Monday, 28 November 2011

Travelling fires paper wins Lloyd's Science of Risk Prize

Feb 2013 update: Read more about this work and how it ended up in a real building in this post.

We have won the 2011 Lloyd’s Science of Risk Prize in the Technology category for the paper "The Influence of Travelling Fires on a Concrete Frame" (published in Engineering Structures 33).

Winners of the 2011 Lloyd’s Science of Risk Prize. Dr Law is is second from the right.
The work argues that the trend towards open plan offices has changed the types of fire likely to occur in modern buildings. His paper uses science to look at ways to improve engineering guidelines and building design, reduce the risk of travelling fires, and help insurers better quantify and model fire risk. The work was founded by BRE Trust and Arup.

 Progression of the 2.5% and the 25% travelling fires across the floor plate (Fig 4 in the paper)

Temperature profiles for the average rebar in the final bay (Fig. 8. in the paper)

The Science of Risk Prize was launched by Lloyd’s in 2010 to stimulate cutting edge research into the latest emerging risks facing businesses.

For more details on the work, see here the paper (open access), a poster and related presentation.

NOTE: My team also won the 2010 Lloyd’s Science of Risk Prize in the same category with a paper on the modelling of tunnel fires. Two in a row :)

Tuesday, 15 November 2011

Smouldering mega-fires in the Earth system

I just gave the presentation "Smouldering mega-fires in the Earth system" at the conference Exploring the Mega-fire Reality, Florida State University. It went well very,  good questions (~8) from audience and great feedback. The abstract is below.

Smouldering mega-fires in the Earth system

Smouldering fires, the slow, low-temperature, flameless burning of organic matter release anually at a global scale the equivalent to ~15% of man-made carbon emissions. It accounts for the accidental burning of fossil fuels, including natural as well as antropogenic causes. Very large fires of organic matter (mostly in peatlands) have burnt since past millennia for long periods of time (months, years, decades; the longest continuously fires on Earth). Flaming forest fires have been the central focus of most research, but smouldering mega-fires are paramount to the Earth System and have received very little attention. Smouldering is the most persistent type of combustion phenomena; the easiest to ignite, and the most difficult to suppress. Peat fires propagate slowly (~1 mm/min) through organic layers of the ground and can reach depth >5 m when large cracks or a natural piping system exists. It is a 3-dimensional phenomena, spreading deep into the soil and over extensive areas of land. The depth of burn is given by the location of the inert layer, very moist layer (>125%MC) or firefighting attempts. Observed depths of burn reported in the literature range from 0.1 to 5 m, with the average around 0.5 m (=75 kg/m2 of fuel consumption). This is 40 to 90 times larger than flaming fires. In terms of fuel consumption, these are mega-fires. This is of great concern given that world peatlands contain more terrestrial carbon than the forests or the atmosphere. Compared to the natural carbon flux to the atmospherefrom from peatland degradation, smouldering fires is 3,000 times faster. These wildfires burn fossil fuels and thus are a carbon-positive fire phenomenon via soil moisture deficit and self-heating. Warmer temperatures at high latitudes are resulting in more frequent Artic fires and unprecedented permafrost thaw.