Context 165 - August 2020

C O N T E X T 1 6 5 : A U G U S T 2 0 2 0 7 designing not just the functional performance of systems but also their aesthetic performance. He writes that, as with other aspects of historic buildings, a range of acceptable design approaches can be applied, from conservation to complete but sensitive replacement. Regardless of the selected design approach, each must be developed and validated, based on rigorous analysis and understanding of the historic materials and design intent. Most important, the success of these projects will require an even closer partnership between heritage professionals and mechanical, electrical and plumbing engineers. In most historic buildings it has been a sine qua non that for aesthetic reasons services should be concealed. So a multi- disciplinary approach is no less vital where these compete for the hidden space available, and where the cumulative effects of minor alterations may grow unnoticed until repairs, refurbishment or replacements are needed. In ‘Measured performance’, Derek Trelstad, Rebecca Buntrock and Alex Vandenbergh offer greater understanding of the structural capabilities of hollow, clay-tile, flat-arch floors. They emphasise that measurement is central to the design, analysis and repair of existing buildings. Documenting an existing structure through field measurement is the first step in understanding how a building works.With field notes in hand, engineers can turn to a number of tools to evaluate the capacity of the structure. They quote Lord Kelvin’s 1883 observation: ‘When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you can not measure it, when you can not express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.’ Lifts (elevators) span the same period of development as the MEP systems described in this issue. In the USA it was Elisha Otis’s safety elevator (1852) and the initially empty shaft at Fred Petersen’s Cooper Union Foundation Building in NewYork (1853) that were major advancements beyond the traditional floor openings created to hoist material. Romas Bubelis tellingly reminds us that the manually controlled Otis-Fensom elevator in the Birkbeck Building in Toronto was installed when the building was constructed in 1908, the same year that the famous Ford Model T car was first produced. A regularly driven vintage Ford is now a rarity, but the Birkbeck elevator still functions daily as it has for the past 110 years, serving the offices of the Ontario Heritage Trust. Nevertheless, in general the modern demands for larger capacity and the fragility of the original lift enclosures and complex operating mechanisms make preservation of historic lifts exceedingly rare. The ingenuity of early 20th-century electro-mechanical technology is a credit to the engineers of that time who resolved a set of electrical problems using mechanical solutions. In recent years, however, reliability has been a problem. Essential century-old electro-mechanical components were badly worn from usage and while the machinery generally worked, tolerances between moving parts were loose. Furthermore, it was difficult to find, and even more difficult to retain, lift- service personnel who had an understanding of the archaic technology and experience in sourcing or machining replacement parts. The author relates that since a splendid (and well-illustrated) restoration, the operation is again accompanied by the clapping of electrical contacts, the flash of electrical arcs, the whine of the motor, the whirl of the drum and the twang of steel cables, as before, all under the control of an attendant’s hand. Riding in the cab watching the floors pass by is an elevator experience unlike any other. Journal of Architectural Conservation The latest issue of the Journal of Architectural Conservation (Vol 26, No 1, March 2020) is international in coverage, but as always there are wider lessons beyond the UK for professional heritage policy and practice. The March issue begins with a paper from Ülküİnceköse of the department of architecture at the İzmir Institute of Technology in Turkey, dealing with the assessment of the landscape and architectural characteristics of 147 uniquely configured and constructed dovecotes in Anatolia. The author suggests an approach to their sustainability and preservation, with wider insights regarding the assessment of spatial characteristics, construction techniques and materials, and landscape setting. The interest to readers is in the value in methods of close observation and synthesis, thereby defining an overall building typology and informing an understanding of significance, and the needs of structural repair and future conservation. The definition and assessment of the evolution of urban villages in the Shenzhen province in China forms the second paper from Ning Mao and Beibei Gu of the eponymous university school of architecture and urban planning. The authors explore the tensions