NS FS Article Basement Fire Modeling

8/13/2019 NS FS Article Basement Fire Modeling

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UL.COM/NEWSCIENCE

NEW SCIENCE

FIRE SAFETYARTICLE

WINTER 2014

BASEMENT FIRE

COMPUTERMODELING


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NEW SCIENCE

FIRE SAFETY

OVERVIEW

ULs dedicated team of scientists, engineers and researchers is

creating New Science in a variety of ways. From live experiments to

computational modeling, statistical analysis to quantification of risk,

we are constantly seeking to improve products, techniques,

methodologies, processes and standards.

FIRE SAFETY ARTICLE/BASEMENT FIRE COMPUTER MODELING 2


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3FIRE SAFETY ARTICLE/BASEMENT FIRE COMPUTER MODELING

WHY BASEMENT FIRE MODELING MATTERS

Basement fires are an extremely dangerous challenge for firefighters. In the late

1970s, fire deaths inside a structure occurred at a rate of 1.8 deaths per 100,000

structure fires. By the late 1990s, the mortality rate had risen to three per 100,000.1

Fire Engineering notes that a large majority of firefighter fatalities or significant

injuries occur at what were ultimately basement fires.2 For these reasons, it is

critical to understand the particular safety risks associated with basement fires

through experimentation and advanced engineering analysis. To build on and further

the knowledge gained from physical experiments, UL relies on computational fluid

dynamics (CFD)-based fire modeling tools to expand the available experimental

dataset and deepen insights.3

CONTEXT

Today, the combination of larger homes, open floor plans, synthetic fuel loads and new

construction materials speed up the stages of fire development, creating more hazardous

fire conditions.4One important contributor to the increased fire safety risks meriting

close examination is engineered wood products, which are increasingly used to help

meet the demand for environmentally sustainable and economical building products.

Under fire conditions, lightweight engineered floors can lead to greater risk of structural

failure in a shorter time period as a result of the reduced cross-sectional dimensions of

engineered products relative to traditional lumber floors. When there is a basement fire,

or a fire that started in the basement, once on the scene, the fire service is often unclear

regarding how long the fire has been burning, the type of floor system exposed to fire

conditions and the structural stability of the floor system.

In our previous New Dynamics of Basement Fires article, we detailed the results

and insights from a variety of research experiments UL conducted to better

understand the response of residential flooring systems to fire.5 In addition to

those research experiments, we generated both thermo-mechanical finite element

models to simulate the structural response 6and CFD-based fire models to simulate

the fire dynamics and effects of different ventilation schemes. In this article, we

describe the effects of different ventilation schemes on basement fire dynamics

through our fire modeling work.

WHAT DID UL DO?

Using data from live experiments of a basement fire with an engineered wood

I-beam ceiling, we built a CFD-based fire model of the same experiment, using

As the use of engineered wood pro

has increased to help meet the dem

for environmentally sustainable an

economical building products, fire

safety risks are increasing.


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Fire Dynamics Simulator software, and compared the results. The model for a

fully ventilated condition generally replicated data from the experiment, providing

first-order validation. As the fire dynamics depend strongly upon ventilation

conditions, we ran several different models, rather than conducting more expensive

large-scale fire experiments, to determine this sensitivity. The other models included

changing the ventilation conditions by opening or closing a door or window at

different points in time. The choice of scenarios aimed to help examine the qualityof the model predictions over a range of ventilation regimes, from fully ventilated

to under-ventilated.

Based on modeling the different scenarios, we found that:

For the Fully Ventilated Basement scenario, where all doors and windows

were open for the entirety of the simulation, model predictions compared

quite well with experimental data. As compared to an experiment, where

data is only available at a few discrete points, the model of the basement fire

generated temperatures (gas and thermocouple), airflow, smoke movement

and other variables over the entire domain of the basement. This allowed for

greater insight into the dynamics of the fire. The model captured some of the

key features, such as the movement of air and heat along the channels created

by the engineered I-beam structure of the ceiling, leading to heat and flames

at the doorway to the first floor.

With some of the other scenarios where a door or window is suddenly opened

after a fire has started, the model showed how the timing of the doors or

windows opening and the location of the opening could have a dramatic

effect on the fire dynamics.

Using modeling in advance of experiments can potentially provide insights

into better and more useful placement of sensors within the structure.

Extending experimental and field

data with innovative modeling

techniques is one way UL is helping

advance safety science.


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IMPACT

This work was part of a 2010 DHS grant UL received. Our purpose was to

help assess and advance the state of CFD modeling of compartment fires.

In this research, compartment fires represent a residential basement with

an unprotected engineered wood ceiling with a variety of openings.

UL continues to support and advance the use of fire modeling tools for practical

and important topics, such as the effect of different ventilation strategies on

firefighting outcomes. Extending experimental and field data with innovative

modeling techniques is one way UL is helping advance safety science.

Since you were interested in reading Basement Fire

Computer Modeling, we thought you might find the

following related articles of interest.

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SOURCES

FIRE SAFETY ARTICLE/BASEMENT FIRE COMPUTER MODELING

1 Fahy, D.R, U.S. Fire Fatalities in Structure Fires, 1977-2009, National FireProtection Association Fire Analysis and Research Division, 2010.http://www.nfpa.org/~/media/Files/Research/NFPA%20reports/Fire%20service%20statistics/OSFatalitiesInstructures.pdf

2 Our Most Hazardous Environment, Fire Engineering, 3 Mar., 2011.,http://www.fireengineering.com/articles/2011/03/fdic11-martin1.html.

3 Tabaddor, Mahmood, Ph.D., Fire Modeling of Basement with Wood Ceilings,

UL Research Paper, Dec. 2011. http://www.ul.com/global/documents/offerings/industries/buildingmaterials/fireservice/basementfires/2009%20NIST%20ARRA%20Appendix%20F%20-%20Fire%20Modeling%20of%20Basement%20with%20Wood%20Ceiling.pdf.

4 Kerber, S., Study of the Effectiveness of Fire Service Vertical Ventilation andSuppression Tactics in Single Family Homes, UL Firefighter Safety ResearchInstitute, 2013. Web: 7 Oct. 2013. http://ulfirefightersafety.com/wp-content/uploads/2013/06/UL-FSRI-2010-DHS-Report_Comp.pdf.

5 Kerber S., Madrzykowski, D. et al., Improving Fire Safety by Understandingthe Fire Performance of Engineered Floor Systems and Providing Fire Servicewith Information for Tactical Decision Making, UL Research Paper, March2012. Web: 7 Mar. 2013. http://www.ul.com/global/documents/offerings/industries/buildingmaterials/fireservice/basementfires/2009%20NIST%20ARRA%20Compilation%20Report. pdf.

6 Tabaddor, Mahmood, Ph.D., Modeling the Thermal and Structural Behaviorof Wood Beams in a Fire Environment, UL Research Report, Dec. 2011. http://www.ul.com/global/documents/offerings/industries/buildingmaterials/fireservice/basementfires/2009%20NIST%20ARRA%20Appendix%20E%20-%20Modeling%20the%20Thermal%20and%20Structural%20Behavior%20of%20Wood%20Beams%20in%20a%20Fire%20Environment.pdf.

JOURNAL ISSUE 2

WIRELESS CHARGING OF ELECTRIC VEHICLES

ADVANCED COMPUTER MODELING

STATISTICALLY PREDICTING ELECTRICAL ARCING

NEW DYNAMICS OF BASEMENT FIRES

JOURNAL ISSUE 1

PV PANELS

REDEFINING SMOKE

LITHIUM-ION BATTERIES

MODERN RESIDENTIAL FIRES

ARTICLE

INNOVATING FIRE ATTACK TACTICS

NEW SCIENCE FIRE SAFETY JOURNALS


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NS FS Article Basement Fire Modeling