CHRISTS COLLEGE GUILDFORD AT3.1 CASE STUDY
Andrew Bates
PROJECT OVERVIEW
Christ's College Guildford was built to replace a failing 1960s secondary school - it aims to reconnect the local community through a new public route. The brick exterior is punctuated with windows set deep into the façade, and houses an innovative ‘breathing wall' system providing each classroom with sustainable heating and ventilation through the perforated brick skin. Staff, pupils and visitors enter into a lightfilled, three-story atrium clad in timber that radiates a generous theatricality, the focal point within a compact building footprint.
Architects DSDHALocation Guildford, UK Floor area 7,350m2 Cost £14.4 millionStart on site June 2007Contract duration 20 monthsForm of contract Design and buildTotal cost £14.4 millionCost per m² £1,960Client Diocese of Guildford, Christ’s College, Surrey County CouncilStructural engineer Adams Kara TaylorM&E consultant/lighting design Atelier TenQuantity surveyor/project manager/CDM coordinator Davis Langdon Landscape design Townshend Landscape ArchitectsMain contractor Wates ConstructionAnnual CO2 emissions 24.17kg/m2
PROJECT OVERVIEW Exterior
Interior
MATERIALS, STRUCTURES & CONSTRUCTION > BRICKWORK Brick Work
Outer Leaf Support Details
290/90/50 mm Cottbus Bricks, pigmented mortar joints, stainless-steel anchors
Facing masonry
Load bearing leaf
This joint is sealed with permanently elastic sealant
Strips for distributing load Joint sealed Additional thermal insulation if required Continuous stainless steel angle support Joint sealed
Stretcher Bond - quarter brick overlap-
This buildings formation is made of a stretcher bond. It is simple formation, you can use a variety of compositions with this formation using different shades of brick Christ's College kept the brick work simple so that the architecture is viewed as a whole Movement joint
Outer Leaf Support Details
The details show how the brick anchors to the block work by stainless-steel anchors Using a metal anchor as a support creates continuous thermal bridging which means additional heat loss of 0.15 W/mk.
Stainless-steel anchors
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structural system – concrete frame
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structural system – concrete frame
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM > live loads
Live loads – people and furniture. Dead Loads – Weight of Structure Loads transferred across concrete floor plates and down concrete columns and dispersed to the ground through foundations.
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM > dead loads
Live loads – people and furniture. Dead Loads – Weight of Structure Loads transferred across concrete floor plates and down concrete columns and dispersed to the ground through foundations.
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary Structure Axonometric showing reinforced concrete strip foundations 1000 x 1000mm
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structure In-situ reinforced concrete floor slab is cast on top of the strip foundations 320mm thick with a 150x150mm kicker up stand.
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structure In-situ reinforced concrete columns are cast on top of the ground floor slab 200x800mm
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structure Insitu reinforced concrete floor slab is cast on top of the ground floor columns 320mm thick with a 150x150mm kicker up stand.
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structure In-situ reinforced concrete columns are cast on top of the 1st floor slab 200x800mm
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structure Insitu reinforced concrete floor slab is cast on top of the 1st floor columns 320mm thick with a 150x150mm kicker up stand.
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary structure In-situ reinforced concrete columns are cast on top of the 2nd floor slab 200x800mm
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Primary roof structure Insitu reinforced concrete roof slab is cast on top of the 2ndst floor columns 100mm thick with a 200x200mm kicker up stand.
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Bracing system Internal block walls 140mm thermal block work are built as each floor cast.
MATERIALS, STRUCTURES & CONSTRUCTION > STRUCTURAL SYSTEM
Bracing system Cladding 290 x 90 x 50mm Cottbus bricks, pigmented mortar joints, 50mm ventilation cavity, 60mm phenolic foam thermal insulation, 200 x 800mm concrete column, block work infill.
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
Foundations: In-situ reinforced concrete strip foundations 1000 x 1000mm
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
Primary structure In-situ reinforced concrete floor slab is cast on top of the strip foundations 320mm thick with a 150x150mm kicker up stand.
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
Primary structure In-situ reinforced concrete columns are cast on top of the ground floor slab 200x800mm
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
Secondary structure Internal block walls 140mm thermal block work are built as each floor cast.
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
MATERIALS, STRUCTURES & CONSTRUCTION > CONSTRUCTION SEQUENCE
Cladding 290 x 90 x 50mm Cottbus bricks, pigmented mortar joints, 50mm ventilation cavity, 60mm phenolic foam thermal insulation, 200 x 800mm concrete column, block work infill.
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > External Window 4 8 7
1. 290/90/50mm Cottbus bricks with pigmented mortar joints. 2. stainless steel anchors 3. 50mm ventilation cavity 4. 1mm DPM with 60mm phenolic foam thermal insulation 5. 200/800 reinforced concrete column 6. 2mm aluminium cladding of internal lintel 7. Fixed glazing: 6mm toughened glass + 16mm cavity or 20mm argon filled + 6.4mm solar control laminated safety glass in aluminium profiles 8. 2mm aluminium on 18mm plywood sill 9. Seal: PVC channel with rigid foam core
1
6 2 3 5
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > external window
1
7
1. 290/90/50mm Cottbus bricks with pigmented mortar joints. 2. stainless steel anchors 3. 50mm ventilation cavity 4. 1mm DPM with 60mm phenolic foam thermal insulation 5. 200/800 reinforced concrete column 6. 2mm aluminium cladding of internal lintel 7. Fixed glazing: 6mm toughened glass + 16mm cavity or 20mm argon filled + 6.4mm solar control laminated safety glass in aluminium profiles 8. 2mm aluminium on 18mm plywood sill
6 8 2 4 5 3
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > internal window
5
1. 50/18mm wood boarding, 2. Fire-resistant 50/50mm squared timber, 3. painted 25mm acoustic insulation
4
4. 18mm plywood, painted black 5. Fixed glazing to adjoining rooms: 5mm toughened glass + 12mm cavity + 6.4mm laminated safety glass
2 3
1
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > internal window
5
1. 50/18mm wood boarding, 2. Fire-resistant 50/50mm squared timber, 3. painted 25mm acoustic insulation
4
4. 18mm plywood, painted black
2
5. Fixed glazing to adjoining rooms: 5mm toughened glass + 12mm cavity + 6.4mm laminated safety glass
3 1
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > suspended ceiling
1. 2. 3. 4. 5. 6.
7.
50/18mm wood boarding, fire-resistant 50/50mm squared timber, painted 25mm acoustic insulation, 2x 12.5mm plasterboard, as base for stretch ceiling, painted black 18mm plywood, painted black Fixed glazing to adjoining rooms: 5mm toughened glass + 12mm cavity + 6.4mm laminated safety glass Cable channel in fastening rail
7
4
5
6
3
1
2
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > suspended ceiling
7
1. 2. 3. 4. 5. 6.
7.
50/18mm wood boarding, fire-resistant 50/50mm squared timber, painted 25mm acoustic insulation, 2x 12.5mm plasterboard, as base for stretch ceiling, painted black 18mm plywood, painted black Fixed glazing to adjoining rooms: 5mm toughened glass + 12mm cavity + 6.4mm laminated safety glass Cable channel in fastening rail
4
5
6
3
1
2
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > roof and skylight
1 1.
Skylight: 6mm toughened glass + 16mm argon filled cavity + 6.4mm laminated safety glass Uvalue = 1.3W/m2k
2.
Powder coated aluminum sandwiching 50mm insulation, operated by control motor 1mm DPC 200mm of insulation covered in waterproof resin, 2mm aluninium cladding 200mm concrete slab inset structural I Beam system 50/18mm wood boarding, fire-resistant 50/50mm squared timber,
3. 4. 5. 6. 7. 8.
2
6 5 4 3 8 7
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > roof and skylight
1 1.
2. 3. 4. 5. 6. 7. 8.
Skylight: 6mm toughened glass + 16mm argon filled cavity + 6.4mm laminated safety glass Uvalue = 1.3W/m2k Powder coated aluminum sandwiching 50mm insulation, operated by control motor 1mm DPC 200mm of insulation covered in waterproof resin, 2mm aluninium cladding 200mm concrete slab inset structural I Beam system 50/18mm wood boarding, fire-resistant 50/50mm squared timber,
2
6 5
8
4
7
3
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > floor to wall
8 1. 2. 3. 4.
Reinforced concrete foundations 300mm concrete floor slab DPC 1mm 60mm phenolic thermal foam insulation 5. DPM 1mm, 6. 100mm screed floor finish, 7. 290/90/50mm Cottbus bricks with pigmented mortar joints 8. 50mm ventilation cavity 9. 60mm phenolic foam thermal insulation 10.Block work infill 11. 20/15mm timber batons 12.2 x 12.5mm plasterboard
7 9 5 3 2
1
11 10 12 6 4
MATERIALS, STRUCTURES & CONSTRUCTION > DETAILED DESIGN > floor to wall
9 1. 2. 3. 4.
Reinforced concrete foundations 300mm concrete floor slab DPC 1mm 60mm phenolic thermal foam insulation 5. DPM 1mm, 6. 100mm screed floor finish, 7. 290/90/50mm Cottbus bricks with pigmented mortar joints 8. 50mm ventilation cavity 9. 60mm phenolic foam thermal insulation 10.Block work infill 11. 20/15mm timber batons 12.2 x 12.5mm plasterboard
12 8
11 10
7 5
6
3 2 1
4
MATERIALS, STRUCTURES & CONSTRUCTION > FIRE STRATEGY > means of escape Ground floor
MATERIALS, STRUCTURES & CONSTRUCTION > FIRE STRATEGY > travel distances
This diagram shows the regulations for travel distances in buildings other than dwelling houses as set out by Part B - fire safety.
MATERIALS, STRUCTURES & CONSTRUCTION > FIRE STRATEGY > travel distances
MATERIALS, STRUCTURES & CONSTRUCTION > FIRE STRATEGY > compartment zones Ground floor
MATERIALS, STRUCTURES & CONSTRUCTION > FIRE STRATEGY > compartment zones First and Second floors
MATERIALS, STRUCTURES & CONSTRUCTION > FIRE STRATEGY > escape cores
MATERIALS, STRUCTURES & CONSTRUCTION > FIRE STRATEGY > protected corridors First and Second floors
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > solar shading Spring Equinox This shows the range of shadows produced throughout March 22nd 08.00 – 17.00 The Sports Hall has been designed with limited amount of glazing on the north side. This could be because a sports hall does not necessarily need direct sunlight and can function with artificial lighting.
Time
Angle
08.00
18°
12.00
39°
17.00
11°
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > solar shading Summer Solstice This shows the range of shadows produced throughout June 22nd 08.00 – 17.00 During June The South East and West facade of the Christ’s College gains a lot of natural light. This most likely influenced the design because all of the education rooms which would benefit from natural light are positioned along these two facades.
Time
Angle
08.00
38°
12.00
60°
17.00
30°
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > solar shading Autumn Equinox
This shows the range of shadows
produced throughout September 22nd 08.00 – 17.00 The North East Facade of the Building has a lot of glazing which allows north light to enter the building, however this is also a disadvantage because the vast amount glazing lets heat escape from the building.
Time
Angle
08.00
20°
12.00
39°
17.00
9°
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > solar shading Winter Solstice This shows the range of shadows produced throughout December 22nd 08.00 – 17.00 In December the group teaching space is slightly over shadowed but this should not cause any major effects to the way this building functions.
Time
Angle
08.00
0°
12.00
15°
17.00
0°
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > annual prevailing wind speed
On average the fastest wind speed throughout the year is 50Km/h from the North-East. Over the year the most common direction and wind speed is from the North-East at 10/15 Km/h for over 606 hours.
Wind flow and speed play a key role in the design of Christ’s College because of the ventilation system that is implemented into the brick facade.
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > wind speed
Ground Level
At ground level the surrounding buildings significantly reduce the wind force on the Christ’s College, creating a pleasant atmosphere for the buildings entrance.
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATION > wind speed
3 metres above ground level
At 3 Metres above the ground the South-West facade is protected whereas the South-East has very little protection, Which will aid will natural ventilation.
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > wind speed
6 metres above ground level
At 6 Metres above the ground wind speeds increase dramatically and only the South-West facade and playing fields are protected.
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > wind speed
9 metres above ground level
At 9 Metres above the ground none of the surrounding buildings offer any wind protection at all. This dramatically increases how effective the natural ventilation system works
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > wind speed
12 metres above ground level
At 12 Metres above ground the Christ’s College sloped skylights deflect the wind and therefore alters the speed of the wind slightly.
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > wind flow
The Entrance to the Christ’s College is slightly protected from high pressured wind flow because of the overhang. Due to the shape and design of the building, the playing fields to the south of the building experience negative wind pressure.
ENVIRONMENTAL SYSTEMS > SITE CONSIDERATIONS > sky lights The skylights allow natural daylight in throughout the year, and also deflect the prevailing winds.
Summer – sun is higher in the sky
Winter – sun is lower in the sky
ENVIRONMENTAL SYSTEMS > PROGRAM The general requirements for the building are heating, lighting and ventilation. The heating and ventilation systems are integrating making this the first public building in England to combine heart recovery and mechanical ventilation.
The spaces that are not around the edge of the school mainly the triple height atrium, and the double height theatre have fresh air provided via a ducting system, entering the space through horizontal slats at first floor height. This provides enough air circulation for the whole space.
ENVIRONMENTAL SYSTEMS > PROGRAM > ground floor
ENVIRONMENTAL SYSTEMS > PROGRAM > 1st floor
NVIRONMENTAL SYSTEMS > PROGRAM > 2nd Floor
ENVIRONMENTAL SYSTEMS > DISTRIBUTION OF SERVICES
Plant room Toilets Waste pipe from building
Fresh water
ENVIRONMENTAL SYSTEMS > DISTRIBUTION OF SERVICES > ground floor
Plant room Toilets Fresh water Kitchen
ENVIRONMENTAL SYSTEMS > DISTRIBUTION OF SERVICES > 1st floor
Plant room Toilets Fresh water Kitchen
ENVIRONMENTAL SYSTEMS > DISTRIBUTION OF SERVICES > roof
Plant room Toilets Fresh water Kitchen
ENVIRONMENTAL SYSTEMS > HEATING, COOLING & VENTILATION Fresh air is delivered to each classroom via its own heat recovery and ventilation unit concealed in a cabinet under the windows. The unit contains two fans, one for supply and one for extract, and a heat exchanger. A damper cuts off the fresh air supply until the room comes to temperature, and the unit works in recirculation mode with and electric battery to heat the air – this means that there is no boiler or radiators in the building. The high thermal mass of the exposed concrete frame and floor slabs help to store heat and regulate temperature fluctuations. Once the room is occupied, the heat generated by the inhabitants is enough to maintain a constant temperature without the need for additional heating. A CO2 sensor on the unit monitors the air so that the CHRV unit only comes on when fresh air is needed.
ENVIRONMENTAL SYSTEMS > HEATING, COOLING & VENTILATION Heat Recovery Ventilation system This ventilation system employs a counter flow heat exchanger between the inbound and outbound air flow. The HRV system provide fresh air and improved climate control whilst saving energy by reducing the heating or cooling requirements. The thermal energy in the stale air discharged from the room, is used to heat fresh, clean outdoor air which is then supplied back into the rooms. The system ensures that the indoor air is refreshed and filtered – this means that up to 90% of the heat is preserved and waste energy is reduced.
ENVIRONMENTAL SYSTEMS > HEATING, COOLING & VENTILATION
CHRV system underneath the window heats the room to it’s optimum temperature, air is released through the skylights to keep a fresh flow.
ENVIRONMENTAL SYSTEMS > HEATING, COOLING & VENTILATION
Until the room comes up to temperature a damper cuts off the fresh supply and the unit works in recirculation mode with an electric heater battery to heat the air, so no boilers or radiators are needed.
ENVIRONMENTAL SYSTEMS > HEATING, COOLING & VENTILATION
A CO2 sensor on the units monitor the air so that the CHRV unit only comes on when fresh air is required
ENVIRONMENTAL SYSTEMS > HEATING, COOLING & VENTILATION
In the summer the systems provides secure night ventilation to cool the structure during the day .
ENVIRONMENTAL SYSTEMS > HEATING, COOLING & VENTILATION Fresh air is delivered to each classroom via its own heat recovery and ventilation unit concealed in a cabinet under the windows. The unit contains two fans, one for supply and one for extract and heat exchanger.
ENVIRONMENTAL SYSTEMS > LIGHTING
Large windows on northern, eastern and southern sides of the building, skylights and two atrium spaces create a mainly naturally lit building, with artificial lighting only used when necessary – a mixture of ceiling mounted strip lighting, pendent lighting & switched lighting sockets.
ENVIRONMENTAL SYSTEMS > LIGHTING > strip lighting
Low voltage energy efficient strip lighting are used in the classrooms as they shine bright white, creating good working conditions as there are fewer shadows. Although the classrooms are naturally lit, this is not sufficient to create a steady light. Although the strip lighting is described as energy efficient, the efficiency of tubes can vary widely, between about 15% and 60%. Commercial and public sector buildings account for 43% of the total electricity used for lighting. Energy lost though lighting - 6.06 kg/m2 per year
ENVIRONMENTAL SYSTEMS > LIGHTING > hanging lighting
The hanging lights are mainly used for the aesthetics of the atrium space. Even though energy efficient bulbs are used, as natural light should be sufficient in this space during the day this is wasted electricity.
ENVIRONMENTAL SYSTEMS > LIGHTING > sky lighting
The skylights perform two functions, they allow sun light to light the atrium space, and assist with ventilation. As natural light may not provide enough light for this space, pendant lights are also used increasing the school’s overall energy consumption.
ENVIRONMENTAL SYSTEMS > LIGHTING > large windows
Although having large windows on three sides of the building allow lots of natural daylight in, it also means that large amounts of energy are lost through the glazing. Energy savings by using double glazing than single glazing - 338 kWh per year
ENVIRONMENTAL SYSTEMS > SUSTAINABILITY Christ’s College is the is the first public structure in England to combine heat recovery and mechanical ventilation. Fresh air is delivered via heat recovery and ventilation unit under the windows. A damper cuts off the fresh air supply until the room comes to temperature, and the unit works in recirculation mode with and electric battery to heat the air – this means that there is no boiler or radiators in the building. The atrium in the centre of the building means that there is greater circulation of air throughout the building – as the ventilation and heating is linked, this means that more rooms will heated at once, using less energy The high thermal mass of the exposed concrete frame and floor slabs help to store heat and regulate temperature fluctuations. This building has a lot of windows – this maximises the use of natural daylight – reduces the need for artificial lighting.
ENVIRONMENTAL SYSTEMS > SUSTAINABILITY Energy conservation/generation/emissions Predicted annual CO2 emissions: 24.17 kg/m2
Although this is the first public structure in England to combine heat recovery and mechanical ventilation, this system relies on the use of battery heaters to bring the building up to temperature initially. The concrete frame provides large areas of high thermal mass. Although this is an integral part of the success of the CHRV system, the embodied carbon dioxide of one tone of concrete varies is in the range of 75 – 175 kg CO2/tone concrete, however the CO2 emission from the concrete production is around 900 kg of CO2 per tonne of concrete.
Waste recycling/ conservation of resources
Each classroom has a designated recycling area, this means that the school recycles most of the waste paper that is produces. - the kitchens also recycle as much waste as possible.
Site orientation – wind direction etc
Fresh air is delivered to each classroom via its own heat recovery and ventilation unit concealed in a cabinet under the windows. The unit contains two fans, one for supply and one for extract, and a heat exchanger. A damper cuts off the fresh air supply until the room comes to temperature, and the unit works in recirculation mode with and electric battery to heat the air – this means that there is no boiler or radiators in the building. The high thermal mass of the exposed concrete frame and floor slabs help to store heat and regulate temperature fluctuations. Once the room is occupied, the heat generated by the inhabitants is enough to maintain a constant temperature without the need for additional heating. A CO2 sensor on the unit monitors the air so that the CHRV unit only comes on when fresh air is needed.
ENVIRONMENTAL SYSTEMS > SUSTAINABILITY > user comfort and control systems The only painted surfaces in the building are the classrooms doors. Other than the art and science rooms which are larger and situated on the north of the building, the arrangement of the rooms could not be more adaptable - if a department expands or contracts all that is required is a repaint of the door.
Many of the internal openings in the Atrium remain unglazed, allowing the space to be monitored effectively by the staff. To allow for this, and fearful of the acoustic implications – this is where the pupils eat lunch - the atrium has highly effective acoustic insulation behind the softwood boarding.
ENVIRONMENTAL SYSTEMS > SUSTAINABILITY > lifespan and potential for recycling The main materials used in this building are concrete – frame and blockwork; brick cladding; softwood cladding; and glazing. Concrete frame– Life expectancy 80 years
Two major factors that determine the life span of concrete are the quality of the mix and the finishing techniques used on the surface. Smaller pieces of concrete are used as gravel for new construction projects. Crushed recycled concrete can also be used as the dry aggregate for brand new concrete if it is free of contaminants. Larger pieces of crushed concrete can be used for erosion control. Wire gabions(cages) are filled with the crushed concrete and stacked together to provide economical retaining walls.
Exterior brick cladding -
life expectancy 100+ years Both new brick that fails to meet the manufacturers' standards, and old unusable bricks can be easily recycled through an inexpensive crushing process. Crushed brick or "brick chips" may then be used as landscape material or reground to manufacture new, quality brick.
Block work – life expectancy
In a similar way to recycling brick, the concrete block work could be crushed and used as aggregate.
Timber cladding in the atrium –
life expectancy 90 years Reused for another structure or burnt for fuel
Window glazing -
life expectancy 20 - 50 years Glazing units could either be reused in another build, or recycled. The current problem with recycling window glass is that it represents a very small proportion of building materials and has a low commercial value. The separation and recycling process is labor intensive with makes it not commercially viable.
CONCLUSION The approach to the site has much room for argument in that there is no real consideration for sun paths, wind speeds and rain/snow fall. The ventilation system is the same on all sides of the building – it would be much more efficient if the system was to take into account the differentiation in wind conditions on the different faces of the building. However the orientation and organisation of the building is good, as it has a nice compact footprint. The simple structural system allows freedom in the planning, although the building is almost identical on each of the three floors.
This photo clearly shows that the roof lights are providing sufficient natural lighting for daytime use, and that the hanging lights are simply for decoration.
The use of low energy bulbs does not make up for the unnecessary amount of electric lighting in the atrium. Added to this fact , all of the energy used in the building is taken from the ‘grid’ – it would match its sustainability claims much more if the building was more self sufficient – for example there is a huge amount of biomass discarded from schools, this could be used to fuel the building?
Although this building has a high solar gain due to the large windows on the south, as it also has equally large windows on the east and north sides, there would be massive amounts of heat loss. If the windows, particularly on the north side were reduced in size, then the amount of heat lost in this way could be much reduced. The amount of open roof space could be better utilised, possibly for energy generation.
CONCLUSION Overall this building is a well designed school – it has been carefully thought about, particularly in the arrangement of the classrooms, for example, if a department expands or contracts all that is required is a repaint of the door, and the atrium space – where the pupils eat lunch is easily monitored effectively by the staff.
In terms of the structure of the building, the main core is made out of concrete - although this is a very durable material, meaning the building will have a longer life span and have large areas of high thermal mass, the CO2 emission from the concrete production is around 900 kg of CO2 per tonne of concrete. Although this is a concrete frame building, I do not think that it stores the heat as effectively as is claimed, as much of the concrete in the building is block work, with a much lower thermal mass than cast concrete. The brick cladding is a separate entity to the building, this should mean it would be easier to replace. The breathable facade would have been made with a sustainable material, not just a standard brick. The Heat Recovery Ventilation system is effective and efficient in circulating fresh air through the building, but as the systems needs electricity to power its two fans and the battery heater used to bring the building up to temperature, it would be much more efficient to have designed a passive ventilation system.
REFERENCES & BIBLIOGRAPHY Articles
“DSDHA school on the RIBA shortlist”BD Online, web source McGuirk,T. “RIBA Stirling prize 2010 - Christ's College Guildford”, pp46-52Architects Journal “College in Guildford”,pp480-485Detail, D2010-5
Books Pfeifer,G. Rumcker,R. Achtziger,J. Konrad,Z.,2001.Masonary Construction Manual.Detail. Germany:Birkhauser