She can make digital models of buildings and predict their future energy performance. She can also go into a functioning building to identify, analyze, and rectify errors in thermal performance. She says that very often, buildings do not end up performing the way experts predicted. These are skills she uses:
Catherine says Forensic Engineers must avoid using clues as if they were actual evidence (of the problem and its causes). These are clues: complaints, anecdotes, consultant reports, BMS data, ad hoc solutions, staff theories, and staff observations. On the other hand, these are useful forms of evidence:
Catherine models problems digitally and physically. She also develops theories that she can combine to test her theories:
Catherine gave an example of a shopping mall that had a very windy atrium and a very steep heating bill. No one could identify the causes of these problems. But after six years experiencing these problems, the owners called her in.
With careful analysis of data she collected (using dozens of different routes, including studying air flow by blowing bubbles in crowded spaces where smoke tests couldn’t be used) she identified a number of problems. One was a poorly placed rotisserie oven that was triggering vents to open. Another problem was that the building controls “thought” the building’s vents were completely closed when many were only partially closed.
Catherine devised a £50k solution to closing the vents in winter that is saving the owner £60k every month, in heat alone. There were reduced wind drafts and reduced tenant complaints. She says it saved about £500k in capital and restored people’s confidence in the facility.
Here’s one tool she uses to measure air speed:
She also uses thermal imaging to study air infiltration, like so:
We use this kind of technology in our Energy Cube project. This is a picture from that class last week:
Forensic engineering, she says, is like a jigsaw. You’re given clues, you find evidence, simulation gives context, you test theories, and ultimately prove a solution. She obviously loves her job!