The response of smoke detectors to pyrolysis and combustion products from aircraft interior materials

The following projects were completed as part of the effort to develop and test economically feasible fire-resistant materials for interior furnishings of aircraft as well as detectors of incipient fires in passenger and cargo compartments: (1) determination of the sensitivity of various contemporary gas and smoke detectors to pyrolysis and combustion products from materials commonly used in aircraft interiors and from materials that may be used in the future, (2) assessment of the environmental limitations to detector sensitivity and reliability. The tests were conducted on three groups of materials by exposure to the following three sources of exposure: radiant and Meeker burner flame, heated coil, and radiant source only. The first test series used radiant heat and flame exposures on easily obtainable test materials. Next, four materials were selected from the first group and exposed to an incandescent coil to provide the conditions for smoldering combustion. Finally, radiant heat exposures were used on advanced materials that are not readily available

Investigations of high power problems in space shuttle antenna designs

A study program is discussed which includes a survey of industry and government laboratories and was undertaken to determine the state of the art in dealing with problems of high power levels in reentry antenna design. A laboratory program to develop techniques for testing dielectric materials for effects on RF transmission is also considered, with emphasis on high power applications in space and reentry flights. The study program resulted in a set of guidelines for avoiding breakdown in antenna design. A discussion of temperature effects on dielectric breakdown is also given. From the laboratory program, a description is presented of techniques for (1) heating with a carbon arc image furnace, (2) temperature measurement (using thermocouples and an infrared pyrometer), (3) mass spectrometric monitoring of outgassing, (4) testing for RF breakdown in both heated dielectrics and the dielectric/air and dielectric/plasma interfaces. Data and observations are reported from technique development using candidate shuttle materials falling into three categories: (1) lightweight refractory foams, (2) dense RF window materials, and (3) ablative materials

Assessment of thermal damage to polymeric materials by hydrogen deflagration in the Three Mile Island Unit 2 Reactor Building

Thermal damage to susceptible material in accessible regions of the reactor building was distributed in non-uniform patterns. No clear explanation for non-uniformity was found in examined evidence, e.g., burned materials were adjacent to materials that appear similar but were not burned. Because these items were in proximity to vertical openings that extend the height of the reactor building, we assume the unburned materials preferentially absorbed water vapor during periods of high, local steam concentration. Simple hydrogen-fire-exposure tests and heat transfer calculations duplicate the degree of damage found on inspected materials from the containment building. These data support estimated 8% pre-fire hydrogen concentration predictions based on various hydrogen production mechanisms

Assessment of extent and degree of thermal damage to polymeric materials in the Three Mile Island Unit 2 reactor building. Volume VI

Thermal damage to susceptible materials in accessible regions shows damage-distribution patterns that indicate nonuniform intensity of exposure. No clear explanation for nonuniformity is found in existing evidence; e.g., in some regions a lack of thermally susceptible materials frustrates analysis. Elsewhere, burned materials are present next to materials that seem similar but appear unscathed - leading to conjecture that the latter materials preferentially absorb water vapor during periods of high local steam concentration. Most of the polar crane pendant shows heavy burns on one half of its circumferential surface. This evidence suggests that the polar crane pendant side that experienced heaviest burn damage was exposed to intense radiant energy from a transient fire plume in the reactor containment volume. Tests and simple heat-transfer calculations based on pressure and temperature records from the accident show that the atmosphere inside the reactor building was probably 8% hydrogen in air, a value not inconsistent with the extent of burn damage. Burn-pattern geography indicates uniform thermal exposure in the dome volume to the 406-ft level (about 6 ft below the polar crane girder), partial thermal exposure in the volume between the 406- and 347-ft levels as indicated by the polar crane cable, and lack of damage to most thermally susceptible materials in the west quadrant of the reactor building; some evidence of thermal exposure is seen in the free volume between the 305- and 347-ft levels

Assessment of extent and degree of thermal damage to polymeric materials in the Three Mile Island Unit 2 Reactor building

This paper describes assumptions and procedures used to perform thermal damage analysis caused by post loss-of-coolant-accident (LOCA) hydrogen deflagration at Three Mile Island Unit 2 Reactor. Examination of available photographic evidence yields data on the extent and range of thermal and burn damage. Thermal damage to susceptible material in accessible regions of the reactor building was distributed in non-uniform patterns. No clear explanation for non-uniformity was found in examined evidence, e.g., burned materials were adjacent to materials that appear similar but were not burned. Because these items were in proximity to vertical openings that extend the height of the reactor building, we assume the unburned materials preferentially absorbed water vapor during periods of high, local steam concentration. A control pendant from the polar crane located in the top of the reactor building sustained asymmetric burn damage of decreasing degree from top to bottom. Evidence suggests the polar-crane pendant side that experienced heaviest damage was exposed to intense radiant energy from a transient fire plume in the reactor containment volume. Simple hydrogen-fire-exposure tests and heat transfer calculations approximate the degree of damage found on inspected materials from the containment building and support for an estimated 8% pre-fire hydrogen

Modern tools to evaluate and optimize fire protection systems

Modern techniques, such as fault tree analysis, can be used to obtain engineering descriptions of specific fire protection systems. The analysis allows establishment of an optimum level of fire protection, and evaluates the level of protection provided by various systems. A prime example: the application to fusion energy experiments

Example of predictive rather than responsive safety research for fusion energy experiments

A fault tree analysis (FTA) was used to study the fire-management systems of two LLL fusion experiments (2XIIB and SHIVA). This technique identified failure modes of existing system components and indicated what the effects of component failure might be in the event of fire in the protected spaces. This paper describes the results of the initial analytical phase of the project and indicates critical unknown parameters required for further analysis. Moreover, the analytical procedures developed are applicable to most, if not all, safety disciplines and could serve as a basis for the logical reestablishment of the FL/SCC by DOE. (MOW

Experimental and theoretical study of flame inhibition by bromine-containing compounds

The present paper represents the first effort to date in which a combined experimental and theoretical approach has been used to study the effects of several inhibitors on hydrocarbon-air flames. This work is part of an attempt to build a consistent picture of chemical kinetic flame inhibition, beginning with a simple halogen molecule such as HBr and progressing sequentially towards more complex and more practical inhibitors such as CF/sub 3/Br. Inhibition efficiency can be defined as the rate of flame speed reduction, the amount of flame speed change per unit inhibitor added. Both the numerical model and the flame tube measurements found that the inhibition efficiency gradually decreases as the amount of inhibitor is increased. The present experimental and modeling results are shown, together with earlier data for CF/sub 3/Br-CH/sub 4/-air and CF/sub 3/Br-C/sub 3/H/sub 8/-air as well as HBr-CH/sub 4/-air, CH/sub 3/Br-CH/sub 4/-air and CF/sub 3/Br-CH/sub 4/-air. In the numerical study it was found that a stoichiometric methane-air mixture with up to 8% methyl bromide could support a flame, propagating at a speed of about 5 cm/sec, even though the addition of the first 1% of CH/sub 3/Br had reduced the flame speed from 38 cm/sec to about 26 cm/sec. Extensions of the model to include CF/sub 3/Br are currently under development. The available experimental data suggest that CF/sub 3/Br is somewhat more efficient as an inhibitor than HBr or CH/sub 3/Br

Investigation of hydrogen-burn damage in the Three Mile Island Unit 2 reactor building

About 10 hours after the March 28, 1979 Loss-of-Coolant Accident began at Three Mile Island Unit 2, a hydrogen deflagration of undetermined extent occurred inside the reactor building. Examinations of photographic evidence, available from the first fifteen entries into the reactor building, yielded preliminary data on the possible extent and range of hydrogen burn damage. These data, although sparse, contributed to development of a possible damage path and to an estimate of the extent of damage to susceptible reactor building items. Further information gathered from analysis of additional photographs and samples can provide the means for estimating hydrogen source and production rate data crucial to developing a complete understanding of the TMI-2 hydrogen deflagration. 34 figures

Caracterização físico-química de farinhas oriundas de variedades de mandioca utilizadas no Vale do Juruá, Acre.

Algumas características de farinha de mandioca dependem da variedade da raiz utilizada para o processamento. Objetivou-se avaliar as características físico-químicas da farinha de mandioca oriundas de variedades utilizadas no estado do Acre. Os tratamentos foram compostos pelas variedades: T1= Paxiubão, T2= Im221, T3 = Caboquinha, T4 = Araçá, T5 = Colonial, T6 = Branquinha, T7 = Panati e T8 = Mansa e Brava. Foram coletadas amostras das oito variedades de mandioca em casas-de-farinha no município de Cruzeiro do Sul, Acre. As raízes foram transportadas via aérea para o Laboratório de Tecnologia de Alimentos da Embrapa-AC, na cidade de Rio Branco, Acre. Foram avaliados: teor de umidade, cinzas, lipídios, proteína, fibra bruta, carboidratos, acidez, pH e atividade de água. Todas as amostras se apresentaram de acordo com os padrões estabelecidos pela Legislação Brasileira para farinha de mandioca quanto ao teor de umidade, cinzas e carboidratos. As farinhas analisadas apresentam teores baixos de fibras e baixa acidez. A atividade de água das farinhas analisadas esteve abaixo do limite mínimo capaz de permitir o desenvolvimento de microrganismos. As variedades Araçá, Colonial e Branquinha se mostraram adequadas para a fabricação de farinha de mandioca devido, principalmente, ao elevado teor de proteína e carboidratos presente nas farinhas produzidas