16 May 2002
All Saints West, Manchester Metropolitan University
All Saints West, a 5500 msq building for the department of Law at Manchester Metropolitan University designed by architect John McAslan Partners, has started on site. Multi-disciplinary consultancy provided by Buro Happold includes structural, building services, fire and façades engineering design, and computational simulation and analysis and BREEAM assessment. Shepherd Construction has been appointed this week as the main contractor.
The building, a stunning, high performance glass box situated next to halls of residence and at the back of an existing library, gave rise to complex and challenging design issues. As it is to be built near to a city centre motorway noise reduction is key. To provide a quiet academic internal environment the glazed façade will work very hard to achieve noise reduction on the north façade.
The mechanical and electrical vertical distribution risers have been consolidated into the western core. This provides a clearer space-planning layout on the eastern core and provides a direct riser link into the roof level plantrooms.
Façades
The aesthetic design of the glass elevation is the lead visual feature for the structure. External pressure caps are used to present a strong horizontal emphasis. The performance of the mainly glazed façade impacted on the sizing of the heating and cooling plant. Buro Happold’s glazing study identified acoustic, heat loss, solar gain and fire resistance issues for each individual façade element.
Structure
The building is a steel framed structure, with cellular composite steel beams and pre-cast concrete floors. The building has a suspended concrete ground floor slab, which is supported on concrete ground beams and piled foundations.
Due to the technical requirements of the façade and the architectural finishes, the structure has been designed to very stringent tolerances. Structural steelwork and concrete elements have been designed to align with the façade transoms to provide a flush finish to the internal elevations. Exposed structural steelwork is also used to manifest the architectural intent, in the atria and through the columns to the lecture theatre and seminar rooms.
The internal room heights have been maximised by restricting the depth of the structural floor and ceiling zone. This has been accomplished by integrating the mechanical and electrical distribution ductwork through holes in the steelwork beams.
The future flexibility of the building has been addressed by placing the structural columns at the extremities of the floor plates. This maximises the current floor plate layout and allows internal walls to be moved without any detrimental effects to the structure.
The structure has been fully co-ordinated with the architecture, the façade and the mechanical and electrical services to allow for seamless integration within this landmark building.
Ventilation
The building is to be mechanically ventilated. All fans on the air handling plant, located at roof level, have inverter drives to reduce energy consumption at times of low occupancy (inter semester weeks for example). The units include heat recovery via thermal wheels. Air handling units distribute air to and from each area via ductwork located in two main risers. The building is divided into six different ventilation zones, each served by a different air-handling unit. The zoning is arranged by grouping areas that have similar function and occupancy profiles together. The air handling units serve three different types of air distribution systems.
Ventilation to the large lecture theatres is provided via displacement diffusers positioned in the vertical step of the rake, with one diffuser per seat. The smaller lecture theatres have removable seating (for examination purposes). CFD analysis to an original proposal for displacement ventilation terminals along the front wall of the lecture theatre concluded that this would produce uncomfortable conditions on the front and back rows. A high level system has thus been adopted instead. Ventilation to seminar rooms and offices will be via ‘active’ chilled beams running parallel to the glazing, sized to accommodate cooling loads in each room.
Background ventilation to the foyer and general circulation spaces comes via jet nozzle type diffusers located at the bottom of the north side of the atrium.
Heating
Perimeter heating to all areas of full height glazing offsets the heat loss through the façade and prevents discomfort to occupants working in spaces next to the glazing. A perimeter heating system fits into the 100mm raised floor.
Chilled beams in the rooms overlooking the atrium will be fitted with heating coils. A chiller plant to serve the air handling units and the chilled beam systems will be located at roof level.
Lighting
The lighting design for the building and in particular the offices, lecture rooms and atrium developed from several daylight analysis simulations. The simulations provided detailed numerical analysis and photometrically accurate visualisations of the spaces within the building. With this input was provided to the architecture to improve / control the daylight within the spaces. Numerical analysis then allowed the level of automatic control required throughout the various spaces of the building to provide energy savings to be determined
Combined intelligent dimmable luminaries with a natural daylight occupancy controlled system and manual override switches will be provided for office areas. Lighting will be co-ordinated with the active chilled beams with direct/indirect lighting for areas with VDU usage.
The Atrium, with its barrel shaped lecture theatre, requires both working lighting and feature lighting. The working lighting will be metal halide flood lighting recessed into the spandrel panel detail aimed and controlled to provide an indirect light without glare to the ground floor. The metal halide indirect lighting will also provide a feature highlight on the barrel lecture theatre wall, which then diminishes as the angle of light becomes more acute to the lecture theatre wall. This will enhance the visual curve of the barrel. For the upper areas of the atrium 90 low power LED luminaires recessed into the spandrel panels will be installed to provide definition of the floor levels above the lecture theatre barrel. The use of low power LEDs ensures both feature lighting, which does not distract from the barrel feature lighting, and minimum maintenance for the high level mounted luminaires. Lecture theatre lighting will consist of fully recessed downlights and wall mounted luminaries dimmable to 5 lux, with a separate dimmer under the control of the lecturer.
Computational simulation and analysis
The building services design has been assisted by the computational analysis studies. The following analysis was carried out for this project: dynamic thermal modelling to optimise façade thermal and solar performance and investigate feasibility of natural ventilation/mixed mode operation; CFD study to investigate the effectiveness of ventilation strategy proposed; and system simulation to optimise plant component selection.
The intention of the design of the building was to allow for as much natural ventilation as possible. Thermal modelling work was conducted to demonstrate how to make it work for some areas of the building, including a comprehensive study of glazing types and shading devices in order to reduce solar gains to the building, particularly for the south façade. Due to the high internal load in most parts of the building and that most spaces are used for seminar/teaching purposes, a complete sealed façade has been adopted and the building is mechanically ventilated.
Computer analysis also demonstrated the energy benefit of using the chilled beam system as opposed to a fan coil system. The simulation of the system operation for a typical weather year gave a more realistic prediction of energy consumption of HVAC plant. It also helped the selection of chiller plant on the basis of annual energy consumption. It was concluded that a conventional high performance chiller is more appropriate than a free cooling range chiller for this type of application.
Electrical
Electrical supply to the building will be provided from a new substation with 20% spare capacity, installed under the Mancunian Way (the motorway that runs past the north side of the building), pending on highways agreement.
A standby generator capable of full site essential services electrical load such as fire fighting lift, fire alarm and security, with 25% spare capacity, will be located within the existing storage room in the All Saint West Building loading bay. The exhaust system will be routed in the loading bay to the external wall, and up the building to high level.
General power distribution will be via two vertical bus-bar trunkings located in the two risers at either side of the building. Local distribution boards on each floor will be fed from the bus-bar trunkings via fused tap-off units. Dedicated independent distribution boards for the communications room will be fed via the vertical bus-bar trunking from suitable tap-off units.
Power distribution within the teaching spaces will be from fully recessed wall mounted power outlets conveniently located to serve the rooms. Within the resources room, IT drop in centres, lecture theatres and general offices, the small power distribution will be from flush mounted floor boxes (100mm floor void) fed via under floor bus-bar trunking and flexible conduits.
A fully automatic analogue addressable fire alarm and detection system will give full coverage throughout the premises. A colour, high-resolution CCTV installation will be provided for the 24 hour monitoring of the building periphery and other areas such as access, entrance, and lifts. Super VHS recorders and monitors and multiplex units will be provided for strategic locations for monitoring and recording the CCTV pictures. The CCTV system will be linked to the existing MMU monitoring and recording stations, at All Saints building and Cambridge hall control centres.
The building will be equipped with a fully addressable security system, monitoring doors, windows, spaces and controlling access to specified building areas. The system will be capable of interfacing with the CCTV surveillance systems. An integrated swipe card networked access control system will cover key internal and external doors.
Telecommunication containment and wiring for the voice and data networks will be Category 5E foil, shielded twisted pair data grade premises cable. All cabling will be terminated in RJ45 outlets for voice and data systems.
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Buro Happold is a multi-disciplinary international practice of consulting engineers established in 1976 offering civil and structural engineering, mechanical and electrical engineering, quantity surveying, building services and environmental engineering, infrastructure and traffic engineering, geotechnical engineering, façade engineering, fire engineering, computational fluid dynamics analysis, access consultancy, project management, urban design and a range of specialist CAD services.
