The webinar covered the current planning requirements for Daylight, Sunlight and Pedestrian Comfort Studies in the Republic of Ireland. We also examined the new daylight standard IS EN 17037:2018 and how it compares to the now withdrawn BS 8206-2:2008 standard.

1. Daylight and Wind
Studies for successful
Planning Applications in
Ireland
www.iesve.com
Gary Nixon
Senior Business Development Manager
Harshad Joshi
CFD Consultancy Manager
Dónal O'Connor
Associate Director
24th November 2021

2. What will be covered?
• Pedestrian Comfort Studies
• Current Planning Requirements
• Impact on Design
• Case Studies
• Daylight & Sunlight Studies
• Current Planning Requirements
• Upcoming Changes to Standards
• Impact on Design
• Case Studies
• Live Q&A
•
www.iesve.com
Today’s Speakers
Gary Nixon
Senior Business
Development Manager
Harshad Joshi
CFD Consultancy Manager
Dónal O'Connor
Associate Director
Consultancy Ireland

3. What will be covered?
• Pedestrian Comfort Studies
• Current Planning Requirements
• Impact on Design
• Case Studies
• Daylight & Sunlight Studies
• Current Planning Requirements
• Upcoming Changes to Standards
• Impact on Design
• Case Studies
• Live Q&A
•
www.iesve.com
What will be covered?
• Pedestrian Comfort Studies
• Current Planning Requirements
• Impact on Design
• Case Studies
• Daylight & Sunlight Studies
• Current Planning Requirements
• Upcoming Changes to Standards
• Impact on Design
• Case Studies
• Live Q&A
•

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12. IES CONSULTING
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Pedestrian Wind
Comfort Studies

13. Contents
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• Why carry out a wind comfort/safety assessment?
• When to carry out the analysis
• Requirement for wind micro-climate study
• Procedure
• Pedestrian wind comfort assessment
• Pedestrian wind safety assessment
• Project Examples

14. • Ensure that outdoor spaces are fit for purpose
• Enhance usability of outdoor spaces
• Identify locations where outdoor seating areas for cafés,
restaurants etc. can be located
• Integrate mitigation measures in to the landscape design
for a better blend, rather than an afterthought
• Avoid extreme wind tunnels that can be caused by the
smooth facades and expose pedestrians to unsafe wind
speeds
Why carry out a Wind Comfort/Safety
Assessment?
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15. www.iesve.com
• Design building entrances to reduce effect of heavy
infiltration when doors open
• Potential for higher rental earnings from outdoor
seating tenants, as you will possess documentation
showing the effectiveness of mitigation measures
• COVID world
• Measurable economic benefit
Why carry out a Wind
Comfort/Safety Assessment?

16. When to carry out the analysis
• Ideally, throughout the design cycle
• Start at the massing stage of the model to identify
• Safety Risk locations
• Ideal balcony locations
• Mitigation measure that may be required for amenity spaces
• Best site layout
• Enhance design of the building and surrounding landscape with
pre-understanding of the site characteristics
• Massing model simulation will typically cost and require only
around 25% of the respective quantities of the final model
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17. • As per Urban Development and Building Heights: Guidelines for Planning
Authorities (December 2018) published by Government of Ireland
• What it means:
• Ensure that downdrafts are avoided
• It is recommended when taller building are clustered together.
• When height of proposed building(s) is significantly higher than the
surrounding locality (e.g. 3x high or above)
• Taller buildings will mean 20m and higher (6 storeys and above typically)
• Stand alone buildings being proposed along side similarly tall structures
could be ignored, but downdraft risk can remain
• Wider masterplans – even if height is smaller
• Identify landscape locations
• Avoid accidental wind tunnels
Requirement for Wind Microclimate
Study
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18. Procedure
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• Virtual wind tunnel simulations, typically encompassing 8 or 16 wind
directions.
• Up to 36 wind directions possible for ‘City of London Wind Microclimate
Guidelines’
• Simulation results suitably extrapolated using suitable weather file to obtain
wind speeds for every hour of the year, at every point in the area of
interest.
• Wind comfort results as per the Guidelines or as per Lawson’s Pedestrian
comfort Criterion

19. Pedestrian Wind Comfort Assessment
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Lawson’s Pedestrian Comfort Criteria
Category Pedestrian Activity
Threshold mean hourly speed
(m/s) not to be exceeded for
more than 5% of the time
Beaufort
Scale
Locations
C1 Business Walking 10 Fresh breeze
Thoroughfares, entrances to buildings, access in
and out of the site
C2 Leisurely Walking 8
Moderate
breeze
Garden paths, outdoor exercise areas, dog
walking
C3 Standing 6 Gentle breeze
Controlled entrances, breakout spaces, smoking
zones, open air car parks, taxi ranks
C4 Sitting 4 Light breeze
Garden benches, outdoor lunch areas, children
play areas, bus stops

20. www.iesve.com
Pedestrian Wind Safety Assessment
Lawson’s Pedestrian Safety Criteria
Category Pedestrian Activity
Threshold mean hourly speed
(m/s) not to be exceeded for
more than once (or 0.01%) a
year
Beaufort
Scale
Locations
S1 Normal 20 Gale
Thoroughfares, entrances to buildings, access in
and out of the site, applies to able bodied
pedestrians.
S2 Sensitive 15 Moderate gale
Same locations, but applies to more vulnerable
pedestrians like old people, children, disabled
etc.

21. Examples of design changes to improve wind
comfort - Balconies
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Before After

22. Examples of design changes to improve wind
comfort – Roof terrace
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Before After

23. Examples of design changes to improve wind
safety – Building entrance
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Before After

24. Examples of design changes to improve wind
comfort – Landscape update
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Before After

25. City of London Plan Methodology
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• 36 wind directions
• Wind profile – suitable to site
• Specific formulation provided to
calculate.
• Measure probability of exceedance
from Weibull parameters derived
from larger set of weather data
• Typical weather data required
reliably – 10-20 years
1. Existing site
2. Proposed scheme with existing
surrounding site
3. Proposed scheme with planning
consented schemes
4. Existing site with planning consented
schemes
5. Above cases with mitigation features if
any
6. Proposed scheme with planning
consented schemes and non-consented
future schemes under consideration
7. Existing surrounding with proposed site
flat (demolished) if previous structure
taller than 40m
Procedure Stages to carry out full CFD analysis

26. IES CONSULTING
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Daylight & Sunlight
Studies

27. IES CONSULTING
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Contents
Shadow Analysis
Sunlight to Amenity Spaces
Sunlight to Existing Buildings
Sunlight to New Development
Daylight to Existing Buildings
Daylight to New Development
View Out
Glare
• Guidance / Standards
• Daylight Provision Requirements to New Developments
• BS 8206-2:2008
• IS EN 17037:2018
• BS EN 17037:2018
• Impact on Apartment Design
• Case Study

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Guidance / Standards

29. IES CONSULTING
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Guidance / Standards

30. IES CONSULTING
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Guidance / Standards

31. Daylight Provision - BS 8206-2:2008
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DF (%) = illuminance internal x 100
illuminance external

32. IES CONSULTING
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ET = 50% Working Plane
(300 lux / 2.0% DF)
ETM = 95% Working Plane
(100 lux / 0.7% DF)
Daylight Provision - IS EN 17037:2018

33. There are two methods to assess daylight provision:
Method 1: This calculation method uses the daylight factor targets on the
reference plane as per Table A.3. The assessment is carried out on a
representative day and time during the year, e.g. 21st September @ 12:00 under
standard CIE overcast sky conditions.
Method 2: This calculation method uses the illuminance targets on the reference
plane as per Table A.1. The assessment is carried out for each hour over the
course of the year (8,760 hours) using a local weather file which accounts for
varying sky conditions and sun positions throughout the year.
As outlined in Section 5.1.4, the verification of daylight provision can be
determined using either an adequate software or on-site measurements.
When using a software, “a representative model of the space is required together
with the key parameters (such as any significant nearby obstructions, the
assigned surface reflectance values and glazing transmissivity) that are a
reasonable representation of those for the actual, completed building. This can
be determined using either Method 1 or Method 2.”
Daylight Provision – IS EN 17037:2018
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34. Daylight Provision – BS EN
17037:2018
“The UK committee supports the recommendations for
daylight in buildings given in BS EN 17037:2018; however, it
is the opinion of the UK committee that the
recommendations for daylight provision in a space (see
Clause A.2) may not be achievable for some buildings,
particularly dwellings. The UK committee believes this could
be the case for dwellings with basement rooms or those with
significant external obstructions (for example, dwellings
situated in a dense urban area or with tall trees outside), or
for existing buildings being refurbished or converted into
dwellings. This National Annex therefore provides the UK
committee’s guidance on minimum daylight provision in all
UK dwellings.”
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35. Daylight Provision – BS EN
17037:2018
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“Where one room in a UK dwelling serves more than a single purpose,
the UK committee recommends that the target illuminance is that for
the room type with the highest value – for example, in a space that
combines a living room and a kitchen the target illuminance is
recommended to be 200 lx.”

36. Daylight Provision – BS EN
17037:2018
IES CONSULTING
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“It is the opinion of the UK committee
that the recommendation in Clause A.2 –
that a target illuminance level should be
achieved across the entire (i.e. 95 %)
fraction of the reference plane within a
space – need not be applied to rooms in
dwellings.”

37. Daylight Provision – BS EN 17037:2018
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38. IES CONSULTING
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• Room Depth/Layout
• % Glazing
• Balcony Design
• Depth/Area
• Location
• Finishes
• Internal
• External
Impact on Apartment Design

39. Impact on Apartment Design
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1 2

40. Option 1
LKD recessed under Balcony
Option 2
Bedroom recessed under Balcony
Storage & WC placed at the back of the apartment
2
2
1
1
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Impact on Apartment Design

41. Option 1
Balcony dimensions: 1.55 x 3.40m
Option 2
Balcony dimensions: 1.65 x 3.15 m
Increasing the depth and decreasing the length
of the Balcony while keeping the same area
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Impact on Apartment Design
1 1

42. Option 1
Full width balcony
Option 2
Reduced balcony area to minimum requirements
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Impact on Apartment Design
1 1

43. Results based on:
• Initial apartment design
• Default surface reflectance
values.
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Impact on Apartment Design
Bedrooms
Fail
LKDs
Fail
1.5% - 2%

44. Results based on:
• Initial apartment design
• Typical surface reflectance
values.
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Impact on Apartment Design
Bedrooms
Fail
LKDs
Fail
1.5% - 2%

45. Results based on:
• Typical surface reflectance values
• Maximised glazing width
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Impact on Apartment Design
Bedrooms
Fail
LKDs
Fail
1.5% - 2%

46. Results based on:
• Typical surface reflectance values
• Maximised glazing width
• Shifted balconies
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Impact on Apartment Design
Bedrooms
Fail
LKDs
Fail
1.5% - 2%

47. Case Study
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Recently lodged Planning Application

48. Thank You
Any Questions?
www.iesve.com
gary.nixon@iesve.com
harshad.joshi@iesve.com
donal.oconnor@iesve.com
consulting@iesve.com