Aerosol Cans Research Articles

Upper and Lower Bound Limit Loads for Thin-Walled Pressure Vessels Used for Aerosol Cans

The elastic compensation method proposed by Mackenzie and Boyle is used to estimate the upper and lower bound limit (collapse) loads for one-piece aluminium aerosol cans, which are thin-walled pressure vessels subjected to internal pressure loading. Elastic-plastic finite element predictions for yield and collapse pressures are found using axisymmetric models. However, it is shown that predictions for the elastic-plastic buckling of the vessel base require the use of a full three-dimensional model with a small unsymmetrical imperfection introduced. The finite element predictions for the internal pressure to cause complete failure via collapse fall within the upper and lower bounds. Hence the method, which involves only elastic analyses, can be used in place of complex elastic-plastic finite element analyses when upper and lower bound estimates are adequate for design purposes. Similarly, the lower bound value underpredicts the pressure at which first yield occurs.

Influence of different parameters on droplet size and size distribution of sprayable sunscreen emulsions with high concentration of UV‐filters

The purpose of this study was to evaluate the possible influence of different formulation and technological parameters such as sunscreen type and concentration, viscosity, propellant gas, actuator and valve type on size and size distribution of droplets in emulsions of waterproof sunscreens conditioned in aerosol cans. Different kinds of emulsion, W/Si and W/O, were prepared with high concentrations of organic and inorganic UV-filters. These formulations were incorporated in aerosol cans with gas (a blend of butane, propane and isobutane). The size and size distribution of the droplets were analysed by laser diffraction using a Malvern Spraytec. The results showed that the sprayability of the formulation and the particle size characteristics of the emitted sprays are dependent on the physicochemical properties of the formulations. Sprayable waterproof sunscreen emulsions, with a high sun protection factor and negligible percentage of emitted droplets below 30 mum, were successfully developed by optimizing formulation parameters and using appropriate actuators and valves.

Finite element modelling of the manufacturing process for aluminium aerosol cans

The current paper provides an illustration of the application of non-linear finite element analysis to the modelling of the extrusion and forming processes, using the manufacture of a one-piece aluminium aerosol can by the back extrusion process as an example. It also demonstrates how this numerical method can be used to predict the axial buckling of such cans, which is a potential failure mode during manufacture. The various stages of the modelling process are described and finite element predictions are presented. Where possible, these predictions are compared with experimental results. The paper also highlights some of the modelling issues associated with analyses of this type and provides recommendations as to how the correlation between the model and the actual physical problem can be improved.

Analysis of ethylene oxide gas house explosion

An explosion destroyed a small “Gas House” in which aerosol cans were being filled with ethylene oxide on June 24, 1997. At issue was whether the ignition occurred in the Gas House or from a remote catalytic converter. Our investigation of the pattern of blast damage supports ignition at the catalytic converter that generated a burn-back through the ducting. A strong jet ignition reached a flammable atmosphere in the Gas House and ignited an explosion that well exceeded the yield strength of the prefabricated metal Gas House in spite of the vent panels and access doors being released and discharging of the fire suppression system. One of the doors from the Gas House flew off of the building as hazardous debris, which impacted and catastrophically failed a second door located in an adjoining occupied building. This resulted in the only fatality associated with this event. This study illustrates the damage patterns that indicate the direction of the initial explosion wave. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007.

Field electroantennogram and trap assessments of aerosol pheromone dispensers for disrupting mating in Epiphyas postvittana

An electronically controlled aerosol system for mating disruption was evaluated against Epiphyas postvittana Walker in apple orchards in New Zealand. The area in which male moths were affected by the aerosol system was examined using catches in traps radiating from a central single-point source of either one aerosol can dispenser or 100 polyethylene tubing dispensers, compared with catches in orchard plots without pheromone dispensers. Both pheromone dispensing systems decreased moth catch to similar levels at 5-10 m from the central release point, but there was 5.5-fold more pheromone released from aerosol cans than from polyethylene dispensers over a 24 h period. Trap catches were reduced by about 90% in plots treated with either five aerosol cans per hectare or uniform deployment of polyethylene dispensers. Recordings of electroantennograms in open grassed plots and orchards indicated that the treated cotton pad of an aerosol dispenser and a point source of 100 polyethylene tubing dispensers produced similar electroantennogram recordings. Electroantennogram recordings provided evidence that pheromone plume detection from a single-point source was maintained over a range of 5-40 m downwind in the orchard. On present evidence, aerosol pheromone dispensers could not be recommended for further testing towards control of E. postvittana under New Zealand conditions owing to their higher cost of purchase and operation.

Report on hazardous household waste generation in Japan

Surveys of over 2000 households in Japan were conducted to investigate the characteristics of hazardous household waste (HHW) generation. In Japan, about 2.5 to 4.3 kg of HHW are produced per tonne of the residential waste stream. The percentage of used batteries in HHW was over 50%. Every household using spray (aerosol) cans had more than seven cans on average. The generation of HHW, in terms of both quantities and type of waste produced, appeared to vary with dwelling type. Detached dwelling residents tended to store HHW such as used batteries, whereas apartment residents tended not to store waste. The amounts of discarded HHW were larger at the end of the year in comparison with other months. The data accumulated were used to estimate the quantities of HHW disposed off annually, and the quantities and type of waste that might be received by a typical depot collection programme in Japan.

Failure analysis of three-piece steel aerosol cans

This paper explains how three-piece aerosol cans made from tin-plated steel are designed and manufactured, how they behave structurally, and provides information on doing failure analyses of aerosol cans. Particular emphasis is placed on the metallurgical aspects of the side-seam welding process used to create the body cylinders, the process of attaching the ends, and explains how three-piece aerosol cans made from tin-plated steel behave structurally. The paper also addresses a number of representations and conclusions presented in a paper by M. Fox and R. Hastings entitled “Pressurized 3-Piece Steel Container Explosions and Failure Mechanisms” published in the June 2003 issue of Practical Failure Analysis. Aerosol cans may fail, although not necessarily explode, by internal or external corrosion, by mechanical abuse (puncture, for example), or by being overheated. Understanding the design, manufacture, and structural behavior of these pressure vessels will aid in the formulation of conclusions as to the root causes of aerosol can failures.

The use of can flatteners in MRFs for processing material including post consumer aerosols — a risk assessment

The health and safety issues associated with the recovery of post consumer aerosol cans through MRFs are generally the same as those associated with other recyclables and as such are covered by normal MRF operating procedures. The main hazards specific to the recycling of post-consumer aerosol cans are the generation of flammable atmospheres during can compaction and sort operator exposure to contents of aerosol cans. Previous risk assessments have tended to concentrate on the processing of recovered material using baling presses for compaction. References to the use of can flatteners and shredders provide insufficient data for assessment of risks. This report describes a series of MRF based tests in which can flatteners were used to compact recovered steel and aluminium cans, with known proportions of post consumer aerosol cans present. The trials were carried out under conditions representative of those encountered in normal MRF operation. The experience gained and data collected was used as the basis of a risk assessment. Data was generated through eight can flattening tests with a metal handling rate of 250 kg/h and up to 7.5% aerosol cans by weight. Over a tonne of metal cans and nearly 340 post consumer aerosol cans were processed without any problems being observed. The risk associated with processing material including post consumer aerosol cans by can flattener may be reduced by promoting the recovery of only empty post consumer aerosols and following good operational practices and the recommendations made in this risk assessment.

Health and safety issues in post-consumer aerosol container recycling

Post-consumer aerosol cans are being recovered for recycling through material reclamation facilities (MRFs). This paper reviews current practice on the basis of the published reports and the experience of MRFs. The general conclusion of the risk assessments reviewed is that although potential hazards arise from flammable or harmful residual contents, empty aerosol containers may be included in the domestic post-consumer waste recycling stream provided a number of basic precautions are taken to control risks to an acceptable level. Principle amongst these precautions is that only empty aerosols derived from the domestic waste stream should be handled by a MRF and these should not be segregated from the steel and aluminium streams.

Removal of VOCs from spent aerosol cans

Removal of VOCs from spent aerosol cans

Burns de to aerosol can explosions

This report describes one burn service's experience with burn injuries sustained by 18 patients over a 5-year period as a result of the explosion of pressurized aerosol cans. The burns were predominantly superficial flash burns and involved from 5 to 45 per cent of the body surface area. There were no deaths in the series. Heightened public awareness of the fire and explosive hazards of these cans, as well as a more prominent warning label on the can should aid in decreasing the incidence of these injuries.

Sample preparation for gas chromatographic analysis of organic solvents in aerosol cans

A method for the sampling of chemical products from aerosol cans is described. An aerosol can is frozen in liquid nitrogen, followed by puncturing the can and allowing the propellant to distill off. The conditions for the smaple preparation have been optimized. Solvent content in the products were analysed by headspace gas chromatography-mass spectrometry.

Headspace analysis of chlorinated organic solvents in aerosol cans by gas chromatography

A gas chromatographic (GC) method for the analysis of chlorinated solvents in chemical products in aerosol cans is described. Conditions for the sampling of chemical products from aerosol cans were optimized, so that the recovery of the solvents was better than 90%. Chlorinated solvents were identified by headspace GC—electron capture detection (ECD) as well as by GC — mass spectrometry. Headspace analysis employing the standard additions method and GC-ECD was used for the quantitation of chlorinated solvents. Analysis of 159 acrosol products, for various uses, revealed that 9% of these did not comply with the Danish Aerosol Regulations. The results of the study further indicated that aerosol products for haircare, paints and paint removers, and many others, can be formulated without chlorinated solvents.

Field Trials of Aerosol Formulations of Avermectin Bl, 1991

Abstract Field tests were conducted on the relative efficacy and residual life of two aerosol formulations of avermectin Bl. The Dorie Miller Homes, Duneland Terrace, and Broadway Village, multi-family public housing complexes located in Gary, Indiana, served as the test sites; individual apartments served as the replicated experimental unit. All applications were made with readyto- use aerosol cans containing formulated active ingredients. Bait was applied generously throughout the apartment, focusing attention on the cracks and crevices harboring infestations of cockroaches. Some general surface treatments were made at the intersections of shelves and cabinetry, or floors and walls (particularly around the stove and refrigerator). All obvious harborages (i.e., cracks in walls, along and behind baseboards, beneath and behind sinks, stoves, refrigerators and cabinets, around plumbing and other utility installations) were treated, as well as infested furniture and the inside of cabinets and closets. The amount of bait applied in each apartment was recorded for analysis. Population levels were estimated by visual counts throughout the kitchen and bathroom areas, and a minimum pretreatment count of 20 cockroaches was required for any apartment to be considered as a test. Each treatment was replicated in 11-14 apartments, but posttreatment counts varied due to apartment vacancy or lack of resident cooperation. To determine insecticidal efficacy, posttreatment visual counts were reduced to percentage of reductions of the pretreatment counts. Prior to statistical analysis, percentage of reduction data were transformed to ranks. All data were analyzed with ANOVA models; followed by the F-statistic (P = 0.05) to determine significance between the treatments at each posttreatment census.

Field Trials of Insecticidal Sprays, 1991

Abstract Field tests determined the relative efficacy and residual life of six spray treatments: 0.1% Tempo EC (TEC); 0.1% Tempo EW (TEW); 0.2% permethrin, 0.2% pyrethrins, and 0.5% piperonyl butoxide (PPPB); 0.1% cyfluthrin, 0.05% pyrethrins, 1.0% Baygon, 1.0% piperonyl butoxide (CPBPB); 1.0% Baygon (B); and 0.1% pyrethrins, 0.4% tetramethrin, and 0.15% cypermethrin (PTC). The Dorie Miller Homes, Dorie Miller Homes East, Ivanhoe Gardens, Duneland Village, and Concord Village, multi-family public housing complexes located in Gary, Indiana, served as the test sites; individual apartments served as the replicated experimental unit. PPPB, CPBPB, B, and PTC treatments were made with self-pressurized aerosol cans containing formulated active ingredients. The other treatments were applied using 3.8 liter compressed air sprayers equipped with Multee-jet nozzles. Due to the high cockroach populations and poor sanitation, a general “clean-out” procedure was followed. All accessible harborages throughout the apartment were treated. After 4 wk, all apartments received a second treatment. Population levels were estimated by visual counts throughout the kitchen and bathroom areas, and a minimum pretreatment count of 20 cockroaches was required for any apartment to be considered as a test. Each treatment was replicated in 10-15 apartments, but posttreatment counts varied due to apartment vacancy or lack of resident cooperation. To determine insecticidal efficacy, posttreatment visual counts were reduced to percentage of reductions of the pretreatment counts. Some counts were terminated after 10 wks. Prior to statistical analysis, percentage of reduction data were transformed to ranks. These were analyzed with ANOVA models, followed by the Fisher’s protected least significant difference (P = 0.05) to determine significance among the treatments at each posttreatment census.

Field Trials of Insecticidal Sprays, 1990

Abstract Field tests determined the relative efficacy and residual life of five spray treatments: 0.20% cypermethrin-40 WP (CWP); 0.06% tralomethrin-40 WP (TWP); 0.06% tralomethrin-CS microencapsulated (TCS); PT 270 WB-0.5% chlorpyrifos (PT 270); and PT 270 WB + ETOC + MGK-264-0.5% chlorpyrifos, 0.03% ETOC, and 0.24% MGK-264 (PT 270 +). The Dorie Miller Homes, Dorie Miller Homes East, Ivanhoe Gardens, and Concord Village, multi-family public housing complexes located in Gary, Indiana, served as the test sites; individual apartments served as the replicated experimental unit. PT 270 and PT 270 + treatments were made with self-pressurized aerosol cans containing formulated active ingredients. The other treatments were applied using 3.8 liter compressed air sprayers equipped with Multee-jet nozzles. Due to the high cockroach populations and poor sanitation, a general “clean-out” procedure was followed. All accessible harborages throughout the apartment were treated. Population levels were estimated by visual counts throughout the kitchen and bathroom areas, and a minimum pretreatment count of 20 cockroaches was required for any apartment to be considered as a test. Each treatment was replicated in 12-17 apartments, but posttreatment counts varied due to apartment vacancy or lack of resident cooperation. To determine insecticidal efficacy, posttreatment visual counts were reduced to percentage of reductions of the pretreatment counts. Ranks transformation of the actual data were analyzed with ANOVA models, followed by the Fisher’s protected LSD (P = 0.05) to determine significance among the treatments.

Climate change perceptions and energy-use decisions in Northern Sweden

Lay perceptions of global climate change were examined in the Swedish town of Umeå. Interviews revealed that some residents believed temperatures were becoming warmer, but few perceived linkages between the threat of global climate change and energy use. The desire to reduce household expenditure motivated conservation measures more than concerns about environmental issues. The greenhouse effect was confused with the issue of stratospheric ozone depletion and reductions in the use of aerosol cans were judged to be appropriate policy responses to the threat of greenhouse warming.

A routine gas chromatographic method for the analysis of chlorofluorocarbons in aerosol cans

A gas chromatographic (GC) method for the routine analysis of fully halogenated chlorofluorocarbons (CFCs) in aerosol cans is described. The identification of CFCs by GC was found to be in full agreement with those by GC-mass-spectrometery. The method has been applied to the analysis of CFCs in 448 aerosol products. The most commonly used fully halogenated CFC propellants in aerosol cans were found to be CFC11, CFC12 and CFC114.

An application of noise analysis to quality control

This project investigated the possibility of inspecting the quality of an aerosol can's manufacture by the condition monitoring of its dynamic characteristics. Aerosol cans were excited randomly using an electromagnetic vibrator while the sound produced was analysed using a microphone and a spectrum analyser. The natural frequencies found for a standard can were then used as a ‘fingerprint’ in a quality control process. Experimentation showed that the monitoring of a can's natural frequencies was a reliable method of detecting defects and hence indicating a can's quality.

The Release of Trichlorofluoromethane from Rigid Polyurethane Foams

The use of trichlorofluoromethane (CCl3F or F-11) in rigid closed cell polyurethane foams has risen dramatically during the past decade and now constitutes one of the major applications of this fluorocarbon, whereas previously aerosol spray cans consumed most of the production of F-11. Our study shows that F-11 remains in the foams for a very long time, perhaps for a hundred years or more, if the foams remain Intact. While in the past F-11 was released relatively soon after it was produced, now polyurethane insulating foams may constitute a growing reservoir from which F-11 will slowly and persistently leak Into the atmosphere for as long as the foams are in use. Although uncertainties remain, we estimate that in the next 50 years it is probable that as much F-11 will be tied up in foams as in the entire atmosphere at present.