Spray Painting Operations Research Articles

Characterization and workplace exposure assessment of nanomaterial released from a carbon nanotube-enabled anti-corrosive coating

Improvement of methods to quantify the release and characterization of engineered nanomaterials (ENMs) from nano-enabled products is essential to enhance the accuracy and usability of environmental health and safety evaluations. An anticorrosive coating containing multi-wall carbon nanotubes (MWCNTs) was analyzed for nano-scale material and workplace exposure potential. Worker breathing zone measurements for elemental carbon (EC) and electron-microscopy-based structure counts showed negligible MWCNT exposure to workers during laboratory and spray-painting operations over the course of two 8-hour shifts (arithmetic mean inhalable EC and electron microscopy structure count concentrations were 6.47 μg/m3 and 0.084 structures/cm3 respectively). UV weathering prior to abrasion testing increased the nano-size fraction of released material as measured by a fast mobility particle sizer (FMPS) and visual inspection by SEM indicated increased presence of exposed MWCNTs embedded in the polymer matrix. However, no free MWCNTs were identified, despite evidence of MWCNTs embedded in airborne particles. TiO2, used as a pigment in the coating and not anticipated as a candidate for nano-specific scrutiny, contained a small fraction (3.5% in number) of nano-sized constituents (<100 nm). This work emphasizes need for rigorous characterization of additive materials to properly assess potential health hazards and to better our understanding of what qualifies as “nano”.

Simulation of Spray Painting Using Articulated – Arm Robot

Robot trajectory generation for spray painting have highly demand in modern manufacturing. One of the most common surfaces in spray painting operations is ruled surfaces. In this paper, a geometry based spray paint trajectory generation system for ruled surfaces has been developed to simulate the spray painting process using articulated arm robot. The developed system uses the geometry information of both the required ruled surface to be painted and the paint spot to generate spray painting trajectory for Labvolt RoboCIM 5150 articulated robot. The developed system is designed by using Matlab software, and has been simulated and evaluated using the Labvolt system. The results have shown that the generated trajectory achieves satisfactory performance.

Virtual Planning of Robot Trajectories for Spray Painting Applications

In this paper is presented a Virtual Reality application that can be used for automatic generation of robot trajectories for spray painting operations conducted on products with complex surfaces. The trajectory generation for robots that perform painting operations of complex curved surfaces was achieved by implementing a generic algorithm capable of maintaining an optimal distance for painting. The distance between the effecter of the robot and the surface of the CAD model, used to compensate and maintain an optimal painting distance, is determined by a "rayhit" collision detection algorithm that allows the detection of the contact between a linear segment and the mesh of the virtual object. To visualize in the virtual environment the deposition of paint layers, an algorithm was implemented that is based on mapping techniques for dynamically generated textures on the surface that is being painted. A VR software application was developed for generating and visualizing the trajectories of a KUKA robotic system that performs the activity of painting a complex curved product.

Cost-effective ventilation for large spray-painting operations

To achieve efficient ventilation and purification in the high-ceiling painting workshop is faced with the contradiction between effect and energy consumption. Understanding the characteristics of gaseous pollutants is of paramount importance for ventilation and purification system design. The composition and concentration of volatile organic compounds (VOCs) emitted from aircraft painting workshop were sampled by Tenax-TA tubes and analyzed with gas chromatography-mass spectrometry (GC-MS). Approximately 50 types of VOCs (detection rate>50%) were detected in the aircraft spraying workshop, with percentages of 36.3% for esters, 31.9% for aldehyde ketones, 28.5% for biphenylenes, 1.9% for alcohols and 1.4% for alkanes. The TVOC concentrations in the workshop were 48.6 mg/m3 and 132.4 mg/m3, during the varnish painting and the finish painting processes, respectively, and these are several times higher than those observed in other industries (automobile painting and wooden furniture painting). The field test data of spraying workshops from 197 spraying factories in five industry sectors were collected from field measurement and existing literature. Some VOCs components are the general pollutants in the painting workshops, such as Acetic acid, butyl ester, Toluene, and 2-Butanone. A novel ventilation model using multiple target purification units is proposed to eliminate the pollutants in an aircraft spraying workshop. Compared with the original trench exhaust system, the air volume of the proposed targeted ventilation system is reduced by 75%, and the energy consumption is reduced by 45,000 kW·h per aircraft.

Methods for estimating the transfer efficiency of a compressed air spray gun.

The transfer efficiency of a compressed air spray gun is an important performance index with regard to worker health, environmental, and economic considerations. It is defined as the fraction of paint sprayed that coats the surface. Worker exposure has been identified as a function of the transfer efficiency based on total mass of paint sprayed, which can be predicted by a mathematical model developed with nonvolatile oil. This study extends the existing model to include volatile effects by employing a mathematical approach based on a mass balance. This method allows the current model to predict transfer efficiency bounds at two extreme situations: all volatile compounds evaporate either before or after droplet impaction. Model predictions show that tight transfer efficiency bounds are obtained, especially for high values of transfer efficiency. Thus, the average of the upper and lower bounds should be a reasonable estimate of transfer efficiency. It is also found that the current model prediction, which is based on total mass of paint sprayed, for nonvolatile material can be converted to a transfer efficiency based on the mass of solids. The laboratory study shows that the predicted transfer efficiency based on the mass of solids is within the 95 percent C.I. of the measured value. This work relates the transfer efficiency used in industry, which is calculated on the basis of paint solids, with a model that predicts worker exposure during spray painting operations.

A field evaluation of the impact of transfer efficiency on worker exposure during spray painting.

This paper presents a mathematical model to predict breathing-zone overspray concentrations produced during spray painting as a function of the overspray generation rate, ventilation and work practices. The overspray generation rate required an estimate of the spray gun transfer efficiency, which was provided by a previously developed mathematical model. These models were evaluated in the field under two different scenarios: first in a controlled environment that approximated the assumptions of models, and then under actual spray painting conditions. Results from the first test showed the model overestimated transfer efficiency, but the measured exposures and predicted exposures were not significantly different. During actual spray painting operations, all task exposures were within a factor of three of the model predictions, and there was no statistical difference between the measured and predicted values. The predicted average exposure of each worker was within the 95% confidence interval. The overall mean exposure was within one standard error of the model prediction. The current study expands on the original exposure model by including a transfer efficiency model to provide a better estimate of the overspray generation rate. The theoretical foundation between exposure and its primary determinants is established, and this knowledge can be applied to design and can evaluate optimal control interventions. Also, the general methodology presented here for developing an exposure model is applicable to operations other than spray painting.

Microwave process for removal and destruction of volatile organic compounds

AbstractThe CHA microwave‐based gas cleanup process is designed to capture and destroy a wide variety of both chlorinated and non‐chlorinated VOCs, many of which are commonly found at industrial and military sites. In addition, the CHA process also removes the pollutants SO2 and NOx from flue gases. Recently, we constructed a microwave air purification system to remove solvents from spray painting operations and supply recovered solvent vapor to a biofilter field demonstration unit at Tyndall Air Force Base in Panama, Florida. The potential applications and laboratory test results of the microwave air purification process are presented.

Determination of hexamethylene-based isocyanates in spray-painting operations. Part 1. Evaluation of a polyurethane foam sponge sampler.

A polyurethane foam (PUF) sponge was mounted in a cassette sampler and evaluated as a sorbent for the collection of hexamethylene diisocyanate (HDI) monomer and HDI-based oligomers. Recovery studies indicated 112 +/- 34% average recovery of HDI monomer and 92 +/- 9% and 97 +/- 25% average recovery of HDI-based oligomers when using impregnated PUF sponges. The PUF sponge was also evaluated during actual spray-painting operations. In a series of side-by-side sampling events, an impinger filled with 1-(2-methoxyphenyl)piperazine (MOP) in toluene was compared directly with a cassette sampler containing a PUF sponge impregnated with MOP or 1-(9-anthracenylmethyl)piperazine (MAP) in dimethyl sulfoxide (DMSO). For the analysis of HDI-based oligomer, there is no significant difference (p < 0.05, n = 7) in the air concentration when sampling with either the PUF sponge cassette or the impinger. The results are significant because they indicate that a PUF sponge, which is more convenient than an impinger, may be used for the collection of HDI-based oligomer generated during spray-painting operations.

Evaluation of solvent resistivity of fluoropolymers for use as backup membranes in isocyanate samplers

Four types of fluoroelastomer (VITON) membranes were tested for their resistivity toward dimethyl sulfoxide, dioxane, and toluene at 25, 45, and 60°C, using a gravimetric method. Coefficients of diffusion and permeation were calculated from the sorption results. Analytical solutions of Fick's equation as well as a numerical method were used to calculate the concentration profiles of liquids in the membrane materials at different penetration depths and exposure times. Activation parameters for diffusion, permeation, and sorption were obtained from the Arrhenius equation. These membrane materials were evaluated for their ability to serve as a barrier to solvent permeation in a composite membrane sampler for the analytical determination of isocyanates generated during spray-painting operations. © 1996 John Wiley & Sons, Inc.

Evaluation of solvent resistivity of fluoropolymers for use as backup membranes in isocyanate samplers

Four types of fluoroelastomer (VITON) membranes were tested for their resistivity toward dimethyl sulfoxide, dioxane, and toluene at 25, 45, and 60°C, using a gravimetric method. Coefficients of diffusion and permeation were calculated from the sorption results. Analytical solutions of Fick's equation as well as a numerical method were used to calculate the concentration profiles of liquids in the membrane materials at different penetration depths and exposure times. Activation parameters for diffusion, permeation, and sorption were obtained from the Arrhenius equation. These membrane materials were evaluated for their ability to serve as a barrier to solvent permeation in a composite membrane sampler for the analytical determination of isocyanates generated during spray-painting operations. © 1996 John Wiley & Sons, Inc.

Evaluation of 1-(9-anthracenylmethyl)piperazine for the Analysis of Isocyanates in Spray-Painting Operations

Evaluation of 1-(9-anthracenylmethyl)piperazine for the Analysis of Isocyanates in Spray-Painting Operations

Sampling and Analysis of Isocyanates in Spray-Painting Operations

Several methods were used for the sampling and analysis of airborne 1,6-hexamethylene diisocyanate (HDI) and polyisocyanates during spray-painting operations. National Institute for Occupational Safety and Health (NIOSH)Method 5521 uses an impinger filled with 1-(2methoxyphenyl)piperazine in toluene for collection and derivatization, HPLC separation, and simultaneous UV and EC detection. This method was compared directly to Occupational Safety and Health Administration (OSHA) Method 42, which is based on sample collection on a fiber filter coated with 1-(2-pyridyl)piperazine, HPLC separation, then UV detection. NIOSH Method 5521, modified so that polyisocyanate concentrations were determined based on polyisocyanate standards, also was compared with NIOSH Method 0500, which is a gravimetric assay for total particulates. The results for HDI monomer demonstrate that NIOSH Method 5521 appears to give higher results than those obtained using OSHA Method 42, especially when the total particulate concentration is high. Furthermore, field studies show that polyisocyanate concentrations during spray paint operations may exceed a concentration of 1 mg/m3, which is believed to be hazardous. Finally, preliminary results indicate that the true concentration of polyisocyanate in air, in all cases but one, was within two times the theoretical concentration based on the total particulate mass.

Sampling and Analysis of Isocyanates in Spray-Painting Operations

Sampling and Analysis of Isocyanates in Spray-Painting Operations

Determination of Hexamethylene Diisocyanate in Spray-Painting Operations Using Capillary Zone Electrophoresis

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of Hexamethylene Diisocyanate in Spray-Painting Operations Using Capillary Zone ElectrophoresisWalter E. Rudzinski, Liu. Pin, Ron. Sutcliffe, Andy. Richardson, and Tom. ThomasCite this: Anal. Chem. 1994, 66, 10, 1664–1666Publication Date (Print):May 15, 1994Publication History Published online1 May 2002Published inissue 15 May 1994https://doi.org/10.1021/ac00082a011RIGHTS & PERMISSIONSArticle Views87Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (273 KB) Get e-Alerts Get e-Alerts

Field Evaluation of a Sampling and Analytical Method for Environmental Levels of Airborne Hexavalent Chromium

Hexavalent chromium, Cr(VI), has been classified as a human respiratory carcinogen. Airborne Cr(VI) emissions are associated with a number of industrial sources including metal plating, tanning, chromite ore processing, and spray painting operations; combustion sources such as automobiles and incinerators; and fugitive dusts from contaminated soil. There has been considerable interest within industry and the regulatory community to assess the potential cancer risks of workers exposed to Cr(VI) at levels substantially below the threshold limit value (TLV) of 50 µg/m3. To date, only the workplace sampling and analytical method (National Institute for Occupational Safety and Health [NIOSH] Method 7600) has been validated for measuring airborne Cr(VI), and it can accurately measure concentrations only as low as 500 ng/m3. This paper describes the field evaluation of a sampling and analytical method for the quantitation of airborne Cr(VI) at concentrations 5000 times lower than the current standard method (as low as 0.1 ng/m3). The collection method uses three 500-mL Greenberg-Smith impingers in series, operated at 15 Lpm for 24 hr. All three impingers are filled with 200 mL of a slightly alkaline (pH ∼8) sodium bicarbonate buffer solution. The results of validation tests showed that both Cr(VI) and trivalent chromium, Cr(III), were stable in the collection medium and that samples may be stored for up to 100 days without appreciable loss of Cr(VI). Method precision based on the pooled coefficient of variation for replicate samples was 10.4%, and method accuracy based on the mean percent recovery of spiked samples was 94%. Both the precision and accuracy of the impinger method were within NIOSH criteria. This method could be used to measure ambient concentrations of Cr(VI) in the workplace caused by fugitive emissions from manufacturing processes or chromium-contaminated soils at workplace concentrations well below the current TLV (50 µg/m3) or permissible exposure limit (100 µg/m3).

Field evaluation of a sampling and analytical method for environmental levels of airborne hexavalent chromium.

Hexavalent chromium, Cr(VI), has been classified as a human respiratory carcinogen. Airborne Cr(VI) emissions are associated with a number of industrial sources including metal plating, tanning, chromite ore processing, and spray painting operations; combustion sources such as automobiles and incinerators; and fugitive dusts from contaminated soil. There has been considerable interest within industry and the regulatory community to assess the potential cancer risks of workers exposed to Cr(VI) at levels substantially below the threshold limit value (TLV) of 50 micrograms/m3. To date, only the workplace sampling and analytical method (National Institute for Occupational Safety and Health [NIOSH] Method 7600) has been validated for measuring airborne Cr(VI), and it can accurately measure concentrations only as low as 500 ng/m3. This paper describes the field evaluation of a sampling and analytical method for the quantitation of airborne Cr(VI) at concentrations 5000 times lower than the current standard method (as low as 0.1 ng/m3). The collection method uses three 500-mL Greenberg-Smith impingers in series, operated at 15 Lpm for 24 hr. All three impingers are filled with 200 mL of a slightly alkaline (pH approximately 8) sodium bicarbonate buffer solution. The results of validation tests showed that both Cr(VI) and trivalent chromium, Cr(III), were stable in the collection medium and that samples may be stored for up to 100 days without appreciable loss of Cr(VI). Method precision based on the pooled coefficient of variation for replicate samples was 10.4%, and method accuracy based on the mean percent recovery of spiked samples was 94%. Both the precision and accuracy of the impinger method were within NIOSH criteria. This method could be used to measure ambient concentrations of Cr(VI) in the workplace caused by fugitive emissions from manufacturing processes or chromium-contaminated soils at workplace concentrations well below the current TLV (50 micrograms/m3) or permissible exposure limit (100 micrograms/m3).

Improved Efficiency of Desorption of Oxygenated Solvents from Activated Charcoal Using a New Polar Additive to Carbon Disulfide

Abstract In industrial operations where workers may be exposed to a mixture of polar and nonpolar organic vapors, such as in spray painting, the use of carbon disulfide as the desorption liquid for charcoal tubes or diffusion badges is inadequate. Desorption efficiencies for some polar analytes may be low, and a loading dependency of the desorption efficiency may be present, making quantitation difficult. Many researchers have added polar substances to carbon disulfide or used alternative polar desorption solvents or schemes; however, often the polar additive or solvent may be a compound of interest or interfere in some way with the analysis. Numerous polar and nonpolar solvents were found on charcoal tube and diffusion badge samples collected during automobile assembly spray painting operations. Methanol in carbon disulfide was tried as a desorption solvent but was found to be inadequate. Considerable improvement in desorption efficiencies for the polar analytes was obtained when 2-(2-butoxyethoxy) ethan...

Measurement of the Epoxy Content of Paint Spray Aerosol: Three Case Studies

Abstract Methods for measuring aerosol concentration are usually based upon the physical, electrical, or optical properties of the particles. When the chemical properties of the particles are of interest, the particles are typically collected by filtration for subsequent analysis. This approach is not appropriate when the aerosol is chemically reactive because the properties may change while the particles are airborne and continue to change after the aerosol has been collected on the sampling media. In the case of aerosols generated in spray application of epoxy paints, the epoxide content of the aerosol changes over time due to the epoxide curing reactions which begin when the paint components are mixed for application. These reactions continue while the particles are airborne and are completed as the coating cures on the painted surface. Using a sampling and analytical procedure developed to collect these aerosols and preserve their epoxy content for subsequent analysis, aerosol epoxide concentrations were measured at three spray painting operations. Concentrations ranged from below the method's limit of detection (approximately 3 μeq/m3) to 11.7 μeq epoxide/m3. Epoxy content of the aerosol varied widely between different types of paint and between samples for a single type of paint. Nonvolatile aerosol mass was not a good predictor of aerosol epoxide concentration. While there are no exposure limits for the epoxy resins found in these aerosols, these results indicate that the epoxide content of the aerosols should be measured when assessing the exposures of painters applying epoxy paint by spray techniques.

An evaluation of control technology for spray painting

An evaluation of control technology for spray painting operations was made by a series of field surveys of finishing operations supplemented by a review of the literature. Spray booths that meet OSHA design requirements were found to be capable of controlling total paint mist and organic solvent vapors to within recommended maximums. They are partially effective in the control of toxic metals and other dangerous materials, insofar as they contain the hazard within the booth. The working environment of the spray finisher can also be improved by the use of paint application methods that minimize the energy expended in the atomization process. Respiratory protection was found to be required in those spray finishing operations that employ significant quantities of highly toxic materials, such as lead, chromium, or reactive compounds (isocyanates and epoxy curing agents). It is also necessary for protection against paint mist and organic solvents in painting enclosed spaces or other areas where ventilation is compromised.

An evaluation of control technology for spray painting

An evaluation of control technology for spray painting operations was made by a series of field surveys of finishing operations supplemented by a review of the literature. Spray booths that meet OSHA design requirements were found to be capable of controlling total paint mist and organic solvent vapors to within recommended maximums. They are partially effective in the control of toxic metals and other dangerous materials, insofar as they contain the hazard within the booth. The working environment of the spray finisher can also be improved by the use of paint application methods that minimize the energy expended in the atomization process. Respiratory protection was found to be required in those spray finishing operations that employ significant quantities of highly toxic materials, such as lead, chromium, or reactive compounds (isocyanates and epoxy curing agents). It is also necessary for protection against paint mist and organic solvents in painting enclosed spaces or other areas where ventilation is ...