Criterion 3, the threshold or limit temperature sets a limit beyond which normal adaptive actions will be insufficient to restore personal comfort and the vast majority of occupants will complain of being hot’. This criterion covers ‘too the extremes of hot weather conditions and future climate scenarios. These criteria should be the basis of the thermal modelling of the building, with Criterion 1 defining the minimum requirement for assessing the risk of overheating of School designs. In addition, the asymmetric radiation from hot ceilings in single storey teaching spaces shall be less than 5K in summertime. In order to achieve this hot air must not be trapped at ceiling level and there must be an adequate means to extract hot air from the ceiling zone. For example, cross ventilation can provide adequate airflow across the ceiling and prevent a layer of hot air from building up beneath the ceiling. after consideration of such measures and taking account of other factors that could restrict the use of natural ventilation (e.g. air pollution, traffic noise) the designer deems that the heat load is such that cooling is required, the designer should consider low carbon cooling systems in preference to conventional air conditioning. Such systems could include using cool water from boreholes or drawing in air through earth tubes. Schools be designed without the use mechanical cooling in general teaching spaces. The spaces shall be designed to accommodate ICT equipment heat gains of up to 15W/m² in classrooms, or 25W/m² in practical spaces without the use of mechanical cooling. Practical spaces are generally larger and have a lower occupancy gain per square metre than general teaching spaces which helps to compensate for a higher equipment heat gain. Where the Contractor decides to use of mechanical cooling, for example at times of peak summertime temperatures in areas of particularly high equipment heat load, this shall be justified on heat load and energy efficiency grounds and agreed with the Employer. For example, in teaching spaces where the heat gains exceed 25W/m2 mechanical cooling may be considered. See Section 11.7 for further details on the calculation of internal heat gains. Assessment of Performance in Use Air temperatures rather than operative temperatures shall be used when communicating with the School and to assess thermal comfort in buildings in use, as these are easier for the occupants and the facilities management team to understand. If there appears to be a failure using the criteria based on air
Criterion 3, the threshold or limit temperature sets a limit beyond which normal adaptive actions will be insufficient to restore personal comfort and the vast majority of occupants will complain of being ‘too hot’. This criterion covers the extremes of hot weather conditions and future climate scenarios. These criteria should be the basis of the thermal modelling of the building, with Criterion 1 defining the minimum requirement for assessing the risk of overheating of School designs. In addition, the asymmetric radiation from hot ceilings in single storey teaching spaces shall be less than 5K in summertime. In order to achieve this hot air must not be trapped at ceiling level and there must be an adequate means to extract hot air from the ceiling zone. For example, cross ventilation can provide adequate airflow across the ceiling and prevent a layer of hot air from building up beneath the ceiling. after consideration of such measures and taking account of other factors that could restrict the use of natural ventilation (e.g. air pollution, traffic noise) the designer deems that the heat load is such that cooling is required, the designer should consider low carbon cooling systems in preference to conventional air conditioning. Such systems could include using cool water from boreholes or drawing in air through earth tubes. Schools be designed without the use mechanical cooling in general teaching spaces. The spaces shall be designed to accommodate ICT equipment heat gains of up to 15W/m² in classrooms, or 25W/m² in practical spaces without the use of mechanical cooling. Practical spaces are generally larger and have a lower occupancy gain per square metre than general teaching spaces which helps to compensate for a higher equipment heat gain. Where the Contractor decides to use of mechanical cooling, for example at times of peak summertime temperatures in areas of particularly high equipment heat load, this shall be justified on heat load and energy efficiency grounds and agreed with the Employer. For example, in teaching spaces where the heat gains exceed 25W/m2 mechanical cooling may be considered. See Section 11.7 for further details on the calculation of internal heat gains. Assessment of Performance in Use Air temperatures rather than operative temperatures shall be used when communicating with the School and to assess thermal comfort in buildings in use, as these are easier for the occupants and the facilities management team to understand. If there appears to be a failure using the criteria based on air
Annex_2F_Mechanical_Services_and_PHE__Technical_Annex_.docx