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Robert Friedman

Bio: Robert Friedman is an academic researcher from Glenn Research Center. The author has contributed to research in topics: Fire prevention & Fire protection. The author has an hindex of 10, co-authored 29 publications receiving 308 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors review the findings of microgravity-combustion research that are relevant to techniques of spacecraft fire safety and further illustrate the practical applications of some fire-safety requirements and design features of the Shuttle and those in progress for the International Space Station.
Abstract: Fire prevention, detection, and suppression requirements for spacecraft are based on those established for terrestrial and aircraft systems. In the weightless (or microgravity) environment of an orbiting spacecraft, however, the buoyant upward flow typical of fires in terrestrial environments is nearly absent; and this feature profoundly influences fire characteristics and responsive safety strategies. This paper reviews the findings of microgravity-combustion research that are relevant to techniques of spacecraft fire safety. These practical applications are further illustrated by descriptions of some fire-safety requirements and design features of the Shuttle and those in progress for the International Space Station.

59 citations

Proceedings ArticleDOI
12 Jul 1999
TL;DR: In this paper, material flammability and fire spread in microgravity are significantly affected by atmospheric flow rate, oxygen concentration, and diluent composition, which can lead to modifications and correlations to standard material assessment tests for prediction of fire resistance in space.
Abstract: Research in microgravity (low-gravity) combustion promises innovations and improvements in fire prevention and response for human-crew spacecraft. Findings indicate that material flammability and fire spread in microgravity are significantly affected by atmospheric flow rate, oxygen concentration, and diluent composition. This information can lead to modifications and correlations to standard material-assessment tests for prediction of fire resistance in space. Research on smoke-particle changes in microgravity promises future improvements and increased sensitivity of smoke detectors in spacecraft. Research on fire suppression by extinguishing agents and venting can yield new information on effective control of the rare, but serious fire events in spacecraft.

41 citations

Proceedings ArticleDOI
TL;DR: In this paper, the authors reviewed the understanding and key issues of fire safety in the missions, stressing flame spread, fire detection, suppression, and combustion performance of propellants produced from Martian resources.
Abstract: Despite rigorous fire-safety policies and practices, fire incidents are possible during lunar and Martian missions. Fire behavior and hence preventive and responsive safety actions in the missions are strongly influenced by the low-gravity environments in flight and on the planetary surfaces. This paper reviews the understanding and key issues of fire safety in the missions, stressing flame spread, fire detection, suppression, and combustion performance of propellants produced from Martian resources.

30 citations

01 Dec 1993
TL;DR: In this paper, the authors discuss the important unresolved issues and needs for improved fire safety in the Space Station, including those of material selection, spacecraft atmospheres, fire detection, fire suppression, and post-fire restoration.
Abstract: A fire in the inhabited portion of a spacecraft is a greatly feared hazard, but fire protection in space operations is complicated by two factors. First, the spacecraft cabin is an enclosed volume, which limits the resources for fire fighting and the options for crew escape. Second, an orbiting spacecraft experiences a balance of forces, creating a near-zero-gravity (microgravity) environment that profoundly affects the characteristics of fire initiation, spread, and suppression. The current Shuttle Orbiter is protected by a fire-detection and suppression system whose requirements are derived of necessity from accepted terrestrial and aircraft standards. While experience has shown that Shuttle fire safety is adequate, designers recognize that improved systems to respond specifically to microgravity fire characteristics are highly desirable. Innovative technology is particularly advisable for the Space Station, a forthcoming space community with a complex configuration and long-duration orbital missions, in which the effectiveness of current fire-protection systems is unpredictable. The development of risk assessments to evaluate the probabilities and consequences of fire incidents in spacecraft are briefly reviewed. It further discusses the important unresolved issues and needs for improved fire safety in the Space Station, including those of material selection, spacecraft atmospheres, fire detection, fire suppression, and post-fire restoration.

30 citations


Cited by
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01 Jan 2009
TL;DR: In the first issue of the journal IRECHE - International Review of Chemical Engineering - Rapid Communications as mentioned in this paper, an invited review paper was published for the first time in the journal's history.
Abstract: Invited review paper for the first issue of the journal IRECHE - International Review of Chemical Engineering - Rapid Communications

224 citations

Journal ArticleDOI
01 Jan 2009
TL;DR: In this paper, two kinds of sample wires, made by nickel-chrome (NiCr) and iron (Fe) as core metal, are used in the experiment to study the electric fire spread along a single wire harness in sub-atmospheric pressure.
Abstract: Flame spread along the single wire harness (thin-metal wire with coating of polyethylene film) in sub-atmospheric pressure has been examined experimentally to gain better understandings of the electric fire in the aircraft and space habitats. Two kinds of sample wires, made by nickel-chrome (NiCr) and iron (Fe) as core metal, are used in this study. Ambient gas is fixed as air and total pressure is varied from atmospheric to sub-atmospheric (100–20 kPa). As the pressure decreases, flame shape changes from typical “teardrop” to “oval” and flame becomes less-luminous irrespective of the materials of the wire. It turns out that the dependence of the spread rate on pressure varies with the materials of the wire; when the pressure decreases, the spread rate of NiCr-harness monotonically increases, whereas that of Fe-harness mostly remains as constant. From the simple thermal-length analysis, it is proposed that there are two modes in the spread depending on the controlling factor; one is “wire-driven mode” (the spread is mainly governed by the thermal input through the wire) and the other is “flame-driven mode” (the spread is mainly governed by the thermal input from the flame). Observed two cases (NiCr- and Fe-harness) would be categorized to the latter and former modes, respectively.

110 citations

Journal ArticleDOI
TL;DR: It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity, in particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

107 citations

Journal ArticleDOI
01 Jan 1998
TL;DR: In this article, an experimental study of flame spread over ETFE (ethylene-tetrafluoroethylene)-insulated wires has been performed in microgravity to obtain basic data on the fire safety of wire insulation.
Abstract: An experimental study of flame spread phenomena over ETFE (ethylene-tetrafluoroethylene)-insulated wires has been performed in microgravity to obtain basic data on the fire safety of wire insulation. Three samples with different wire diameters, d w (0.32–0.51 mm) and the same insulation thickness, δ (0.15 mm) were investigated. The effects of the parameters thought dominant for wire combustion in fires: the ambient oxygen concentration, wire initial temperature, T i , wire diameter, d w , pressure, and dilution gas were investigated in the microgravity experiments. A series of comparative experiments were also conducted at normal gravity. The results show that flame spread rates in microgravity are higher than vertically downward spread rates at normal gravity when oxygen concentration is greater than 30% O 2 . However, with wire preheating, the spread rate in microgravity is higher than the downward spread rate at normal gravity even at lower O 2 concentrations. The increase in flame spread rates in microgravity became larger with decreases in d w . The effect of pressure on the flame spreading appeared very small, and lower pressure caused extinction of the flames in microgravity. The increase in flame spread rates in microgravity was especially large with CO 2 dilution, and this must be taken into account when selecting extinguisher gas. The microgravity experiments with CO 2 dilution gave rise to a new unsteady flame spread phenomenon for flame spreading over the wire: this phenomenon involves discontinuous flames partly occurring ahead of the spreading flame front.

93 citations