Sailisbury Grade 1 Listed Thermal Building Survey
English Gothic buildings of this design and using stone construction materials, suffer from significant internal pressure changes that create agressive air movement or draft. External stone staircases and tower blocks where built without cavities, single thin glazing in metal frames and overtime will create cracks and perferations in the building envelope, allowing convected air movement throughout. Planning consent restricts the options to retrofit insualtion, double glazing and heating systems so the net effect is these areas remain at a temperature consistent with the outside ambient temperature and are effectively creating cold thermal air bridges and reverse chimneys.
Thermography Survey 1000 Years in the Making
1400 Page Heating Performance Survey Using Aerial and Ground Thermography
Thermal IEC Building Inspection, On the Ground, From the Air and Internal
It doesn’t matter how old a building is, there is always an opportunity to learn more about how to make it more habitable for the people who live and work there.
We were recently asked to complete a full thermal survey of the Grade 1 listed building on the grounds of Salisbury Cathedral to look at the potential anomolies and faults present in the performance of the heating systems. Our survey used drones with thermal cameras for aerial roof and elevation inspections as well as ground based cameras for internal inspections.
The data capture element took a week, with a further four weeks to complete our report of over 1400 pages, it was a truely interesting study!
Situated to the southeast of the Cathedral in The Close, the Salisbury Cathedral School was established during the 1220s and crenelated during the 14th century. Bishop’s Palace has undergone many phases of construction, alterations and repairs. It was restored during the mid-15th century and extended sometime after 1568. A chapel is first documented in 1588.
Parts of the Palace were demolished post 1648, with the surviving elements being converted into an inn and tenements. However, rebuilding took place during the 1660s with further additions taking place during the later 17th century and early 18th century. The palace was refurbished during the late 18th century with further additions constructed thought out the 19th century.
Further parts were demolished in 1931, with sections of the Palace used by Bishop Wordsworth School in 1890. It has been used by the Cathedral School from 1947.… source: Historic England Research Records
The main building was built to an Early English Gothic architectural design originally, which did away with the earlier use of thick, heavy walls, and rounded arches associated with Norman and Romanesque period by using flying buttresses and ribbed vaulting to relieve the thrust of the building outward, allowing thinner and taller walls to be constructed.
It is assumed that the stone used for the main structural walls is limestone, which has good thermal capacitance typically 3 times that of brick, the walls are solid without cavities and no additional building envelope was added over the years. Limestone emissivity is 0.90 – 0.93.
There is evidence from external inspections that some walls/elevations and roof construction (gable-ends) are made of brick, but it is not known if this is structural, an outer-leaf construction with any kind of cavity, or simply a façade.
The windows appear, and are likely to be, mainly as originally installed, using single glazing to stone or wooden (oak) lintels and frames. Some have shuttering available on the inside.
The roof appears and is likely to be as originally installed (may have been added to over time), with a wooden structure (oak) and clay tiles, with no or limited insulation added over time. Metal lead or zinc material, was used in gullies and valleys. There are numerous areas of tile dislodgement, misalignment, and breakage, consistent with age. Chimneys are uncapped.
n.b. Emissivity for the thermograms was set at 0.9 to accommodate the reflective properties of clay tiles. The lead/metal coverings in the roof will show up hotter in thermograms due to the lower emissivity values of metals.
Cold Thermal Air Bridges and Reverse Chimneys
English Gothic buildings of this design and using stone construction materials, suffer from significant internal pressure changes that create agressive air movement or draft. External stone staircases and tower blocks where built without cavities, single thin glazing in metal frames and overtime will create cracks and perferations in the building envelope, allowing convected air movement throughout.
Planning consent restricts the options to retrofit insualtion, double glazing and heating systems so the net effect is these areas remain at a temperature consistent with the outside ambient temperature and are effectively creating cold thermal air bridges and reverse chimneys.
Cold air, being heavier than the warmer air, drops down all three floors through these air bridges and air chimneys into the adjacent rooms, creating a positive air pressure. This could be considered a ‘super convector’ to the building as a whole and cause a significant draught effect.
Building Survey Thermal Inspections
We are certified Thermographers and drone pilots and work throughout the UK to provide both aerial and ground based thermography services. Thermography is an noi invasive inspection option that provides vaulable data that is not visible to the human eye. Together with traditional building survey techniques, thermography provides significant data on the root cause of many building problems from heat perfomance through to water ingress and insulation failures.
Drone Services Enquiry
Thermography | Inspections | Solar | Photogrammetry
Discover how drone technology can enhance your operations with a free quotation from our experts. Get a Free Quote or Make an Enquiry Today!
related posts
Thermography, a non-invasive technique that uses infrared imaging to detect temperature variations, has emerged as a powerful tool in the field of building diagnostics. By capturing thermal images of structures, thermography enables professionals to identify areas of heat loss and energy inefficiency. This article explores the benefits of using thermography to pinpoint heat loss in structures, providing valuable insights into how this technology can help improve energy efficiency and reduce carbon emissions.
Trained and Certified in Aerial Thermography
Drone Media Imaging use trained and certified thermographers to deliver thermographic services and inspections across many domestic, industrial and commercial sectors throughout the UK. Whether it is solar photovoltaic panel inspection in accordance with IEC 62446-3:2017 and BS EN ISO 62446-1:2016 or fire detection and management in disasters zones or underground landfill fires, Drone Media Imaging can deploy across the UK quickly, efficiently and with the right experience.
Aerial Thermography Category 2 Thermography certification to category level 2 focuses on radiometric temperature measurement analysis and the benefits of obtaining precise temperature data from challenging environments for diagnosing and reporting purposes. Whether for qualitative evaluation or quantitative evaluation our report and diagnosis analysis provide you with answers following a non-destructive inspection format from the air via UAV drones equipped with the latest technology. Drone Media Imaging is a small but unique drone operations company specialising in airborne thermal imaging across the UK. Our certification and experience when paired with our CAA enhanced OSC permissions, means we are more than capable of performing any aerial thermal imaging job however challenging. As level 2 thermographers we dive into the fundamental principles of surface emissivity, reflected temperature correction, spatial and measurement resolutions, and as a result providing clients with accurate data reporting that can be trusted.
Aerial Thermal Imaging Infrared Cameras Thermal Imaging cameras capture the reflected radiation from a surface or heat source and convert the recorded temperatures to an image map for analysis. This unique worldview provides numerous advantageous and cost-effective non-destructive options for commercial and residential needs. Aerial thermal cameras of the highest quality provide non-contact temperature measurements in difficult to reach locations that cannot be observe from the ground. As is the case with all drone inspections, the hazards connected with operating at a height are minimised as is the potential of inflicting damage to the structure during the inspection procedure.
Case Study – Explosion at a Grain Store Port of Tilbury London Following an explosion at the Port of Tilbury London grain store in July 2020, Drone Media Imaging were hired to provide aerial thermal data support to emergency service gold commanders and the senior management for the grain store. Flying thermographic data collection missions, hourly, daily, and weekly for over 13 months from the initial explosion and subsequent silo fires, we provided important thermal data reports as the fire developed, enabling the fire management strategy to be accurately measured over time. Comprehensive reports, thermal imaging, RGB photography, and video pictures were used to provide the information essential to effectively manage the problem until the building was destroyed in 2020.
