Data Collection Methods

7.1.1 Blower Door Tests

Blower door tests were carried out in three individual flats in the north building in August 2013 while the building was vacant (Figure 7.1).

Figure 7.1: South facing elevation of north building indicating blower door test flats [Architect 2, 2006]

The advice for testing student halls of residences is to test whole blocks, but the fan equipment was too small to achieve pressurisation of whole blocks, so only individual flats could be tested. This meant that the blower door equipment had to be fitted to the main entrance door of the test flats, which were internal doors (Figures 7.2 and 7.3). The pressure tubing supplied with the equipment was short, and it was not possible to place the external tubing outside the building; instead it was placed in the stair core (Figure 7.3), which was normalised with atmospheric pressure as much as possible by opening the external door and windows in the stair core. The test flats were selected for the following reasons:

Figure 7.2: Blower door equipment setup in main entrance door of test flat

• The flats have a large area of external walls and small area of internal party walls, which is important because the test aims to measure the external fabric

• The test flats were fully modular, so the tests focus on modular performance • The flat entrance door aligned with the flat corridor, which helps fan pressurisation • The stair core had a simple layout, helping to normalise pressure with outside

There were uncertainties about how best to conduct the tests; primarily in how to treat the adjacent flats. Multiple tests were carried out, with variable door and window positions (open or closed) in the adjacent flats, to determine the optimal setup. The variation in results between different setups was very small, and it was concluded that the setup of the adjacent flats was not critical, other than to ensure to repeat the same setup for each test so the results could be compared.

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The three flats were tested using test method A (ventilation ducting and trickle vents unsealed), only Flat 4 was tested with test method B (ventilation ducting and trickle vents sealed), due to difficulties sealing the extract vents in the shower pods. The surface area used in the calculations was for the whole area of surfaces that bounded the tests zone, including the floor (100.9m2), ceiling (100.9m2), internal walls (37.6m2) and external walls (74.7m2), which is the advised approach for non-standard tests [British Standards Institution, 2001; DCLG, 2016].

All tests had the following features: • Multi-point depressurisation test

• Horizontally and vertically adjacent flats: All windows and doors closed • Stair core: All windows and main door open

There were no issues with the quality of the data obtained from the blower door tests. The external wind speed was low during testing, averaging between 3.6m/s and 4.2m/s, with a maximum of 5.1m/s on the third test day [UK Met Office, 2014c], therefore it did not impact on the accuracy of the test.

Figure 7.3: Architect’s plan drawing marked to show setup of blower door equipment for testing individual flats [Architect 2, 2006]

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7.1.2 Infrared Thermography

The infrared thermal images were taken of the external facade on two days: the 8th and 12th of February 2013. The imaging of the external facade was intentionally done on cold, dry, overcast winter days, early in the morning shortly after sunrise, for the reasons described in Chapter 3.10.

In hindsight the images taken could have been improved. Inexperience in optimising images meant that many images were not taken perpendicular to the facade, which is ideal. There was no possibility to retake the images after this was realised. However, the same temperature variation patterns were observed irrespective of angle; therefore the angle did not appear critical, and the images were deemed to be acceptable.

7.1.3 Building Inspections

The Loughborough study was inspected internally and externally with the aim of identifying anything that could be detrimental to fabric thermal performance. While multiple visits were made to the London study, inspection of the fabric was not really possible because the near constant occupancy did not allow access inside modular rooms, and it was difficult to inspect the external fabric from the ground floor (particularly because the cladding on the non- modular ground floor differed from the modular storeys above). Therefore findings from inspections relate to the Loughborough study only.

7.1.4 Review of Construction Photographs

A review of the photographs from the factory and construction sites was conducted to investigate the thermal performance of the fabric.

Photographs taken during visits to the factory helped provide a detailed understanding of the modules, but they yielded few findings about fabric thermal performance. The visits were made in the early stages of the research; the aim of those visits was to gain a general understanding of the design and manufacture. Therefore, the data collected were not best suited for assessing thermal performance, because there was insufficient focus on the relevant details, such as junctions.

Construction site photographs were included in the design documentation obtained from however there was no consistency between the documents for different buildings, some contained many photographs, and others none. The majority of images focussed on the modular construction (module installation and modular interfaces); there were far fewer of cladding, roofs, foundations, non-modular construction, curtain walling, and the interfaces between these features and the modular construction. Therefore, it was not possible to analyse all aspects of construction on site using the photographs.

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7.1.5 Review of Design and Construction Documentation

provided access to much of their documentation, which included generic documentation and project specific documentation.

The generic design and construction documents detailed the standard module design (for low and medium-rise construction), dimensions, materials, fire testing, acoustic testing, structural integrity, U-Value calculations, interstitial condensation analyses, thermal bridging calculations, and manufacturing drawings used in the factory.

Project specific documentation was obtained for most buildings, and primarily comprised AutoCAD drawings detailing various design aspects, but also meeting minutes, costing information, photographs, material specifications, structural analyses etc. The types, quantity and quality of documentation varied significantly between projects.

Time was spent reviewing these documents, particularly for the case study buildings, to understand the design of the buildings and to assess the quality of the design in terms of thermal performance and buildability.