Agenda item

Daylight & Sunlight Guidance

Report of the Chief Planning Officer and Development Director.


The Committee considered a report of the Chief Planning Officer and Development Director concerning Daylight and Sunlight Guidance.


A Member spoke to remind the Committee why this report had been brought forward and set out that two years ago he had pointed out that, whenever this Committee considered an application for a development that entailed a loss of light to neighbouring properties, a familiar pattern was followed. First, time and money would be spent carrying out an analysis using the BRE guidelines. Usually, the proposed developments would fail the BRE tests as regards some of the affected properties but the Officers report would then typically suggest that this was acceptable due to the City’s dense urban environment. He added that Members could not visualise how much  light would be lost because the NSL and VSC of the BRE were unintelligible to lay people. Members would then therefore have to make decisions without knowing how much the affected properties would be in the dark. However, an expert consultant hired by the Corporation to deliver training on this subject recommended the use of radiance studies as a way of enabling lay people to visualise the loss of light. This led to the Member questioning in Committee why the City did not use these studies and the Chief Planning Officer at the time had responded to set out the reasons for not doing so – one of which had been that an applicant was under no legal obligation to carry out a radiance study. However, it was noted that an applicant was under no obligation to do  anything, including producing a traditional BRE analysis. The Member went on to say that the issue of radiance studies had now been linked to a proposed revision of the BRE guidelines which had still not happened.


The Member highlighted that, earlier this year, he had raised the question of radiance studies again with Officers pushing back to highlight issues with the applicant gaining access to affected properties to gather accurate data. However, the Member was of the view that the applicant could be asked to seek that access especially as those affected should naturally be willing to ascertain the extent of the effect. If the applicant were still unable to gain access after trying, then they could make reasonable assumptions as recommended by the expert consultant. The Member added that he did not see why a report was required for a matter that would do something to improve the current situation whereby Members were presented with BRE analysis that they found difficult to understand and, consequently, made decisions in ignorance. However, the Committee were of the view that a report was needed and, after some delay, it had now been presented. The Member noted that the report repeated the issue about access to affected properties without mentioning the obvious solution that he had already articulated. On the central question, the report did not deny the benefits of radiance studies and acknowledged that this could ‘provide an additional layer of assessment which is helpful in understanding the impact of a development on surrounding premises, particularly if it is represented in a 3D image’. However, the report then went on to conclude that ‘it is considered to be premature to require the provision of radiance analysis on all schemes on the basis that there is no existing policy or guidance basis for it’. The Member questioned why this could not be presented alongside a traditional BRE analysis to provide Members with at least some further clarity. The report also stressed that there ‘may need to be a reliance on assumptions that can lead to inaccurate or misleading results’ or not if the applicant makes reasonable attempts to gain access. It was noted that paragraph 20 of the report did offer some hope, stating ‘nevertheless, the value of radiance analysis is recognised and Officers will continue to work with developers to provide it in appropriate circumstances where it can be used to supplement the assessment of impacts where a BRE assessment indicates there would be an adverse impact on daylight and sunlight’. To conclude, the Member underlined that the report recommended spending £10,000 for a consultant to provide an advice note on this. He added that he opposed this and stressed that what was needed now were images that allowed Members to have some idea of what they were doing when considering applications which involved the loss of light and the provision of tools that were useful to the Committee in assessing the loss – such as radiance studies alongside the traditional BRE studies that he felt were often unintelligible. Should these tools not be provided, it was reasonable for Members to question why not and not give the benefit of the doubt to an applicant.


Another Member questioned whether Officers had contacted the BRE to determine when a new version of the guidelines would be issued. He also questioned what role, if any, radiance analysis would play in the new guidelines. He clarified that he asked this so as to determine whether, if the City Corporation progressed this under its own steam and went ahead with its own guidelines or introduced a new analysis method, it could be open to legal challenge.


Another Member commented that it appeared to be fairly clear that experts in the field felt that radiance was a better way to approach this and would address many of the problems this Committee had had with the BRE guidelines. He noted that BRE guidelines also required an understanding of the interiors of affected properties in the same way that radiance studies would and that he did not therefore foresee this as a particular hurdle. He added that he felt that it was extremely important for this Committee to truly understand the affect that new developments in the City would have on light and that the BRE analysis was not providing this level of understanding. The Member therefore felt that it would be useful for the City to spend money on developing a new policy that actually applied radiance in a way that seemed to be accepted now by the profession. He went on to express some concern around paragraph 20 of the report which appeared to set out that radiance studies would only be presented to the Committee when they were helpful to the developer and not when they might otherwise demonstrate problems with a development.


In response to these points, Officers reported that they had made contact with BRE but that they were yet to respond with a timeline for the introduction of any new guidelines. Officers reported that they had also been discussing this matter with a number of practitioners such as Gordon Ingram and others and were aware that there had been a number of workshops held between the BRE and the various practitioners as to how this would move forward. Officers had been advised that this was work in progress and would be out for consultation by the end of this year.  The report therefore recommended that this should be awaited so that the City Corporation had a full understanding of the emerging guidance context.


As pointed out within the report, having an understanding of the internal layout of affected properties was one element of radiance assessments but his was also true of Average Daylight Factor (ADF) assessments as well which were generally used to understand the daylight/sunlight implications of new residential developments and the light emitting into this rather than the impact of the development on existing properties.


The Chair spoke to state that he felt that some very valid points had been made around the robustness of using radiance studies both in terms of an expectation of applications using it and also where this could be put into policy. He went on to state that his understanding was that radiance studies had been used more in private rights of light. The Chair stressed that it was important for Members to understand what the legal position on this was in terms of the City Corporation progressing this matter unilaterally and how, if the City Corporation were unable to take this forward, how applicants were able to utilise this. In tandem with this work, the Chair asked that work around the new national BRE guidance continue without delay.


It was suggested that Officers also continue to discuss the use of radiance analysis with the BRE and also make them aware that the current situation was unsatisfactory – seeking further clarity on a timescale for the introduction of new national guidance and strongly encouraging them to include the use of radiance studies within this.


RESOLVED – That the Committee maintain the City’s present policy position as set out in the Draft City Plan 2036 for the present time with Officers tasked with reporting back to the Committee with information around what the legal position was on the City Corporation taking the use of radiance studies forward in terms of its own standards and methods of assessment and also on the ability of applicants to use these within their submissions. It was felt that this piece of work should be done in tandem with exploring the use of radiance studies nationally with the BRE and exploring with them precisely when new national guidance on daylight/sunlight analysis would be coming forward.

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