THE ARUP JOURNAL

3/1993 Front cover: Project Dragonfly. (Photo: Ken Newman) Back cover: THEARUP Holborn Bars. (Photo: Peter Mackinven) JOURNAL Vol.28 No3 Editor: 3/1993 David J. Brown Art Editor: Desmond Wyeth FCSD Published by Ove Arup Partnership Deputy Editor: 13 Fitzroy Street. Helene Murphy London Editorial Assistant: W1P680 Kris Buglear 3 'Future Assurance': The renovation of the Prudential Corporation head offices in The redevelopment London involved upgrading Alfred Waterhouse's celebrated of Holborn Bars building to modern standards without alteration to its listed interiors David Alling, Ken Coffin, and fa<;:ade , the comprehensive refurbishment of the remaining Ian McVitty, Patrick Morreau, Waterhouse buildings on the site, and the replacement of other Roy Wheeler structures there with 36 500m2 of new. high specification offices.

8 British Airways Ove Arup & Partners Cardiff office were design team leaders for Project Dragonfly the creation of this advanced maintenance facility for 747 jumbo Steven Luke jets at Cardiff Wales Airport. Considerable attention to environmental sensitivities was necessary in its planning, whilst the building itself 'llll!= ~~~~ilt;~' involved installing state-of-the-art specialist maintenance structures ~ as well as raising probably the longest continuous space girders in Europe.

16 Pescanova fish factory, Following the recovery of Namibia's fishing industry after the Liideritz, Namibia country's independence in 1990, the Spanish fishing group Barrie Williams Pescanova commissioned Arups to plan and design their new fish factory, plus causeway and jetty, at a bare rock site on the shore, north of the town of Luderitz.

20 The Oxyco development, Ove Arup & Partners Zimbabwe were principal agent and multi­ Harare, Zimbabwe disciplinary consultants for Oxyco Gases' new manufacturing, Lotte Reimer storage, and sales facility. Stringent safety precautions were incorporated in the design, in particular fire protection for handling and storing liquid petroleum gas.

23 Diisseldorf Tower Energy conservation was fundamental in Arup Associates' Alastair Gourlay competition entry design for this 20-storey office building, which Peter Warburton included solar collectors as well as carefully controlled natural Terry Raggett ventilation in its concept.

2 'Future Assurance': The redevelopment of Holborn Bars Architect: EPA Architects Ltd. David Atling Ken Coffin Ian McVitty Patrick Morreau Roy Wheeler

Introduction Department as they. with Ove Arup & Part­ Holborn Bars is both the name and the ners as structural and building services engi­ location of the newly renovated and partly neers, DEGW as office planning consultants. redeveloped offices in London of the Pruden­ and Gardiner & Theobald as quantity sur­ tial Corporation . It has been their home since veyors, developed a scheme for discussion 1875, when the directors decided to move with English Heritage, the Victorian Society, west from Ludgate Hill to Holborn, where land other amenity groups, and the planning offi­ was available on what had once been a cers of the City of London and Camden Roman road from London, and which had Borough, in whose two jurisdictions the site again become a major thoroughfare with the lies. opening of Holborn Viaduct. Here, between The fundamentals of the scheme were to re­ 1876 and 1901 , the Prudential constructed, to tain those buildings identified by Cunning­ designs by Alfred Waterhouse and in stages ham as essential to Waterhouse's concept; dictated by site acquisition, the brick and ter­ and to demolish the 1930s building along racotta buildings which became a London Brooke Street. the relatively inferior 19th cen­ landmark (Fig. 1) . tury buildings at the rear of the complex During the 1980s, the Prudential again recog­ 1. Holborn elevation c . 1905. (keeping only one of the oldest - the 'Jewel' nized the need to change their premises. - a small building at the north-west corner). this time for efficiency rather than expansion. and two 1920s buildings on the far side of The piecemeal growth of the 19th century architectural quality of the various buildings Greville Street. which would be closed to 1 and some subsequent redevelopment (Fig . 3) on it . Dr Cunningham's report makes fas­ extend the site northwards to Beauchamp had created problems which they now sought cinating reading, but space does not permit Street (Fig. 2). In architectural terms, the two to address. Chief among these were the more than a summary of his main con­ key issues were how to join new to old, and variety of floor levels and tortuous com­ clusions: that previous piecemeal growth how to achieve an exterior which neither munications between the various buildings; allowed the possibility of sectional redevelop­ clashed with Waterhouse nor imitated him. ment. but not at the expense of Waterhouse's the inefficiency of the floor plans; standards The first was resolved by retaining the original of heating, cooling and ventilation inappro­ overall concept of a fac;:ade to Holborn lightwells with their white glazed brick walls, priate for the 20th (let alone the 21st) century; backed by a sequence of courtyards. This, adding glazed roofs to convert them to atria, and the total absence of provision for the and the detailed recommendations of the and so articulating the junctions between information technology essential to oper­ report, formed the basis of the planning con­ retained buildings and the new development. ate such a diversified financial services cept adopted by the Prudential Architects The atria thus became major architectural organization. spaces, detailed and finished with granite Gaining the objective 2. Site map. and marble on the columns and, in the circu­ The Prudential's goal was straightforward: a lar main atrium. a sweeping spiral staircase modern office building of at least the same with a 5~ tonne granite sphere (the 'Kugel'), floor area on the same site - a simple rotating on a film of water, to act as a focal enough objective, but not easily achieved point. For the external elevations, the archi­ when the outmoded buildings are listed tects adopted a vocabulary of proportion, Grade W and designed by one of the great detail and material that echoed Waterhouse: names of Victorian architecture. Total demo­ granite panels mounted on frames integral lition and redevelopment was out of the ques­ with windows. cornice. and other details. Two tion, nor did the Prudential consider it: the colours were used, the lighter above, and the buildings had become a symbol of the com­ elevations were stepped back to make the pany. to be conserved and modernized as far building appear less imposing (Fig. 4). as possible. Nonetheless it was evident that. This scheme, which left the main frontages to whatever the scope of the works proposed, Holborn and Leather Lane restored but un­ gaining the necessary listed building and changed, was the basis of extensive dis­ planning consents would require careful cussions with English Heritage and others. preparation. and was granted planning permission in As a first step, the Prudential commissioned December 1988. At this stage, the Prudential Dr Colin Cunningham, a recognized authority retained EPA Architects to carry the project on Waterhouse and his work, to prepare a forward to detailed design and see it through brief history of the site and an appraisal of the to completion.

3. The site from the south-west, 4. North-west corner new buildings, before redevelopment. showing stepping of fai;ade and colours.

3 5 . The completed redevelopment. from the north-west

Thus the Holborn Bars development com­ prised three distinct areas (Figs. 5, 6): • the 9000m2 Holborn frontage - described by Cunningham as the 'Flagship' of the Prudential - to be renovated and heated and air-conditioned to modern standards with­ out. as far as possible, alteration to its listed interiors • the remaining Waterhouse buildings (24 OOOm2) to be stripped internally and refur­ bished as 'shell and core' • 36 500m2 of new buildings to be con­ structed to a high specification and com­ pleted as 'shell and core '. Although it was anticipated that some build· ings would be occupied by the Prudential, separate lettings in the future were a possibil­ ity and so. for that purpose. the new scheme was designed so that each block could if necessary function independently, with its own (or a shared) entrance and core. Thus the complexities of circulation were resolved. The engineering issues For the structural engineer the principal issues particular to Holborn Bars were the condition and load-carrying capacity of the existing buildings, the effects on them of the new con­ struction, and the alterations needed to install the new services. The strategy for building services was crucial. Discussion with English Heritage and the planners revealed that space for rooftop plant would be severely restricted, so to avoid using office quality accommodation for ser­ vices installations. basement locations were Key: considered. The subdivision of the develop­ ment into three possibly differing tenancies suggested that each block be provided with its own plant, though considerations of outlay dictated that centralized chiller. boiler, and water storage systems be provided in a base­ ment plantroom below the new building at the northern end of the site. A 1.5m deep basement level building ser­ vices trench provides the distribution route between the central plantroom and the numerous services risers located throughout the complex. With the centralized plant strategy estab­ lished, the challenge still remained of accom­ Flagship modating the distributed plant within the re­ Refurbished buildings stricted space available in the refurbished New structures buildings and the Flagship.

6. Early south-north cross-section: the new building to the north. as completed, has a deeper basement than illustrated

4 Building services 7. Chiller room. General The central plantroom houses 6MW of chilled water plant (Fig . 7). 5.1MW of boiler plant. the central water storage system, an emergency generator enclosure (with the landlord's SOOkVA essential services generator and space for up to 5.SMVA of tenant's genera­ tors), basement air-handling plant, and a 3.6MVA substation to serve the plant.

Adjacent to the central plantroom are intake 8. Interior of the rooms for other utilities: Flagship, showing • gas supply for tenants' catering facilities installation of • 11 kV electrical supply services trunking • BT and Mercury. at floor level. Electricity is distributed from the intake room at 11 kV to substations in each of the three 'tenancy' blocks and central plantroom area. A central addressable fire alarm system is provided to protect the development, with landlord's areas fully fitted out and connec­ tion points for tenants' future use located in the numerous building services risers. It was anticipated that the retained existing drains and sewers would be in poor condi­ tion. and a CCTV survey confirmed that extensive remedial work was required. Connection into the existing sewer running under High Holborn was particularly difficult, since the new outfall from the complex required extensive tunnelling; this revealed unrecorded statutory services such as a walk-through BT cableway. In all, 28 lifts were installed throughout the complex. For the new buildings, on-floor VAV (variable air volume) air handling units (AHUs) were accommodated in areas adjacent to cores, provided with connection points to allow future installation of on-floor distribution duct­ work by tenants. In the refurbished areas the location of such plant was not possible, due and within new enclosures finished to match To allow the extensive installation, all wood to the existing storey heights and the limited the individual decor of each office. Horizontal panelling and doors were identified and re­ areas. The solution adopted here was to use servicing required the recreation of sculpted moved for safe storage. A close temperature central AHUs located in pitched roof voids ceilings below originals, giving void space for and humidity control scheme was designed and lower ground floor plantrooms: both loca­ ductwork and wireways. The ornc~te Board­ and installed for this storage area to prevent tions required major structural alterations. room ceiling was recreated incorporating possible damage due to shrinkage. The Flagship supply and return air diffuser plates above Early in the design stage it became clear that decorative brass grilles. (This required a Air-conditioning of the Flagship is generally the Flagship would be reoccupied by Pruden­ computational fluid dynamics (CFD) study to by cill-level four-pipe fan coil units (FCUs). tial staff. The sensitive nature of the interiors predict the room air flow pattern, the theory of installed within retained or new wood pan­ dictated that it should be fully fitted out by a which has since been confirmed by smoke elled casings. The FCUs are served by specialist team with experience of this type of test.) remote fresh air plant with humidity control to work. protect the listed finishes. The retained or A new false floor of the shallowest achievable new FCU casings also house chilled water, High 'sculpted' ceilings and predominantly depth, to minimize impact on original skirting heating water and condensate pipework, tiled and wood panelled interiors offered little and marble fire place surrounds. has been power supply cabling, four-port control valves accommodation for vertical and horizontal created, incorporating flush floor trunking and an individual ddc controller linked to the servicing. New risers were created in the with floor outlet boxes for power, telecommu­ building management system (BMS). Areas existing structure. both behind original finishes nications and network wiring (Fig. 8). away from the listed interior offices, where accessible ceilings are installed, are pro­ vided with ceiling-mounted fan coil units or, where possible, VAV units fed from a central VAVAHU. The Flagship lighting has involved close liaison with heritage groups to recreate the mixture of Victorian, Edwardian and 1930s luminaires. using high efficiency lamps for improved lighting levels and runn ing costs. A variety of fittings have been used to suit indi­ vidual office decor; in some cases these incorporated individual three-hour emergency lighting modules. The nature of this building eliminated sprink­ ler protection, but means of escape, compart­ mentation, fire detection, and fire fighting facilities have been improved. Fire detection is via a fully addressable system incorporat­ ing smoke detection. breakglass units. sounders and plant overrides, with new hose­ reels and dry rising mains installed for fire fighting purposes. Hose-reel outlets have been carefully integrated into the existing decor and sounders have been hidden from view in the most sensitive areas. 5 9. The central courtyard. 10. Faience roof in the Flagship.

Refurbished buildings panels and terminal direct digital control (ddc) of the exterior brick and terracotta, the works The refurbished buildings surrounding the units. The BMS provides facilities for plant on site revealed nothing to alter the view that, central courtyard (Fig. 9) and fronting Leather monitoring and set point control as well as properly maintained, the buildings had a long Lane have listed fa9ades and minor areas of time event control and management func­ life ahead of them. listed interior. Generally, the interiors have tions , such as maximum demand monitoring. New structures been completely refurbished to create a The fully addressable fire alarms system pro­ For speed of erection and to reduce weight modern office environment, and subse­ vided within each of the three buildings has on the raft foundations, the superstructure of quently the refurbished buildings have been been linked back to the management suite the new buildings is a braced steel frame with fitted out to developers' finish standard, pro­ via a central monitoring processor, which columns on a 9m x 7.Sm or 9m x 6m grid sup­ viding fully serviced office space ready for provides overall complex control on a block­ porting primary and secondary beams; the tenants to partition as required. Offices are by-block evacuate-and-alert basis. In addi­ floor slab is of metal decking topped with a air-conditioned from fan-assisted VAV ter­ tion , the central fire alarm system controls 130mm lightweight concrete deck acting minal units located in ceiling voids, complete plant installations under fire conditions, with­ compositely with the beams. Allowable with low temperature hot water re-heat coils. out the need to 'hard wire' between the imposed loading is 5kN/m2. individual control via a ddc controller linked various systems. to the BMS, and supply and return air from The space for services was carefully planned central VAV AHUs. The existing structures with deflection limits imposed to ensure an The Waterhouse buildings are among the adequate ceiling void. Holes were provided Lighting is by modular fluorescent air-hand­ earliest examples of steel construction: load­ through the steel beams to allow for sprinkler ling luminaires and perimeter downlighters, bearing brick exterior walls with terracotta and drainage pipes, thus freeing the area arranged to allow partitioning flexibility, while ornamentation, internal rivetted steel columns below for ductwork and cabling only. Floors maintaining lighting levels. The fully acces­ and girders built Vp from angles and plates, were stabilized by diagonal bracing in the sible metal tile ceiling also incorporates full and rolled steel beams supporting, in the core areas. In addition to analY1ical predic­ sprinkler protection using pop-down sprinkler main , filler joist floors. An exception is the tions of lateral deflection under wind loads, heads and smoke detection, linked to the 1895 building at the north end of Leather some allowance was also made for move­ east court building addressable fire alarm Lane where a deep steel trough deck - ment in the bolted connections. This was a system via riser link boxes. Lindsay's patent decking - spans directly significant proportion of the total - important The fit-out also provides a fully accessible between masonry arches. Later construction when considering the movement joints be­ false floor, incorporating an underfloor plug-in includes two floors of reinforced concrete tween the new and existing buildings. bus-bar system and wireways for tenants' added during the 1920s to all the buildings The effects of the new telecommunications and data wiring. The com­ behind the Holborn fa9ade, and the south­ In general, increases in load to the columns, bination of false floor and ceiling, coupled to west corner of the Holborn frontage, a 1930s walls and foundations of the existing build­ letting agents' floor to ceiling heights, all steel and concrete reconstruction of the first ings were avoided, usually by screeds and within the existing structural zone, proved a of the buildings on the site. masonry partitions being removed to offset major co-ordination feat. All the buildings have a basement (now the the additional loads from mechanical plant at New buildings lower ground floor) at approximately 3m roof level and other sources. Where replace­ The new buildings have been constructed to below street level, and all are founded on ment walls and finishes had to be provided , shell and core standard , with the exception of strip or pad footings on the gravel directly their weight was limited to that of the original a show suite at level three fully fitted-out to below the basement and immediately above structure. For the atrium roofs, however, other indicate to potential tenants how it may look. ground water level. measures were adopted and the tubular steel The loadcarrying capacity of typical parts of trusses supporting the glazing are canti­ New cores have been constructed providing levered from the new structure to float over plantrooms, passenger and fire lift installa­ the existing structure was evaluated by calcu­ lation using information from some of the the old, with provision in the roofing detail for tions, fully fitted toilet facilities, building the sizable vertical and horizontal movements services and fire protection risers, with plug­ 4000 drawings in the Prudential archives, site measurements from surveys and trial pits, that were predicted to occur under wind in points for tenants' connections at each load. core, on each floor. Fully functioning on-floor and laboratory testing of samples taken from VAV AHUs are provided, requiring only the various materials used in the construction. Indeed, detailing the interface between the tenant's system. From these studies. it was apparent that the new and the old buildings was one of the floors added during the 1920s used what more difficult issues faced by both the archi­ For normal and smoke ventilation, the four reserve there had been in the original walls, tects and the engineers. Not only were there new atria have variable speed mechanical columns and foundations, and that these questions of differential foundation settle­ extract systems, whilst the conservatory is elements would have to be strengthened if ments and thermal and wind movements to naturally ventilated via roof units. Inlet air at they were to carry any further additional load. be addressed, but the permitted tolerances the atria bases comes from a mix of auto­ In the subsequent development of the de­ on the new construction combined with un­ matically operated doors and louvres. Each sign, every effort was made to avoid this. The certainties in the position of the old to atrium system is activated by its own beam calculated capacity of the floors themselves smoke detectors via the addressable fire varied considerably but was nowhere found 11 . Basement plantroom excavation. alarm system. 2 to be less than 3.5kN/m , the statutory mini­ Nonh Block Retained Building Counyard Each core has its own sprinkler main, fire mum. +19.2m alarm link box, hose reel outlet, and dry riser, The existing buildings were found to be with facilities for extension to provide full fire sound; although there had been some cases +15.2m protection services for future tenants. of local damage from rainwater penetration, Building management system these were remarkably few; altogether. the LJI Gravel GroundWater Holborn Bars is provided with a central man­ condition of the fabric reflected the Pru­ ~ 1------lev_e_l__ agement suite, where building services con­ dential's high standards of maintenance. trol and monitoring is carried out by the BMS Although isolated instances of corrosion to system via local outstations within control steel lintels were found during the renovation Clay 12. Basement excavation at September 1990. The retained building on the left forms the south side of the main atrium. On the right is the retained 'Jewel', with secant pile walling in its foreground. create problems calling for ingenuity from contractor and consultants' site staff alike. Risks of damage 14: Main atrium: The greatest threat to the relatively brittle the retained wall brick and terracotta walls of the Waterhouse (see Fig. 12) is on buildings came from new construction below the extreme left. ground level. Under most circumstances, the cost of preventing damage can be assessed against the cost of repair, and some accept­ able level of risk arrived at. In the case of Holborn Bars, and especially where the faience and ceramic tile interiors of the Flag­ ship were concerned (Fig. 10), English Heri­ tage sought prior assurance that no damage would occur; this could not be given, but it was clear that exceptional measures would be necessary to reduce the level of risk to a 15: North elevation with conservatory practical minimum. stepped to preserve Three sources of ground movement were of ~ rights of light for particular concern: the basement excavation existing residential (Fig. 12) extending 5m below and as little as building opposite. 3m away from the foundations of the existing buildings (Fig. 11 ); the service corridor with its building services trench between and slightly below the foundations of the western block of retained buildings (Fig. 13); and a deep lift pit abutting the finest tiled staircase in the Flagship. Fortunately, the effects of these three did not interact; each could be addressed and resolved separately. Cost and programme considerations had led the sands and gravel, the risks were three­ maybe beyond. It has been rewarding to to a raft foundation under the new buildings fold: that the excavation would cause the work for a client who cares about the building and the basement plantroom. The basement existing foundations to settle; that dewatering for its own sake, rather than only the invest­ walls were constructed with secant piling the excavation might draw down the ground­ ment or capital return it represents. The design propped at two levels during excavation and water and cause settlement elsewhere; and team and contractor's efforts were publicly supported by an earth berm at the base. The that installing sheet piling to uphold the exca­ rewarded when the building received the risk of damage from basement construction vation might cause damage through vibra­ 1993 City Heritage Award for Building Con­ arose from ground settlements caused by tion. The solution adopted was minipiled servation in the City of London. inward movement of the toe of the retaining underpinning of the adjacent foundations Reference wall. Because the strength and stiffness of followed by a pressure-injected tubes a (1) CUNNINGHAM, Dr. C.J.K. A history and appre­ the clay soil within the excavation diminish manchette grout curtain to provide a ground­ ciation of the Prudential chief office buildings in with time (as the clay becomes 'drained'), water cut-off; the services trench was then Holborn Bars. Ward Taylor Associates, n.d. giving rise to progressively greater wall constructed using local dewatering and con­ CreclHs movements and settlements at ground level, ventional strutting and planking techniques. Client: the contractor was required to complete the Similar methods were used to construct the Prudential Portfolio Managers basement raft construction against any sec­ deep lift pit at the Flagship. Architect: EPR Architects Ltd. tion of the wall within 40 days of removing the Monitoring berm or, failing that, to provide a further level Structural and services engineers: Throughout these operations the behaviour of Ove Arup and Partners of propping. In the event, the time criterion the Waterhouse buildings was closely moni­ was always satisfied. Duncan Michael, Tom Barker, Ken Coffin, Peter Evans, tored, using levelling points on the walls com­ Ian McViny, Patrick Morreau, Richard Santner, Mel Garber, Services trench bined with constant careful examination. Alan Dean (structural), David Atling, Paul Wellman, G0

2. Site location. 3. Site plan. 4. Three-bay hangar plan.

Workshops

100m f Undercarriage pits •N

8 The roof over the street is fully glazed to pro­ vide a bright, naturally illuminated space. To break up the expansive hangar fa9ade, the wall columns, the roof structure support towers, and the roof overhangs were deliber­ ately expressed as features . They were also used for building services distribution and maintenance access to minimize exposure within the hangar. To test the chosen scheme, several photo­ montages were made, from viewing points 500m-2km from the site. A 1: 1250 scale model was also produced to confirm the site planning, whilst the building form itself was studied using a 1:2 50 model. These aids were also used to progress the planning application. Envelope details The building fabric is insulated to at least the current Building Regulations standards and in some areas better. The cladding to the hangar walls and doors is silver/grey HP200 profiled steel single sheeting supported by Main considerations are summarized below: to reduce the internal volume and energy cold rolled rails. Mineral wool insulation is • aircraft docking position to be nose-in requirements. by using distinctive external secured to the inner face, and is protected in turn by an inner liner sheet of lightweight pro­ • minimum internal volume to obtain tubular steel triangular girders. Aesthetically, this filigree of structure combined with the filed steel sheeting . The inner skin masks all maximum environmental control the structure and minimizes dust-collection, • a column-free double bay, external fa9ade also reduced the apparent mass of the building from a distance by soft­ reducing future cleaning and maintenance. 150m wide x 90m deep To reduce the potential for heat loss, 4.1m • a secure single bay, 75m wide x 90m deep ening the stepped profile. The study also considered the most effective high doors are incorporated in the side walls • smooth inner surfaces to for vehicle access and to avoid frequent minimize dust collection. support building arrangement. The chosen form separates maintenance areas from opening of the main hangar doors. The early building studies were also influenc­ offices: they are connected by a wide circula­ As soon as the heating system was opera­ ed significantly by a number of constraints on tion street with linking balconies and stair­ tional , the completed building was thermo­ the building form and appearance: cases, thus providing optimum circulation graphically surveyed to confirm integrity of • large mass and scale routes between the technical workshops, the insulating properties. This located weak • location on an exposed site administrative areas, and the hangar. thermal links which could not be identified by • height of building relative to normal visual inspection. the surrounding area The support building is clad with aluminium • exposure to the elements. composite bi-modular panels supported by In addition, the height was influence.d by the secondary sheeting rails . Office inner walls 'inner transition slope' of the 'obstacle-free are of blockwork to control noise penetration, zone' dictated by the closeness of the runways. whilst the glazing is a thermal double-glazed At the front elevation of the hangar the inner system designed to allow selective installa­ transition slope is 35m above the hangar slab tion of secondary acoustic glazing. The sup­ and levels out at 42m over the building itself. port building is separated from the hangar by Exposure to salt air and discharges from a a movement joint (concealed by detailing}, nearby power station and cement works were needed to deal with the differential move­ also important factors in the selection of the ments between the two structures generated building fabric. by wind and thermal effects. The support building structure includes composite floor Building form construction with 130mm thick power-floated Much consideration was given to the eleva­ floor slabs. tion , to establish an interesting appearance The hangar roof is covered by a single skin both close to and from a distance. The profile membrane, sloped at 1.5° to perimeter gut­ finally chosen was a stepped roof: this suited ters. On the support building the roof slopes the functions within each area of the facility, are 6° and the covering is a standing seam from maximum height at the front of the metal roof. Both roof areas are designed for hangar to accommodate the tail of the aircraft general maintenance access and are free of to the low-rise support building at the rear. external mechanical services. The low roof over that part of the hangar con­ taining aircraft fuselage was lowered further The nine main hangar doors are vast - each is 22.6m high, nearly 26m wide, and weighs 45 tonnes. Arranged in sets of three, with each supported on a rail recessed into the 6. (Above) Circulation 'street' in workshops. hangar slab, they can be opened to allow a 5. Hangar cross-section. looking towards rear wall of hangar. maximum of two bays to be accessed fully at the same time . Many existing BA hangars 90m have doors fully glazed, but following a natural lighting design study, much-reduced glazing was recommended since the hangar faces south-east. and during the winter months will be subject to low sun angles which could cause glare. This study estab­ lished tt"3.t with 20% roof glazing and 15% glazing in the hangar doors, the lighting and Mezzanine floor internal environmental control was optimized 0 by balancing heating and lighting costs. The 3 distribution of glazing provides a low level vision panel plus a vertical strip aligning with the aircrafts' tail sections, giving natural light­ Fall1 :200 - ing to the working areas. What appears to be an aesthetic consideration is in fact the result of efficient use of glazing in providing day­ light distribution and amenity closely related Nose wheel lifting platform Main undercarriage lifting platform to the building function. 9 Environmental considerations Justin Abbott

BA has adopted a 'good neighbour' policy as part of its overall corporate environmental management strategy. In support of this approach, Arups were commissioned to undertake an environmental review of the technical and management aspects of the new maintenance facility. The review - undertaken alongside the design - concentrated on the interaction between the facility and its environment. The brief was to pro­ duce an Environmental Management Report (EMA) which should serve to: • ensure good environmental per­ formance during operation through A. Aircraft City of Norwich in acoustic ground run enclosure. the implementation of control features and operational/emergency procedures The emissions from the facility were Acoustic studies acoustic lining, with an angled pre­ of five kinds: discharges to surface cast concrete blast screen at the • allow for assessment of environ­ waters, discharges to foul sewers. Nigel Cogger rear to deflect the thrusts generated mental performance at a future date emissions to atmosphere. disposal of during the engine run tests. The through the adoption of monitoring solid wastes, and noise. For each of Acoustic studies were an important external cladding of the enclosure and review programmes. these the following information was part of the Dragonfly project from the matches that of the hangar, the The study required a thorough presented: early stages: design quality being maintained as examination of the likely emissions • to ensure that environmental noise • the characteristics of emission(s) this facility is very visible from the from the facility. Since at the time of from the engine test pen would not and the receiving environment site boundary and from the airport preparing the EMA the project was cause disturbance to the community terminal. • details of any discharge consents still at the design stage, it was • to provide a high quality working The support building is sited rela­ or authorizations necessary to refer to existing opera­ environment in the support building tively close to the pen. and the build­ tions at Heathrow, where operational • recommendations for control and • to ensure clarity and intelligibility of ing envelope was also designed to procedures and environmental moni­ emergency procedures the public address/Voice alarm attenuate the engine noise during toring records were examined. This • recommendations for monitoring (PANA) system, particularly in the testing to a sufficiently low level to information was complemented by and review programmes hangar and circulation street. avoid disturbance to the occupants discussions with the design team • identification of management and restrictions on direct and tele­ and BA staff to establish the parti­ An ambient noise survey in the resi­ responsibilities. phone speech. cular characteristics of the Cardiff dential communities around the Air­ operations. As a result, an opera­ The primary benefits expected from port was initially carried out to enable This requirement is particularly tional procedures flow sheet was the review will be operational in that environmental noise limits to be pro­ important for the training rooms , drawn up, highlighting key emissions the implementation of appropriate posed. The environmental noise which directly overlook the pen. or waste arisings. Alongside these control procedures should serve to report and proposed criteria were In addition, the detail development of investigations, consultations were minimize the risk of any adverse fundamental to obtaining planning the meeting rooms, training rooms, also held with local regulatory emissions to the environment. In consent for the facility. and offices had to ensure an appro­ authorities to gain information on the addition, however, the adoption of The design and construction of the priate standard of acoustic privacy. ambient environment and to estab­ monitoring and review programmes ground run pen enclosure for test­ Particular attention had to be given lish the standards that would be will enable performance to be running the aircraft engines were to the video conference room linking imposed on any emissions, in the assessed on a regular basis and will devised to provide maximum attenu­ the BA facilities, which needs a high form of either discharge consents or identify areas where further action ation during engine testing. The 10m level of noise insulation and control authorizations. may be required. high steel-framed wall has an inner of reflected sound to operate sue-

Building services have circular web holes to allow flexibility for two gas-fired distributed combined heat and future installations. power (CHP) units in conjunction with top-up boilers. The CHP units provide a proportion of General Heating, ventilation and comfort cooling the · building's total electrical and heating The services have been purpose-designed The hangar bays are heated by a high tem­ demands in an energy efficient manner and for the varying activities and requirements of perature and high velocity direct gas-fired provide a measure of back-up in a power the hangar, support workshops and adminis­ system. Air-handling units in the spine beam failure. trative offices, with particular attention given (which contribute 280 tonnes of load sup­ to the quality of the internal environment and ported by the roof structure) supply air to All spaces within the building are mechani­ to energy efficiency. insulated high velocity primary air ductwork cally ventilated , though a good proportion of systems serving strategically located induc­ the windows are also openable. Both the workshops and administration build­ tion units. By utilizing direct gas firing, and ing have been designed tor specific client This is generally as a result of the building's reducing duct lengths from the heating location in an airport environment and the use and are cellular in layout to suit their source. the system is some 95% efficient, requirements. The offices, however. are nature of the building's functions internally. A compared to 70-80% tor alternative indirect limited amount of the office space has com­ basically open plan and the current partition systems. layout can be modified should the users' fort cooling from a four-pipe fan coil unit sys­ requirements change. The system also destratifies the air within the tem, with chilled water provided by water hangar by forcing warm air, which naturally chillers using low ozone-depleting R22. The hangar floor is uncluttered, with service circulates in such a lofty space, back down to plantrooms along the side walls and in the floor level, and so prevents excessive heat Key workshop areas are given high-efficiency dividing wall between the double and single displacement ventilation which provides a loss at roof level. The viability of the hangar clean air layer within the working zone. All hangar bays. A mezzanine 4.8m above the heating system in such a high building was hangar slab links it with the support building ventilation systems have heat recovery de­ modelled and proved mathematically prior to vices, the majority being thermal wheels and provides direct access to the aircraft and construction by computational fluid dynamics additional working space. This floor is also which rotate between supply and exhaust (CFD) techniques. used tor services distribution below its soffit airstreams and have a heat recovery effi­ and a substantial number of structural beams The support building's heating system utilizes ciency of some 70-80%. 10 Fire safety systems and property protection; the empha­ which can be delivered at a rate of sis on a high level of fire safety with 80 OOO 1/min, mixed with a foaming Peter Bressington rapid extinguishment is reflected in agent, to the double bay. The pump­ the fact that the fire protection ing equipment and the water storage Since the hangar is an unconven­ installation is the single most costly tanks are located at the rear of the tional building, it was necessary for item of the building services. aircraft ground run pen. a comprehensive fire strategy to be The foam sprinkler and cannon sys­ developed, covering both active An automatic foam deluge system protects the aircraft bays with tems can be activated manually or and passive protection measures. automatically, with the detection sys­ The strategy was discussed, devel­ automatically oscillating monitors (cannons) and foam sprinklers. tems responding to a 5MW design oped and agreed with British fi re anywhere in the hangar. The fire Airways' Fire Protection Manager, Conventional sprinklers are also detection system operates in con­ the building's insurers, and the Fire included in the hangar below the underwing docking, mezzanine floor junction with the PA system which and Building Control Officers sends out voice/tone alarms; a com­ throughout the development period. and in the hangar roof directly above the mezzanine working area. plete automatic addressable site fire The specialized fire detection and detection system is provided suppression systems developed for The fire protection system incorpo­ throughout the complex. In the event this project provide both life safety rates storage for 4M litres of water of a fire the information is displayed on VDUs in three central control A. Section showing foam cannon coverage. centres and automatic diallers give a direct alarm to the local Fire Service. Apart from the additional, uncodified inclusion of the cannons, the design cessfully. Impact and airborne noise Linear heat detector cable of the deluge and foam monitor sys- from the kitchen were also attenu­ tem was developed from that given ated to avoid disturbance to the Foam/Water sprinklers in the US Standard NFPA 409, training room below - achieved by 'Aircraft hangars', 1990 edition - floating the kitchen's structural floor the guide usually adapted for the screed on a resilient layer. design of hangar protection systems. Acoustic considerations also had to Both directional throw and a mini­ be observed with the design and mum design discharge density over specification of the sitewide public the aircraft and hangar floor are address and voice alarm system. incorporated. High expansion foam While this was relatively straightfor­ generators protect the undercar­ ward for the support building, the riage pits. To prove the design, a full long reverberation times in the hydraulic and discharge test was hangar space (5-7 seconds at mid­ arranged in the double bay as part of the planned commissioning frequency) posed severe difficulties Meuanine UV/IR detectors with intelligibility. requirements: it provided an impres- sive demonstration of the system's Specialized 3-D electro-acoustic capability. modelling software was used to opti­ C. Foam cannon. mize the system, the solution being to use high quality loudspeakers with a 100° coverage angle, pointing vertically downwards. Intelligibility and naturalness of voice were shown at commissioning to be better than for any other hangar PA system known to the listeners. The emergency alarm system was treated differently, with electronic alarms being adopted to ensure clarity of operation.

Power supply date, time of day, presence of people and the material, amounting to some 120 QOOm3, was The total power demand is supplied by three use of the space. graded on site for use as structural material. 11 OOOV to 41 SV transformers, each with a The cut and fill requirements were balanced dual rating of 1.6MW. To operate the aircraft Aircraft services and all material was re-used within the site. on-board electrical systems during mainte­ Specialized services are provided for the air­ The consistency of the bearing pressure in nance, a 200V three-phase 400Hz power craft whilst in the hangar. These include a the weathered Porthkerry formation was moni­ supply is provided by motor generating 400Hz power supply system, hydraulics, fuel tored throughout by zone tests, in situ density equipment. tank venting and high mass air by means of testing, and rotary percussive probing. mobile rigs. An extensive compressed air The hangar and apron slab was unreinforced Lighting system is provided throughout the hangar, Within the hangar special multi-vapour lamps workshops and on the docking and staging with undowelled joints, the preferred solution provide an optimum balance between lamp systems. since it is both reliable and simplifies con­ life, efficiency and colour rendering for parti­ struction. It also avoids inducing high local­ cularly sensitive work. Lighting in the support Substructure ized stresses in the concrete and potential for building consists of high efficiency fluores­ The soil conditions below the original ground local crushing or cracking - the main con­ cent and compact fluorescent sources with level were found to be fairly uniform: a thin sideration being to avoid small concrete controllers such as low brightness to suit the layer (about 250mm) of topsoil over com­ particles getting sucked through the aircraft task. Artificial lighting in the hangar and in the pletely weathered Porthkerry formation be­ engines during taxiing across the apron to coming moderately and slightly weathered atrium are photocell-controlled whereas other the hangar. areas have manual switches. with depth. Ground conditions were good The use o~superplasticizers was avoided and and allowed mass concrete and lightly re­ the slab 11nished with a mineral application Energy management inforced pad foundations to be specified, with and then power-trowelled to a uniform light All the building services are controlled by a 12m ground anchors in some of the founda­ grey colour with a dense surface to minimize computerized Building Management System tions to resist uplift against lateral overturning chemical and oil absorption. The light grey (BMS) , which provides energy efficient con­ loads. mineral finish also helped to increase light trol and monitoring of plant and systems con­ The topsoil was stripped and stockpiled for reflection in covered areas below the aircraft trolled by outside conditions. the calendar use in the landscaping and all excavated wings and fuselage. 11 Specialist operation, providing access to the the spine girder and at the other by nose, wings, fuselage , and tail. To the meuanine floor. these structures aircraft maintenance achieve a tight fit of structure and contributing 500 tonnes to the load structures aircraft. the tail and fuselage dock­ supported by the hangar roof struc­ ing can be moved laterally on rails ture. Support for the tail docking Steven Luke and vertically using screw jack from the hangar slab would have mechanisms. Fine adjustment for air­ been a more economical solution but craft positional tolerance is provided BA's preferred arrangement freed Roof cranes by sliding fingers with rubber buffer the hangar floor working spaces. The hangar roof structure is designed edges in the nose and fuselage The underwing access docking is to support five Mannesmann Demag docking structure, whilst the tail principally a fixed system supported 10-tonne capacity cranes, one at docking is designed to provide a by the hangar slab but contains high and one at low level in the nominal horizontal 150mm clearance moving platforms around the engine single bay, one at high and two at to the aircraft in the parked position. areas to provide flexibility for access low level in the double bay. They Because of the tight fit requirement. at all levels. provide total coverage of the hangar control of roof deflections was criti­ Development of this package took floor and can act in tandem to lift a cal to avoid damage, and the 20 tonne point load at any position. the design team to Europe and the imposed load mid-span roof deflec­ USA, but none of the facilities visited The high level cranes are single­ tion in the double bay area was con­ span gantry, supported by two crane matched BA's requirement. In fact trolled to approximately 150mm for an existing BA double bay facility at rails. The low level cranes are on five all imposed loading conditions. rails and the gantry beam incorpor­ Heathrow, although constructed over ates mechanical hinges between This limited the movement of the 20 years ago, is still considered to each support rail to allow movement docking on the centreline of the air­ be the current flagship for aircraft of the hangar roof. Each crane is craft to 1OOmm and this amount of maintenance. to be surpassed only provided with a side maintenance leeway, combined with the features by the new BAMC facility. walkway, also usable for access to described, provides security of oper­ To prove aircraft fit and operation of the roof fittings. This equipment con­ ation in all conditions. the access docking , arrangements tributes 250 tonnes to be supported The tail docking staging is sus­ were made for a 747 to visit each by the roof structure. pended from the door and spine bay before completion and the 'City The cranes operate by infra-red girders. The fuselage docking struc­ of Cardiff' was the first to assist the system. A radio control alternative ture is supported at one end from trial fit procedure. was considered but discounted due to the interference which may occur in an airport environment. Undercarriage lifting platfonns The lifting platforms are provided in the floor below the nose and main undercarriage wheels. This equip­ ment incorporates electro-mechani­ cal screw jack devices in concrete pits up to 6m deep: installation design was completed by GEC

12 ~ C. Aircraft City of Cardiff entering the hangar during construction for access docking trial flt.

T D. Engine bay

T E. Aircraft tail docking.

13 8. Door girder fully erected, 1000 tonne spine girder awaiting lift, February 1992.

7. 600 tonne door girder lift, January 1992.

9. Spine girder lift, February 1992. 12. (Right) City of Cardiff entering hangar.

The hangar superstructure towers. Each lifting operation required ap­ Lateral stability is provided by the high level From the outset, the supply and erection of proximately eight hours to complete, with the roof plate interacting with the girder support the hangar steelwork was identified as a girders being raised in 300mm incremental towers, which are linked with cross-bracing critical element. with simplicity of erection a strokes to a height of 32m at their top; sliding to resist wind normal to the hangar doors. priority. Consequently, the frame concept the girders onto the main supports took a The wind loading on the gable walls is re­ was developed to allow each primary element further two hours. It is believed that these sisted by the central support towers and to be self-supporting. Full space structures structural roof members are the longest to be braced steelwork frames. working as vertical would have provided a lighter structural solu­ lifted by this method in Europe. cantilevers in the central wall between the tion but minimum weight in this instance did The infill high level roof plate between girders single and double bays. To confirm the be­ not achieve minimum cost or programme. incorporates single-span trusses with hori­ haviour of the principal hangar roof structure The hangar's main members are two con­ zontal wind bracing. The low roof is a 60m x a three-dimensional spaceframe analysis tinuous space truss girders. The one over the 30m two way-spanning plate structure, and was undertaken using Arups' OASYS GSA main doors is 9m deep x 5m wide, whilst the was selected to cope with the high point load­ program. spine girder at the step between the high and ing from the crane gantries. This arrangement low level roof areas is 14.5m deep and Sm was achieved by introducing support from wide. They weigh 600 tonnes and 1OOO the triangular girders to break the roof into tonnes respectively and are 232.5m long with small zones, and reduced the depth and 11 . North-west elevation. spans of 153.75m and 78.75m. The total weight of the structure. This concept achieved weight of structural steelwork in the hangar is the objective of minimizing the building vol­ 4000 tonnes plus another 2000 tonnes on the ume and was a prime consideration during remainder of the project. The main member the development of the hangar form. tube diameters are up to 762mm with wall There are no thermal expansion joints in the thicknesses between 12mm and 32mm. At hangar roof structure and the detailing of the the main joint locations some tubes are fabric and wall structure was developed to strengthened using thicker-walled sections accommodate overall movements of 130mm between 25mm and 50mm. expansion and 90mm contraction longi­ The roof girders were fabricated on site at tudinally. The largest positive temperature dif­ ground level with built in pre-camber. The ference in the exposed triangular girders erection procedure provided a notable con­ generated 10mm differential expansion and struction event since both were lifted into 25mm contraction. These movements were position from two points approximately 200m taken into account to establish the secondary apart using hydraulically operated lifting effects on the support structure. 14 Information Management System -..-...... Priscilla Tang BA's data networking equipment and voice system (PABX), located in the The operation of the maintenance systems room, control the operations facilities in the hangar demands an within the complex and provide con­ efficient, reliable and flexible com­ nections to the BA-wide area net­ munications network. A structured work. The requirement for electrical/ cabling system was designed to mechanical services and the layout provide an open solution using of the systems room were co-ordi­ copper and fibre optic technologies, nated in order to achieve effective with centralized control and flexibility use of space and to allow for future points (patch panels) provided at expansion. strategic locations throughout the A combination of the complex main­ complex. Voice and data services tenance machinery within the hangar are distributed from the systems A. Fibre (left), voice (above and the proximity to Cardiff Airport centre) and data (below centre) room within the administration build­ terminations in hangar bay, with radar equipment makes the hangar ing to offices, workshops, and han­ heavy duty power socket on the a potentially hostile environment to gar bays by means of patching at right. the communications and computing the flexibility points. Workstations in networks. Frequency spectrum the hangar bays are served by addi- analyses were undertaken to assess tional fibre optic cables to satisfy the the impact of electro-magnetic inter­ distance limitations specified by B. Rear of cabinet for structured ference on the network during the international network standards. cabling termination patch panel. design phase.

Credits Client: British Airways pie Client project managers: British Airways Property Branch, Property Construction Group Design team leaders, contract administrators, engineers, and architect: Ove Arup & Partners, Cardiff office Gabe Treharne. Dick Hensby, Steven Luke Alf Perry. Howard Corp. Simon Pickard. Peter Richardson (hangar structure), Justine Garbun (structures), Adrian Baker (access docking), Richard Thomas, Kamb1s Ayoubkharn (civil wo,ks). Robin O'Brien (environmental management), David Fullbrook, Andrew Boughton. Bryan W1lhams, Franc Coles (building and ground support services). Gerald Pickin. Terry Burns, Ian Jones. Rob Gordon. Cohn Williams, Mike O'Grady, Stephen Bowen, Michelle Richards. Margaret Williams (site team), Eddie King, Peter Monkley, Kevin Jones, Mike Cronly, Phil Hughes. Karen Winder, Wendy Hoare (draughtspersons) SPECIALIST ADVISORS: Paul Craddock, Chris Murgatroyd (steelWO

1. Southern Africa.

2. The factory against the background of Luderitz.

------3

Fulure 1eny ex1enSton

3. Model of Arups' proposal for the ultimate development. Future process facilities 4. Site development plan.

Government legislation after constructing Phase I, however. made it imperative that a percentage of wet fish production be carried out on land. This involves bringing ashore headed and gutted fish which have been stored under melting ice on the trawlers, one or two of which will operate as 'long liners'. Scale· Om 20m 40m 60m 80m 1OOm (Imagine a fishing line up to 10km long with 10 OOO hooks on it, each having to be baited by hand!) The Namibian fishing industry The company's interest in Namibia is pri­ Namibia's natural resources, apart from the marily in catching and exporting the white fish Incidentally, the fish offal removal and people, are primarily limited to minerals, hake, which enjoys much popularity in screening system has been designed to cope tourism and a slowly recovering fish resource. Europe. Although the best fishing grounds with fish heads; environmentalists are con­ It is estimated that in the early 1970s, fish are north of the harbour of Walvis Bay, the cerned about the effects of trawlers dumping catches were as much as five times their pre­ political uncertainty as to its ownership is still large quantities on the sea floor. Apparently sent level, but during the late '70s and '80s, unresolved between Namibia and South hake themselves are by far the biggest con­ the resource was not protected and was virtu­ Africa. Consequently, Pescanova decided to sumers of hake, but they object when only ally destroyed through indiscriminate fishing take advantage of the relatively good local heads are dished up ... by many foreign countries. Since Namibia's fishing grounds some 400km to the south. off The site and its environs independence in March 1990, however, when the town of LOderitz which has a natural U.ideritz is a small town of 8000 inhabitants, a a 200-mile fishing zone was proclaimed, for­ harbour. fascinating , mainly German-speaking rem­ eign fleets have operated in the area only Pescanova recognized that the Namibian nant of the old Colonial days, when people under licence. Already there are strong indi­ government was eager to create jobs for its were lured there to search for diamonds. cations that the fish stocks are recovering people and that pressure would be brought Apart from fighting wind-blown sand, the and quotas for the current season have been to bear on fishing companies to create work main occupations of the town have been lob­ substantially increased. opportunities on land. The company had pre­ ster fishing , which only has a very short sea­ It was in anticipation of this ongoing recovery, viously operated in the area with factory son , and servicing the local diamond indus­ and of the Namibian government's ability to freezer-type fishing trawlers which could try. For the locals. general fishing does not manage the resource successfully, that the transfer fish to other vessels at sea for trans­ seem to have been considered as a prof­ Spanish fishing group Pescanova SA de­ port direct to Europe. In establishing a factory itable alternative. cided to make an initial R 140m investment. on land, their original intention was to use LOderitz is about 780km south of Windhoek, One of the world's largest fishing companies, it only for a 'dry' process, including final so although there is a rail track from the Pescanova have operations in many coun­ quality inspection, trimming, weighing and re­ hinterland, road transport involves travel over tries, including Scotland, Ireland, Canada, packing the hake into cartons and deep­ hundreds of kilometres of gravel roads. The Australia, Chile, Brazil, Namibia, Mozam­ freezing them ready for the supermarket town is also 1500-1800km from the industrial bique, and of course Spain. shelves of Europe. areas where many components of the facility 16 5. Robert Harbour, LOderitz.

6. (below): View from east.

have been manufactured. It is surrounded by Background to Arups' The brief inhospitable desert and many a story is told responsibilities The expanding and changing process re­ of luckless drivers who arrive in sandstorms Arups have been providing a principal quirements led to a dynamic brief and on­ only to discover the paintwork on the sides of agency and full multi-disciplinary service on going construction activity over the three their cars has been sandblasted away. industrial projects in several parts of southern years from 1990 to 1993, in which good docu­ The climate is very temperate with a maxi­ Africa for many years. This project, though, mentation and regular reporting was essen­ mum average annual diurnal range of only has demanded exceptional communication tial. The brief required the establishment of a 8°C and an average rainfall of only 30mm. skills because of its isolation and the neces­ fish factory on a greenfield (or rather bare Not being allowed to water their small gar­ sity to involve more than one Arup office. granite) site on the edge of Robert Harbour, just beyond the northern outskirts of the town . dens, residents tend to allow them to reflect Although the client originally approached the the surrounding landscape, i.e. a few rocks, architects Kerry McNamara of Windhoek, he Phase 1 much sand and maybe a hardy succulent or accepted their recommendations and in The initial facility was to comprise: two (though a few years back they had three March 1990 appointed Arups as principal • A 1500m2 packaging hall, fully serviced years' precipitation in one hour from an errant agent, to undertake all the brief definition, site and air-conditioned to 14°C thunderstorm). planning, engineering, management, quantity • A 60Qm2 x Bm high cold store to The most significant climatic feature. and one surveying and cost control. operate at - 25°C which has a serious effect on building design, With the architect in Windhoek, local mech­ • A cold store air lock is the wind. Although it blows mainly from one anical and electrical engineers and quantity 2 direction, i.e. the south, records show that its • A 1500m store building, insulated and surveyors' staff were used for construction constructed for easy future conversion velocity is greater than 40km/hour for more inspection and cost control. Arups' Windhoek than 40% of the year. to a packing hall office co-ordinated communications, handled • A refrigeration engine room With its considerable sand load this had sig­ all the local authority approvals, and provided nificant influence on the design of cladding, the resident engineer. The client's process • Staff ablutions and amenities windows, doors, louvres. air filters, the carry­ specialist was based in Vigo, Spain, although • A single-storey administration building ing and offloading of fish (normally in open the executive decision-making was made (designed for two floors) trays). and the orientation of the jetty. through a subsidiary. • Workshop facility. 17 ~Centre line of I column ' I '

Roof void as service plenum

Fibre cement 7. Fish processing. cladding

Phase2 A few months after completing construction of Phase 1 in February 1991 , Pescanova re­ quested Arups to proceed with : • A causeway and 130m long jetty to accom­ modate vessels up to 7000 tonnes (to avoid double handling of fish and transport to ~...... --- 100mm insulated and from the main LOderitz harbour) ,,...... ___ Seawater • An ice-making plant, initially of 50 tonnes panel capacity per day

• Storage facilities for 150 tonnes of flake ice •------Potable water • A 40 tonnes/hour ice discharge blow line • A wet fish chill room for holding the product before processing • A covered off-loading and Flexible hose to crate store building conveyor framing • An additional refrigeration engine room • Conversion of two packing halls to wet fish processing • An additional floor on the administration building • Seawater intake facility and UV seawater treatment • Forklift maintenance and battery charging workshops • Extensions to the staff ablutions • A new laundry.

Further facilities had been added subse­ Plastered and quently as an extension to Phase 2: painted brick dado wall, epoxy • A treatment plant and boiler house in which painted internally fish offal is dried, milled and bagged • A temporary seawater pumphouse • A stevedores' ablution and amenity facility. All the above were completed for the official opening in August 1993. Future development During the initial design of Phase 2, a number of circumstances persuaded the client to 8. Typical section of process hall. ask Arups to carry out new masterplanning 9. Process hall in operation. studies. These were because: ( 1) There were already signs of recovery in the fish stocks. (2) The cliertt was considering and subse­ quently purchased the adjacent site to the north. (3) If further process facilities were to be built, there would be a substantial increase in piped services, power, and refrigeration require­ ments. (4) Wet fish processing, being highly labour­ intensive, required substantial increases in staff amenities. A number of planning options based on 'what if' scenarios were produced, assuming vary­ ing increases in fish quotas. These have assisted Pescanova to determine the broad direction of future process requirements and thus future construction. In fact, the results of these studies were used to locate the later Phase 2 buildings on the new property. In anticipation of possible future requirements the client authorized modification of the model of the facility to include Arups' pro­ posed development for the new site. 18 250 The jetty and causeway 2.71 5m mm 6m road 2% crossfall It was determined that a rock/rubble North Armour layer m1 n1mum 1.Sm thK:k: at access causeway (Fig. A) was the most maximum sk>pe 1 :1.5 economic in the shallow water zone up Armour layer minimum 2m thtek at to Sm deep. The local authority re­ nwcimum sk>pe 1: 1.5 quired an independent desk study by the South African Council for Scientific 1.5 and Industrial Research to determine what effects such a causeway would ~:A _I_Sf_____ " ~ 1 have on the local marine environment. " _ _ ------Seabed 1 5 tlli Having obtained clearance on this ,-" ___ .:_ ____ .,:______200mmlhicl< 40MPaconcretepavlng aspect Arups held discussions with the ------J - - · 400mm lhicl< 25MPa mass concrete cap client's fleet captain and the port cap­ Armour layer - minimum two armour stone units thtek. GeoteXble separator tain to resolve the jetty orientation and Armour stone umts to be nominal mass 3 tonnes Core _ unilormty graded quarry run berthing procedures. A. Causeway cross-section. ma,umum1m1n1mum mass: 11onne11kg Inevitably, the orientation of the jetty Jetty ended up as a compromise, giving cen~eline preference to berthing into the very 7.67m 7.67m dominant southerly winds. Although the harbour is reasonably well-protected, the jetty is exposed to swells from the Highesl astronomical open sea to the north-west, which tide level 1 76m means that it may not be operational _ ;t_, __ Chart datum rldal 100% of the time. In fact the over-riding level Om range design forces applied to the jetty are from this condition and allow for a side wave effect on a berthed vessel IM>--- Precast 380mm square columns: equivalent to a force of 11 tonnes/m. lenglhs adjusted 10< Bollard pulls of 30 tonnes were also s,lt depths designed for. Beyond the causeway section, the jetty comprises precast concrete columns in Foundation cast In penmanent ~ Pea gravel and sitt rows at Sm centres, with a precast beam steel shuttering positione

Possible work in the near future may include: of wind-blown sand . The steelwork was fabri­ Credits • Commissioning of a second wet process cated elsewhere at rates substantially lower Client: hall including additional plate freezers than those quoted locally. On al l the many Pescanova SA contracts the client took a very pragmatic atti­ Principal agent, civil, structural, mechanical and • Additional ice-making: total 1001/day electrical engineering, and quantity surveying: • Additional ice storage to total 300 tonnes. tude and was prepared to 'sponsor' Namibian industry if it was within 10% of the lowest Arup Namibia This requires the full refrigeration equipment Frank Louw (project CO-Of'dinator), Jan Hofmeyr (structural), to be installed in the second engine room. price. He also insisted on maximum use of local labour where non-Namibian contractors Pat H,ng (mechanical). Ed Schmidt (electrical). • A packaging material storage bu il ding Bruce Sulley (geotechnical). Paul Monk (civil), were involved. All other building construction Andrew Hakin, Donie O'Loughlin (REs) • Extension of the jetty to a final 210m. incorporated load-bearing brickwork using Architect: Building design cement bricks manufactured on site. Kerry McNamara Architects Planning of the facility was developed in con­ Conclusion Refrigeration engineering: junction with the client's process engineers The project has been challenging, especially Worthington-Smith and Brouwer to minimize the effects of the solid granite in relation to interpreting the client's needs Phase I construction stage only: covering the site, and to provide a hygienic, into a practical brief and planning solution , in Quantity surveying: straight through, product flow that does not working at long range in such a remote part Wicks, Goosen and Pineo 'back track' on itself. of the continent, and in such a unique en­ Mechanical and electrical engineering: The major buildings at the facility were the vironment. It also gave the Arup team an in­ Juliohn Taylor Consulting Engineers process halls (designed to EC standards) sight into a fascinating industry from which it Contractors: International Construction (Pty) Ltd (Phase 1) and the cold store, which are insulated with is hoped further commissions will arise. Salz-Gossow (Pty) Ltd (Phase 2) prepainted zinc-coated steel panels sepa­ Special recognition must go to the client pro­ Marine Civil Namibia Ltd (Jetty) rated with varying thicknesses of polystyrene. ject team for their valued contribution: A. Illustrations: These are supported by galvanized structural Tordesillas , Pescanova CEO; Capt. J. Nimo, 1, 4, 8, A, B: Elaine Lawrie; 2, 5, 6 Photos: Toni's steel framing, each being clad with fibre Operations Manager; G. Mantecon and V. Studio; 3 Photo: Arup Namibia; 7, C Photos: Donie cement to minimize corrosion and the effects Garcia-Echave, Process engineers. O'Loughlin; 9 Photo: Frank Lauw. 19 • 1. Birmingham Road. Phases 1 & 2, with part of the Glasgow Road site.

Introduction shipped the 200km to Harare for distribution The main objectives were: Oxyco Gases is part of the Oxygen Industries in the Mashonaland area. Distribution was {1) to improve customer calling facilities Group, Zimbabwe. a subsidiary of the British previously from Oxyco's Glasgow Road site, (2) to update and increase production Oxygen Company Group (OCG). Oxyco is which also housed the existing dissolved the main supplier of gases to the Zimbabwe acetylene (DA) and hydrogen plants. and distribution of gases market. being sole producer of acetylene, (3) to concentrate all gases functions nitrogen. argon. and nitrous oxide. It also pro­ LPG and carbon dioxide were stored and in one area. vides oxygen for all the country's users filled into cylinders at Manchester Road. 4km away. In 1986 Oxyco appointed Ove Arup & Part­ except Zimbabwe Iron and Steel Co .• which ners as principal agent and multi-disciplinary has its own suppliers. Furthermore, Oxyco With rising demand for their products in consulting engineers for the development. imports and distributes 100% of the carbon Harare and Mashonaland generally, Oxyco Arups were to lead the professional team of dioxide and 30% of the liquid petroleum gas embarked on further development. The main architect Rob Cobban and quantity surveyors (LPG) used in Zimbabwe. part was to be at the new 1.7ha Birmingham Nudds, Mahachi McCormick. Tower Con­ Production of oxygen. nitrogen, argon and Road site, divided by a railway siding from struction successfully tendered for the main nitrous oxide is centered in Gweru and then the Glasgow Road site (Fig. 2). contract.

Hull Road I Mam entrance/exit

O 10 20 30m Oxyco Ca]2 I only I 2 I c...:J Customer calling

I 15 I 'I 23 26 25 Cyltnder marshalling t area 27 J \ Level I \ 1 crossing I \ O:? storage vessel 5 L ;:J \ \ \ I i---1=1,----,1~ 24 l l • CO:? storage vessels Key Phase 1 development 6 I;::: I Road & ----- L Existing building Phase 2 development 1 ~ I rad :i :~!ng D Demolished building [ Phase 3 development 8

10 1 Customer sales & stores 2 Sales office 15 Weighbridge . CJ) 9 3 Platform 16 Senior canteen I §; 4 Guard house 17 Sub-station 1'5 5 Cyltnder charging 18 DAplant 6 LPG cylinder filling 19 Loading slab I 7 Drawing office 20 New hydrogen plant I 8 Sub-station 21 Junior canteen I 9 Maintenance workshop & offices 22 Ablutions 18 10 LPG tanks 23 Existing office block 11 Washbay 24 Existing hydrogen plant : ~ 12 1 2 Carbide platform 25 Existing DA plant I 13 Refuse 26 Workshop 14 19 2. Site plan. 14 Dog kennel 27 Paint & oil store

20 A 4 Rail decanting area sprinklers. A 5 LPG pipes with check-fire tubing.

Project description s1dered before the present 'one-stop' solution Safety was the paramount consideration. The The brief was to manage the project and to was chosen. Customers drive in through the greatest potential hazard is the 190 tonne plan and design the site, including civil work, customer area gate, park alongside the ser­ capacity LPG tank farm and the safety pre­ site services. traHic flow, all buildings and vice platform and, while paperwork is dealt cautions in the design have made it one of building services. All this had to be done in with in the centrally-positioned sales office, the most advanced and safest of its kind in close liaison with Oxyco, responsible for the their empties are replaced with full cylinders. the world. process design. Phase 1 included the follow­ They can then drive straight off and out of the The tank farm was designed to: ing elements: site without turning round (Figs. 1, 2). Stream­ (a) receive and unload both rail tank cars and • customer calling area lining of the process has reduced the time road tankers into the bulk storage vessels customers spend collecting gas by more than • cylinder charging building (b) fill portable handigas cylinders half. • drawing office (c) fill the road tankers which distribute LPG A parking area is provided for other custo­ gas to bulk customers. • maintenance workshops mers who have business with the gases and • LPG storage and cylinder filling facilities welding sales office. Accidents are most likely to occur during • water and electrical reticulation decanting of the LPG from tankers, so strin­ Since the area was to be in constant use by gent safety precautions have been intro­ • fire protection and alarm systems forklifts. cars and trucks, concrete hardstand­ duced. The decanting pipework is embed­ • rail siding ing was chosen for durability. ded in heavily reinforced concrete walls so • surfacing and drainage of the site. The production area has a separate entrance that it cannot be dragged out of the sidings in After a site start in May 1987, all this was in from Hull Road and a driveway incorporating a tow-away situation and is provided with full operation by March 1989 except for the the 22m long, 60 tonne capacity weigh­ emergency shut-off valves. This ensures that LPG tank area which was commissioned in bridge. Again traffic flow was carefully in the unlikely event of such an accident while June 1990. planned in an area used both by forklifts and the tank is being decanted, the flow of LPG big road tankers, as well as being connected out of the tank farm and its pipework system Phase 2 consisted of a new dissolved ace­ to the Glasgow Road site by a railway siding will be stopped immediately and no major tylene (DA) plant and a 60-tonne weigh­ crossing. This area was also surfaced with spillage will occur. bridge, both at Birmingham Road; at the concrete hardstanding. Both the rail and road decanting bays are same time a new substation was constructed Waste water, mainly from the vehicle wash at Glasgow Road . Phase 2 started in July served by a deluge system. On activation, bay and the DA plant, is led via separators to sprinklers drench the tank cars with approxi­ 1988 and the DA plant was commissioned in the municipal sewer system. This is a major May 1991 . Phase 3, a new hydrogen plant at mately 10litres/m2 per minute (Figs. 3, 4). The environmental improvement from the old DA system is automatically operated in the event Glasgow Road, began in January 1991 and plant site which had no such provisions. was commissioned in November 1992. of a fire by a check-fire system, the first of its Waste water from the new Pase 3 hydrogen kind in Zimbabwe, which comprises a nitro­ Also included in the project was a total reno­ plant - small quantities with a low caustic gen-filled plastic detector tube strapped to vation and upgrading of the stormwater and soda concentration - passes through the LPG pipes and strategically positioned sewerage system in Glasgow Road . The total neutralizing tanks to the municipal sewer. all round the central valves at the decanting project value at 1992 cost is approximately these facilities are designed to strict environ­ points (Fig. 5). The plastic tube will melt at a Z$35M (US$6M). mental requirements. certain temperature, triggering the deluge Civil and planning works Oxyco's supply of LPG is transported by road valve by loss of nitrogen pressure. The sys­ The Birmingham Road site had to be cleared and rail. A siding was constructed from the tem can also be manually activated and each of the remaining structures and debris left by main line to the rail decanting area, laid to a segment of the decanting bays can be iso­ the previous occupier before the new facility fall of less than 1: 600 to ensure that tank cars lated individually to conserve water and re­ could be planned and developed. Previously, do not run away if inadvertently parked with­ direct it to where it is most needed. cylinders had been manually handled for out setting the brakes. As an extra safety In both road and rail decanting areas granite filling and horizontally loaded at a site which measure the siding terminates with a sand chips in concrete beds act as heat sinks to incorporated production, storage, filling and drag and a buffer stop. evaporate rapidly any liquid spillage. customer calling. For improved safety and se­ The rails in the siding are insulated from the The same system of heat sinks was designed curity, however, Oxyco now decided to sepa­ service siding rails, bonded together elec­ for the storage vessel area. The tanks are rate the latter from the other production func­ trically, and connected to an earth pin to mounted on reinforced concrete foundations, tions. Cylinders were now to be stored minimize the risk of a static electrical spark in an area specially designed to channel any vertically on pallets and moved by fork lift occurring. major spillage away from the centre of the trucks, reducing the number of back injuries. Mechanical individual tanks and sloped to a catchment crushed fingers and damaged cylinders. The mechanical services include water retic­ pit filled with granite chips, at one end of the The critical factor for the customer calling ulation. cooling water for pr.ocess equipment tank area. The individual tank areas are sepa­ area was traHic flow. Due to the limited size of (DA plant and hydrogen plant) and ventilation rated by low walls to prevent spillage from the site. the area had to be planned very for the DA plant. Fire protection throughout one tank spreading to the other tank areas. carefully to cater for trucks of all sizes without the site, however, was the most significant This system will minimize the spread of fire wasting space, several proposals being con- part of the mechanical design. should a spillage occur. 21 Protection of the tanks themselves was a major concern, water alone being insufficient since the supply required could not be guar­ anteed from the municipal fire mains. After several proposals the best solution was found to be a combination of fireproof insulation and water spraying. Pyrocrete insulation, to reduce heat input from any fire near the tanks, was plastered onto their surfaces over fine metal mesh to hold it in place. To back up this insulation system four fixed monitors were installed to cover the tanks, rotating through 360° horizontally and from below horizontal to vertical. The nozzles. which deliver a constant volume of water, are variable between a sin­ gle solid jet to a fog mist position, giving excellent flexibility of use. Again, they are the first of their kind in Zimbabwe and most spec­ tacular in operation (Figs. 6, 7). The monitors are automatically activated by a check-fire system as in the decanting areas, with the tubes strategically located on control valves on the tanks themselves. They operate separately from the other check-fire system .., and can also be operated and isolated 6 & 7. Monitors in action. 8. Sprinkler support portals. LPG decanting area. manually. ,.. ... The LPG cylinder filling building is protected ---- by a deluge system. Upon activation by heat sensitive bulbs. the entire·building is immedi­ ately sprinkled with large volumes of water. The whole LPG area was designed to the most stringent safety requirements from the latest American and British Standards and the BOGG Technical centre, New Jersey, who recently praised the design as one of the newest and safest LPG tank farms in the world. Electrical The sites are served separately by Zimbabwe Electricity Supply Authority (ZESA) with dup­ licate incoming feeders at 11 kV terminating in a sub-station on each. They provide a maxi­ mum demand load in the region of 2.4MVA. Because of the development proposals for Glasgow Road the existing sub-station, in­ adequate for future demand, had to be demolished. The new sub-station had to be established prior to demolition, which pre­ sented many complexities for transfer and re­ routing of installed distribution cables, with the brief to maintain the existing plant and facilities in operation. All this was successfully Building structures Conclusion achieved. The buildings were designed to be functional, The new development has resulted in a great aesthetically pleasing, and economical. Use improvement to Oxyco's customer service. From each of the sub-stations an under­ of locally available materials to minimize for­ both in terms of increased output and effi­ ground distribution cable network has been eign exchange was a governing factor. They cient service. It has also led to vastly im­ provided in the form of a medium voltage were mainly designed as reinforced concrete proved working conditions for Oxyco's staff. radial supply serving buildings and process frames with brick infill panels and structural With the fire protection of the LPG area in plant. The underground pipe duct system steel roof trusses with asbestos cement roof­ particular and the facility in general, the incorporates draw-in pits with removable ing sheets. The structural steelwork was Harare site is now among the safest pro­ covers to allow access into the system. designed using local sections, the only duction and distribution works in the world. Other facilities include a signal cable network imported item being chequer plate flooring for the DA plant filter press floor. Credits: between all of the buildings, comprising fire Client: and security alarm systems where signals are A number of reinforced concrete portals were Oxygen Industries Group (Pvt) Ltd. Zimbabwe relayed to the Guard House to monitor alarms designed to support the pipework and sprink­ Project manager; design team leader; structural, in any of the buildings. Also included is an ler system for the LPG road and rail de­ civil. electrical and mechanical engineers: underground pipe duct network for tele­ canting area, which was designed to accom­ Ove Arup & Partners Zimbabwe Stuart Perry. phones. modate the largest road tankers and tank Lotte Re,mer (pro1ect management, and suuctural), cars operating in Southern Africa (Fig. 8). Andy Marks (c,v,I ), lgnauus Dube (structural). James Rooney, The installations serving process areas and Chns du Cane, Andy Howard (mechan,cal). Chns Wood , associated plant are to international flame­ The new DA plant, incorporating a carbide Steve Done (elecu,cal) proof standards because of the high risk of store and an acetone store, had very strin­ Process engineers. explosion. These include the power and con­ gent safety requirements. The former had to Oxyco trol systems required for process plant opera­ be absolutely waterproof (calcium carbide Rail engineers: tion, together with plant shutdown facilities in reacts with water to produce highly explosive Civil Technics emergency situations. acetylene) and was covered with a concrete Architect: slab as well as being closed off from the other Rob Cobban Architect Externally, floodlighting has been provided areas of the plant. The carbide loading plat­ Quantity surveyor: Nudds Mahachi McCormick throughout the traffic areas comprising ?OW form was covered, stormwater drains were Hydrogen production unit: SON lanterns wall-mounted on buildings. The constructed on both sides, and a low hump general amenities and administration build­ Bamag GmbH was installed across the doorway to ensure ings have been provided with emergency Main contractor: that no water would be able to enter the store Tower Construction lighting using self-contained luminaries along under any weather conditions. Flameproof all exit routes. Specialist contractor (Phase 2): areas like the acetylene cylinders' filling room Quick Freeze These fittings illuminate automatically on and acetone store were sealed off from the Photos and illustrations: mains or sub-circuit failure and provide three compressor motor room and other areas with 1, 3, 4, 6, 7: Lotto Reimer; 2: Kris Buglear; hours' duration of emergency lighting. potential 'spark danger'. 5. 8: Margaret Waller 22 DOsseldorf Tower Designers: Arup Associates in association with Eller Maier Walter Alastair Gourlay Peter Warburton Terry Raggett

Arup Associates' recent proposal for The building was designed to be a new high-rise building in Ousseldorf naturally ventilated with opening was designed to minimize the impact windows on the east and west of the development on the environ­ assisted by the stack effect of the ment. Prepared in response to an atrium. However, it was also designed invited competition to design an to provide the facility for a consider­ energy-conserving urban office able number of cellular offices. tower, the scheme proposed a Consequently each cellular office was 20-storey block planned around a ventilated by using a separate hollow raked atrium. core plank ensuring that cross ventila­ The site. in the heart of the city on tion was not interrupted by a central Rheinferstrasse am Labnweg near to corridor. the State Parliament buildings and In extreme winter and summer tem­ overlooking a large city park, is peratures the windows in the offices and cross-flow ventilation openings located above a major road which 1. (above): Site plan. 2. (below): North-south section. runs under the site in a tunnel. Con­ are closed and a mechanical plenum sequently the plan of the building is heating and ventilation system used. organized with two 12m wide wings of This makes it possible to recover office space aligned on either side of heat, a technique which is not this tunnel with an atrium between. By normally possible with natural venti­ planning the atrium over the tunnel lation. In the extreme summer con­ and supporting the atrium roof off dition, the ventilation plant introduces each of the office wings, it is possible cool night-time air through other to avoid imposing structural loads hollow core planks. This cools tt·.a within the zone of the underground building for the following day. In the tunnel wh ile creating a daylit hall at extreme winter condition the plenum the centre of the building . heating plant uses heat from the solar The two wings of offices are linked salt store and the co-generation salt by a core housing services, main store depending on demand. entrance, lifts and stairs. In section The east and west facing far;ades the office floors rake back with these were designed to incorporate a sys­ cores acting as buttresses. The whole tem of external rotating screens. glazed terraced building was These provide sunshading as well as designed to reflect a 'green' upward night-time insulation. They can also curve at the end of the Park. The far;ade incorporated solar collec­ small changes in temperature, in con­ respond to the differing requ irements Exhaust fumes and noise from the tors facing south. Behind the solar trast to systems which are normally for daylight throughout the year. entrance to the road tunnel precluded collectors are two towers containing activated only by large temperature The scheme was placed second in openable windows on one face of the phase change salts: a mixture of changes. One was to be regenerated the competition, which was won by building. As this was also the south· selected chemicals which changes by the solar collectors at a phase the local Ousseldorf architect. lngen­ facing elevation, the design created from a solid to a liquid and vice versa change temperature of 30°C and the hoven Overdiek Petzinka und Partner, a solid far;ade wh ich was utilized as around a prescribed temperature. other by a co-generation plant at a who is now working on the detailed an energy source. Th is stores and releases energy with phase change temperature of 50°C. design with Ove Arup & Partners.

3. Model: 4. Model: south north fa9ade fa9ade

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