November 2001

BFRL Monthly Highlights

November 2001

December 2001

January 2002

February 2002

March 2002

PAST Highlights

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Smoke Detector Tests in Kinston, N.C.

During September 2001, a BFRL team of engineers and technicians instrumented and burned a two-story, single-family home in Kinston, N.C., in order to characterize the performance of different types of smoke detectors. Smoke detector arrays were located in the hallway and bedroom upstairs as well as exit paths downstairs. Each smoke detector array consisted of a number of detectors including photoelectric, ionization, photo/ion combination, aspirated, carbon monoxide, and mechanical heat sensor. Additional instrumentation included smoke meters, thermocouple arrays, and carbon monoxide, carbon dioxide, and oxygen analyzers.

Each fuel package, either a mattress in the upstairs bedroom, an upholstered chair in the living room, or a frying pan of oil in the kitchen, was ignited and the movement of the smoke was monitored as it moved throughout the house. The overall purpose of this project is to determine if different types of fire alarms can respond to threatening residential fire settings in order to permit egress of typical residential structures.

CONTACT: Nelson Bryner, 301-975-6868
Leader, Fire Fighting Technology Group
Fire Research Division

Fire Suppressant Dispersion in a Cold Aircraft Engine Nacelle

Halon 1301 is the current fire suppressant used to extinguish aircraft engine-nacelle fires. Due to its adverse effect on the ozone layer, halon 1301 has been banned from production in the United States since 1994 in compliance with the Montreal Protocol on Substances that Deplete the Ozone Layer. BFRL has since been extensively involved in the search for the replacements for halon 1301. Trifluoroiodomethane (CF3I) has been proposed as a potential candidate for halon 1301 in aircraft engine nacelles.

The current work at BFRL focuses on the dispersion and distribution of CF3I at temperatures below its normal boiling point (-22 degrees Celsius). Under such conditions, which are encountered during cold start of an aircraft engine on a cold tarmac or high-altitude cruising, there is a potential deterioration in the dispersion of the suppressant and its transport to the fire zone.

An engine nacelle simulator was built to conduct the research. The simulator, with observation windows and measurement ports, has a configuration and dimensions commensurate with a typical small engine nacelle. To simulate low temperature conditions, the entire facility was housed inside a large environmental test chamber in the U.S. Army CECOM Research, Development and Engineering Center at Fort Belvoir, and the suppressant discharge experiments were performed inside the chamber. The dispersion effectiveness of CF3I was assessed based on concentration measurements inside the engine-nacelle simulator using fast-response fiber-optic-based UV spectormeters. Discharge experiments in room temperature were also conducted to establish baselines for comparison.

The concentration measurements indicated that significant reduction in the dispersion effectiveness of CF3I occurred when it was used at temperatures below its normal boiling. Then a fire suppression system designed based on room-temperature test data may fail to provide adequate fire protection. Other parameters that could affect the dispersion and transport of the fire suppressant are currently being examined in our laboratory. Means to improve the performance of the fire suppressant in low temperature applications are also being explored. Extension to other high boiling-point liquid fire suppressants are being planned.

CONTACT: Jiann Yang, 301-975-6662
Research Mechanical Engineer, Fire Metrology Group
Fire Research Division

 

 

MSEL & BFRL Develop Recommended Practice Guide on Dispersion Nomenclature

A new NIST Recommended Practice Guide (SP960-3), The Use of Nomenclature in Dispersion Science and Technology, is now available. The guide is the product of a cooperative effort between MSEL and BFRL research-ers and should have wide appeal.

Ceramic suspensions, gels, and pastes are the starting materials for a wide variety of applications, playing critical roles in the manufacture of products ranging from concrete and sunscreens to multilayer ceramic capacitors and integrated circuits. Unfortunately, researchers and engineers working in these diverse fields often do not speak the same language. Even within the same field, variations in terminology are common. There is a clear and present need for a broadly accepted, uniform and precise nomenclature for describing experimental methods and instrumentation, for sharing technical ideas and concepts and to provide a sound basis on which to standardize measurement methods and data reporting practices. This new guide will serve as a resource for practitioners working in fields in which ceramic dispersions are used. The guide focuses on commonly encountered terminology, providing a consistent framework for improved technical communication.

CONTACT: Chiara Ferraris, 301-975-6711

Physicist, Inorganic Materials Group
Building Materials Division

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