1
Minimizing FSI (gross floor space) will maximize the potential for direct solar irradiation. (+9)
2
Functions with higher heating needs should be placed on top of functions with lower heating needs. (+11)
4
East-west streets are preferably wider than north-south streets; the impact of H/W on direct solar access to all canyon surfaces is largest for east-west streets and smallest for north-south streets. (+10)
5
In tissues with a low GSI, buildings are best spaced at considerable distances to allow direct irradiation of the facades. In tissues with a high GSI the roofs are the primary collectors of solar radiation, limiting the importance of street width for passive solar gain of the buildings. (-18)
6
Squares, courtyards, gardens and other enclosed outdoor spaces meant for sitting, waiting or recreation are best elongated in the north-south direction and should have a H/W of ¼ or smaller to allow direct solar access in winter. Solar shading should be provided in summer. (-22, +37)
7
In dense urban environments, spaces with a high SVF, such as squares and parks with sparse tree cover, should be placed at regular intervals of about 2 diameters to promote nocturnal long-wave radiation loss in summer. To avoid overheating, (flexible) shading should be employed in these spaces during the day. (+53)
8
Buildings along east-west running streets preferably have single-pitched roofs (highest side facing south), as this benefits both outdoor and indoor solar access. (-29, 35)
9
Minimizing FSI will maximize the potential for natural daylighting. (+1)
10
For a given FSI, tissues with a low GSI have a better daylight performance than tissues with a high GSI. In other words: high and slender buildings placed at large distances from each other perform better than low and deep buildings placed at short distances and are thus preferable. This effect increases with increasing FSI, as daylight access decreases with increasing density. (+4)
11
Functions with the highest daylight demands are best placed at locations with the highest daylight availability, e.g. on the highest floors of a building (and/or in the potentially passive zone near the façade (the floor area within twice the floor to ceiling height from a façade)). (+2)
12
Large courtyards, squares or other enclosed spaces have a high potential for indoor daylighting.
13
Building depth should be minimized for indoor daylighting.
14
Differences in building height increase average and maximum daylight factors. (-16, 18)
15
In canyons with high H/W, materials or colours with a high albedo should be used to maximize reflection. This is most important for east-west canyons (with north/south facing buildings), as they are heavily overshadowed in wintertime. (+44)
16
Buildings twice as high or more than fifteen meters higher than the buildings in its direct surroundings will cause discomfort, as downwash of high wind speeds will occur. Such differences in building height should therefore be avoided, or, if this is not possible, higher buildings should have their longest side placed parallel to the prevailing wind direction, so that the frontal vortex and corner streams are minimized. (-14, +18)
17
Routes meant for pedestrians or cyclists should preferably not cross the frontal vortex and/or corner streams of tall buildings, nor should areas meant for stay (squares, parks, bus stops, etc.) be placed in these locations.
18
It is possible to design high-rise without (much) discomfort; if all buildings are more or less the same height and placed at distances less than 0.7 building heights from each other, the skimming flow regime will occur, preventing the downwash of high wind speeds. (-5, 14, +16)
19
Street grids in line with the (prevailing) wind direction will have streets (and other outdoor spaces) with a high level of shelter (those perpendicular to the wind), but also streets with high wind speeds (those parallel to the wind). Furthermore, these grids have the possibility of transverse flows in streets perpendicular to the wind direction, which may cause discomfort. Grids oblique to the wind direction will have a more ‘even’ wind pattern. (+3, 28)
20
Street crossings or other openings in canyons and buildings parallel to each other are best placed in line to the (prevailing) wind direction to prevent pressure short-circuiting.
21
Streets parallel to the prevailing wind direction should not be directly connected to open terrain, such as rural areas, lakes, rivers, etc. If this cannot be avoided, such streets are preferably short or have crossings at short intervals (L/H < 4). (+26, -33)
22
Square, relatively small (W<2Lg) enclosed spaces (courtyards, squares) give the most shelter, as corner streams, frontal vortices and transverse flows are prevented. (-6, -37)
23
Areas that generate a lot of air pollution, such as industrial areas, harbours, etc., should be placed downwind (of prevailing wind directions) from residential areas. (+30)
24
Areas meant for stay, such as squares, bus stops, etc., should not be placed in wake areas near busy roads or other pollution-emitting sources, as particles are accumulated and trapped in these locations for a long time.
25
Foot and cycle paths along busy roads are preferably placed on the downwind side of the street, where relatively cleaner air enters the canyon from above and pollutant concentrations are thus the lowest. Streets with two contra-rotating vortices stacked on top of each other form an exception to this rule; in these canyons concentrations are the lowest near the upwind side.
26
Busy roads preferably have intersections or side streets at short intervals (L<6H) as this promotes ventilation; through strong vertical flow in streets parallel to the wind direction and through a combination of along-canyon and upward flow in streets perpendicular to the wind direction. (+21, -33)
27
Busy roads should be executed as step-up canyons (in case of perpendicular flow), as this configuration yields the lowest pollutant concentrations.
28
For natural ventilation of buildings, street grids should be placed at an angle (of at least 15 degrees) to the governing wind direction. (+3, 19)
29
Pitched roofs (as the only roof shape) should be avoided in roads with high pollutant concentrations, because they decrease ventilation. (-8, +35)
30
On the scale of the city or district it is not preferable to place functions that produce a significant (mechanical) noise, such as industry and heavy traffic, immediately next to recreational green spaces and (low-density) residential areas. Business areas, commercial areas, mixed-use areas or green buffers may be placed in between. (+23)
31
Parks or other recreational green spaces should be placed at a considerable distance from busy roads, as traffic noise is found most annoying in green areas.
32
On neighbourhood level, placing a few main roads with higher traffic intensity around the neighbourhood, relieving roads in the rest of the neighbourhood, will lead to a larger area with lower noise levels than a homogeneous traffic distribution.
33
Busy roads should be bordered with a continuous row of buildings, with as little intersections as possible, to minimize the leaking of sound to the area behind. When executed with flat and/or green roofs, these bordering buildings will also limit the diffraction over the rooftops, thus providing extra shielding. (-21, 26)
34
Sound absorbing road material is advisable for busy roads, as it will reduce the noise load on and next to the roads themselves as well as in shielded areas. (+43)
35
Along busy roads, gable, shed, dual pitched, and half-monitor roofs should be avoided (as the only roof shape; a mix of different roofs shapes is advisable, as this increases scattering), unless executed with highly absorbing materials. (-8, +29, 48)
36
Enclosed shielded spaces (without sound sources), such as courtyards, can be expected to be quiet, as sound can only enter via diffraction over the roof.
37
An elongated square will have quieter areas than a square with sides of the same length and as such may be more suitable for a mix of functions. (+6)
38
Avoid specular surfaces (all-glass facades), as they yield higher average sound levels and reverberation times.
39
Minimizing paved surfaces in general will enhance (the potential for) evapotranspiration.
40
Paving materials with relatively low thermal admittance and high albedo will limit the amount of heat stored. Light coloured bricks are a good choice, as brick surfaces also allow water to seep to the substrate, contributing to evapotranspiration.
41
Pervious paving materials applied in parking areas, sidewalks, sitting decks, etc., and if possible open pavements filled with grass further increase evapotranspiration.
42
Roads or other surfaces covered with low albedo/high thermal admittance materials (e.g. asphalt) should be shaded as much as possible in summer. (Another option is to use these surfaces as a solar energy collector.)
43
Paving materials with a high sound absorption coefficient (e.g. porous asphalt) should be used in busy roads and streets.
44
Highly reflective building/cladding materials or light coloured finishing (e.g. white paint) will result in relatively little heat stored by buildings (but an increase in radiation towards the street surface). Care should be taken to avoid glare. (+15)
45
Reflective roofing materials/finishing will result in relatively little heat stored.
46
Green façades/walls along roads/streets with high traffic intensities filter the air, and if executed as living wall systems also reduce sound levels through absorption. Furthermore they provide cooling through evapotranspiration, which is beneficial as busy roads are often paved with asphalt.
47
Green facades facing (south)west will provide cooling through shading and evapotranspiration at the moment when it is most desirable and furthermore minimize infiltration losses from the building (the governing wind direction in the Netherlands is southwest).
48
Green roofs should be applied where possible, as they absorb sound, cool the air, shade the roof and improve air quality. (+35)
49
A combination of trees and bushes at the southwest side of a large open space will provide wind shelter as well as shading in the (late) afternoon.
50
Deciduous trees on the north side of an east-west running street or on the east side of a north-south running street will provide shade to the facades that need it most and also provide extra shade to the street surface in summer, while providing access to the sun in winter. (-51)
51
Coniferous plants and/or trees or other evergreen vegetation along roads with high traffic intensity provide air filtering year round. (-50)
52
Small green areas at small distances (i.e. pocket parks or gardens of about 100m2 at distances of 200m) that have a combination of well-irrigated grass and trees form a network of Park Cool Islands during the day, cooling the entire urban tissue in their surroundings.
53
Larger green areas with H/W<6 at larger distances (i.e. parks or fields of about 20 hectares at a distance of about 1km) with sparse tree cover will form a network of Park Cool Islands at night, providing nocturnal cooling to the entire urban fabric in their surroundings. (+7)
54
Fountains can be placed in public spaces, such as parks or squares, close to or bordered by busy roads for noise masking.
55
Multiple fountains placed along the boundaries of a larger public space will create a quieter, noise free area in the centre.