1998 Fiscal Year Final Research Report Summary
Understanding and Modeling of Backdraft Phenomena Occurred in Fires of Highly Insulated and Air-Tightened Houses
| Project/Area Number |
09650643
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Architectural environment/equipment
|
|---|
| Research Institution | HOKKAIDO UNIVERSITY |
|---|
Principal Investigator |
HAYASAKA Hiroshi Grad.School of Eng., Hokkaido Univ., Asso.Professor, 大学院・工学研究科, 助教授 (40142195)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HASHIMOTO Yoshihiro Sapporo fire Science Laboratory, Chief Researcher, 消防局・消防科学研究所, 主任研究員
KOJIMA Hideyoshi Sapporo Fire Science Laboratory, Chief Researcher, 消防局・消防科学研究所, 主任研究員
|
|---|
| Project Period (FY) |
1997 – 1998
|
| Keywords | Backdraft / Smoldering / Self-extinguishment / Ghosting Flame / Mass Loss Rate / Persistent Flame / Spontaneous Ignition / Pyrolyzates |
|---|
| Research Abstract |
This research is carried out to understand backdraft phenomena in fires. Backdraft phenomena was observed experimentally, Experiments were carried out in a 0.85 m high, 0.82 m wide, 1.05 m long compartment by using actual wood. The mass pyrolysis rate of actual wood, and O_2, CO_2, CO and THC (Total Hydrocarbons) in the upper and lower layers in the compartment were measured. Precise temperature distribution maps were made. Backdraft and its related phenomena caused by pyrolyzates from wood were observed through the side wall made of a newly developed refractory glass. The results obtained from experiments in a one third scale compartment under highly insulated and low-ventilation conditions may allow the following conclusions : l. After the fire had consumed almost all the oxygen in the upper layer, the flame lost its activeness and a drifting or ghosting flame occurred. The flame moved slowly between the rear wall and the opening. 2. Suddenly, the flame at the opening disappeared. It self-extinguished. 3. Just after the self-extinguishment of the fire, there were no visible flames in the compartment but a constant mass pyrolysis rate was observed. Smoldering of the wood became main reaction. A relatively long, about ten minutes, smoldering period was observed before a first backdraft occurred. 4. After the first backdraft, a persistent flame was formed near the opening and lasted about three minutes. This kind of flame might killed firefighters in the reported backdraft fires. 5. The observed backdraft flame started from near the ceiling and then rapidly spread to the floor and the opening. 6. Second and third smoldering period were observed before second and third backdraft occurred. But their period became very short, forty and nineteen seconds respectively. 7. Spontaneous ignition of wood may play an important role in an occurrence of backdraft in our experiments.
|
