Rules for design success in sustainable schools

Keeping a few key issues in mind can deliver comfortable and sustainable schools while making sure you are in tune with the latest thinking on effective design.

There might be billions of pounds pouring into rebuilding and refurbishing our schools through Building Schools for the Future and the Primary Capital Programme, but remembering a few simple rules will ensure designers and contractors really do deliver a legacy we can be proud of in the coming decades. We spoke to Hampshire County Council's senior mechanical design engineer Neil Boardman about the rules which he feels deliver effective and sustainable schools.

Rule One -  Involvement at an early stage

Understanding the building form and working closely with the project team to provide advice on passive features and how to extract the best performance from them is essential. Early engineering input for a project is now considered the norm. Wherever possible ensure passive features are working for you. Get the orientation, facade, thermal weight, availability of natural daylight and ventilation strategy working as effectively as possible and then you can begin to reduce the reliance on mechanical systems.

Rule Two - Keep It Simple

Do not overburden primary schools with highly complex services that will never be understood by the staff and will be difficult to operate and maintain. Recent studies have found little difference in energy consumption between schools dating back to the Victorian era and modern so called 'low energy' primary schools. Occupancy can often be considered intermittent which may limit servicing options. This means you need to carefully think about issues, for example, would biomass boilers and under floor heating really be ideal for a small primary school? 
 

Rule Three - Streamline

Reduce loads down as much as possible before turning to renewable options. Some renewables such as biomass, which in practical terms may not be practical for a primary school, are too often used as a get out of jail card without first homing in on reducing loads.
With considerable fresh air ventilation demand in schools, the natural versus mechanical debate is a valid one. However, where good potential for natural ventilation is available, this should be the default option. When carefully considered with other factors natural ventilation (with mechanical back up if necessary) should serve the needs of IT spaces without recourse to mechanical cooling.
Reducing the risk of summer time overheating should also be given priority, this is particularly important with refurbishments where older buildings were not designed with this criterion in mind and suffer accordingly. Building Regulations (BB101) says there should be no more than 120 hours when the air temperature in a classroom rises above 28 deg C, but you should aim for less than 60 hours. With the right approach, this can be achieved with natural ventilated passive buildings.

Rule Four - Renewables

Do not treat the application of renewables as a quick fix option when the building thermal performance is inherently poor. Embodied energy should also be considered when investigating renewables. Ensure they are separately metered so their contribution can be accurately assessed. Ensure the buildings and its systems are as efficient as possible before considering renewables. Taking high efficiency condensing boilers and ventilation heat recovery as standard practice these days, the following additional types of measures should also be adopted:
쳌œ Control of artificial lighting to natural daylight levels
쳌œ Fresh air and occupancy demand driven ventilation (for both mechanical and natural)
쳌œ Use of Variable Speed Drive's for pumps and fans
쳌œ Sub metering for a breakdown in energy use. This should include heating, hot water, catering, lighting and small power.

Rule Five - Operation and Management

We design our schools and then have to operate and maintain them for the next 25 years. Services must be accessible and plant properly labelled. How often do we see the commissioning period of a project squeezed? Ideally contracts should allow for a revisit to recommission under full load. Demonstration to the staff is also essential.

Rule Six - Continuing Involvement

Provide good, relevant, accurate, yet simple and effective site documentation which suits the needs of the intended reader. These are basic issues, yet the standard of information the user is expected to operate the building with is sadly shockingly poor. Clear instructions in the form of a single laminated dummies guide sheet are often a god send to staff.
Demonstration to the relevant staff at handover and then again 6 or 12 months afterwards is essential for the staff to gain trust in the building ' s operation. The BSRIA  'Soft  Landings'  scheme should be seriously considered.

More information

Hampshire County Council is at the forefront of good practice in relation to the built environment and was a pathfinder project for the Primary Capital Programme. In this role it has been used as a Case Study by the Department for Children, Schools and Family to highlight effective procurement and delivery strategies. Its Engineering Services Unit (ESU) is a multi-disciplinary engineering team working within the Property Business and Regulatory Services department  and the unit's 50 staff provide mechanical, electrical and structural design for new build and refurbishment projects. The team also manages planned and reactive maintenance for a wide portfolio of existing county council buildings within Hampshire - including 500 schools. www.hants.gov.uk