Article 6 : 30 St. Mary Axis, London

The Swiss Re tower, the City of London's latest landmark Photo: Norman Foster & Partners


London’s first sustainable skyscraper

London’s Swiss Re Tower, officially known as 30 St Mary Axe, is the city’s first environmentally sustainable tall building. In keeping with its commitment to sustainable development, the Swiss re-insurer, Swiss Re, sought to minimise the building’s impact on the environment. Among the building’s most distinctive features are its windows, which open to allow natural ventilation to supplement the mechanical systems for a good part of the year.

The building takes maximum advantage of natural light. This is largely thanks to the lightwells that are one of the building’s hallmarks. The lightwells create the distinctive spiral design that wraps around the exterior. These triangular cutouts, six in each floor, allow penetration of daylight and fresh air to penetrate deep into offices. Floor-to-ceiling windows also contribute to the sense of openness.

Natural daylight and ventilation
The six fingers of accommodation on each floor, configured with lightwells between, maximise daylight penetration, reducing the time that artificial lighting is required. Light level and movement sensors prevent unnecessary lighting, reducing energy consumption and cooling loads.

Wind pressure differentials generated by the building’s aerodynamic form assist natural ventilation through the lightwells and reduce the requirement for conventional air conditioning. As a result energy consumption and carbon dioxide emissions are significantly reduced.

External envelope
The ventilated double skin façade reduces heating and cooling requirements. Its performance can be tuned to maximise benefits that the prevailing internal and external environment might offer. Blinds located within the cavity of the ventilated double skin façade intercept solar gain before it enters the office environment, intercepted heat can then be reclaimed or rejected depending on the requirement for heating or cooling.

Building systems
The building’s primary fuel is gas, one of the cleanest available. Low energy light fittings are specified wherever possible. De-centralised on-floor plant offers the flexibility to supply and control mechanical ventilation on a floor by floor basis. By closely matching supply with demand, energy consumption is reduced compared to a central system for the whole building.

Transportation
Comprehensive public transport facilities surround the site to reduce dependency on private cars without placing undue load on any one element of infrastructure. The provision of cycle spaces within the basement is three times that of the minimum standard required, which together with shower and changing facilities, encourages this alternative means of transport. There are no private car parking spaces in the building.

A common definition of sustainable development is given by the World Commission on Environment & Development 1997: “…development that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

taken from http://citymayors.com/government/london_corp.html



30 St Mary Axis, or known as the Gurkhin, is one of the most popular land mark in the world right now. There are so many elements of the building that can be used as a discussion topics, from the sustainable materials use to the unusual shape of the building.

However, as I have said in earlier post, I love skyscrapers in general - the taller the better :) , but I particularly have interest in the ones with glassy façade. The 30 St. Mary Axis will be a perfect example of the topic. I have done an extensive research on this particular building for my previous assignment, but for the purpose of this blog, i will focus on the most interesting technology it adopts.

The building uses the double skin façade system, which means there are two layers of glass skins. In this case both of the skins are single glazed, with open able internal skin mainly for fresh ventilation and maintenance.


The ventilated double skin façade also reduces heating and cooling requirements. Its performance can be tuned to maximise benefits that the prevailing internal and external environment might offer. The way this works is by having an air buffer in the cavity of the two skins, this air buffer will prevent heat loss form the inside of the building.