CPD PROGRAMME | BB101 UPDATE considered the benefits of using natural and hybrid lighting where possible for a beneficial impact on occupant wellbeing and on cutting carbon emissions and energy costs. There have been many research projects in the education sector that have linked daylighting with improved achievement rates, health and attendance. Historically, many classrooms were predominantly lit using large vertical windows at the back of the room. By applying natural daylighting systems, a classroom can be supplied with 300% more daylight,6 while also reducing the lighting energy cost significantly. Research has shown that there can be a conflict between classrooms built in this style, as they may not be thermally comfortable being too warm in the summer and potentially draughty in the winter. Glare can also become an issue. BB101 points to CIBSE Lighting Guide LG5,7 Lighting in Education to give the criteria for lighting design in schools. Thermal comfort Designs may require compromises in terms of thermal comfort. A building that is either mechanically or naturally controlled for thermal comfort may have particular systemrelated adverse impacts on acoustics or air quality, and these need to be holistically considered when evaluating the system needs. The BB101 thermal comfort recommendations are derived from those in BS EN ISO 152518 and the guidance in CIBSE Guide A, 2015. However, they have been modified to account for the needs of children and schools in the UK. To maintain comfort conditions for people with specific requirements such as those with physical disabilities, pupils with special educational needs that affect their temperature response or for very young pupils an assessment of their particular needs will be required. Higher categories of thermal comfort may be needed in all or part of a school. Notable BB101 updates BB1014 has been updated to bring it in line with the output specification requirements for schools funded by the DfE. It has been aligned with the revised Gas safety in educational buildings IGEM/UP/11 published in 2018 The guidance on pollutants has been brought up to date, and now covers airborne particles and the range of indoor and outdoor pollutants Advice is given on reduction of pollutants by positioning of air intakes and use of filters Extensive references are provided to research on air quality in schools A new calculation procedure for prevention of summertime overheating uses an adaptive comfort temperature and the Design Summer Year (CIBSE DSY1 2020 50th percentile range) for modelling Openings are sized using dynamic thermal modelling using CIBSE DSY 2020 (50th percentile range) weather file most appropriate for the location of the project. when hybrid systems are operating in mechanical mode in general teaching and learning spaces, sufficient outdoor air should be provided to achieve a daily average concentration of CO2 of less than 1,000ppm. The maximum concentration should also not exceed 1,500ppm for more than 20 consecutive minutes each day. 2. In general teaching and learning spaces where natural ventilation is used or when hybrid systems are operating in natural mode, the following standards apply: a. Sufficient outdoor air should be provided to achieve a daily average concentration of CO2 of less than 1,500ppm, during the occupied period. b. The maximum concentration should also not exceed 2,000ppm for more than 20 consecutive minutes each day. c. The system should be designed to achieve a carbon dioxide level for the majority of the time of less than: 1,200ppm for a new building (800ppm above the outside CO2 level, taken as 400ppm) for the majority of the occupied time during the year. 1,750ppm for a refurbished building (1,350ppm above outside air level) for the majority of the occupied time during the year. Calculations at concept design stage and scheme design stage need to be carried out for summer, winter and mid-season design conditions, to prove that the design will operate satisfactorily throughout the year. Figure 1: The interdependencies between the elements that are covered in BB1014 Air quality Good air quality is an essential element of the BB101 guidelines. It is evaluated by measuring CO2 levels and delivered through appropriate natural, hybrid or mechanical ventilation. Air pollution can originate from inside the room, such as from furniture or occupants, or externally. In recent years there has been a heightened focus on external pollutants near schools and classrooms, such as traffic9 or industry, and the effect it can have on schoolchildrens health. BB101 has set the following performance standards for teaching and learning spaces: 1. Where mechanical ventilation is used, or 48 December 2018 www.cibsejournal.com CIBSE Dec18 pp47-50 CPD138 v2.indd 48 23/11/2018 16:15