News

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Limiting Oxygen Index of Smouldering Revealed

Sep 2022

The standard test of Limiting Oxygen Index/Concentration (LOI/LOC) is widely used to determine material flammability. However, the LOI of smouldering fire is never explored. We propose a standard test to measure the LOI of smouldering under the forced oxidiser flow. It is surprising that smouldering peat fire can be maintained below 2% oxygen concentration, which is much lower than ~15% for a flame. This work is led by Yunzhu Qin and published in Combustion and Flame. This new test method is also patented (No. 202211154962.3)

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Group Tour to Sotheby's Show

Oct 2022

It is a tradition of PolyU Fire Safety Lab to visit Art Gallery. This time we visited Sotheby’s Hong Kong Autumn Sales & Exhibition at the Hong Kong Convention and Exhibition Centre. The highlight in the show is the private collection of the late Sir Joseph Hotung, featuring hundreds of distinguished works spanning Chinese Art, English Furniture, Old Masters, Impressionist Paintings and more. Nevertheless, most members are more interested in these luxury watches. 

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Layer-to-Layer Battery Fire Spread in Low Pressure

Sep 2022

Low atmospheric pressure is a typical ambient condition for batteries in air transport. However, the understandings of thermal runaway propagation in open-circuit batteries at low pressure are still limited. Our latest work revealed that layer-to-layer thermal runaway propagation rate decreases with SOC decreasing, as low pressure can weaken both external flaming combustion and internal thermal runaway reactions. This work is led by Yanhui and published in the Journal of Energy Storage.

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Minimum heat flux for wood to smoulder

Sep 2022

For most of the fuel, the minimum irradiation to pilot a flame is about 10-15 kW/m2. However, for smouldering ignition, the minimum irradiation could be only 5.5 kW/m2, providing a shortcut for fire incidents. Under low irradiation, a much longer heating duration is needed to create a smouldering front of about 3 cm. Otherwise, the smouldering ignition cannot be sustained without irradiation. This work is led by Dr Zhirong Liang and Dr Shaorun Lin and published in Fire and Materials

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Smouldering Direction Alters Emission Flammability

Sep 2022

Using smouldering combustion to process the waste is promising, but it will generate toxic and flammable gases. Nevertheless, forming a 2nd-stage self-sustained flame to process the emission makes the whole process clean. Our latest study found that the flame is easier to be sustained for the emission from the opposed smouldering process. Thus, the combination of opposed smouldering and flame is preferred for the waste processing. This work is led by Yuying Chen and published in Fuel Processing Technology

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Using AI and Image to Find Real-time Fire Power

Aug 2022

In the fire lab, we can measure the power of fire by the consumption of fuel or oxygen. However, there is no method to measure the power of a fire incident. We propose an AI-Image Fire Calorimetry to measure the real-time fire heat release rate. It uses the fire image and power from the NIST database to train the deep-learning model and then can calculate the power of any other fire. This tool can be installed as a mobile APP and in UAVs to help fire emergency response and decision-making, so it has great potential in future smart firefighting. This work is led by Zilong Wang and Tianhang Zhang and published in Proceedings of the Combustion Institute

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GNN Network to Predict Flashover

Aug 2022

Critical fire events like flashover have been the leading causes of firefighter deaths and injuries. This new work proposes a scene-agnostic model (FlashNet) to predict flashover based on limited heat detector temperature information. It adopts the graph convolutional neural networks (GNN) to effectively learn features from the limited temperature information and building structure variations to support firefighting. This work is in collaboration with the National Institute of Standards and Technology (NIST) and published in Engineering Applications of Artificial Intelligence

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Deep learning to Forecast the Transient Tunnel Fire

Aug 2022

Real fire changes with time and space rapidly, influenced by fuel distribution and wind. Most existing AI models can only identify the fixed fire location and size but cannot handle a transient fire. We propose a new AI model that is trained by massive transient tunnel fire (changing fire location and power). Then, this model can forecast the potential fire development with at least 30 s lead time. This work is led by Xiaoning Zhang and published in Tunnelling and Underground Space Technology

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New Members Join in PolyU Fire Safety Lab

Aug 2022

This autumn, we have a few new members. Big welcome!

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Lab Demonstration for PolyU Alumni 

Aug 2022

In celebration of the PolyU 85th Anniversary and to foster and strengthen the bond between the Faculty and its alumni, the Faculty of Construction and Environment hosted the first ever Alumni Reunion Day on campus on 13 August 2022. More than 200 participants attended the event. PolyU fire lab made a series of fire test demonstrations to our alumni, showing the latest research on smart firefighting. Ho Yin Wong and Tianhang Zhang are introducing the fire dynamics to visitors.

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 Peiyi Passed PhD Viva with a Rating of Excellent

Aug 2022

Peiyi successfully finished her PhD thesis defence on 15 August 2022 with a unanimous rating of “Excellence”. The thesis title is “Dripping Ignition Mechanism and Fire Risks of Thermoplastic Drips”. The chief supervisor is Dr Xinyan Huang. The external examiners are Prof. Kazunori Kuwana (Tokyo University of Science) and Dr Cristian Maluk (University of Queensland). The content of Peiyi’s thesis is now published in four journal papers in Combustion and Flame, Applied Thermal Engineering and Fire Safety Journal. Big congratulations to Dr Peiyi Sun.

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Xinyan Visits University of Technology Sydney  

Aug 2022

Dr Xinyan Huang received the Key Technology Partnerships Visiting Fellowship to be a visiting scholar at the University of Technology Sydney (UTS) in the Summer of 2022. The hosting professor is Dr Nic Surawski. Xinyan also gave a seminar about the latest clean smouldering waste processing technology. Currently, Yuying Chen is pursuing her dual PhD degree in UTS, and more research collaborations will be established in future. 

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Xinyan Visits University of Queensland Fire Group  Aug 2022

As invited by Dr David Lange and Dr Vinny Gupta, Xinyan gave a talk, “Smart Firefighting Driven by Artificial Intelligence”, to the Fire Group at the University of Queensland. This talk introduces the latest research from PolyU SureFire Group. The full video can be found on the YouTube channel of UQ SFPE student chapter.

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 Xinyan Visits Australia Bushfire National Lab and ANU  

Aug 2022

As invited by Dr Andrew Sullivan, Xinyan visited the Australia Bushfire National Lab in Canberra, one of the best wildland fire research labs, and saw the demonstration of fire spread experiments in the latest wind tunnel. Xinyan also visited the Australia National University (ANU) and gave a Seminar - Smouldering Wildfires in Peatlands: Challenges from the Earth’s Largest Fire. The presentation video can be found on the official YouTube channel of Fenner School of Environment & Society at ANU.

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Xinyan attended 39th Combustion Symposium

July 2022

The 39th International Symposium on Combustion is finally held in a Face-to-Face model in Vancouver, Canada. This bi-annual event is the largest conference in the combustion area, attracting about 1000 attendees. Dr Xinyan Huang attended this symposium, probably as the only one who had flown from China, because of the travel restriction under Covid-19. Xinyan gave an oral presentation on the latest AI-Image Fire Calorimetry and another two posters on smouldering combustion and AI-driven forecast of backdraft. 

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What is the Shortest-Time Fire Spread Curve? 

July 2022

Fire spread is a continuous piloted ignition of the unburnt fuel in the condensed phase. This study extends the conventional problem of the fastest fire spread to the shortest-time problem of the whole fire path. Two typical fuels, thin wires and thick PMMA bars, are chosen, and the transient and overall fire spread rates are measured. Multiple paths of different shapes are explored by fixing the overall fire-spread length and the same elevation of start and endpoints. This work is published in Scientific Reports

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 Pressure Promotes or Limits Battery Fire Spread?

July 2022

With the extensive application of batteries in low-pressure scenarios, such as plateau, aircraft, and spacecraft, battery safety at low atmospheric pressure has been an emerging topic. Our recent experiments found that the thermal runaway propagation rate in parallel-connected battery modules would first increase and then decrease as ambient pressure decreased from 100 kPa to 0 kPa. The dual effect of ambient pressure and limits of thermal runaway propagation have been explained. This work is led by Yanhui and published in Applied Thermal Engineering.

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Modelling near-limit flame above smouldering wood

July 2022

Last year, we found an interesting near-limit blue flame sustained on the hot smouldering wood surface. This time, we further numerically simulate this near-limit flame. The solid phase smouldering is modelled by Gpyro, and the flame is modelled by Fire Dynamics Simulator (FDS) with the DNS solver. This work is led by Dr Shaorun Lin and published in Fire Technology

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Zilong won the SFPE Student Research Grant

July 2022

Zilong Wang (2nd year PhD student) wins the latest Student Research Grant from the Society of Fire Protection Engineers (SFPE), and there are only four awardees worldwide. SFPE will provide US$5,000 to Zilong for doing independent research on Smart Fire Calorimetry Driven by Image Analysis and Artificial Intelligence. Zilong is the 2nd awardee of this student grant in PolyU and Asia after Shaorun won the 1st one in 2021. Congratulations to Zilong! 

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 Xinyan Visits UK Universities

July 2022

Dr Xinyan Huang made an academic visit to UK universities, including Imperial College, Kings’ College London (KCL), and the University of Edinburgh. New research collaborations have been established with Dr Francesco Restuccia on battery fire safety and artificial intelligence. Hosted by Dr Stephen Welch, Xinyan gave a talk about the latest development of the SureFire smart firefighting system to the fire research group at the University of Edinburgh.

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SFPE HK Student Chapter Won the Gold Medal Again

July 2022

The SFPE HK Student Chapter was founded in late 2019, and it is the first student chapter in Asia. Since the winning of the Gold Medal in 2021, the chapter has won the Gold Medal again after organising many seminars/webinars and other extra-curriculum events over the late year. The current chapter president is Tianhang Zhang (2nd year PhD student). Congratulations to everyone! 

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What is the Flashpoint of Plastics?

June 2022

The melting and dripping of burning thermoplastics can cause a new ignition and form a plastic pool fire, resulting in a significant fire risk. This work investigates the burning dynamics of polyethylene (PE) vs polypropylene (PP) pools fully melted at 380–410 C on a hot plate with a controlled area and initial temperature. The flashpoint of the plastic pool can be defined when an intensive burning Pattern III occurs, that is, 310 C for PE and 260 C for PP. This work is led by Peiyi Sun and published in Applied Thermal Engineering

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 Review Structure Fire Tests of Composite Floors

June 2022

The utilisation of composite floor systems in modern construction allows for building large floor areas with efficient use of material and labour. We first summarised the composite floors being studied. Then, theoretical design and analysis methods are discussed in light of the reviewed literature. Finally, this review coalesces the knowledge generated from the literature and lists the remaining challenges in the area, and set out a set of recommendations for designing composite floor systems for fire. This work is led by Dr Anwar Orabi and published in Fire Technology

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Smouldering + Flame = Clean Waste Removal

June 2022

We successfully apply a newly developed smouldering-based waste removal technology that can remove coffee waste, wood waste, and simulated sludge via using a flame to clean smouldering emissions. This work enriches strategies for the clean treatment of smouldering emissions and promotes an energy-efficient and environmentally friendly method for organic waste removal. This work is led by Yuying Chen and published in the Journal of Cleaner Production

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Gulzhan got Full PhD Scholarship from UPenn

May 2022

Our undergraduate student, Gulzhan Aldan, will continue her study as a PhD student at the University of Pennsylvania (UPenn) with a full scholarship. Gulzhan got the BEng degree in Building Services Engineering with first-class honour at PolyU. Her final year project is on immersing cooling for battery thermal management and won the student award from the Hong Kong Institute of Engineers. Congratulations to Gulzhan!

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 How to Slow Down the Battery Fire Spread

Apr 2022

Mitigating thermal runaway propagation is of great significance to ensure the safe application of high-energy lithium-ion batteries. The recent work collaborated with the Guangzhou Institute of Industrial Technology has comprehensively investigated the characteristics of thermal runaway propagation in the large-format battery module and developed ultra-light firewalls to slow down the battery fire spread. This work is co-authored by Xinyan and Yanhui and published in Process Safety and Environmental Protection.

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12th Int Conference on Structures in Fire

 SiF 2022 @ PolyU Call for Papers

Apr 2022

The 12th International Conference on Structures in Fire (SiF 2022) will be hosted by PolyU in Hong Kong at 30 Nov - 2 Dec 2022. The conference is organised by the fire group at the Dept of Building Environment and Energy Engineering.

  • Abstract Submission: 27 May 2022

  • Abstract Results Announcement: 15 July 2022

  • Full Paper Submission: 16 Oct 2022

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PolyU Subject Ranking Keeps Increasing

Apr 2022

In the latest QS World University Rankings by Subject 2022, PolyU has attained remarkable results across different disciplines, reflecting our accomplishments in both education and research.

Our Dept. of Building Environment and Energy Engineering as well as Fire Safety Research Group mainly contribute to Architecture / Built Environment and Civil and Structural Engineering. 

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 Tianhang elected as SFPE GCI Student Fellow

Apr 2022

Zhang Tianhang was elected as one of four Global Student Research Fellows of the Society of Fire Protection Engineers (SFPE) Grand Challenges Initiative. SFPE Grand Challenges Initiative aims to identify how fire safety science and engineering can contribute to addressing pressing challenges. Tianhang will be awarded USD 5,000 to conduct independent research in the area of Digitalization, Artificial Intelligence, & Cybersecurity. 

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 Forecasting Flashover Using Deep Learning 

Apr 2022

People trapped in fire and firefighters are facing unknow fire risks due to the lack of fire information. This work proposed a deep learning framework to predict temperature growth and flashover in real-time. We found that the deep learning model can predict the flashover occurrence with a 20 s lead time in a 1/5 scale model. This work is led by Tianhang Zhang in collaboration with the National Institute of Standards and Technologies (NIST) and published in Fire Safety Journal

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Microgravity Fire Spread over Ultra-thin PE Film

Mar 2022

The fire in microgravity spacecraft environment is a big safety concern, but the fire dynamics are difficult to study on Earth. This work explores the fire spread in ultra-thin PE film in a microgravity drop tower. We found that without fuel removal by dripping, the fire in microgravity could be more dangerous. This work is in collaboration with Institute of Mechanics, CAS and published in Microgravity Science and Technology

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Comparing building facade fire standard tests
Mar 2022

The building facade system is a key part of green buildings and carbon neutrality, but its fire safety is a global problem. Many large-scale facade fire standard tests are different from country to country, and their test results are difficult to compare. This unique numerical work explores the equivalent façade fire scenarios for different standard tests. By adjusting the total fire HRR, the matching fire intensity can be achieved without setup changes. This study, led by Yizhou Li and Zilong Wang, is published in Journal of Building Engineering.

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 Smart fire detection based on the alarm sound 

Mar 2022

Nowadays the fire alarm system has been commonly installed inside buildings to produce an alarming sound in case of a fire. Such a stable and recognizable sound field inspires us if we can use it to monitor the fire development. This work was therefore carried out, which investigates using the pressure variation of the alarm sound to estimate the HRR variation of a room fire from ignition to extinction. In particular, only one microphone is required in the room for detecting the sound variation. This work is led by Dr Caiyi Xiong and published in Journal of Building Engineering.

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Flammability Database of Historical Buildings

Feb 2022

Chinese historical buildings contain massive flammables like candles and incense burners and decorate rooms with various textiles, posing a significant fire hazard. This work forms a flammability database for common fuels used in Chinese Historical Buildings that lays a foundation to quantify their fire risk. This work is led by  University of Science and Technology of China and published in Combustion Science and Technology

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 Ventilation and Limitation of Kawagoe's Law 

Feb 2022

Kawagoe’s Law is an essential correlation in compartment fire research, which defines the relationship between the ventilation factor and maximum fuel burning of the compartment. Although this law has been widely used, there is still a lack of numerical validation and knowledge on the limiting conditions of its application. This work performs a numerical study of a full-scale compartment fire to validate Kawagoe’s Law and explore the limiting conditions of applying Kawagoe’s Law. This work is led by Zilong Wang and published in Fire Technology. 

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Will concentrated sunlight ignite a fire?

Feb 2022

Concentrated sunlight is a potential ignition source of residential and wildland fires, but its ignition mechanism is still poorly understood. Our latest work cooperated with Prof. Gollner at University of California at Berkeley, and it demonstrated and quantified the smoldering ignition of tissue paper by a concentrated sunlight spot which is focused by a transparent glass sphere. This work is led by Siyan and Shaorun, and published in Fire Safety Journal.

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How to sustain a flame above smoldering?

Jan 2022

Recently, smoldering combustion became an attractive method for organic waste removal. However, as smoldering is an incomplete combustion process, the pollutions from the smoldering emissions are significant concerns. Thus, this work puts forward a novel way to clean the toxic smoldering emissions via sustaining a flame on it and explores the critical conditions for sustaining such a stable flame above smoldering wood. It is found that the critical smoldering burning rate for maintaining a stable flame remains constant at 10-12 g/m2∙s. This work is led by Yuying Chen and published in Combustion Science and Technology

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 Full-scale Fire Tests in the Underwater Tunnel 

Jan 2022

Compared with normal tunnels, underwater tunnels tend to be longer, deeper, and more enclosed, increasing the difficulty of fire protection, evacuation, and smoke extraction, whereas related full-scale fire tests and knowledge are rare. A set of fire tests were conducted in a 1:1 full-scale Hong Kong–Zhuhai–Macau Bridge tunnel section model to study the smoke transportation characteristics in underwater tunnels with sidewall extraction. This work is in collaboration with the Sichuan Fire Research Institute and published in Tunnelling Underground Space Technology.