, "3":"Case study everyman theatre, liverpool leading man Four ventilation chimneys named John, Paul, George and Ringo are central to the environmental strategy at the Everyman Theatre in Liverpool, which wowed critics at the Stirling Prize. Andy Pearson reports from the front row T he judges citation for the winner of this years RIBA Stirling prize makes clear that Waterman Building Services low energy servicing strategy as much as Haworth Tompkins striking architecture was the reason for their decision to award the best building of the year prize to the Everyman Theatre, in Liverpool. They praised its naturally ventilated auditoria, applauded the use of concrete labyrinths to supply and expel air, and described the design as exceptionally sustainable. The judges comments should come as no surprise to the design team; from the outset, sustainability was integral to the concept of the new building. The original Everyman Theatre opened in 1964, converted from the shell of a 19thcentury chapel. Over time, however, the fabric of this much-loved institution deteriorated badly, while the increasing needs of its users meant the space was no longer viable. Originally, the plan was to build a larger theatre on a new site, but Haworth Tompkins argued successfully for maintaining an important sense of continuity by reusing the existing, Figure 1: Keeping the audience cool KEY 1 Intake plenum taking air from outside and cooling by thermal mass within plenum in summer, heating in winter 2 Air enters auditorium beneath stalls and circle seating 3 Incoming air warmed by occupants 4 Air further warmed by lighting, helping to drive buoyancy 5 Acoustic exhaust plenum 6 Exhaust plenum 7 Warm air exhaust via chimney louvres 7 Everyman Theatres auditorium ventilation system Click to enlarge image 6 5 4 3 2 1 worn, cosy ambience, the reclaimed bricks add thermal mass to the space, as part of the theatres ventilation strategy. The client wanted a very, very sustainable, low energy theatre, so natural ventilation was seen as the obvious solution, says Jonathan Purcell, director of building services for Watermans, who was charged with developing the ventilation solution for the windowless, artificial environment of the theatres auditorium. We had to find a way to ventilate what is essentially a black box. The auditorium is lined with 25,000 red bricks, reclaimed from the old theatre, that add to the spaces thermal mass Low ImPACT CoNSTruCTIoN Below 21C, the AHU heating is on Between 21C and 24C, the actuator behind the intake louvres gradually opens to increase the ventilation rate At temperatures above 24C, the AHU fan will start to boost the ventilation rate Should the temperature rise above 26C, the auditorium will switch to mechanical cooling, closing the fresh air louvres and running the heat The attention-grabbing west faade is formed from 105 movable, aluminium sunshades. These are set in three rows, running the length of the elevation, and each one features a life-size portrait of a contemporary Liverpool resident, cut out of the metal sheet. In contrast, the restrained red brick of the north, east and south elevations help the building sit comfortably with its listed neighbours. That same red brick is also used to form the four giant chimneys, which are a key component of the auditoriums natural ventilation system. The 400 seat auditorium is at the heart of the 4,690m2 building, literally and metaphorically. It has been designed to accommodate a thrust stage (one that extends into the audience), which is encompassed on three sides by seating to recreate the intimacy of the old Everyman Theatre. This familiarity is enhanced by the use of reclaimed bricks from the original theatre, which are exposed in the new auditoriums walls. As well as giving the auditorium a compact, Hope Street site. To accommodate the new building on an area of just 1,610m2, the shell of the existing structure was carefully dismantled to allow most of the chapels bricks to be salvaged for use in the theatres reincarnation. Haworth Tompkins designed the new Everyman Theatre to derive as much functionality from the building as possible, while incorporating the best-loved features of its predecessor all within a similar volume. The outcome is that the buildings public spaces including the foyer and bars have been arranged in a series of half-level floors, set around the perimeter, to create what the architect describes as a continuous winding promenade, from street to auditorium. In addition to the main auditorium and the catering spaces, Haworth Tompkins has also managed to slot in numerous creative spaces, including a rehearsal room, workshops, an audiovisual studio, a writers room, and a community studio. Externally, the most striking architectural features are the theatres main, west-facing elevation, and four, giant, cylindrical chimneys, perched on the roof. Cooling the stalls The design teams aim with the auditorium ventilation strategy was, according to Purcell, to provide a nice, clean, swept path for the air to enter the space at low level, then meet very little resistance as it is allowed to rise from low level to high level in the auditorium; and, finally, to provide a simple route out through the roof-top chimneys. As a result, fresh air enters the building through an inlet louvre on Arad Street, a quiet road at the rear of the building. It then passes through acoustic attenuators and into a giant, concreteencased plenum, constructed beneath the workshop area behind the theatres stage. eor Rmade ProJeCT TeAm AND CoSTS BreeAm DATA [taken from Haworth Tompkins BREEAM case study] Predicted electricity consumption: 86.76KWh/m2 Predicted fossil fuel consumption: 186.51 KWh/m2 Predicted energy generation by CHP: 29.18 KWh/m2 Predicted percentage of WC water use provided by rainwater collection: 45% Fresh air enters the theatre through an inlet louvre at the rear of the building The theatres public spaces are arranged in a series of half-level floors The brise soleil panels provide shading to the cafe and box office areas Weve got a massive cavern of concrete in contact with the ground, which we use to cool the supply air in summer before it enters the auditorium, Purcell explains. From here, the air passes beneath the stage, through secondary attenuators, and into a horseshoe-shaped plenum beneath the banked rows of seating lining the auditorium walls. The fresh air finally enters the auditorium through a series of perforated grilles beneath the seating. Heat given off by the audience, and from the theatre lighting, increases the buoyancy of the air, causing it to rise upwards through the lighting gantries to an acoustically attenuated 2.5m-high exhaust air plenum. A giant duct, which doubles back on itself, then delivers the air from the plenum to the four louvred chimneys nicknamed John, Paul, George and Ringo by the design team where it is exhausted (see Figure 1, cross-section drawing). For the system to work effectively, Watermans had to generate enough buoyancy to drive a sufficient quantity of air through the auditorium to keep conditions comfortable for the audience. The air inlet size and location was set its dimensions defined by the street, basement and ground-floor slab levels. Building Regulations requirements for fresh air of 10 litres per second per person for a capacity audience of 450 people, plus 40 staff and actors, set the minimum quantity of supply air at 5m3/s. As a result, the only variable open eade Rmor BreeAm DATA Figure 2 Cross-section of rehearsal spaces and foyer, showing environmental strategy to Watermans in developing the auditorium ventilation solution was to adapt the height and diameter of the four chimneys, to produce a solution capable of maintaining excellent air quality and of dissipating heat gains from the space. Lighting is the biggest heat source within the auditorium. The stage has 140kW of lighting installed, of which approximately 65kW will be on at any one time during a production. Occupants and other heat sources contribute another 50kW of heat. We did a huge amount of modelling work to establish the size, open area, and height needed between the inlet Last year was the warmest on record, and the theatre operated all year on full natural ventilation, without need to resort to cooling, even during a Saturday matinee Jonathan Purcell and tops of the chimneys to drive the stack effect to pull air through the auditorium, explains Purcell. Fortunately for the design team, these early modelling studies showed that the fresh air requirement of 5m3/s would be sufficient to flush the 115kW heat gains eor Rmade Low ImPACT CoNSTruCTIoN from the auditorium. Thermal dynamic simulation modelling was used during the design development to assess conditions inside the auditorium throughout the year. The cooling solution was modelled between the months of May and September to see where the temperature peaks were occurring. Once we found this out, we used computational fluid dynamics (CFD) to model the space at these particular moments in time, Purcell says. Thermal mass helps keep the auditorium cool in summer. CFD modelling predicted that wed get a temperature drop of between 2.5C and 3.0C as a result of the thermal mass, says Purcell. In addition to the concrete air-intake plenum, 25,000 bricks reclaimed from the old theatre line the auditorium and add significantly to the thermal mass of the space. The only bit of the auditorium enclosure that is lightweight is the roof structure, but we were not too worried by that because once the air has risen to high level it is drawn out of the auditorium by the chimneys, says Purcell. A night-time cooling strategy helps purge the inlet plenum and auditorium Low ImPACT CoNSTruCTIoN Demolition waste: 90%+ recycled Construction waste: 89% recycled The sites energy and water use, and the impact of transport to site, were monitored An on-site biodiversity champion ensured no harm came to established flora and fauna The restrained red brick helps the new theatre building to sit well with its listed neighbours An array of actuator-controlled dampers within the basement and highlevel auditorium regulates the airflow through the auditorium. In winter, the fresh-air rate is kept to a minimum by carbon dioxide and temperature sensors. When you have the heat load from the audience and from the theatre lighting, the space does not need heating, says Purcell. The designers have, however, made clever use of the AHU to preheat the auditorium ahead of shows in winter reversing the cooling heat pump enables the unit to provide heating without needing to run the boilers. A fully automated control system based on threshold temperatures regulates air flow (see Temperature control panel). . Backstage In addition to the auditorium, the low energy servicing strategy means that the community room which doubles as rehearsal space and the main rehearsal room are also naturally ventilated. The community room ventilation system is similar to that of the main auditorium, with a street-level air intake delivering air to the space through a series of floor grilles, with air exhausted supplemented by opening terrace doors to the Arad Street faade, while radiant panels provide heat to the room. The foyers, too, are naturally ventilated via opening sliding windows in the front faade. The warmed air from these spaces rises up and out of the building through a large lightwell. The only principal space to be mechanically ventilated is the basement bistro (see Figure 2, cross-section of rehearsal spaces and foyer). Solar gains and glare to the foyer and bars are kept to a minimum by the 105 aluminium, life-size-portrait shutters. The shades, which rotate around a central pivot, are positioned by occupants opening a window, manually moving the shade, and then locking it into position. In practice, this means each screen is set at a different angle, at different times of the day, to create a dynamic faade. The users have bought into this solution completely; on grey days, most of the shades are open, while on sunny days the faade is a wall of Liverpudlians, says Purcell. These quirky sunshades and the buildings natural ventilation strategy have helped the new Everyman Theatre to achieve a BREEAM excellent rating. of additional cooling measures as insurance against the failure of natural ventilation to keep the audience comfortable. As a consequence, two air handling units (AHUs) complete with direct expansion cooling systems connected to air source heat pumps are hidden away in the plenum beneath the stage. These have yet to be needed. Last year was the warmest on record, and the theatre operated all year on full natural ventilation, without need to resort to cooling even during a Saturday matinee, says Purcell. ventilation strategy a small, lowspeed transfer fan is used to drive air through a ducted system, which links a small plenum beneath the galleries to the large plenum beneath the main auditorium seating. Using detailed modelling demonstrated to Watermans that the natural ventilation strategy would be sufficient to keep conditions comfortable in the auditorium throughout the year. The theatres trustees, however, were sceptical, and sought the reassurance structures of heat in summer. The auditorium modelling also highlighted the problem of insufficient air movement around the upper level gallery seating. When we modelled the air flow, we found that it by-passed the galleries altogether, says Purcell. Vomitories (entrances between seating) at the front of the stage, and a corridor beneath the galleries, meant that it was impossible to create a freshair path from the plenum beneath the banked seating to the galleries. Instead in a minor deviation from the natural Ground floor Everyman Theatre Liverpool 1 Office 2 Actors quiet room 3 Stage management 4 Dressing room 5 Workshop 6 Stage 7 Youth and community (Y&C) studio 8 Cafe 9 Office 10 Box office 9 10 7 1 2 3 8 4 5 Once we found where the temperature peaks were occurring we used computational fluid dynamics to model the space at these particular moments in time - Jonathan Purcell 6 through two, roof-top chimneys. Unlike the main auditorium, however, the room also includes trench heating to pre-heat incoming air during the winter. The main rehearsal room is ventilated using roof-mounted windcatchers to both supply and extract air from the space. The rooms ventilation is The giant chimneys nicknamed John, Paul, George and Ringo which help ventilate the theatre ProJeCT TeAm Client: Liverpool and Merseyside Theatres Trust Architect: Haworth Tompkins Services engineer: Waterman Building Services Acoustic engineer: Gillieron Scott Acoustic Design Structural engineer: Alan Baxter Associates QS: Gardiner and Theobald Theatre consultant: Charcoalblue Contractor: Gilbert-Ash CoSTS Basic building cost: 2,300/m2 Services cost: 500/m2 The building also includes: a gas-fired micro CHP engine, sized to meet the buildings hot-water demand for toilets, showers and catering; a daylight-linked LED lighting scheme to all public spaces; and rainwater-harvesting for toilet flushing. No wonder the Stirling Prize judges described the building as exceptionally sustainable. CJ eor rmade temperature control in the auditorium