Urban Quality
Adapting to intensified living
The rationale of this objective is that our urban areas are comprised of buildings grouped together so that each building may affect others adjacent and the spaces between. At ground level we use these spaces for movement, relaxation and entertainment. Above ground level the air, light and heat within these spaces can be used to light, heat and ventilate our buildings.
With intensified living it is increasingly likely that buildings will influence adjacent buildings and the spaces between. Inner city areas are becoming areas where many people spend a much greater portion of their time for work, recreation, entertainment and residence.
The questions this objective seeks to answer are:
- Do people find the physical environment of inner city areas conformable for the activities they intend there?
- Can we develop descriptors (or indicators) of the physical environment which relate to peoples comfort and then establish performance criteria for them?
- What is an appropriate methodology that combines the individual physical parameters, eg light, heat, wind etc so that we can model comfort/liveability?
- What is the physical environment of our inner cities like?
- How well does the inner city built environment support a more sustainable architecture of natural heating, lighting or ventilation for the buildings there?
The main physical effects that the project will be limited to are:
- wind
- sunlight/warmth
- daylight
Pollution will also be included, and noise to a small extent also.
The product
Our intent is to produce a tool or process which could be applied to a proposed change to an inner urban area, so that we could firstly identify the extent to which that physical environment will change, and then to understand how that changed environment will be acceptable to inner city users with respect to factors such as comfort and to the priorities which they have for that environment.
Methodology
The method used will be a case study approach using the five Wellington areas listed in the case study section. One of the main reasons for the case study approach is that the physical environment of the city areas already exist and people are already using the city in response to the comfort that they experience.
The purpose of this project is to reveal the comfort that they are experiencing and gain understandings as to how they might respond if conditions were altered. The use of their favourite parts of the city is also linked to a history of conditions over time. Facilities will be located and people will use those inner city environments which experience tells them are most likely to provide the conditions/activity they find acceptable.
Frequency of particular conditions, and population expected over time will all be important parts of this research.
While the core of this project concerns characterising the physical environment of the urban spaces of the inner city and determining whether these meet the needs/desires of the users of these urban spaces, three related areas are included in the wider project.
These are:
- Determining the exposure of urban users to motor vehicle sourced pollutants. This will first require development of pollution modelling techniques.
- Determining indicitave levels of noise and response of the urban users to them.
Assessing the suitability of the physical environment for supporting more natural venilation, heating and lighting for inner city buildings.
Case studies
The case study areas intended for this project are:
Courtenay Place
A lowrise, wide street area. Entertainment area with afternoon but especially night time focus. Draws wide spectrum of the population.
Cuba Street/Ghuznee Street
Low rise, narrow streets. Combination of exterior walls and busy streets. Residential and retail/cafe/restaurant areas. Some unpopular parks. Draws more of the 'alternative' population.
Midland Park/Lambton Quay
High rise business/office/retail, limited residential use. Draws higher income retail/office/business workers. Region of congregration.
Lambton Quay/Willis Street Intersection Area
High rise retail/business area. Transitory region for people moving from Willis/Harbour area through to Lambton Quay area. Also includes a substantial underground area of controlled environment.
Cable Street/Taranaki Street/Wharf Area
A typical waterfront recreational leisure area and also a point of transition from Te Papa, Civic Centre and Queens Wharf area.
Research task
A summary of the research tasks proposed:
1L Experimental design
- Develop methodology, divide tasks between Opus Central Laboratories and Victoria.
2L Pollution modelling
- Further develop pollution model to better match field results.
- Use file model on case study areas and develop understanding of pollution movement through and air quality of these areas.
- Produce paper on findings.
3L Physical environments
- Model wind speed and sunlight/shade over the seasons for the case study areas.
- Undertake frequency analysis of weather to determine coincidence wind speed/sun-could conditions.
- Using the "comfort" descriptor developed in Task 5L categorise the case study in terms of this comfort indicator for the more frequent conditions.
- Assess noise levels within case study areas.
4L Sustainable architecture
Determine adequacy of inner city environment for natural ventilation, lighting and warmth in adjacent buildings by:
- Developing some typical building cells.
- Fitting data from task 3L to these cells and comparing the resultant environment with those expected for residences, cafes, offices, etc.
5L Urban user attitudes
- From literature and using judgements prepare indicative "comfort descriptors" for combinations.
- Using the characterised urban environments of Task 3L, and after devising an appropriate survey, test these comfort indicators against the sample population, then refine the indicators and survey and retest them.
- Devise a survey appropriate for use in determining:- acceptable levels of comfort for typical inner-city suburbs.- the priority that urban users place on urban environment features such as sunlight, shade, wind (views, noise, air quality?)
- Analyse and prepare findings.
Findings
Physical environments
The aim of this project is to create an index of liveability for urban spaces, combining sun, wind and temperature data. As our cities undergo more intensified occupation, more needs to be done to increase human comfort in the public areas created between our buildings. The index would enable designers to take into account the comfort of users of the space and the priorities they have for that environment.
Based on a review of the relevant literature, potential “comfort descriptors” for combinations of physical measures of the environment (wind speed, temperature) were prepared. The result was a preliminary report on how a survey of people in public spaces might be constructed and the type of information needed from it.
From NIWA’s National Climate Database, data was obtained of solar radiation, temperature and wind speed and directions recorded at Wellington Airport. The data was subject to a cross-tabulation analysis. The results were then displayed in graphs summarising for each dry bulb temperature band, the likely solar and Northerly and Southerly wind conditions. These graphs allowed for several climatic patterns to be identified.
From the beginning, it was assumed two existing techniques would be used to establish how to combine wind and solar data. Computer Aided Design (CAD) models would analyse hourly solar access, defining sunny and shady parts of urban environments. These results would be combined with existing wind tunnel test reports of specific areas within Wellington. An existing CAD model of the city (spanning from Te Aro through to Lambton Quay) was obtained from the Wellington City Council.
Grids of 1m, 2m, 5m and 10m were created at ground level in the case study urban areas to establish which size was the best method of quantifying the amount of sunlight/shade in the various spaces. The models were lit at 9am, 12pm and 5pm and the ratios of sun to shade were calculated for each grid size at the different times of the day. This method established the 1m grid as giving the most accurate results.
Bead erosion tests and single point speed measurements from existing wind tunnel test reports by Opus International were used for the purposes of constructing the index. The initial plan was to combine these two pieces of data into a comprehensive graphic. A similar grid system as used for solar data would then be used to quantify wind data, allowing wind and sun to be combined at the grid square level prior to constructing a summary index.
It has proved difficult to draw wind contour lines and thus produce a clear, legible map when a large range of wind data is concentrated within a small area. An index of liveability requires solar information to be combined with the wind data (and possibly temperature data as well). Due to the different types of information contained in the solar, wind and temperature data, the map needs further development if it is to display all of the data in an easily understandable manner.
For more detail please download the report from the downloads page.
Acquiring the scale score
To arrive at a scale score for an Urban Environment this project combines sun, wind and temperature data in an index of the liveability for public spaces. This index can be used and applied to a proposed change for an inner urban area. The index will take into account the comfort of users of the space and the priorities they have for that environment.
This brief report records the process by which a scale score is arrived at, including:
raw data used
computer programs used and their limitations
data transformations
problems and limitations encountered at each stage of the Scale Score method.
It must be made clear that this report outlines a test that has been performed on data from Midland Park, and may not apply to other urban areas until further testing has been done.
The report is divided into five main sections. The first section (Method Flow Chart) provides a quick guide to the process that is used to arrive at a scale score.
Section 2.0 (CAD Model), looks at how the Computer Aided Design Model was constructed and what this model represents. This section describes in detail how to calculate a sun/shade ratio for any given space, and the difficulties and concerns in this process.
The third section (Weather Data) consists of the step by step process for using a National Institute for Water and Atmospheric Research (NIWA) weather file to predict scale score values for an urban space. This section also includes any issues that have arisen that can influence the outcome of this process.
Section 4.0 (Urban Score), combines the information from the previous two sections to arrive at a scale score.
Lastly, the conclusions section sums up the whole process and suggests whether or not the method used does in fact come up with a valid scale score for Midland Park.
For more detail please download the report from the downloads.
Current work
Urban environments for Intensified living
Work is continuing on the project currently, below is a description of the work that is being undertaken and a rough timeline of events.
Determine the framework of a model which can be used to link the exterior environments that are typical of intensified urban living with the habitability of adjacent indoor spaces and the associated transition areas where there is an emphasis on natural ventilation, natural lighting and solar heating. The model will encompass parameters such as availability of sunlight, daylight and acceptable wind conditions as well as urban environmental quality measures from the literature relating to the definition of quality urban space by the surfaces (typically walls of buildings, lines of trees, areas of paving) that define that urban space. The model framework will be developed through case study scenarios incorporating literature based assessment methods for urban aesthetic quality and physical and digital modelling of building performance.
A minimum of two case studies will be developed. One will be for an area of Wellington which is currently unoccupied by buildings but is slated for intensive development. The area of the Wellington waterfront north of Queen's Wharf or the Chaffers beach / park areas would be candidates for this type of analysis. In this type of scenario issue of street width and orientation, building scale and set backs, urban place definition and the environmental qualities both between and inside the buildings would be examined. The second case study would be of an area of the existing city slated for intensive development. An area of the Auckland or Wellington CBD would be candidates for this type of analysis. In this scenario the street widths and orientation are largely fixed. What are to be examined are the relationships between these, the environmental quality indices for these urban spaces and the environmental quality potential in the surrounding buildings that define these streets and plazas.
Completed tasks:
- Brief report on the selection of urban places for case study analysis listing rationale for selection.
- Literature study of measures or means of measuring qualities of urban place definition.
Download Literature Study from downloads below.
March 2003:
Completion of the digital and physical modelling of the scenarios. Input data and results (computer output and test results). Compose a brief report.
May 2003:
Completion of an abstract for a paper for the ANZAScA conference in November 2003.
Downloads
Reports
Physical environments downloads
Acquiring the scale score downloads
Literature study
Utilities
The process used required the development of tools that enabled the data to be generated quickly and efficiently and then to be analysed. To facilitate the rendering of a series of sun conditions an AutoLISP routine was created. Solrender creates a series of renderings of the current scene from the current view under changing sun conditions for specified hours of the day over the specified days in the year.
The solrender lisp contains instructions on how to use it, so all you should need to do to get it working is load it.