As any teacher will tell you, conditions within the classroom can have a big impact on students’ ability to concentrate and learn. Research has shown that attainment can be clearly affected by factors such as access to daylight and thermal conditions within the classroom
. To support designers, the Education and Skills Funding Agency recently updated Building Bulletin 101 (BB101) — Guidelines on ventilation, thermal comfort and indoor air quality in schools
What is BB101?
BB101 pulls together the relevant regulations and standards for managing conditions within the indoor education environment, providing guidance on how these can be met along with supplementary advice on best practice.
One of the most significant changes within the updated document is a completely revised approach to how thermal comfort is measured.
What does thermal comfort mean?
The way we experience temperature can be affected by a wide range of personal and environmental factors, from our health and the types of clothes we wear, to our position in the room and the air temperature. Measures of thermal comfort attempt to consider all these factors and determine whether occupants are likely to feel too hot, too cold or just right.
As you might imagine, this provides a significant challenge for designers as the personal nature of many of the factors means that, within any given space, there can be a wide divergence in opinion on whether it is too hot or cold.
How is thermal comfort measured within BB101?
To estimate the thermal comfort of all students and staff within a room, BB101 uses a modified version of the adaptive thermal comfort standards within BS EN ISO 7730:2005 – Ergonomics of the thermal environment.
The standard uses two indices to estimate this: predicted mean vote (PMV) and percentage people dissatisfied (PPD).
PMV considers a number of personal and environmental factors to generate a score on a seven-point comfort scale (from hot +3 to cold -3). The PPD is then calculated from this score with the percentage of people dissatisfied exponentially increasing as PMV moves away from the central comfort scale score (neutral – 0).
BB101 provides a list of recommended operative temperatures for different spaces within a school during the heating season. Outside of the heating season, BB101 uses an adaptive approach, changing the maximum indoor temperature for day-to-day based on external temperatures.
How can thermal comfort be managed?
A wide range of measures are available to control thermal comfort and the most suitable solution will vary from project to project. One way to develop a solution is through dynamic thermal modelling where a 3D simulation model is created. Through this approach designers and engineers can:
- predict internal comfort conditions;
- identify the likelihood of overheating during summer months;
- establish likely heating demands; and
- maximise available natural light via daylight calculations.
BB101 also suggests the use of night purge strategies, where air is introduced through windows and vents during the night, helping to efficiently cool the building. More information on this can be found in section 4.13 of the document.
Whatever approach is taken, it will be easier and more cost effective to maintain constant internal temperatures if the building is adequately insulated. With section 4.15 of BB101 highlighting the need to future-proof spaces, it makes sense to look beyond the standard U-value requirements outlined in the Building Regulations and Standards. We provide recommended starting point U-values within the tables for our Building Regulations guide.
With a wide range of insulation options available, it’s important to carefully consider which solution is most suitable for any given project. Our Kooltherm K100 range products are a popular choice for education buildings due to their easy handling and excellent thermal performance. In applications where the slimmest possible construction is required, such as refurbishments over solid floors, we also offer our vacuum insulation panel (VIP), OPTIM-R, which can be used in a variety of applications. The panels have an insulating performance up to five times better than commonly used insulation materials. To ensure the best results, it is important that installers pay close attention to detailing around junctions and openings to minimise thermal bridging.
Better learning environment
With our understanding of how buildings impact users growing all the time, it is important that building methods keep pace, creating healthy and pleasant environments. BB101 provides a sensible approach for improving thermal comfort within schools throughout the year and by utilising a fabric first approach, designers can help to maintain internal temperatures whilst also reducing energy bills and emissions.