bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation and Prediction of Galvanic Corrosion in Oxidizing Solutions
Authors: Sridhar N , Kolts J
Published: February 2009

Galvanic corrosion of several alloys has been examined before in simple acids or salt solutions, and good predictive capability has been achieved using numerical solution of appropriate Tafel equations. In this paper, more complex solutions, containing an acid and an oxidizing agent, are examined. Galvanic current measurements and gravimetric (weight-loss) corrosion measurements indicated that galvanic current measurement is not always a reliable method to determine the difference in corrosion rate of an alloy between the coupled and uncoupled conditions. Sometimes an alloy showing a cathodic current showed an increase in corrosion rate while another alloy showing an anodic current showed a decrease in corrosion rate. Graphical superposition of polarization curves in the oxidizing solutions did result in correct prediction of galvanic potential and current in most cases. However, in order to predict the change in corrosion rate of an alloy on coupling to another, polarization curves of the coupled alloys in both the oxidizing solution and the solution without the oxidizing agent have to be superimposed.
Galvanic Corrosion Resistance of Welded Dissimilar Nickel-Base Alloys
Authors: Corbett RA , Morrison WS , Snyder RJ
Published: February 2009

A program for evaluating the corrosion resistance of various dissimilar welded nickel-base alloy combinations is outlined. Alloy combinations included Alloy ALLCORR, Alloy C-276, Alloy 72, and Alloy 690. The gas tungsten arc weld (GTAW) process involved both high and minimum heat input conditions. Specimens were evaluated in the as-welded condition, as well as after having been aged at various conditions of time and temperature. These were judged to be most representative of process upset conditions, which might be expected. Corrosion testing evaluated resistance to an oxidizing acid and a severe service environment in which the alloy combinations might be used. Mechanical properties are also discussed.
Experience with Cathodic Protection of Power Plant Condensers Operating with High Performance Ferritic Stainless Steel Tubing
Authors: Redmerski LS , Eckenrod JJ , Pinnow KE , Kovach CW
Published: February 2009

Galvanic corrosion is an important consideration in brackish or seawater cooled power plant condensers containing dissimilar metal components. Cathodic protection is often used to minimize galvanic corrosion, but under certain conditions of operation, many condenser components, including high performance ferritic stainless steel tubing, can become susceptible to hydrogen embrittlement. Results of laboratory experiments indicate that conditions can be defined for the operation of a cathodic protection system, which will minimize corrosion of dissimilar, less noble, tubesheet, and waterbox materials and avoid embrittlement of high performance ferritic stainless steel tubing. These conditions are similar to those now recommended for use with condensers operating with titanium tubing. Several power plant condensers using SEA-CURE® (Unified Numbering System [UNS] S44660) ferritic stainless steel tubing are now successfully operating with impressed current cathodic protection systems, and no difficulties with hydrogen damage to the tubing have been encountered.
Model for the Mass Transfer and Decay of Hydrogen Chloride in a Fire Scenario
Authors: Galloway FM , Hirschler MM
Published: February 2009

It is now well established that hydrogen chloride is unusual among common fire gases in that it decays from the atmosphere. No model of hydrogen chloride transport and decay exists as yet, which has been formulated in such a way that it is generic enough to be used for scenarios different from the one in which the experiments were carried out, and can be incorporated into more comprehensive fire hazard models. The present paper introduces such a model. It deals with the influence of various surfaces [poly(methyl methacrylate) (PMMA), painted gypsum board, ceiling tile, cement block and Marinite], of surface to volume ratio and of humidity, on atmospheric hydrogen chloride concentration, both inside and outside the room of origin of the fire.

The present model incorporates generation of hydrogen chloride from poly(vinyl chloride), mass transfer to various wall locations, partition between the atmosphere and the surface, and a combination of diffusion and reaction inside the surface. The parameters in the model were fitted by using a non-linear (Marquardt) optimization procedure.

The model was corroborated using various experiments which involved the combustion of poly(vinyl chloride) in large- and small-scale scenarios.

It was found that, for a non-sorptive surface such as PMMA, the rate of mass transfer to the surface is much larger than the rates of the various reactions at the surface, in all cases. Such a surface, thus, allows much higher peak hydrogen chloride concentrations and much lower rates of decay than any of the sorptive surfaces investigated.

For sorptive surfaces and static systems the rate limiting process is the mass transfer to the surface. The activity of the various surfaces investigated was found to follow the order: ceiling tile > cement > Marinite ≥ painted gypsum board ≫ PMMA

The significance of this model is that it can predict hydrogen chloride decay in a real fire scenario. It is relevant to point out that normal construction surfaces are sorptive, and that hydrogen chloride decay will generally be quite fast in a fire, whereas it will be much slower in a small-scale toxicity test exposure chamber.
A Fire Loss Modeling Code for Industrial Facilities
Authors: Cohn BM
Published: February 2009

Property owners and insurance companies have a need for being able to predict how far an accidental fire will spread in an industrial complex under the most probable adverse conditions and under the worst foreseeable conditions. The information is necessary for establishing the values at risk and for planning fire safety improvements. Estimating the extent of future fire events is now largely dependent on experienced judgment; a sound mathematical model can provide better, more reliable answers. The desirability of such a model is also shown by ASTM Committee E-5's fire risk analysis development efforts. A probabilistic model using a critical path approach was suggested ten years ago and is now being developed into a unified fire behavior prediction model, called UNIFIRE, having as its principal purpose the prediction of the paths and extent of fire spread through buildings. Unlike prior analytical systems that grade the fire risk by deficiency points for generalized features, UNIFIRE is site specific. The model consists of numerous subroutines, each capable of analyzing the probable contribution of site-specific factors in a fire event, and of a main program that organizes all of the fire prediction data and develops a unified evaluation of the fire threat at that facility.
A Program for the Development of a Benchmark Compartment Fire Model Computer Code
Authors: Cooper LY , Rockett JA , Mitler HE , Stroup DW
Published: February 2009

With a variety of objectives in mind, many different compartment fire model computer codes have been developed within the fire safety/research community. Yet, not one of these can be described as being a “benchmark” model in the sense that it is reliable enough to be accepted as a standard of reference for the performance of design-oriented fire models. It is the major objective of the Compartment Fire Modeling Research (CFMR) Group in the Fire Science and Engineering Division of the Center for Fire Research (CFR) to develop such a Benchmark Compartment Fire Model (BCFM) computer code. This paper describes the characteristics of this BCFM, and outlines the program that will lead to its development.
Selection of Rolling-Element Bearing Steels for Long-Life Applications
Authors: Zaretsky EV
Published: February 2009

Nearly four decades of research in bearing steel metallurgy and processing has resulted in improvements in bearing life by a factor of 100 over that obtained in the early 1940s. For critical applications such as aircraft, these improvements have resulted in longer-lived, more reliable commercial aircraft engines. Material factors such as hardness, retained austenite, grain size and carbide size, number, and area can influence rolling-element fatigue life. Bearing steel processing such as double-vacuum melting can have a greater effect on bearing life than material chemistry. The selection and specification of a bearing steel is dependent on the integration of all these considerations into the bearing design and application. The paper reviews rolling-element fatigue data and analysis, which can enable the engineer or metallurgist to select a rolling-element bearing steel for critical applications where long life is required.
Failsafe Rating of Ball Bearing Components
Authors: Voskamp AP , Hollox GE
Published: February 2009

Methods used traditionally throughout the bearing industry to calculate the life of rolling bearings predict a finite life under all conditions of application, even at very low contact stresses. More recently, endurance tests on heavily loaded 6309 deep-groove ball bearings have demonstrated that virtually infinite fatigue life is a practical reality for some applications, provided that bearings are accurately manufactured from high-quality steel. Accordingly, a new method to calculate rolling contact fatigue life has been developed in which an effective fatigue limit has been introduced. Metallographic and X-ray analysis of the highly stressed subsurface volumes of tested bearings have shown that a critical stress exists for a given material and test condition, below which microplastic deformation, transformation of retained austenite, and the development of residual stresses and texture do not take place, consistent with the concept of a fatigue limit.
Measurement of Extremely Low Inclusion Contents by Image Analysis
Authors: Vander Voort GF
Published: February 2009

Image analysis measurements using a stereological approach have been performed on the inclusions in VIM/EBR, VIM/VAR, and VIM/ESR material from the same parent VIM heat of M-50 bearing steel. Tests made on billet samples produced excessively high, inaccurate results due to very fine microshrinkage cavities associated with the carbide due to insufficient hot reduction. Subsequent tests on bar specimens revealed a closer correlation with the calculated volume fractions based on sulfur and oxygen chemical analysis. However, the measured area fractions were consistently lower than the calculated values. Details of the metallographic preparation problems are provided.
The Ladle Refining Process for Bearing-Quality Steels
Authors: Odar JA , Fecich DJ
Published: February 2009

Bearing-quality steels that have been previously refined by the vacuum degas carbon deoxidation process for microcleanliness considerations are now able to achieve lower levels of oxygen and inclusion content by ladle refining. Through aluminum deoxidation in the presence of strong stirring energy, inclusions are removed by mechanical rather than chemical means. Such refining techniques are provided by ladle reheat capability, slag control, de-slagging, stirring, alloy and deoxidizer injection, and vacuum degassing, further enhanced with bottom pouring, shrouding, and casting.

Several ladle refining options were studied to evaluate the relative cleanliness levels that the processes were capable of producing. Superior levels of steel quality and chemistry control were achieved by these out-of-the furnace techniques in terms of microcleanliness as measured by the JK-worst field and SAM ratings, and of macrocleanliness as measured by magnetic particle inspection procedures of AMS 2301.
Fatigue Life of High-Carbon Chromium Ball Bearing Steel Produced by Electric Furnace—Vacuum Slag Cleaner—Ladle Furnace—RH Degassing—Curved Continuous Caster
Authors: Kumagai K , Takata Y , Yamada T , Mori K
Published: February 2009

Rolling contact fatigue life of continuous-cast ball-bearing steel was 1.5 to 2 times as long as that of conventional ingot-cast one. Continuous-cast ball-bearing steel, when made by a double ladle furnace process with lower contents of oxygen, lower residuals (sulfur, phosphorus, and titanium), and lower number of finely scattered inclusions, showed fatigue life over six times as long as that of conventional ingot-cast ball bearing steel. Studies have been conducted to determine the effect of residuals and inclusions on fatigue life. The reason of longer fatigue life is thought to be due mainly to a lower content of finely scattered oxide inclusions.
Chemically Induced Community Responses in a Compartmentalized Microcosm Assessed by Multidimensional State Space Transitions
Authors: de Zwart D , Langstraat H
Published: February 2009

A test has been developed to assess the chemically induced disturbance produced by interactions between functionally different groups of organisms. Algae, daphnids, polyps, and decomposer organisms—representing adjacent trophic levels—were housed in separate containers. Water containing algae and nutrients was circulated through the compartments. In some experiments, according to a realistic scheme based on empirically derived knowledge of the needs of the individual populations, an interactive relationship was maintained between standing stock parameters and the circulation rate and between predation on daphnids and feeding by polyps. Since, for each compartment, input and output fluxes were experimentally determined, the rates of processes could be calculated. One of the major drawbacks of the small volume (14 L) of the microcosm was the necessity for nondestructive or micro methods of analysis.

In the experiments presented in this paper, only the standing stock parameters for the algae, daphnids, and polyps, and occasionally the pH, were measured with enough adequacy to construct a multivariate “normal operating range” (95% confidence interval) out of the rather long time series of preexpositional data. This “normal operating range” was used as a reference state for the changes after perturbation.

Perturbation of the model ecosystem with a toxic chemical (in this case, 2,4-dichloroaniline) was followed by a gradual displacement outside the normal operating range. All four systems tested showed a temporary or permanent shift in the three-dimensional state space outside the normal operating confinement within ten days after the addition of 0.010 mg L−1 of the toxicant, whereas the lowest “no-observed-toxic-effect level,” determined by semichronic tests on the susceptibility, individually, of populations of green algae, daphnids, and polyps, was slightly higher. (For Daphnia magna, this level was 0.032 mg L−1.)
Use of Microbial Colonization Parameters as a Measure of Functional Response in Aquatic Ecosystems
Authors: Pratt JR , Cairns J
Published: February 2009

Microbial colonization of artificial substrates introduced into aquatic ecosystems is affected affected by the relative levels of nutrients and toxicants. The productivity of microbial biota integrates several factors affecting organism survival and is expressed in relative rates of propagule production and colonization. It is now possible to examine factors affecting microbial colonization in laboratory microcosms. Colonized artificial substrate species sources can be used in the laboratory to measure nutrient and toxicant effects. Studies have shown that microbial colonization is at least as sensitive a technique as long-term single-species testing and has allowed controlled measurement of complex community responses to disturbance. It is possible to model the nonlinear colonization process and to compare colonization rates, equilibrium species numbers, and biomass production in test systems. Such testing can examine effects of nutrients, pure toxicants, or complex effluents. The authors found adverse effects on species dispersal in static test systems for cadmium and copper at concentrations of < 1 µg Cd/L and 18 µg Cu/L, although low levels of copper enhanced the species numbers. In microcosm systems receiving continuous toxic input, we found adverse effects of chlorine on species dispersal at 2 µg/L; however, net production was elevated at concentrations up to 100 µg/L. In tests with the herbicide atrazine, the number of species and the net production were stimulated at low levels (3 to 30 µg/L). Stimulation of the species number and production may be a result of effects on control mechanisms and not the result of a subsidy to the community. The study of natural community dynamics in evaluating the effects of toxic materials provides evidence of effects on the emergent properties of systems, which are not available from studies of individual species. In many cases, effects on communities may occur at concentrations similar to those producing effects on sensitive single species. However, testing at the community or system level can provide predictions of community or system components most at risk. As such, system level tests should provide predictions that can be directly validated in ecosystems receiving toxic inputs.
Developing a Portable Automated Biomonitoring System for Aquatic Hazard Evaluation
Authors: Morgan EL , Wright JR , Young RC
Published: February 2009

In the spring of 1986, an intensive aquatic biological testing program was carried out over a 45-day period in an attempt to evaluate possible toxicity in an important fishery resource in the French Broad River of East Tennessee. Since 1969 a marked decline in sauger (Stizostedion canadense) populations has occurred below Douglas Dam. In addition to toxicity tests with the water flea (Ceriodaphnia spp.), fathead minnow (Pimephales promelas), and sauger in various life stages, a portable automated fish breathing rate biomonitoring system (AFIRMS) was field tested at streamside in a mobile bioassay trailer. The personal computer based AFIRMS was equipped with 24 channels for continuously monitoring adult sauger breathing activities and various physical sensors. Though all the tests revealed no apparent toxicity in the tailwater reaches of the river, a simulated field test with AFIRMS using toxic leachate from a landfill source induced immediate sauger responses and ultimate mortality to most of the test animals.
Effects of Complex Effluents from the River Raisin on Zooplankton Grazing in Lake Erie
Authors: McNaught DC , Bridgham SD , Meadows C
Published: February 2009

Functional ecosystem tests should reflect the hazards of toxic chemicals, as well as stimulation by nutrients, by measuring a single flux of phytoplankton to the dominant members of the community. The flux of phytoplankton and detritus to zooplankton is reflected by the filtering rates of individual organisms, expressed as millilitres per animal per hour. The authors used common particle counting techniques to measure such fluxes in the waters of Lake Erie. They then examined the impact of complex effluents on the filtering rates. These effluent effects are scored as inhibition or stimulation of filtering by the dominant herbivores in the Lake Erie ecosystem. In the River Raisin, a tributary to Lake Erie, specific effluents usually inhibited grazing by the herbivores Daphnia, Diaptomus, and Cyclops, although one effluent was stimulatory. These results were directionally consistent and probably depended on the characteristics (especially the concentrations of metals) of the effluents. The inhibitions were also of considerable magnitude. The authors recommend the use of such a secondary ecosystem functional bioassay (SEFB) for detecting hazards in point sources or tributaries to large systems, such as Lake Erie.
Use of Freshwater Macroinvertebrate Microcosms in the Impact Evaluation of Toxic Wastes
Authors: Livingston RJ
Published: February 2009

The author compared the impact of toxic waste sites on three streams in South Carolina and Florida. In addition to the field evaluations of macroinvertebrate distribution (as determined by artificial leaf-pack collectors), a series of acute (4-day) and chronic (30-day) leaf-pack bioassays were carried out with polluted water and leaf-pack microcosms taken from the related study sites. The comparison of laboratory and field data was carried out over a one to two-year period at quarterly intervals. These experiments were designed to evaluate and verify the use of microcosms in predicting field impact and to test for possible seasonality in the laboratory-field relationship.

Leaf-pack data from the field indicated that there was no impact in a South Carolina stream (Myers Creek) because the toxic wastes never entered the surface water system. The four-day leaf-pack bioassay was useful in confirming the lack of adverse effects in the field. Field gradients of macroinvertebrates were evident in Hogtown Creek, Florida (from the low dissolved oxygen and high levels of phenolic derivatives), and in the Little Dry Creek/Dry Creek system, Florida (from the low pH and high lead and aluminum). The acute leaf-pack tests in the Hogtown Creek system did not predict the field impact as well as the chronic tests, whereas both forms of testing in the Little Dry Creek/Dry Creek system were effective in the prediction of field impact. In both systems, the presence of pollution-resistant species complicated the direct extrapolation of bioassay results to field conditions. There was considerable variation in the responses of individual species to the laboratory conditions; however, species richness was a relatively robust laboratory indicator of impact in both streams. Variables that had some influence on the ability to predict field impact using bioassay tests included local features of the stream system, the type of toxic waste, the duration of laboratory exposure to the toxic agents, and the community index used for the comparison. In some instances, the period of sampling was a factor in the laboratory-field relationship. These test results indicate that calibration of the macroinvertebrate microcosm with field data is necessary if such tests are to be used to predict field impact of toxic wastes. Such microcosms, properly used, can be effective for extrapolation of laboratory results to complex field conditions.
A Decade of Protective Clothing Standards Development
Authors: Henry NW
Published: February 2009

ASTM Committee F23 on protective clothing will complete a decade of standards development activities this year. Since its original formation as an official ASTM committee in 1977, it has grown in size from 36 to 170 members, produced three standard methods, held one successful international symposium on protective clothing, and published one Special Technical Publication. Charged with a responsibility to develop standard test methods and standard terminology, classifications, and performance specifications for clothing used to protect against occupational hazards, Committee F23 has become the worldwide focal point of protective clothing standards development. This presentation reviews the history and development of Committee F23, looking at highlights of its past, present and future activities.
The Need for International Cooperation Regarding Approvals
Authors: Hougaard M
Published: February 2009

Research shows that chemical protective equipment should be permeation tested against the exact chemical it is expected to protect against. Because more than 10 000 different chemicals are used today, the amount of permeation testing is immense.

Public reaction to and the legal ramifications of inadequate protection are discussed. A negotiation model, including the four major interests to be fulfilled by an international approval or certification system, is established.

Standards and certification concepts are defined as well as the roles of the organizations involved. Due to the amount of testing, if a national approval or certification system for chemical protective clothing is created, then it should be designed with the prospect of becoming international at a later stage.

A data presentation form that can be implemented immediately by manufacturers of chemical protective equipment is proposed.
International Standards for Assessing the Effect of Clothing on Heat Tolerance and Comfort
Authors: Olesen BW , Dukes-Dobos FN
Published: February 2009

Three standards recently developed by the International Organization for Standardization (ISO) Working Group for Thermal Environments for assessing the thermal load of workers are examined for how they deal with the effect of clothing on the worker's feeling of thermal comfort or heat tolerance. In the standard for assessing thermal comfort, only the thermal insulation of the clothing worn is taken into account, but in the standard for analytical determination of heat stress, values for both the insulation and vapor permeability of the working uniform and protective garments are needed for estimating the worker's heat load. However, data on these thermal properties for protective garments are not available. In the third standard examined, the assessment of heat stress is based on measurement of environmental heat and estimation of metabolic heat, while clothing insulation and permeability are considered to be constant.
Thermal Properties of Protective Clothing and Prediction of Physiological Strain
Authors: Holmér I
Published: February 2009

Heat stress and reduced work performance are often linked to work in protective clothing, especially when the rate of work or temperature or both of the environment are high. The resultant thermal insulation (IT) and evaporative resistance (RT) of garments and protective clothing systems have been measured using indirect calorimetry on subjects exercising in a climatic chamber. In different series of wear trials, the physiological responses associated with wearing these garments during 60 min of treadmill walking in hot environments (35 to 45°C, 30 to 40% relative humidity) were evaluated for young, male, healthy subjects. Obtained values for IT and RT were used in a physiological model to predict rectal temperature response to the same conditions as for the wear trials in order to compare predicted and measured rectal temperatures. The results showed that a combination of clothing heat exchange measurements on subjects and simple physiological modeling may be a useful technique for assessment of clothing thermal function.
Evaluation of Fourteen Fabric Combinations, One Glove Material and Three Face Shield Materials to Molten Steel Impact
Authors: Forsberg K
Published: February 2009

The heat resistance of fourteen fabric combinations, one glove material, and three face shield materials has been evaluated by controlled splashes of 1 kg of molten steel. The test procedure is described in ASTM Evaluating Heat Transfer through Materials Upon Contact with Molten Substances (F 955-85). Five- and forty-second calorimeter thermal responses were plotted. The heat resistance was determinated by measuring the temperature rise and calculating the maximum heat flux. The test materials were also visually examined.

The test materials were aluminized rayon; jacket/pant materials in wool, cotton, and wool/Cordelan; underwear materials in wool, cotton/modal, and Cordelan/polyester; Kevlar; and face shield materials in polysulfone polycarbonate and acetate.

The test results indicated <1 cal/cm2/s of maximum heat flux in six of the fabric combinations and the three face shields.

The evaluation of the fabric combinations and face shield materials to molten steel impact was a part of the project named “Development of Protective Clothing Working at Continuous Casting.”

It was concluded that the proper combination of outer clothing and underwear clothing for the “8-h garment” can be a more comfortable substitute for the combination of aluminized clothing and outer clothing used today in front coats and flame-retardent clothing.
A Comparative Evaluation of Test Methods and Materials for Thermal Protective Performance
Authors: Day M
Published: February 2009

The American Society for Testing and Materials (ASTM) has developed Test Method for Thermal Protective Performance of Materials for Clothing by Open-Flame Method (D 4108-82). A modified version of this test is utilized in the National Fire Protection Association's NFPA 1971 (1986 Edition) and the International Organization for Standardization's (ISO) Draft Proposal 9151. The influences of these modifications on measured Thermal Protective Performance (TPP) values for composite assemblies have been determined. The sample restraining technique was identified as a critical factor in influencing the results obtained. An alternative system of mounting involving pins, is described, that prevents fabric shrinkage without compression. The behavior of a series of assemblies has been investigated using the technique and the contribution of each component (outer shell, moisture barrier, and thermal liner) to the measured TPP values evaluated.
Determination of Solubility Parameters of New Suit Materials
Authors: Bentz AP , Billing CB
Published: February 2009

The U.S. Coast Guard set out to determine three-dimensional solubility parameters for several new materials. The final approach employed three measures of responses to exposure of material to each of 56 solvents of diverse solubility parameters. The intent was to identify the best measure for this purpose in terms of ease of conducting the test and its statistical reliability. The responses measured were: visual observation of changes, volume increase, and weight gain. Weight gain proved to be the best measure of the three, providing the greatest amount of information with the least experimental error. Tests were conducted on: butyl rubber, chlorobutyl rubber, “three-ply” chlorinated polyethylene, Viton A (copolymer), Viton B (terpolymer), and Teflon. Tests conducted for 24 h gave essentially the same results as those conducted for one week. No three-dimensional solubility parameter could be obtained for Teflon, because of its minimal interaction throughout the solubility parameter space.
Innovative Method for Determining Minimum Detectable Limits in Permeation Testing
Authors: Verschoor KL , Britton LN , Golla ED
Published: February 2009

A method has been developed to determine minimum detectable limits for permeation testing of protective clothing. A syringe pump is used to deliver the chemical of interest into the ASTM standard permeation cell at a very slow rate. A constant low-level concentration is sent to the detector via the same pathway the permeant would travel. Efforts have been made to optimize the method. Validation experiments designed to check the linearity of response have been performed. The syringe pump method for determining minimum detectable limits is applicable to other permeation testing systems.
Approaches to Predicting the Cumulative Permeation of Chemicals Through Protective Clothing Polymers
Authors: Goydan R , Schwope AD , Reid RC , Krishnamurthy S , Wong K
Published: February 2009

Approaches for predicting the permeation resistance of chemical protective clothing polymers were investigated and assessed for accuracy and applicability to the Premanufacture Notification (PMN) review process of the U.S. Environmental Protection Agency (EPA) Office of Toxic Substances (OTS). The approaches emphasize the prediction of cumulative permeation and include: (1) a predictive model based on Fickian diffusion theory and (2) test methods for directly assessing permeation resistance.

The predictive model is based on refinements of existing theoretical approaches for estimating diffusion coefficients and solubilities from the physical properties of the solute and polymer. Permeation model predictions were compared to well-documented permeation data from the literature. Examples of the model's range of applicability and its limitations are provided. Although the results of the permeation modeling approach are promising, direct testing is the most accurate approach to assess clothing performance for the variety and complexity of chemicals and chemical mixtures that are typical of PMN substances. Consequently, chemical resistance test methods were reviewed for accuracy and applicability. Test methods reviewed include permeation tests, degradation tests, liquid immersion weight change tests, and sorption/desorption methods. Based on this review, a hierarchy is proposed that ranks chemical resistance tests according to their ability to generate data needed to assess PMN clothing requirements.
Carbon-14 Tracers in Permeation Studies: Feasibility Demonstration
Authors: Ursin C , Drabaek I
Published: February 2009

This paper deals with results from a feasibility study initiated by the U.S. Coast Guard under Contract DTCG39-85-R-80272 on Radioactive Tracers in Permeation Studies.

Permeation tests using 14C-labeled permeant chemicals have been performed according to ASTM Test Method for Resistance of Protective Clothing Materials to Permeation by Hazardous Liquid Chemicals (F 739-81). The method has included water as the collecting medium, discrete sampling with replenishment, and counting of the samples with liquid scintillation counting. Tests with Viton/chlorobutyl laminate on polyester support and acetone as permeant plus neoprene and nitrobenzene are reported. Due to a high sensitivity, breakthrough is seen in both cases in the first samples, that is, after 2 min for Viton/chlorobutyl laminate/acetone and after 2 s for neoprene/nitrobenzene. Steady-state permeation rate is achieved after 3.5 h at 0.49 mg/m2/s1, and 1 and 0.3 h at 5.93 mg/m2/s1 for the Viton/chlorobutyl laminate/acetone system and the neoprene/nitrobenzene system, respectively.

For the Viton/chlorobutyl laminate/acetone system, the propagation versus time of the permeant front inside the membrane has been visualized by autoradiography using a freezing technique and a cryomicrotome.

An autoradiographic calibration technique has been developed and applied giving the absolute concentration (mg/g) versus depth in microns from the exposed side of the membranes.

The tracer technique in combination with dry combustion has been applied to well-known decontamination procedures with the neoprene/nitrobenzene system. After thermal treatment, a residual amount of 0.08% nitrobenzene was found, implying a decontamination efficiency of 99.9%.
Testing the Quality of Breathable Textiles
Authors: Salz P
Published: February 2009

New laboratory methods have been developed for the evaluation of the waterproofness and water vapor permeability of breathable rainwear. The waterproofness was measured using a dynamic shower tester than combines mechanical action and wicking effects, thus closely simulating actual wear conditions. It is shown that some microporous fabrics that have a high water entry pressure allow leakage when they are periodically compressed. Multiple-layer assemblies of water-repellent fabrics were also evaluated. The water vapor transmission of breathable fabrics in rain was determined using a heated cup method in combination with an artificial rain installation. The results indicate that vapor transport characteristics of fabrics are subject to change depending on the weather.

The new methods provide a means for selecting fabrics for high-performance rainwear.
Using Dipropyl Sulfide to Test the Leakage of Protective Clothing
Authors: Fang G , Dingmao H , Huaimin W
Published: February 2009

Dipropyl sulfide is used as a leakage testing gas for either a carbon-containing permeable chemical protective suit or a permeation-resistant suit. It has the advantages of low toxicity, easiness of adsorption by activated carbon, relatively high vapor pressure, and commercial availability.

A sensitive Chloramide-Ester-Congo Red (CEC) indicator paper (cloth) was developed that can detect 0.014 mg/dm3 of dipropyl sulfide vapor by color change within 2 min.

Testing procedures are demonstrated that can evaluate the protective suit's airtightness.
Test Kit for Field Evaluation of the Chemical Resistance of Protective Clothing
Authors: Schwope AD , Carroll TR , Huang R , Royer MD
Published: February 2009

Personnel involved in emergency response and hazardous waste site activities often have the need to reach on-scene decisions regarding the effectiveness and limitations of chemical protective clothing. Three gravimetric techniques were evaluated as means for providing essential information for aiding such decisions. For four neat chemicals, three two-component solutions, and two clothing materials, permeation cup tests yielded breakthrough time and permeation rate data comparable to that from testing performed according to ASTM Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids and Gases (F 739-85). Three prototype kits based on the cup test are presently undergoing field trials. The permeation cup test was selected over a simple immersion test and a proposed degradation test. Recommendations for further development of the cup test and the degradation test are given.
Evaluation of Protective Clothing Materials Challenged by Petroleum and Synfuel Fluids
Authors: Gammage RB , Dreibelbis WG , Allen White D , Vo-Dinh T , Huguenard JD
Published: February 2009

The permeation characteristics of eleven petroleum, coal, and shale oil hydrocarbon liquids through eight different types of glove were measured over 24 h. Two analytical techniques, photoionization and room-temperature phosphorescence of polynuclear aromatic compounds, were used to measure breakthrough times by volatile and low-volatility constituents, respectively. Serious drawbacks to the general use of these techniques for measuring steady-state rates of permeation were noted.

The lighter, smaller molecular-size constituents permeated faster than the larger, multi-ringed aromatic constituents. For the light hydrocarbon fuels, especially gasoline, there was preferential permeation by benzene and toluene. Nitrile was severely corroded after extended exposure to hydroxybenzene-containing coal-derived liquids. A general ranking, from worst to best, of the protection afforded by the different gloves was latex ≪ neoprene < butyl rubber, polyvinyl chloride (PVC) < nitrile < Viton, Tyvek/Saranex 23, and polyvinyl alcohol (PVA). No breakthroughs within 24 h were observed with the latter three glove materials.
Decontamination of Chemical Protective Clothing Exhibiting Matrix Release
Authors: Berardinelli SP , Hall R
Published: February 2009

This study was conducted to evaluate decontamination methods for a glove material/liquid chemical combination that, together, demonstrated matrix release. A glove material/liquid chemical combination was assumed to exhibit matrix release if the following two conditions were met: (1) the glove material, which was exposed to the challenge liquid chemical until equilibrium saturation was attained, slowly released the entrapped challenge chemical for at least 72 h after exposure; and (2) upon re-exposure to the challenge chemical, the glove material demonstrated a significantly different breakthrough time. A neoprene/n-butyl acetate (glove/liquid chemical) combination, meeting these conditions, was investigated in detail. Neoprene/p-xylene and nitrile/n-butyl acetate combinations were reviewed, but did not exhibit matrix release.

Three decontamination methods were tested: (1) air drying at 25°C, (2) 15-min manual detergent wash, and (3) elevated temperature washing-drying. For the neoprene/n-butyl acetate combination, both air drying and a single 15-min manual detergent wash were ineffective in cleaning the saturated matrix. Breakthrough time changes and measurement of the concentration of n-butyl acetate in the material demonstrated that the matrix was still saturated. However, elevated temperature washing and drying (45°C wash and 95°C drying) did remove the residual n-butyl acetate from the neoprene.
Effects of Water Rinsing on Subsequent Permeation of Rubber Chemical-Protective Gloves
Authors: Nelson Schlatter C
Published: February 2009

The author investigated four solvents of varying volatility and water solubility in order to determine if workers can use gloves longer in chemical-resistant applications if they rinse their gloves periodically. The solvents were tested against glove materials selected to give moderate resistance to permeation, on the assumption that these would be most sensitive to changes in the way that gloves are handled. The results of the test were unexpected: water washing improved performance of the glove only for the solvent DMF. The author's conclusion is that water rinsing can help protect workers only when the solvent in use is toxic on skin contact, very water soluble, and not very volatile; it must also permeate relatively slowly.
Development of a Comprehensive Approach to Chemical Protective Clothing Use
Authors: Mansdorf SZ
Published: February 2009

Chemical protective clothing (CPC) is a “last line of defense.” As such, proper selection and use are essential to the safety and health of the wearer.

A comprehensive approach to CPC selection and use should include at least eight key elements. They are: (1) assessing the need; (2) determination of the level and type of chemical and physical protection required through a hazard assessment of the proposed task; (3) proper selection based on the hazard assessment; (4) lab and field validation of the effectiveness of the selection; (5) establishment of reuse and decontamination guidelines; (6) worker and supervisory training in the use and limitations of the selected equipment; (7) establishment of a routine inspection, maintenance, and repair program; and (8) development of a management audit scheme to assure all elements of the CPC selection process are being properly followed.

Chemical protective clothing can be an effective hazard control measure; however, the protection provided will only be as efficacious as the quality of the methodology or program utilized for its proper selection, use, and maintenance.
CPCbase, a Chemical Protective-Clothing Data Base for the Personal Computer
Authors: Goydan R , Schwope AD , Lloyd SH , Huhn LM
Published: February 2009

In recent years, interest in and testing of chemical protective clothing has increased significantly. Permeation and immersion testing have produced large amounts of breakthrough time, permeation rate, and weight-change information on clothing materials. This information has been compiled into a relational data base system which operates on a personal computer and is available as a commercial product, CPCbase. Also included in the system are descriptions of the clothing materials tested, their sources, and the literature references for the data. The system is menu-driven with fixed search routines and produces formatted reports. In addition, the user can add new or proprietary information and can tailor searches and reports to meet specific needs.
Physiologic Field Evaluation of Hazardous Materials Protective Ensembles
Authors: Veghte JH
Published: February 2009

Five experienced hazardous material (HAZMAT) fire fighters participated in three cities to evaluate three HAZMAT protective ensembles. The climatic conditions for these field studies were hot/dry (above 40°C), hot/wet (above 32°C) and comfortable (18 to 27°C). Each fire fighter served as his own control and wore a specific HAZMAT protective ensemble once a day for three days. Each test involved an operationally relevant 45-min work session during a total test duration of 55 min. Rectal temperatures (TR), heart rates (HR), blood pressures, respiration rates, clothed weights, and climatic parameters were recorded before and after each test. Test results show TR, HR, and sweat losses increased to 39°C, 208 beats/min, and 2.4 kg, respectively, during the hot/dry, hot/wet exposures. The wet bulb globe temperature levels for the hot/dry conditions exceed the National Institute for Occupational Safety and Health recommended limiting criteria and were marginal for the hot/wet tests. Physiologic parameters measured during comfortable conditions were lower than those measured during the hot/dry or hot/wet conditions. Differences in suit design were clearly reflected in the measured physiologic parameters and the effort required to perform work. Suggested suit modifications are discussed to reduce clothing encumberance and enhance work efficiency.
Hydrogen Fluoride Exposure Testing of the U.S. Coast Guard's Totally Encapsulated Chemical Response Suit
Authors: Stull JO , Johnson JS , Swearengen PM
Published: February 2009

The U.S. Coast Guard Chemical Response Suit was field tested at the Department of Energy's Nevada Test Site in controlled releases of hydrogen fluoride. Two suits were placed on specially designed mannequins in two separate tests and subjected to hydrogen fluoride vapor concentrations up to 12 000 ppm for a 6-min period. The mannequins contained a pulsed breathing air supply to simulate normal operation of the suit's exhaust valves and four different hydrogen fluoride detection systems. The analytical results of the two tests indicated no penetration of hydrogen fluoride into the suit.
Propellant Handler's Ensemble: A New-Generation SCAPE
Authors: Ahmie KS
Published: February 2009

Kennedy Space Center is currently using a self-contained atmospheric protective ensemble (SCAPE) inventory which is more than 20 years old. The present inventory is being replaced with a new-generation SCAPE—the propellant handler's ensemble (PHE). The PHE has design features which allow it to have a leakage rate less than 100 cm3/s (6.1 in.3/s) when tested at an internal positive pressure of 1494.5 N/m2 (31.2 lbf/ft2). Manned testing in helium atmospheres shows the PHE to have excellent protection against inward leakage. Extensive testing was performed on the materials that would be exposed to the hazardous atmospheres. Testing with both hypergolic fuel and oxidizer proved the ensemble very capable of meeting both nominal as well as extreme atmospheric hazards.
Kennedy Space Center Maintenance Program for Propellant Handlers Ensembles
Authors: Dudzinski DJ
Published: February 2009

The Propellant Handlers Ensembles are utilized at the Kennedy Space Center to provide protection to personnel performing tasks in hostile environments related to launch activities, and represent state-of-the-art developments in protective clothing. Problems encountered in attaining a successful maintenance program have been overcome through utilization of available resources and the combined efforts of users, engineers, and maintenance technicians.

This paper provides an overview of the methods used at the Kennedy Space Center to maintain a sizable inventory of Propellant Handlers Ensembles. Discussion includes description of the maintenance facility, suit decontamination, leak testing, cleaning, visual inspection, and repair techniques.