Post-Occupancy Evaluation of a Primary School. Kate McCartney Atkins Energy Management. February 2004

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1 Post-Occupancy Evaluation of a Primary School Kate McCartney Atkins Energy Management February 24 WS Atkins Consultants Ltd. Chilbrook Oasis Business Park Eynsham Oxfordshire OX28 4AH Tel.: Fax: Kathryn.McCartney@atkinsglobal.com

2 INTRODUCTION As part of a contract with a local authority department, Atkins provides energy management services for all the client s buildings, mostly primary schools. In 2 Atkins launched an initiative to carry out post-occupancy evaluations of all the new schools Atkins had designed for the client. Three schools were evaluated as a pilot project and the results were used to develop a methodology for future post-occupancy evaluations. The results have also influences future decisions on primary school design. This report outlines the findings from School A, the first to be evaluated under this revised methodology, using the lessons learnt from the pilot schools. For confidentiality reasons, neither the school nor the client is identified. School A replaced an existing school on the same site and was completed in summer 22. The post-occupancy evaluation was carried out between autumn 22 and autumn 23. This report discusses: the methodology used; the results of the evaluation; the implications of the results, including a comparison with School B, one of the pilot schools. The conclusions include recommendations for further improvement of the methodology. METHODOLOGY The post-occupancy evaluation (POE) was carried out following the handover of the school. The approach was developed from our previous experience, together with the checklist from BRE s project on feedback in the first year of occupancy simplified to suit a primary school. Unfortunately, owing to staff changes, we lost the opportunity on this particular project to attend handover meetings or to give instruction to staff on using the building before they moved in (as in the Soft Landings approach). This will be incorporated in the future. The POE methodology focused on four main issues: Occupant feedback and satisfaction. Occupant training on building systems (to ensure correct and efficient operation). Monitoring the internal environment and energy performance. Reporting of any problems with the building and its systems to the design team. The school was visited every six to eight weeks. Each visit included: a meeting with the head teacher and the school caretaker to gauge general feedback and to ascertain any problems; a walkaround, including observation and where possible investigation of these problems; taking meter readings and downloading environmental dataloggers;

3 Details from each visit were noted on site meeting records which were circulated to the school, the client and the design team. At every second visit (approximately quarterly), an additional meeting was held with all staff of the school to gain general feedback on the school s performance. Twice per year (summer and winter) an occupant feedback questionnaire was issued to the staff. All feedback was again relayed to the client and the design team. Finally, a training programme was developed for the staff on the various environmental systems operating within the school. The training was carried out during the second POE visit. Follow-up sessions were arranged ad hoc for any new staff or in response to requests if a particular system needed additional explanation. The training was designed to be simple and non-technical, with the aim of ensuring that the school s environmental systems were operated for optimum performance. The methodology was developed from pilot POE studies of three earlier schools for the same client, which had proved to be relatively effective. The overall aim of the service was to ensure that the school was operating as intended and that the staff were satisfied, with the ultimate goal of ensuring reduced CO 2 emissions. RESULTS Energy Use The annual energy use per square metre of gross floor area for the year following handover was compared to: the annual energy use for the old school on the same site (School A(old)); one of the new schools surveyed in the pilot project (School B); the average energy use for schools in the local authority area; and good practice for primary schools in the UK. Figures to 3 below show the results for electricity use, fossil fuel use and CO 2 emissions respectively. The results show that whilst School A s fossil fuel consumption is in the good range and below the local authority average, its electricity consumption is in the typical range and higher that the LA average. However, the slightly older School B s electricity performance was in the poor range and reflects a tendency for newer schools to use more electricity owing to increased IT, more sophisticated controls, more evening use and so on. Further investigation is required. The overall CO 2 emissions are lower than both the average and School B: a positive result. School A and School B use gas as their primary fossil fuel. School A(old) used oil as its primary fossil fuel. CO 2 emissions have been calculated accordingly.

4 School A 34 School A(old) 22 School B 47 LA Average Good Practice 26 Good Typical Poor Annual Consumption (kwh/m2/year) Figure : Comparison of Annual Electricity Consumption School A School A(old) School B LA Average Good Practice Good Typical Poor Annual Consumption (kwh/m2/year) Figure 2: Comparison of Annual Fossil Fuel Consumption School A 38 Schhol A(old) 47 School B 44 LA Average 44 Good Practice Good Typical Poor Annual Consumption (kg CO2/m2/year) Figure 3: Comparison of Annual CO 2 Emissions

5 Use of Lighting Dataloggers were used to monitor daylight in the classrooms during a half-term week in winter, when daylight outside was close to its lowest and the need for electric lighting at its peak. The results, shown below in Figure 4, reveal that even in winter, daylight levels in the classrooms were above the CIBSE recommended 3 lux for the afternoon teaching period and so electric lighting should only be required outside this time. Figures 5 and 6 show the use of electric lighting over typical weeks in winter and summer respectively. Electric lighting is being used more than required, resulting in higher electricity consumption. In the summer period, the electric lights are used less, but still more than necessary. Daylight level (lux) :: 9:: :: :: 2:: 3:: 4:: 5:: 6:: 7:: 8:: Figure 4: Classroom Daylight Level (Winter) Monday 24 Feb 23 Tuesday 25 Feb 23 8:: 8:3: 9:: 9:3: :: :3: :: :3: 2:: 2:3: 3:: 3:3: 4:: 4:3: 5:: 5:3: 6:: 6:3: 7:: 7:3: 8:: 8:: 8:3: 9:: 9:3: :: :3: :: :3: 2:: 2:3: 3:: 3:3: 4:: 4:3: 5:: 5:3: 6:: 6:3: 7:: 7:3: 8:: Wednesday 26 Feb 23 Thursday 27 Feb 23 8:: 8:3: 9:: 9:3: :: :3: :: :3: 2:: 2:3: 3:: 3:3: 4:: 4:3: 5:: 5:3: 6:: 6:3: 7:: 7:3: 8:: 8:: 8:3: 9:: 9:3: :: :3: :: :3: 2:: 2:3: 3:: 3:3: 4:: 4:3: 5:: 5:3: 6:: 6:3: 7:: 7:3: 8:: Figure 5: Electric Lighting Use (Winter)

6 The lights are initially switched on by a normal switch, to a circuit which contains a presence detector. If this detector senses no movement within a specified time period, the lights go off automatically; but they come on again if new movement is subsequently detected. For the lights to stay off regardless, they need to be switched off manually. During the monitored period, the automatic lighting controls had not reduced the electricity consumption by as much as anticipated. Discussions with the staff and observation during site visits suggested that the occupants had become too reliant on the automatic controls. Since the controls ensure that the lights are turned off after the room is empty for a period, the staff tended not to bother to switch off on the way out. However, if not switched off manually, the lights come on again automatically when the next person comes in next morning, regardless of daylight level. Similarly, after the classroom has been vacated for a short period, e.g. for lunch, the lights will come on again as soon as someone enters, even only for a brief time. This helped to explain the high use of lighting on winter afternoons; while if the lights had had to be switched on manually after lunch they might well have stayed off until dusk. Monday 3 Jun 23 Tuesday Jul 23 8: 8:3 9: 9:3 : :3 : :3 2: 2:3 3: 3:3 4: 4:3 5: 5:3 6: 6:3 7: 7:3 8: 8: 8:3 9: 9:3 : :3 : :3 2: 2:3 3: 3:3 4: 4:3 5: 5:3 6: 6:3 7: 7:3 8: Wednesday 2 Jul 23 Thursday 3 Jul 23 8: 8:3 9: 9:3 : :3 : :3 2: 2:3 3: 3:3 4: 4:3 5: 5:3 6: 6:3 7: 7:3 8: 8: 8:3 9: 9:3 : :3 : :3 2: 2:3 3: 3:3 4: 4:3 5: 5:3 6: 6:3 7: 7:3 8: Figure 6: Electric Lighting Use (Summer) Occupant Satisfaction The pilot studies had recommended the use of a standard occupant survey technique (e.g. from the Feedback Portfolio) in order to produce reliable results and enable benchmark comparisons. However, the client preferred not to pay the associated licence and/or consultancy fees and decided use its own questionnaire. In the event, not enough staff responded to allow any meaningful analysis.

7 Comments made by the staff during visits were however noted. These highlighted a number of issues, mainly relating to poor temperature control; and these were reported to the design team. In some instances, the dissatisfaction with temperature was due to the staff misunderstanding the design philosophy and the various ventilation controls. In addition, the designers had not realised that many teachers prefer to keep their classroom doors open and had instead designed the system to work best when they were shut: this experience will be fed back into future projects. One area of the school, however, was found to have a problem with heat distribution as a result of using low surface temperature heat emitters, and the design team was able to put this right. It should be noted that merely undertaking a survey particularly by the design team - raises occupants expectations than something is going to happen. For an effective evaluation process, occupants must be kept informed and not be given false expectations. Although all of the issues reported were fed back to the design team, the team itself was by then doing other things and had not been given extra resources to deal with them. Hence many problems were either ignored or not dealt with quickly enough. This caused frustration amongst the building occupants, who became progressively less cooperative with the feedback process as the evaluation proceeded. DISCUSSION The new school uses less fossil fuel (gas) than its predecessor and has lower carbon dioxide emissions overall. On the other hand, while its electricity use is less than in some other new schools monitored, it is higher than in the old school and the average for the client s primary schools. Such increases are often attributed to greater IT provision in new schools, but requires deeper investigation, as other systems may also not be operating as efficiently as anticipated. For example, automatic lighting controls were provided to reduce the amount of electricity used, but the lighting analysis shows that the lights were on more than anticipated. As discussed above, staff seem to have become over-reliant on the new technology, leading to complacency and excess use. Extra staff training did take place later in the evaluation schedule to tell the staff about the importance of good lighting management, even with an automatic control system. New signs have now been placed on the light switches to encourage staff and pupils to be more vigilant; and the caretaker reported that this had been successful. For the future, it may be better to adapt the control system so that while the lights continue to switch off automatically when no-one is in the room, they do not come back on again unless a push button is pressed. This will help to ensure that lighting is used only when required. For future post-occupancy evaluations, the actual methodology should be revised to ensure that design team members have a clear reporting structure to let occupant complaints and queries be responded to quickly and effectively. Even if a problem cannot be solved, occupants will be much more sympathetic if they are kept informed.

8 CONCLUSIONS AND RECOMMENDATIONS The school is performing well from in terms of gas consumption and carbon dioxide emissions, but electricity consumption could be improved and this may be assisted by better lighting control. Further investigation of the electrical systems is also desirable as there may be other lessons for design, installation, commissioning, management and maintenance, or in relation to user behaviour. The school should be reviewed on an annual basis to ensure that good energy performance is maintained. An occupant satisfaction survey should also be conducted to ascertain the effect of any changes. Recommendations for future school designs: Continue undertaking the POEs, but with improved processes for handover and initial training of staff in the understanding and use of the systems. Specify semi-automatic lighting controls and encourage good lighting management Ensure heat emitters achieve appropriate heat distribution Have a clear framework for dealing with occupant complaints and queries and keeping the occupants informed on progress and results.