The Pirbright Institute’s latest building is seeing John Sisk complete a transformation from drab post-war development into modern scientific campus.
Project: Pirbright Institute CL4 building
Client: Pirbright Institute
Contract value: £16.5m
Contract type: Design and build
Main contractor: John Sisk
M&E subcontractor: Hoare Lea
Structural engineer: Ramboll
Start date: April 2014
Completion date: October 2015
Happy scientists make productive scientists.
That is the design philosophy behind the redevelopment of the Pirbright Institute in Surrey, which aims to create a modern, campus-style environment to replace the rather tired post-war buildings that currently house its animal health research facilities (see masterplan).
The first phase of the redevelopment already presents a striking contrast to the rest of the site, with its timber cladding and multi-coloured window frames.
The first building in the second phase will also be high-impact.
However, the £16.5m facility is noticeably different from phase one, with a colonnade of brick piers on the eastern elevation, the entrance, and the colonnade effect continuing along the northern elevation.
“It is a very distinct design compared to the phase one building, and is intended to be so,” explains Denise Pate, senior project manager for Pirbright’s redevelopment programme.
“The building is smaller and has a lower containment level – CL2 as opposed to CL4 (the highest hazard rating) in the first phase.
“But it is an equally important building, so it needs to hold its own and not appear diminished alongside the CL4 building.”
The 3,700 sq m, two-storey building will house 90 scientists when complete.
The architect is NBBJ and John Sisk is main contractor, neither of whom worked on phase one.
“It is a very distinct design compared to the phase one building, and is intended to be so”
Denise Pate, Pirbright redevelopment programme
The building uses a pad footing and ground bearing slab for the foundations. The structure is a reinforced concrete frame, apart from the colonnade and the roof plant room, which are both structural steel.
The CL2 building has been designed to fit in with the aims of the wider site masterplan.
“The colonnade on the north elevation faces on to what eventually will become an Oxford-style ‘quad’, part of a ‘campus effect’,” explains NBBJ project leader Cheyenne Chong.
Deciding the entrance location was a key challenge.
“There will be considerable movement of people between this and the phase one building, so the entrance needed to face in that direction,” Ms Pate says.
“However, as that is the eastern side – or the back – of the building, we wanted the entrance design to draw people’s attention.”
“That’s where the colonnade design idea came from,” Mr Chong adds.
The rectangular-shaped piers in the colonnade are formed from structural steelwork that bolts into the main building structure.
“Each pier comprises two steel columns that are clad with bricks,” Mr Chong says.
The ‘Mystique’ bricks were sourced from the Netherlands, after tours of a couple of finished projects in central London.
“The light colour and texture fits with the palette of the overall scheme and the natural countryside surroundings,” Mr Chong says.
“Also, the mortar is lime, which gives a traditional look and is more sustainable.”
Internally, the floorplates have been designed cleverly.
The south side of the building will become an airy, open-plan office, and uses passive design to control the temperature.
The laboratory areas are on the northern side of the building, so there is no solar gain, but they face on to the ‘quad’ area and the rest of the campus.
“Biophilia was part of our thought process. It is the notion that people are happier and therefore more productive surrounded by nature”
Cheyenne Chong, NBBJ
The southern elevation faces the rolling Surrey countryside. A theme of the NBBJ design is to “harmonise with the local vernacular” as well as provide views for the scientists working inside the facility.
“Biophilia was part of our thought process,” Mr Chong explains. “It is the notion that people are happier and therefore more productive surrounded by nature.
“So as well as facing the countryside, the south side of the building has structural timber facade curtain walling – timber mullions made from American white oak – and to match it, a ‘feature wall’ made from the same timber on the internal wall opposite the facade. This also provides acoustic absorption.”
There is a brise soleil in the facade and the rest of the elevation is glazing interspersed with ceramic back-painted glazing panels, apart from a louvre which screens a freezer area on the ground floor.
The ceiling soffit in the open-plan office is exposed and painted to improve thermal mass properties.
The office area has a mixed-mode ventilation system. Windows auto open and shut, controlled by a BMS and sensors in each room. “We are taking advantage of the climate; that it’s non clinical space allows this approach,” Mr Chong says.
The labs area is split in half by a corridor running east-west. On the ‘quad’-facing side are larger, primary labs, which are “quite generic”, according to Mr Chong.
On the other side are smaller, secondary labs, which have more specific clinical needs, such as positions for incubators and fridges. Glazed doors and partitions on the corridor let in more natural light.
The laboratories are modular, which allows for reconfiguration with minimal disruption, should clinical requirements change.
“Senior management at Pirbright are keen on collaboration – they didn’t want staff closed off in boxes – but recognise that creating smaller or bigger workspaces may be necessary as science evolves,” Mr Chong explains.
M&E services between the labs run in the ceiling corridor and branch off into each lab. “They have been designed this way so that if a lab breaks down it can be shut down and repaired without other labs being affected,” Mr Chong says.
“The labs with higher containment levels use a lot energy – the fuel bill here runs to millions annually – so they will be designed to BREEAM Very Good (the level achieved by the first phase building)”
Denise Pate, The Pirbright Institute
The air supply runs under the floor – there is a 450-mm drop between the ground floor level and the ground bearing slab.
Construction of the CL2 building has been relatively straightforward, compared to the phase one building.
“We have a design-and-build contract, but the building was substantially designed,” explains John Sisk contract manager Niall Flynn. “However, we have needed to understand the design rationales and decisions.”
On the earlier project, leakage considerations shaped the build process, and penetrations had to be cast into precast concrete panels.
“The leakage tolerance level is lower here,” Mr Flynn says. “There needs to be inward airflow to the labs, and the containment of any virus is within microbiological safety cabinets, which delivers the required containment level for the building.”
However, the building is targeted with achieving a BREEAM Excellent 2010 rating, so the air-tightness level will still be high at 2.5 cu m/hour/sq m at 50 Pascals.
“This is the only building in the redevelopment programme that will achieve BREEAM Excellent, and it is possible because of the lower containment levels,” Ms Pate explains.
“The labs with higher containment levels use a lot energy – the fuel bill here runs to millions annually – so they will be designed to BREEAM Very Good (the level achieved by the first phase building).”
Other BREEAM features include 125 photovoltaic panels and an air source heat pump.
“The concrete has used GGBS (ground granulated blast-furnace slag) as cement replacement to boost credits,” Mr Flynn adds.
The project is scheduled to be completed in October 2015, the first of two buildings in the second phase of Pirbright’s redevelopment.
The Pirbright redevelopment masterplan
Pirbright was first used as a research site in 1914, testing cows for tuberculosis, with further development in the 1920s and during the post-war period.
In 1987, the site became the Institute for Animal Health, along with other facilities in Cambridgeshire and Berkshire, whose operations have subsequently moved to Pirbright. The facility has been known as the Pirbright Institute since 2012.
It is now undergoing a transformational redevelopment (see masterplan drawing), the value of which will run to hundreds of millions.
The new buildings are in stark contrast to the ageing facilities on the rest of the site, as the Institute is striving to create a ‘campus’ feel. The first phase, a containment level 4 building, was designed by architects HDR and constructed by Shepherd.
The £100m scheme was completed in 2014. It houses 150 scientists undertaking research on viruses such as foot-and-mouth, swine fever and avian influenza.
The first building in phase two, which has a relatively low containment level, will be finished later this year.
The second building of this phase, a biological resources facility, was awarded to Shepherd last year. This £70m development will be completed in 2018.
Pirbright awarded Client of the Year
The Pirbright Institute triumphed in the 2015 Construction News Awards Client of the Year category for its exceptional leadership in delivering the £135m Plowright Virology Centre project.
The job was delivered a week early and also produced significant savings, coming in around £1m under budget – highly unusual for such a facility.
The client surveyed its supply chain, asking for scorings on questions like whether it was supplying all the information that was needed and if it was paying on time.
The judges said it was an outstanding achievement from a standing start, showing true innovation delivered with a total passion and commitment.