic level.

The heat balance of paving materials is affected by their colour, permeability, conductivity and their ability to shed heat. Lighter coloured materials with a relatively low density are more efficient in shedding the radiant energy from the sun than darker coloured materials and therefore a colour range that incorporates lighter tones has been considered in the hard landscape materials strategy.

In addition to material selection, the use of planting to improve micro climates is integral to the thermal comfort strategy. Trees and other plants effectively lower the ambient temperature and assist in creating a more pleasant and hospitable pedestrian environment. Wherever possible, trees have been integrated into the design to provide shade.

The provision of shade throughout the Public Realm of Yas South will utilize shade from palm and tree canopies and some key location shade structures.

Throughout the streetscapes we find that the positioning of trees (and therefore also foundations) is entirely dictated by underground utility corridors and with the arrangement of the cycle and pedestrian footpaths dictated by the USDM, the possibility to rearrange the profile of the streets to maximize the shade cast onto pedestrian routes, is not flexible. These limitations do not provide the opportunity to selectively position routes and shading elements relative to where shadows will be cast.

Shade through the open spaces is provided by either shade from tree or palm canopies or fixed shade structures of different types. Spatially defined areas for picnic tables have fixed shade devices to ensure that shade is provided to these areas; seating areas are located either under tree/palm canopies or under fixed shade devices so that a variety of opportunities are provided; and children’s play areas are fully shaded. Plaza spaces are not only defined with paving patterns, but also offer experiences that are palm covered, tree covered, or include a feature shade device that spans and defines the area.

During the Preliminary Design stage the shading that is offered by the concept design will be further studied and the shade strategies developed that add to the overall aesthetic and thermal comfort for users of the public realm. A balance between preserving views of the ocean and providing continuous linear shade structures along the waterfront promenade is under review so as not to negatively impact on the qualities of the recreational asset or the functional requirements of requiring emergency vehicle access. The design currently considers the distance covered in a 5 minute walk or 300m and provides fully shaded rest areas.

As part of the Estidama Credit Submission for the Design Rating related to PRRS LS-R1: Outdoor Thermal Comfort Strategy, the submission will demonstrate that the following targets are intended to be met within the Public Realm Design at the Detail Design stage of the design development. To demonstrate how the shade study will be used to communicate the provision of shade through the public realm, the following sheets provide an example of the information generated that validates the shade levels obtained. This information will be prepared throughout the Preliminary Design and Detail Design stages and reviewed with the PQP and Estidama Assessor for compliance with the intention to attain the targets presented:

Soil Edaphology

Refer ‘Softscape Strategy’ for details of soil amendments that are required to ensure soil conditions are optimised for tree growth and to ensure tree canopy formation, which is integral to the shade strategy.