British consulting engineer TME has been working with architect Ahrends Burton and Koralek (ABK) on the Embassy in Moscow since October 1998. The project is one of the largest British Embassies in the world, and located on a site – a kink in the river Moskva – that most developers would kill for.
ABK's Hugh Morgan had a vision combining work, leisure and relaxation, which he describes as "rather un-British". Modernity was a key theme – it is intended to promote the building as "a showpiece of British culture".
The resulting T-shaped grouping of buildings consists of an office block with a high security tower, apartments and leisure facilities. Originally the scheme was intended to be much larger, with an even tighter security overlay – designed with a siege mentality.
Not surprisingly, this proved to be prohibitively expensive, and with the Russian political rapprochement, it was trimmed back. However, it will still cost £60 million.
It was a traditional form of contract with competitive tendering. Contractors Taylor Woodrow International had a 50:50 joint venture with the Finnish firm Skanska OY – already well versed in Moscow building.
Taylor Woodrow procured most of the services, and bought most equipment in the UK. This was good for TME, because they could be confident its design would be adhered to.
The building in context
Surprisingly, perhaps, the building follows European and British Standards, including the UK Building Regulations. A local architect was employed to negotiate with planners and the utilities – a protracted process in Moscow, particularly for the British government which cannot line functionaries' hands with silver.
Russia's parliament building, the White House, is half a mile up river from the new embassy, and the American Embassy is also nearby. However, rather than being a political centre, the district is mainly residential. It is a mile and a half from the Kremlin and city centre, and has a single street of shops.
The 21 000 m2 Embassy complex has a square plan, with a T-shape of prominent tall buildings (five to nine storeys) occupying the western edge of the site. This western edge runs parallel to Moscow's river and a road built on the embankment.
The top of the T consists of the political building – which includes the very high security 'Chancery tower' – and three apartment blocks. The press and commercial departments are housed in the vertical of the T which extends to the eastern edge of the site.
The T is flanked by two lower buildings: a leisure centre with swimming pool, squash court and social club, and a building for visa applications. All buildings are linked at the first floor by a covered walkway – the podium.
The parts of the complex that are closed to public access effectively form a self-contained, mixed-use enclave. Communal areas are located at ground level on the double-height covered walkway.
Accommodation in the three apartment blocks is, like the plantrooms, located on the third floor – well above the snow layer.
A brief history
The design team was first appointed in 1989. From the start TME had "a very loose rein" over building services design. However, the reins were tightened somewhat during value engineering meetings that pushed out some of the more costly design concepts.
The final sketch plan (equivalent to RIBA Stage C/D) formed the basis of the brief. TME's engineering design criteria were drawn out of this plan, as was an internal sub-division of treated areas. The client specifically wanted a commercial consultant's specification and input early on to keep costs down.
The flexible brief in this project is unusual in public sector procurement, says TME. This project was exceptional, however: embassies must vary to meet particular needs and political situations. Each is unique.
The Foreign Office steered away from the private finance initiative (pfi) – partly because of the security overlay required in this location. There was even some talk about the risk of the Russian Mafia becoming involved in the project had it gone the pfi route.
During design work there were weekly meetings between TME, the architect, project manager London Group, Ove Arup & Partners and the quantity surveyor Hanscoms.
High security, high-rise
During construction, a 2·5 m high concrete wall with razor wire encircled the site. If this wasn't enough of a deterrent to would-be spies, cctv cameras, a strict entry pass regime and 24 h surveillance were also set up to maintain site security.
The Chancery area used only UK labour, and strictly vetted labour at that. Chancery security measures also dictated how construction materials were sourced. The tower had to be built entirely from EU materials – preferably British – which were stored and delivered under a diplomatic seal.
Ultimately, increased purchasing power from sourcing the materials together, and relatively simple logistics, sealed the case for shipping all materials en masse from the UK.
Open doors
Many parts of the complex will be open to the public – partly because of the Embassy's desire to promote UK trade. Russian nationals are also expected to be working in the buildings as cleaners, maintenance staff, etc. This clearly opens up security issues.
However, Russian nationals will be excluded from the Chancery tower, as indeed will TME themselves when building is complete. Of course, this lack of access means that the building must be snag-free at handover.
Although Moscow is, at 548, on the same latitude as Glasgow, ambient design criteria were startling by comparison to those used in the UK. Design temperatures of 30°C in summer, falling to -30°C in winter, cause massive frost coil and humidification loads.
On top of this, diurnal swings are relatively small – lower than in the UK – which, together with very poor air quality and road noise, means that night cooling is not an option.
As if the 2·5 m wall with razor wire wasn’t enough of a deterrent to spies, cctv and 24 h surveillance were also set up
Keeping it clean
It seems ironic that in Moscow, with unburnt hydrocarbons heavy in the air from small-scale coal and gas-fired power stations, the authorities insist that new buildings have flue emissions that meet Scandinavian quality standards. There is also a requirement on new developers to pay for upgrading the dilapidated infrastructure: the electricity network, gas supply and drainage.
Regarding drainage, TME was obliged to filter surface water drainage. There are separate foul water and surface water drains in the city, with no treatment of surface water before it is returned to the river.
TME used a bespoke mechanical filtration system, which produces water that meets "more or less fishery standards", claims TME director Alan Bacon.
The low technology backdrop prompted TME to design services to be as simple, and common, as possible. Conventional reciprocating chillers are used for refrigeration, for example, because these are often used in Moscow, so local engineers are able to repair them.
On the heating side, however, TME took a different tack. While heat energy is usually served from Moscow's district heating system, here the client went to great lengths to obtain a gas supply, which is very rare in Moscow.
TME learnt during concept design that even the military can't get permission to use gas. Therefore, despite a medium pressure gas main running past the site, TME actually designed a district heating fall-back position. Protracted negotiations with the authorities were only resolved when the deputy mayor stepped in to sanction the use of gas.
This was just as well: Moscow's district heating is notoriously unreliable – turning off for a month in summer, for example, which means no hot water is available.
In winter the district heating system is even worse: it can take days to respond to a dip in temperature. Even when working properly, it is better suited to the two-a-penny Stalinist buildings with high thermal mass and a slow response time, than to more modern, lightweight construction like the Embassy.
Letting the air in
Although formal energy targets were not set, U-values were strict – about half the UK equivalent for the whole building: 1 W/m2K overall, or 0·23 for walls. The architect was also careful to ensure low infiltration and no cold bridging in detailing.
TME's aim was to supply tempered air to all occupied spaces: accommodation, offices and leisure/amenity spaces. Natural ventilation was ruled out because of traffic noise, poor air quality and mosquitos. Nevertheless, at the architect's insistence, there are openable windows throughout the complex – in an attempt, says project architect Hugh Morgan, to "humanise" the embassy.
Plantrooms have been designed to draw air into a plenum through low velocity louvres. Air comes in under carefully detailed overhangs that minimise snow entry. As an additional fail-safe, the plenum is large enough for maintenance staff to enter and sweep the snow out, and has drainage to remove snow that melts before it can be dealt with.
Designers worked with the client to score possible air conditioning systems: fan coil hybrid systems, variable refrigerant volume systems, variable air volume hybrids, chilled beams and ceilings.
They considered the effect different systems would have on flexibility, maintainability, plant and riser space requirements, capital cost and running costs. The client's strong preference for partitioned cellular offices and separating maintenance from office spaces (to cut the risk of bugging) made the Carrier Air Treatment Module (ATM) system a clear winner over the alternatives.
This system is a four-pipe fan-coil unit that generates higher external pressures than normal fan coils: about 200 Pa. It is housed in plantrooms on each level rather than plenums (which are potential hiding places for bugging devices).
The apartments have a separate ventilation system. They are supplied with 1 ac/h for a full 24 h/day as mechanical background ventilation, supplemented by natural ventilation from the windows at residents' discretion.
Staying warm and cool
TME designed for 23±C in internal spaces, which is now its standard for office areas. 21 or 22°C is felt to be too cold – especially for Muscovites, not used to air conditioning.
TME looked overseas – and particularly to ASHRAE – for guidance about how to deal with the very low winter temperatures. It used hygroscopic thermal wheels for sensible and especially latent heat recovery on all air handling units. Radiators linked to dual fill gas and oil boilers meet space heating needs.
The heating system does not conform to UK conventions: radiator flow temperature is 908C, while return is 70°C. This is close to the continental norm, say the engineers, but the flow is 10°C higher than the UK standard. The choice of return temperature is part of the legacy of keeping district heating in mind – district heating users are fined if they fail to return water at 70°C.
The main rationale for the high temperature difference was to cut pumping costs. By doubling the differential between flow and return, only half as much water needs to be pumped – an important consideration on such an extensive site. The high temperature difference brought an additional benefit: radiators could be smaller, again reducing costs.
Turning its attention to summer conditions, TME provided comfort cooling for apartment bedrooms in the shape of two-pipe chilled water fan coils, along with conditioned fresh air. Chilled beams are used to cool the medical centre and nursery. Both areas are highly glazed, and may therefore be vulnerable to overheating.
TME has not gone for the UK norm of steam humidification – commonly thought to be the most reliable way to avoid Legionella. This approach would have needed so much electricity an extra substation would be needed. Instead, the engineers chose a wetted cell system, as favoured in Germany and Scandinavia, with extra belt and braces precautions against Legionella.
Bringing in power and light
High voltage power is brought into the site on two independent ring circuits feeding four transformers – so any one transformer in either circuit could fail with no loss of power. Unusual in Russia, the embassy also has diesel generators as back-up protection against a terrorist threat or power failure.
Procurement of lighting for the project was straightforward. Most was sourced in the UK. Lighting designer Eric Maddocks chose a fairly standard modular system for the offices.
It supplies 400 lux for 12-15 W/m2. A single compact fitting from Whitecroft, 400 mm x 150 mm and rated at 36 W, is installed at each point in the 1·5 m grid to allow for future flexibility – a 'safe' design.
Design for cold climates
This project isn’t TME’s first taste of designing embassy buildings. It also designed the British Embassy in Oman, the Quito embassador’s residence, and the Saudi Arabian Embassy in London. It is unusual among consultants to the Foreign Office in having worked on three separate buildings – usually the work is spread around. TME also had prior experience of working in cold climates – particularly Canada – so knew what points to make clear to the architect. Oversizing of the louvres, for example, to prevent snow from entering, and locating air intakes in places at low risk of snow cover. Similarly, rainwater pipework has to run internally where possible to prevent freezing, and with trace heating in the external gutters to encourage thawing. The gutter heating may seem trivial, but casualties from falling guttering icicles are common in Moscow, so this kind of forethought is appreciated by passers-by. Underground drainage is trickier in cold climes too. On-site drainage has to be below the frost layer – 1.5 m–which means outfalls need pumps to reach deep enough. In the plantrooms, air handling units need very large frost coils, which added a consideration to the sizing equation for plantrooms. During building, too, innovative techniques were needed to cope with the cold. Plastering, for example, was sprayed on very thin to dry more quickly. Concrete for foundations had to be heated with hot air to dry.Source
Building Sustainable Design
