IES Blog

Questions & AEC 5: BREEAM HEA 1 Daylighting

Posted : June 3, 2011 by John G, Category: Questions and AEC

This month’s question and answer comes directly from a discussion that was taking place on our LinkedIn IES VE user group. The group acts as a great platform for users to share their knowledge, experience and opinions and we have recently reached over 1,000 members (Go us!). The question that features in this edition comes from Ciaran McCabe, a thermal modelling consultant using the VE in Ireland. The answers were kindly provided by Rosemary, our BREEAM expert.

Do you guys tend to use IES VE Radiance or Flucs DL to measure daylight factor and uniformity to demonstrate compliance with BREEAM HEA 1? Flucs DL is a much faster module to use on larger buildings. Any opinions on this topic welcome.

We would tend to use FlucsDL for large buildings as all the rooms can be analysed at once. For BREEAM I would recommend that you set up rooms groups so that you have “occupied” and “unoccupied” rooms grouped together. The “occupied” rooms can then be selected and average daylight factors/uniformity output produced.

I now see there is a new feature in Flucs DL which deals with Sky View. Sky view at 0.7m is one way of demonstrating compliance with BREEAM Hea 1 - Daylighting. I was just having a play around with this recently and wondered if this feature is fully operational or is it still being tested. Is there any documention on how the VE calculates sky view? I suppose what I am getting at here is if I was to use this feature I would need some way to validate the result.

Sky View was included in FlucsPro and FlucsDL for BREEAM HEA1 Daylighting purposes; however it is active whenever you have performed a daylight calculation. If there is a direct line from any point on the sky grid to any point on the working plane grid (through windows and openings but without passing through any obstruction) then that point has a sky view of 1. If not it has a sky view of 0. Using a threshold value of, say, 0.5 will allow you to see the percentage area with a sky view. It is easier to see the levels if you are not in contour view (choose filled contours or grey-scale instead).

To have your question featured in our monthly Questions & AEC series, just get in touch with us on Twitter, Facebook or drop me an email at john.goucher@iesve.com.

Tags:aec, BREEAM, daylighting, IES, LinkedIn