NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
Bremmer HJ, van Engelen JGM. Paint Products Fact Sheet: To assess the risks for the consumer: Updated version for ConsExpo 4 [Internet]. Bilthoven (NL): National Institute for Public Health and the Environment; 2006.
Paint Products Fact Sheet: To assess the risks for the consumer: Updated version for ConsExpo 4 [Internet].
Show detailsConsumers can spray paint products with aerosol spray cans and, to a lesser degree, also using a compressor. When using a compressor, paint products are sprayed almost always pneumatically. During pneumatic spraying the working pressure is about 2-6 bar, and the air consumption rate circa 130-250 l /min (product information; http://www.ferm.nl/nl, dd 03-01-2007; http://www.sikkens.nl/nl/Products/ProductsOverview/Rubbol+BL+Easy+Spray+Gloss.htm?ser=937070365, dd 11-12-2006), user information via the internet (http://www.brommerforum.nl/topics/5, dd 20-10-2006).
On the internet one company was found, which offered spray guns for airless spraying for consumer use (http://www.onlinebouwmarkt.nl/winkel/view_product.php?product=VERW8QWE1&searchlink=yes&search=VERFSPUIT&page=1, dd 20-10-2006). During airless spraying the spraying pressure is much higher, circa 130 bar. It is assumed that airless spraying by consumers will hardly occur.
Airless spraying is a spray painting process that uses hydraulic pressure instead of air to atomize the paint. Atomization is achieved by forcing the paint at high pressure (ca 125-200 atm) through a spray nozzle with a small orifice. The spray pattern and flow of paint are controlled by the size and shape of the orifice. One of the main advantages of airless spraying is that the paint materials do not need to be thinned as much as in air spraying, thereby producing higher film build and better hiding
There is one pump sprayer on the market, which can be used to spray garden stain on wood in the garden, for example on fences. The working pressure is 4 bar (http://www.cuprinol.nl/cuprinol_sprayer_assortiment.php, dd 20-10-2006).
In this chapter spraying with aerosol spray cans and pneumatic spraying using a compressor, are described. No examples were found of airless spraying by consumers; therefore, no default scenario for this type of spraying is described. The inhalation exposure to aerosol particles formed during spraying is described by the spray model from ConsExpo. In section 3.1 general information about the spraying process, paint spraying and general parameter values for the spraying process are described. In section 3.2 and 3.3 default models with default parameter values are stated for spraying with a spray can and for pneumatic spraying.
Spraying garden stain with a pump sprayer should be described with the same model, which describes pneumatic spraying, if spraying occurs indoors. The working pressure is comparable, and it is assumed that the initial particle distribution is also comparable. The ConsExpo models, which describe the inhalation exposure, are developed for indoor application. The spray model from ConsExpo does not describe outdoor application. In the ‛Technical Notes for Guidance, Human Exposure to Biocidal Products’1) spraying outdoors by consumers is only described for spraying of fences with an electric powered sprayer (consumer product spraying and dusting, model 3), not for other spraying devices. Other models, which describe surface spraying outdoors by consumers are lacking. Surface spraying indoors by consumers can be described with ConsExpo and with consumer product spraying and dusting model 2 and model 3 from the TNsG1). It is assumed that the inhalation exposure indoors will be higher than outdoors for an identical application. Describing an outdoor application with these models, which are meant for indoor application, results in a too high value for the exposure. However, this might serve as a worst case estimate.
3.1. General parameters for the spraying process
During spraying, an aerosol cloud of very small to small droplets is formed. The user can inhale these aerosol particles.
To calculate the inhalation exposure to aerosol particles, the ‘spray model’ from ConsExpo is used for both spraying with a spray can and spraying using a compressor. In section 3.1.1 some parameters from the ‘spray model’ are discussed, which are used for both spraying applications.
To calculate the dermal exposure of the user during application the ‘constant rate’ model from ConsExpo is used for both spray applications.
In the previous version of this report other default models were proposed to describe the spraying process. The ‘spray model’ from ConsExpo is developed after the previous version of this report was written.
3.1.1. Parameters for the spray model
The ConsExpo spray model is developed on the basis of the results of experimental work and describes the indoor inhalation exposure to slightly evaporating or non-volatile compounds in droplets that are released from a spray can or pump spray (Delmaar et al.)2,12). For volatile compounds, the evaporation model is more appropriate. If the spray model is used for volatile compounds, inhalation exposure will be underestimated, because exposure to vapour is not considered in the spray model.
‘Volatile’ is defined as compounds with vapour pressure > 0.1 Pa, ‘non-volatile’ < 0.01 Pa and ‘slightly volatile’ between 0.01and 0.1 Pa13).
Initial particle distribution
The droplet size is an important parameter when estimating exposure via inhalation. Smaller drops fall at a lower speed and stay in the air for longer. The large droplets will quickly disappear from the air after being formed. As an indication: the falling time of droplets with a diameter of 100 µm from a height of 3 metres is calculated at 11 sec, and for droplets of 10 µm it is calculated at 17 min14). If a larger droplet is sprayed, part of the aerosol cloud will consist of finer droplets, which stay in the air longer, as a result of edge effects around the nozzle and the ‘bounce back’ effect due to spraying onto a surface. A WHO classification concerning the droplet size of sprays is provided in Table 10, according to data from the Biocides Steering Group14).
Table 10
Classification of aerosol droplets.
The Dutch Aerosol Association15) distinguishes between aerosol sprays in aerosol cans with very fine atomized dry sprays (such as asthma sprays and insecticides) and fine atomized wet sprays (such as hair sprays and paint sprays).
Matoba et al.16) measured the droplet size of an aerosol can with a spray for air space applications. The average droplet size was 30 μm with a range of 1-120 μm. Based on the measurements, Matoba et al. classified the droplets into three groups: 10 % of the particles have a droplet size of 60 μm, 80 % have a droplet size of 20 μm and 10 % of the particles have a droplet size of 5 μm. A spray for air space applications generally has a smaller droplet diameter than a spray for surface applications.
TNO-PML17) has investigated the initial particle size distributions from aerosols spray cans and trigger sprays. The investigated spraying devices were aerosol spray cans, ready-to-use trigger sprays and plant sprayers with an adjustable nozzle to produce a spray with droplets as small as possible or a spray with coarse droplets.
In this investigation, the initial particle size distribution of two spray paints was measured. The percentiles of these sprays are given in Table 11. The 10, 50, and 90 percentiles for the volume distributions of the spray cans are given as dp (V, 0.10), dp (V, 0.50) and dp (V, 0.90), which means that 10%, 50% or 90% of the product mass is below the mentioned size.
Table 11
Percentiles of the initial volume distribution of aerosol spray cans with paint.
In paint 1, water is one of the solvents. Paint 2 is a solvent based paint.
More information about particle size distributions of aerosol spray cans with paint was not found.
Aerosol spray cans
The default initial particle distribution is based on above-mentioned data generated by TNO-PML. Default: lognormal distribution with median 30 µm, coefficient of variation 0.8. (see Figure 1)
Pneumatic paint spraying and pump spraying by consumers
No information was found about initial particle size distribution of non-professional pneumatic spraying of paint, nor about spraying stain using a pump sprayer. The investigated spraying devices by TNO-PML17) were aerosol spray cans, ready-to-use trigger sprays and plant sprayers with an adjustable nozzle to produce a spray with droplets as small as possible or a spray with coarse droplets. For trigger sprays and plant sprays all measured initial particle distributions had median values higher than 50 µm19). Until more information is available the default value for the initial particle distribution of spraying paint pneumatically or using a pump sprayer is set at a lognormal distribution with median 50 µm, coefficient of variation 0.6, (see Figure 2), which is the default value for the initial particle distribution for trigger sprays.
The default values for the initial particle distributions are given in Table 12.
Figure 1
Default initial particle distribution for paint spray cans i.e. a lognormal distribution with median 30 µm (C.V. 0.8).
Figure 2
Default initial particle distribution for spraying paints using a pneumatic sprayer or a pump sprayer i.e. a lognormal distribution with median 50 µm (C.V. 0.6).
Table 12
Default values initial particle distribution spraying paint.
Airborne fraction
The airborne fraction is the fraction of non-volatile material that becomes airborne in the form of droplets. The ‘airborne fraction’ combines the non-volatile material fraction that ends up in the smaller droplets and the fraction of droplets that becomes airborne. The latter is closely connected to the type of spray and the way it is used, for example spraying on a surface (paint, wood preservative) or spraying in the air (spraying against flies), and on the droplet size distribution that has been specified.
Airborne fractions have been determined experimentally for different sprays. The airborne fraction is derived from the TNO-PML17) survey on the exposure from spray cans and trigger sprays (Delmaar et al., in prep.)12. The airborne fractions for the investigated spray cans and trigger sprays are presented in Table 13. Based on these values, default values are set (see Table 14).
Table 13
Airborne fractions of investigated spray cans and trigger sprays.
Table 14
General default values for the airborne fraction.
Based on these general default values the airborne fraction the default value for paint spray cans is set at 1 and for paints sprayed pneumatically or with a pump sprayer at 0.2.
Inhalation cut-off diameter
The inhalation cut-off diameter is the measure for the diameter of the spray droplets that can be inhaled and reach the lower areas of the lungs (alveoli, bronchioles, bronchia). Particles larger than this diameter deposit in the higher parts of the respiratory tract and will be cleared via the gastro-intestinal tract, leading to oral exposure. The inhalation cut-off diameter is only an approximation of the complicated process of deposition of particles in the lung. In general, this value will be around 10-15 µm. The default value is set at 15 µm.
Density
In the spray model, the density of the non-volatile fraction is one of the parameters. Many non-volatile substances in paint products are composed of large organic compounds with densities usually between 1.0 and 1.5 g/cm3. For a complex mixture of (especially organic) compounds, the density is set at 1.8 g/cm3. The density of salts generally varies between 1.5 and 3.0 g/cm3. In Table 15 default values are described for solvents and for non-volatile compounds.
Table 15
Default values for density.
3.1.2. Parameters for the ‘constant rate’ model
To calculate dermal exposure of the user during application the ‘constant rate’ model from ConsExpo is used for both spray applications, i.e. spray cans and pneumatic spraying. Exposure measurements of surface spraying with pre-pressurized aerosol spray cans and hand-held trigger sprays spraying by consumers are described in the TNsG1). The measured data for dermal exposure have a wide range. The default values for the contact rate (the main parameter in the ‘constant rate’ model) are derived from these measurements.
Contact rate aerosol spray cans
In the TNsG1), in ‘Consumer product spraying and dusting’, a surface spraying model is stated in which the consumer uses an pre-pressurized aerosol spray can for spraying surfaces, i.e. a skirting board, dining chairs, a sofa and carpet. The dermal exposure on hands and forearms ranges from 1.7 to 156 mg/min with a 75th percentile of 64.7 mg/min. The dermal contact rate for legs, feet and face ranges from 17 to 45.2 mg/min with a 75th percentile of 35.7 mg/min.
Using these data, the default value for contact rate during spraying with a spray can, for the total dermal exposure, is set at 100 mg/min.
Contact rate pneumatic spraying
In the TNsG’s1) ‘Consumer product spraying and dusting’ a surface spraying model is stated in which the consumer uses a hand-held trigger spray for spraying surfaces i.e. skirting boards, shelves and horizontal and vertical laminate with a wood preservative. The dermal exposure on hands and forearms ranges from 3 to 68.2 mg/min with a 75th percentile of 36.1 mg/min. The dermal contact rate for legs, feet and face ranges from 1.9 to 12.4 mg/min with a 75th percentile of 9.7 mg/min. Using these data, the default value for contact rate for hand-held trigger sprays in the Pest Control Product Fact Sheet18) was set at 46 mg/min. In the TNsG’s1) ‘Consumer product spraying and dusting’ a surface spraying model is stated in which the consumer uses an electric powered sprayer outdoors for all types of fence with a wood preservative.
The dermal exposure on hands and forearms ranges from 32.4 to 144 mg/min with a 75th percentile of 72.6 mg/min. The dermal contact rate for legs, feet and face ranges from 13.4 to 84 mg/min with a 75th percentile of 39.9 mg/min.
Based on the data above the default value for the contact rate during pneumatic spraying, for the total dermal exposure, is set at 110 mg / min.
Table 16
Default values contact rate for spray cans and pneumatic sprayers.
3.2. Spraying paint with a spray can
Composition
Propellants used in paint spray cans usually are di-methyl ether or a mixture of propane and butane. If propane/butane is propellant in paint spray cans, often white spirit/acetone is the solvent (product information;20; 21)).
The Dutch sector association for paint and printing ink manufacturers (VVVFa)) indicates that ether is by far the most used propellant in paint spray cans. If ether is propellant, it functions as solvent too. As binder, in solvent soluble acrylates are used. Therefore the product in the spray can is not a dispersion.
The Netherlands Organisation for Applied Scientific Research (TNOb)) declares that the binder usually is an alkyd resin, and that, to a much lesser extent, cellulose lacquers are used.
In paint spray cans the solid compounds are dissolved in the solvent. Most other paints are dispersions; the solid compounds are colloid particles in the liquid. Paint products which are sprayed pneumatically, usually are dispersions.
Based on the composition of paint spray cans the weight fraction of the non-volatile part of the components in the spray can is assessed at 0.3. The default value for the density of the non-volatile part of the components is set at 1.5 g/cm3, based on the composition of the product and the densities as described in Table 15.
Use
Paint spray cans are for example used for painting of radiators, bikes and auto repair. In Weegels4) one person using spray paint is described. The distance from the nozzle to the nose varied between 20 and 50 centimeters.
Scenario
As default scenario for spray paint with a spray can, spraying of a whole spray can of 400 ml, to paint a radiator in a garage is selected. It is assumed that the garage is left 5 minutes after spraying.
Inhalation and dermal exposure of spray particles is described below. To describe the inhalation exposure, the spray model is used, and to describe the dermal exposure, the constant rate model.
Inhalation exposure of propellants and solvents is not described. In ‘ConsExpo 4 Spray Model. Description and Experimental Validation’12) it is assumed that propellants and solvents evaporate instantaneously during spraying. To calculate the inhalation exposure of these components the instantaneous release mode of the evaporation model can be used.
Inhalation exposure
Product amount
In the scenario it is stated that a paint spray can of 400 ml is sprayed. Based on the composition of the product and the densities, as described in Table 15, it is assumed that the density of the product in the spray can is 0.75 g/cm3, therefore the product amount in the spray can is 300 g.
Application duration / release area
In Weegels4) one case of paint spraying with a spray can is described. In total 29 g of paint was sprayed, the time during which the spraying took place was 5 minutes.
Product information of Akzo Nobel21) indicates that 1.5-2 m2 can be sprayed with a spray can of 400 ml. The distance from the spray can to the object ought to be 15-30 cm; 5 minutes after spraying the paint is dust-dry, and can be resprayed. After 15 minutes, the paint is dry (propellant/solvent: ether).
The Dutch sector association for paint and printing ink manufacturers (VVVFa)) indicates that spraying a surface of 1.5-2 m2 with a spray can of 400 ml can be seen as maximal value, in practice the sprayed surface usually will be smaller. The time span of emptying a 400 ml spray can is estimated at 10 to 15 minutesa).
Based on these data the default value for the application duration (the time span which is sprayed) is set at 15 minutes. For the release area (the painted surface) 2 m2 is assumed.
Mass generation rate
As described above, 300 g of paint is sprayed in 15 minutes. The mean mass generation rate is calculated to be 0.33 g/sec.
In the TNO report ‘Aerosols from spray cans and trigger sprays’17) the mass generation rate during actual spraying of the two investigated spray cans is described: 0.6 g/sec.
This indicates that in the time span during which spraying take place (= spray duration) about half of this time actually is sprayed.
Table
Default for spraying paint with a spray can.
3.3. Pneumatic spraying
Composition
The paint which is sprayed during pneumatic spraying is the same as the paint which is applied by means of brushing or rolling. The only difference is that paints which are sprayed have to have a specific viscosity. Solvents can be added to make a product which can be sprayed properly. The solvents are the same as used by brushing / rolling (usually white spirit).
The general composition of the sprayed paint equals the composition of a conventional solvent rich paint6).
| Binder | ± 35 % | for example alkyd resin |
| Pigment | 25 % | for example titanium dioxide |
| Solvent | 40-50 % | for example white spirit |
| Additives | ± 2 % | dryer 1 %; anti-skin product 0.2-0.5 %; anti-sag product 0.5 %; moistener 0.5 % |
Use
The distance between the spray gun and the surface to spray ought to be 30 cm22). The working pressure is about 2-6 bar, and the air consumption circa 130-250 l /min (product information; http://www.ferm.nl/nl/, dd 03-01-2007).
Scenario
As default scenario for pneumatic spraying, painting of two radiators in a garage is selected. It is assumed that the mean mass generation rate is 50 % higher than for a spray can, i.e. 0.5 g/sec.
Inhalation exposure
Product amount / release area
The painted surface (= release area) is set at 4 m2, twice as much as for one radiator, as described before for spraying with a spray can.
If it is assumed that the quantity of paint, expressed as non-volatile substance per m2 painted surface, is the same as for spraying with a spray can (spraying with a spray can: 300 g for 2 m2, 30 % non volatile substances), then the product amount to paint 4 m2 with a pneumatic sprayer (paint 50 % non volatile) is calculated at 360 g paint.
For brushing/rolling with a solvent rich paint (see section 2.3) 100 g of paint is necessary per m2. The default value for the product amount to spray 4 m2 radiators is set at 400 g paint.
Spray duration / exposure duration
Spraying 400 g of paint with a mean mass generation rate of 0.5 g/sec (see scenario) lasts 800 sec (13.3 minutes). It is assumed that cleaning after spraying lasts circa 10 minutes and that the garage is left afterwards. Therefore the exposure duration is 25 minutes
Table
Default for pneumatic spraying of paint.
Footnotes
- a)
Personal communications VVVF, dd 24-10-1997; 12-11-1998
- b)
Personal communications TNO-Industrie, dd 22-12-1997; 12-11-1998
- Spray Painting - Paint Products Fact Sheet: To assess the risks for the consumer...Spray Painting - Paint Products Fact Sheet: To assess the risks for the consumer: Updated version for ConsExpo 4
Your browsing activity is empty.
Activity recording is turned off.
See more...