On the 16th of May three members from the University of Edinburgh research team (Dr Lesley Gibson, Dr Yu Wang and I) headed to South Africa to join the research team at Stellenbosch University. The goal of this trip was to help in preparing and running the first large scale test to be done by the IRIS-Fire group. This test was based on burning 12 dwellings and was planned to in such a way as to reveal valuable data/information regarding the flame spread between the dwellings. The test will also give a sense of the critical factors and measurements which need to be considered in the upcoming larger tests.
To prepare for the test which was planned to be done on Tuesday the 22nd of May, on Thursday and Friday the 17th – 18th of May, we joined Dr Charles Kahanji and Antonio Cicione from the Stellenbosch team to build the measuring equipment e.g. The thermocouples trees (which was used to measure the temperatures in and outside the dwellings), flow probes (which was used to measure the air flow through the dwellings’ doors) and the Thin Skin Calorimeters (which will be used in calculating the incident heat flux outside of the dwellings).
On Saturday the 19th of May Dr David Rush joined the group coming from London and we put the last touches on the measuring equipment and tested it to avoid any surprises on the day of testing.
On Sunday the 20th of May, the IRIS-Fire group had its last meeting before starting the building of the 12 dwellings on Monday. In this meeting, Dr David Rush and Dr Richard Walls lead the talk and explained all the details for the building plan and distributed the roles of every team member. A weather forecaster provided us with the weather updates in the run up to and during the week of the experiments as wind direction/speed was expected to be one of the main factors affecting the flame spread speed and directions.
Unfortunately, based on the weather forecaster update on Monday early morning and because of the strong winds on sire, the experiments had to be postponed from Tuesday the 22nd of May to Thursday 24th of May to allow for construction in safe weather conditions.
It was disappointing to have to change the plan particularly as many stakeholders were invited to watch the experiment and they had to be informed and change their plans.
However, based on experience of large scale experiments, there are often delays and there must always be a workable plan B which is why the Edinburgh team was already planning to stay in South Africa for the whole week. After consulting the weather forecaster, the IRIS group discussed all the possibilities and since Tuesday and Wednesday was forecast to have light wind increasing strength on both Tuesday and Wednesday, the plan changed to building the set up in two days instead of one. We also aimed, to start early in the morning to have a significant progress before the late afternoon, not just because of the wind but also because of the short days of the South African winter.
With a lot of efforts from the team and also the hard working group of workers that were helping in building the setup, the 12 dwellings were up by Tuesday evening.
On Wednesday morning at 6:00 am the team met up and started to carefully set the measurement points and follow the plan to protect/isolate the wires from the fire to keep the measuring apparatus running to as long as possible on the day of testing. The positions needed for the cameras were chosen by Dr Yu Wang who brought all the cameras’ sets from Edinburgh. Cardboard lining on the dwelling’s walls was applied and lastly the wood sticks (fuel load) were distributed inside the dwellings.
Around noon-time, the visitors and stakeholders started to arrive to the site, the attendees were from many different backgrounds, e.g. the fire department of Cape Town, the fire protection and safety engineering technology from Oklahoma State University (USA) and people from the media to cover the event.
At 2:00 pm we started to set the cameras in the pre-planned positions and make sure that all the cameras were working, well protected with fibre glass insulation blankets and also viewing the desired angle. Finally, the step up was complete and we were ready to start the test.
Around 3:00 pm, Dr Rush and Dr Walls gave a brief talk about the test and the safety issues during the experiments. After that, Dr Rush and two firemen started the fire within the first two shacks.
The wind had been forecast to switch from northwest to southeast by the time the experiment started but unfortunately the wind only changed direction later in the day and the experiment took place with the wind blowing in the opposite direction that was planned in the layout.
Because of this, the flame spread was slower than expected and couple of dwellings did not ignite. That showed how effective the wind is to the flame spread. However, there are still a lot of findings not only on the wind effect but also the effect of the insulated walls on the flame spread was clear in this test. More about the results and observations will be published on the IRIS-Fire website later on after the data analysis.
Finally, the Edinburgh team have some field visits to Imizamo Yethu informal settlement in Western Cape.
More large scale tests are planned by the end of the year and early next year in South Africa, the date will be announced on the IRIS-Fire project’s website. Also, large scale experiments will be done this autumn at Worcester Polytechnic Institute (WPI) in the USA. Till the next blog/ paper is published all questions and inquiries are welcome to be received by the principle investigator of the project Dr David Rush via the provided contact details on the IRIS- Fire website.
By Mohamed Beshir