Vertical Sky Component Daylight Report

Decision
Appeal

Vertical Sky Component And Average Lux

REPORT Amended PFC

FOR

BRIDGE WORKS,

FOR

DANDARA LIMITED AUGUST 2015 – Rev -

Dandara

commercial limited

Content

1. INTRODUCTION
2. DAYLIGHT LEVELS (Lux)
3. CONCLUSION
4. REFERENCES
5. APPENDIX A Steps For Running the Analysis
6. APPENDIX B Full size drawings with Analysis results

1.0 Introduction

1.00

This daylight analysis and report has been compiled in support of the design for proposed Bridge works, Old Castletown Road, Douglas, Isle of Man.

Day lighting levels guidance is contained within BRE IP 23/12 and BS 8206-2: 2008 for a full range of accommodation and the report and analysis is undertaken to reflect accepted daylight quality for the well-being of occupants (on the apartment former Jack frost building) which sets out criteria to enhance the overall appearance of interiors, using sunlight direct beam and skylight (diffuse daylight) and for lighting of visual tasks.

1.01

The Daylight Analysis shown in this report has been completed using Ecobim daylighting software 2011. Ecobim calculation procedure is based on high performance EDSL. Tas simulation engine. This analyses in detail the daylighting lux levels of each habitable space from a model of the ground floor space of the building. The analysis is based on the model of the building and opposing buildings and features to include the worst case scenario on the ground floor and takes into account projections and obstructions and orientation in relation to daylight entry into the rooms. Upper floors have better exposure to daylighting if 25 degree rule is utilised.

1.02

The natural daylight levels in this report are not date or time dependant. They represent worst-case design conditions based on an overcast sky distribution on 21 June. Calculations are based on the BRE Split Flux Method which uses daylight factors and the design sky illuminance value to determine likely natural light levels in a model.

1.03

Ecobim calculates the natural light levels within a building by calculating the lux levels using the Sky Component, external and internal reflection along with using the design sky illuminance. The Design Sky Illuminance has been set at 3000Lux which is calculated based on the global latitude of Douglas Isle of Man (54.1) ° and average window cleanliness which multiplies the transmittance by the factor of 0.90m. Please refer to Appendix A for the step/settings used to complete the analysis.

1.04

The Analysis has been run consistent with the original methodology as described in the "BRE Estimating Daylight in Buildings".

2.0 Daylighting Levels (Lux)

2.01

Daylight is about bringing natural light into a space. Many day-lit spaces do not want or need direct sunlight. Diffused or indirect lighting provides glare free daylight which is often an issue with direct sunlight.

2.02

Daylight is important in any building to reduce the need / dependency for electrical lighting and is also very important for a person's overall health and wellbeing. Energy conservation and health benefits therefore can be achieved from maximising natural daylighting in buildings.

2.03

The results shown in Appendix B below are based on a working plane 900mm above the internal floor level.

2.04

The daylight lux levels analysis fig 1 provides the actual levels within each room. The recommended level under the guidance is 150 lux lighting in residential, this can be achieved by introducing both artificial and daylighting. The daylighting model results serve to demonstrate that good quality lighting levels are provided not only from the sky at high level but also open directional aspects to the East and West.

Figure 1 – Ground level (Lux levels) showing a comparison before and after the proposed building (results not significantly different) 1a - With proposed building

1b - Without proposed building

Table 1 - an extract from (CIBSE Code for Lighting 2002: Addendum 2004) which indicates recommended lux levels for residential properties.

Notes:

1. The recommendations in this section refer to institutional accommodation, it is not the intention of the Code for Lighting to give guidance for private dwellings.
2. Uniform lighting in small spaces is unlikely to be appropriate.
3. Supplementary wall/table lighting to create appropriate atmosphere.
4. Avoid shadows on work surfaces and sink.
5. Additional shaver light at mirror position.
6. Possibly supplemented by wall/picture lighting.
7. Low level late night lighting with override facility.
8. See also Lighting Recommendations for traffic zones (page 55) for information on this type of space in other buildings
9. Luminaires to provide contrast between treads and risers. Safety will be enhanced by the use of coloured nosings which contrast with the finish of the treads and risers.
10. Multiple switching levels desirable. Use wall/picture lights to create a pleasing atmosphere.

3.0 Conclusion

The daylight analysis shown in Appendix B demonstrate that the difference in the results with and without the proposed building do not differ significantly. Natural lighting levels without the proposed development model in place are showing to be well in excess of CIBSE guidance. The model with the proposed development maintains levels which are also in excess of the guidance recommendations.

Residential buildings	Maintained illuminance (lux)	Limiting Glare Rating	Minimum colour rendering (R0)	Notes
Flats/bedsits				1,2
Entrance lobbies	200	–	80
Lounges	150	–	80	3
Kitchens	150–300	–	80	4
Bathrooms	150	–	80	5
Toilets	100	–	80
Communal areas				1,2
Main entrances	200	19	80	6
Corridors	20–100	19	80	7,8
Staircases	100	–	80	8,9
Lounges	100–300	19	80	10
Television lounges	50	–	80
Quiet/rest rooms	100	–	80
Dining rooms	150	–	80
Laundries	300	–	80
Stores	100	–	80