PAINTS AND VARNISHES FOR BUILDINGS AND RISK PREVENTION RELATED TO EXPOSURE TO HAZARDOUS CHEMICAL AGENTS ASSOCIATED WITH THEM

RISKS CAUSED BY OCCUPATIONAL EXPOSURE TO PAINTS AND LACQUERS USED IN CIVIL CONSTRUCTIONS

Tamara MORARIU, Stefan Gelu CONSTANTIN

The paper presents different types of paints recommended for the covering of various materials used in civil engineering.It details the generic composition of paint and the potential risks determined by different constituents. There are, as well, mentioned the advantages the paints based on water present for the workers safety and health, as compared to those based on solvents.The article also presents the legal provisions on the identification and the assessment of the chemical risks, on the measures of diminishing those risks and on the training and the health surveillance of the workers executing painting operations.

Keywords: painting, civil constructions, chemical risks, labor protection.

1. Introduction

Within the civil constructions field are used various materials such as: wood, metal, concrete, bricks, etc. In order to protect them against the atmospheric factors (rain, snow, sun), mechanic factors, but also for aesthetic reasons, must of the surfaces are covered with pellicle products.Paint is a fluid product (liquid, paste, powder) to be applied as a pellicle on different types of materials as supports. After drying, a thin covering (pellicle, layer), adherent and resistant, protective or decorative is done.There are four main substances, in the paints composition (Fig.1): Resin, as binding material, vehicle or polymer, consists the paint pellicle Pigment, gives to the pellicle color Solvent, a volatile liquid, dissolving the binding materials Additives, added to give special properties to the paints (wet or dry) [1]

Fig.1 Paint Composition by volume

The paints based on solvents contain organic solvents. The paints based on water contain a water mixture (60-80 % liquid part) and organic solvents. If the binder is in emulsion in this mixture, we have a waterborne or emulsion waterborne paint, but if the binder is in solution in the mixture, we have a soluble paint.The emulsion waterborne paints are frequently used in civil constructions for painting the ceilings, walls, woodwork or metalwork, front walls, etc.

2. Components

Each type of paint is composed of: binders, solvents, pigments, filling materials and additives [2].Supplementary, the paints based on water contain coalescence agents (emulsion waterborne coatings), neutralization agents (emulsion waterborne coatings and solution waterborne coatings), and antifreeze agents (emulsion waterborne coatings)

2.1 ResinThe role of the binder is to maintain the link between all components and the adherence of the pellicle. This will influence the drying of the pellicle as well as the physical-chemical feature of the pellicle.This is a macromolecular product of natural origin (oils, natural resins) or synthetic (acrylics, vinyls, polyesters, epoxies, cellulosics, latex, etc).

2.2 PigmentsThese will influence the covering and the color, The pigments are also important for the resistance of the pellicle against outside factors.They are mineral or organic solid products insoluble in the dispersion environment.Examples of inorganic pigments are chromium trioxide (Cr2O3 CC1), cadmium yellow (CdS - T, CC3), chrome yellow (xPbCrO4 CC3).Examples of organic pigments are phtalocyamine blue or green, toluidine red, benzidine, etc.)

2.3 Filling materialsFirst, the filling materials were used only for economic reasons, for the replacement of the pigments, but now they are used to improve some pellicle features. The most used materials are: Carbonates(chalk, dolomite) Sulphates (barium, calcium) Silicates (kaolin, micelle) Oxides and hydroxides(silica, aluminum, magnesium)

2.4 Substances adjusting the viscosityThey facilitate the dispersion of the pigments and increase the storing stability of the paints. In the same time they influence the properties.The main agents for adjusting the viscosity are: polyacylates, polyurethanes, cellulose derivates, silica gels

2.5 SolventsThey are liquids added in paints leading to the decreasing of the viscosity for a better appliance. These products evaporate in order to permit the shaping of the paint pellicle. The function of a solvent in a paint composition is transitory. There are two main categories: organics and water.The organic solvents may be: oil derivates, chlorinated hydrocarbons, oxygen compounds.An emulsion is defined as a stabile dispersion of two unmixable liquids, but the resins within an emulsion have the solid properties.

Fig. 2 Drying of Emulsion Waterborne Paint [3]

2.6 Coalescence agents and co solventsThey are added only in waterborne paints in order to reduce the curing temperature of the coating. Generally, they are hydrocarbons and glycols: naphta solvent (CC2), white spirit, ethylglycol acetate, methylethy acetate, etc.

2.7 Neutral agentsThe emulsion waterborne paints are in general using ammonia and amines in order to improve the stability. The amount depends on the nature of the paint (ph), molecular amount, volatility, solubility and the nature of the binder.

2.8 AdditivesThese additives give various properties to liquid paints or pellicle. Their ratio is ~ 1% from the total amount of the paint. The antiblok agents reduced the tendency for paint films to stick together when they are not quite cured. Antifreeze materials may be added to waterborne paints to reduce the likelihood of freezing. Antimicrobial agents. Bacteria are able to use organic resin portions of paints film as nutrients for growth and replication. House paints in hot humid regions need fungicide additives to prevent them turning an unsightly from mildew. Gloss modifiers. Various can reduce gloss levels without affecting film strength if low or nongloss surfaces are desired. Storage stabilizers are used to increase paint storage stability. These additives will reduce the tendency of paints to skin over and can reduce pigments settling during storage. UV stabilizers can increase a paint films resistance to ultraviolet light.

3. Appliance

The painting of the civil constructions elements may be done by:a. brushingb. rollingc. compressed air sprayingd. air less spraying

3.1 Brushing paintingIt is the most safety method when is correct done. It is simple, no equipments and special devices are necessary. The productivity is low, , it cannot be used for the appliance of the fast drying painting materials and requires a large amount of qualified staff.

3.2 Rolling paintingThe procedure is applicable for smooth and large surfaces. There are, in general, the same advantages and disadvantages like the brushing painting.

3.3 Compressed air sprayingIt is a painting procedure by witch the pellicle material applied on support as fine divided particles, joining again and forming the pellicle. Particle size is between 5 and 15 micrometers.In general, a compressed air spraying painting plant is composed a compressor, an oil separator, a paint reservoir and the spraying pistol.The quality of a compressed air spraying painting depends on the qualification of the operator and some parameters.The spraying distance (between the pistol and the painting surface) must be 25-30 cm for plane jets and large surfaces and 40-45 cm for round jets applied for small surfaces. The fog paint losses may be up to 50% depending on the painted surface and working parameters.

Tab.1Viscosity 4 mm

(sec)Nozzle diameter

(mm)Air pressure

(at)

30-352,23-4

25-351,4-1,83-4

18-221,2-1,52,5-3

15-200,8-1,22,5-3

3.4 Air less paintingThe air less painting (hydraulic spraying) is a more efficient procedure by witch the pellicle materials spraying is done through a hydraulic pump at high pressure (180-200 at). There are used painting pistols equipped with special nozzles for high speed paint. Due to the pressure difference, a fine spraying is carried on. The velocity of the fine paint particles decreases, and the paint fog forming is avoided. By these procedure, a paint saving is carried on (the losses are up to 25 %) and, consequently a less noxious working environment is achieved. The productivity is high, especially for smooth and large surfaces.

4. Risks

The risks of pigments, resins, filling materials and additives are the same, for water paints or organic solvent paints. For the paints using as solvents only organic products, there are toxicological risks and fire risks. Of course, the risk level depends on the applying procedure. Table 2 presents the risks occurring at painting.

Tab.2FazeRisk sourceRisk tipe*Risk evaluation**

SolventWaterborn

Storage, transport Raising of temperature Spills (displacement of the lid, damage of the package) Storage of half full cansITcut

IMM

MNN

N

Application by:sprayingbrush, roll Solvents Tcut, Tinh, ITinh, IR

RS

S

Drying Solvents AminsTinh, ITinhRNSS

Cleaning SolventsTinh, IRN

* I= fire risk, Tcut = skin toxicity, Tinh= inhalation toxicity** M = medium risk, N = non risk, S = low risk, R = high risk

4.1 Toxicological risksToxicological risks may be caused by ingestion, inhalation or cutaneous contact. More risks occur by spraying appliance. By brushing and rolling, there are less important risks (cutaneous-irritation or allergy and sometimes respiratory).

BindersMost of the resins do not have a special toxicity. There are some irritant effects (cutaneous or allergic) of the epoxides and formaldehyde [5].The risk of the isocyanates is missing for water paints, but only for polyurethanes.

SolventsThese materials are most dangerous for the human body. Their high volatility permits body penetration through lungs. Most of the organic substances irritate the eyes and respiratory system, and the prolonged inhalation of the solvents produce asthma. More, the solvents have a narcotic influence expressed by head pains, dizzies and other similar symptoms like alcoholic intoxication. Some solvents may cause blood diseases, neurotic debility, eye diseases, liver diseases and other.The most dangerous solvents are aromatic hydrocarbons especially benzene and chlorinated hydrocarbons. The benzene, inhalated in a few minutes causes chronic intoxication which may lead to death. As a matter of fact benzene was interdicted.Other solvents used in painting, like white spirit, terpenes, ketones, alcohols are in general non toxic. Even those products in unfavorable situations may cause diseases or allergies. For must of them there have been established limit values for professional exposure. The exposure level to hazardous chemical agents must not exceed them. Supplementary, the employer has the duty to try systematically to decrease the exposure level to low values, technically possible.For the public, the emulsion waterborne paints have no risks, due to the high amount of water. What is important is the fact that these kinds of paints contain different amounts of solvents, pigments, filling materials, which are risk sources. So, it is important to assess the toxicological and fire risks for the water paints and to establish prevention measures.

Pigments and filling materialsThe mineral pigments are responsible for diseases according to the metallic elements contained. Chromates may cause skin irritation, skin or respiratory allergies (asthma, asthma). Hexavalent chrom derivates may cause lung cancer. Lead and the lead derivates may cause plumbism affecting the liver, kidney, nervous system or may be dangerous for the unborn baby. It accumulates. Cadmium compounds affect the lungs, digestive system, kidney and bone system. Cobalt compounds are sensitive for the skin and respiratory system Organic pigments are responsible for irritation and cutaneous and respiratory diseases (benzidine, toluidine).

Coalescence agents and co solventsThey are present in the composition of all paints, but in different amounts. In general they are alcohols and glycols. These substances may cause skin irritation and diseases of the blood and reproduction system. Some of them were classified as toxic for reproduction [7]. The present tendency is to replace them with propene oxie derivates

Neutralizations aminesFatty amines are very irritating substances and sensitive for skin and respiratory system. In the composition of the emulsion waterborne paints there are some little amounts, so the risks are reduced.

4.2 Fire risks

In order to analyze the fire risk, for the paints, some properties of the materials have to been considered: the inflammable point, the self ignition point and the explosion risk [4].The inflammable point is the minimum temperature for the ignition of the inflammable material vapors, due to a flame or a spark. The classification of the paints, depending on the inflammable point is: IP less than 21 C: very inflammable paints IP between 21 C and 55C: inflammable paints IP more than 55 C: noninflammable but combustible paintsThe emulsion waterborne paints, due to their small amount of solvent have an inflammable point higher than 55 C. If these paints will be involved in a fire, they will maintain the fire.The only solvents igniting spontaneous, in the absence of a flame or spark, at low temperatures are ether and carbon bisulphide, having self ignition temperatures 1800C and 1200C.If the combustion of a material is fast, it becomes explosive. The mixture between inflammable product and air is not explosive in any circumstances. If the concentration of a inflammable substance is to low or to high, the mixture is not explosive. There are low limits and high limits of explosion for the mixtures of inflammable gases and air. This information is available in the material safety data sheet of the products.

5. Prevention of working accidents and occupational diseases

Painting is a working process involving hazards; the greatest danger is given by the hazardous substances in the composition of the pellicle products. Other dangers, depending on the technology and the type of the paint, are: Manual handling Ignition sources Work at heights Spraying plant Noise Working environment(organization, ventilation, cleaning) Closed spaces

The hazardous substances may cause accidents and occupational diseases, during using and storing at the workplace.According to the legal provisions, the hazardous products are mixtures containing hazardous chemical substances, classified according to the Ordonancy 200/2000 regarding classifying, labeling and packaging of the hazardous chemical substances and with H.G. 92/2003 regarding the Methodological Norms regarding the classification, labeling and packaging of the hazardous chemical substances [8].As mentioned before, many of the substances in the paints composition may seriously affect the health. If the exposure is not controlled properly, the effects on health may be: professional asthma; contact dermatitis; lung cancer reproduction system kidney and liver diseases

The effects on short term may be: skin and eyes irritation eczema vomit and diarrhea nose, throat pain

According to the General Norms of Labour Protection, the employers handling hazardous chemical substances have the duty to: consult the employees get information and train the employees identify the hazardous chemical agents used or stored at the workplace assess the risks caused by hazardous chemical agents at the workplace take measures for monitoring these risks determine the noxious and ensure the medical surveillance to keep the evidence of the activities

The employees have the obligation to: respect during the activity the labour protection measures; to inform the chief of the working place about the deficiencies regarding labour protection measures linked to hazardous chemical substances

According to the prevention principles the following steps must be taken in order to control the risks:

Hazards identificationRisks assessmentMeasures for reducing the risksReview the measuresHave the measures eliminated or reduced the risks?Have the measures induced new hazards?Is the management system working properly? Could the way it is done be improved?

Fig. 3. The main steps of the hazardous chemicals management

Risk assessment must be carried on by consulting the employees and creating the organizational framework to facilitate different points of view and the exchange of information between the employers and employees or their representatives. Although the responsibility for the decisions regarding the safety at work belongs to the employer, the consultation is useful with suggestion based on employees experience.The consultation of the employees may lead to well documented decisions. Consulting the employees, the problems can be avoided and the awareness of the employees increases.The employers and their representatives must participate during all the four phases of risk management and the decisions regarding training. They must be also consulted before any modification at the workplace. The consultation must start since the planning stage and must continue until the implementation in practice of the modification. In this way the aspects regarding health and safety at work may be include in the modification and the dangerous consequences may be avoided.

5.1 Risk identification The risks must be identified when: a new company acting in painting is setting up; the workplace is changing a new painting method or a new product is used; new information from employers associations. Research, Labour Inspection, or producers is provided.

Risk identification is based on: instructions and warnings of the equipment and pellicle products producers ; workplace inspection and discussion with employees; analyze of the working accidents, dangerous incidents and occupational diseases

A substance or hazardous chemical product may be identified after the data included in the label and in the Material Safety Date Sheet (MSDS), The employees must ensure that: all the substances are correctly labeled the information regarding labour protection, including the fiches were provided by the producer, importer or deliver

The labels may be damaged. That is why the employees must: trained to read the labels before opening the vessels to take measures against spreading the content or destroying the label The damaged labels must be replaced nobody is allowed to remove or modify a label.

Fig.4. Contents information and risk phrases can be found on the label

If the content of a vessel is not known, it must be properly marked, for example:Warning not to be used: unknown substance. Such a vessel must be stored separately until it can be identified or destroyed according the legal provisions.When paint or a solvent is poured from a recipient to another which is not used immediately, this must be labeled with the product name and with risk phrases.Risk and safety phrases are standardized information to characterize a substance/hazardous product. They appear on labels, SDS or other documentation.The employers must get SDS for all hazardous substances to be used.According to the legal provisions, the deliverer is responsible for the correct labeling of the product and for the informing the client about labour protection in SDS. This information must be given: before or in the same time with the first delivery; at any SDS modification at client demand

The employer must update a file about all the substances handled or produced at the workplace. This file must contain a list on all hazardous chemical agents in the company and one piece of all SDS. The employees, their representatives, the emergency services and public authorities must have immediate access at this file.The dealers have the duty to ensure SDS. If the substance/hazardous chemical product is achieved in this way and the SDS is not available, then a copy from the producer or importer must be get.If the hazardous products are manufactured at the workplace, for example by mixture and a SDS is not available, the employers must get information about the effects on health and the necessary precautions for the safety using and handling of the substances. This information must be provided to the employees and their representatives.The utilization of certain substances in paint composition, like benzene, ceruse, lead sulphate and all products containing this pigment is not permitted for any painting operation with the exception of railway bridges. It is not permitted the painting by spraying with lead oxide. Always, the SDS must be checked, if in paint composition is such substances, especially if these are imported products.

During the inspection of the workplace, it must be considered that: the static electricity may appear at paint pouring from a container to another; the incorrect storage of flammable materials represents a risk source; any paint waste deposit in the workplace area is a danger. Materials impregnated with paint or solvent can ignite if they are not dry and stored in a special vessel after using; combustion engines must not work in the painting area; spraying plant defects may occur; the following may be risk sources: inefficient lighting, dirty areas, slippery areas, height work, temperature, the lack of first aid, rest places.

The risks regarding the personal protective equipment (PPE), are linked to incorrect maintenance, storing and utilization.The following practices may be applied: PPE must me marked with user name; PPE must be daily cleaned and checked; PPE must be stored in a special place, separate from clothes; The cartridges must be updated and changed at regular date; The replacement must be easy; The operators must be well trained; The operators must be shaved.

5.2 Risk assessmentRisk represents a probability that a danger will produce damages. The employers will consult the employees and must assess the identified risks. The purpose of this action is to determine the risk level and the efficiency of the control of these risks.The assessment means to determine the risk represented by each hazardous product. The risk level depends on the kind of the risk and on the manner in which the workers get contact with these risks. The exposure may occur in different ways: inhalation, skin, ingestion, eyes. The severity of the risk depends on the substance and may be between minor and severe: for example from skin irritation to lung cancer. The hazardous substances may be inhaled after opening a reservoir or a tank.For some paints, besides the toxicological risk there is a fire risk due to the solvents.As regards the way in which the workers contact risks, it must be noticed: Number of the workers exposed Duration and frequency of the exposure The adequacy of the risk control methods

The staff executing the assessment must have knowledge and enough abilities about the painting activities and the legal provisions regarding hazardous substances and safety at work. The employers may assess themselves the activity together with the employees or can delegate one or more employees properly trained. If necessary, other specialists may be appealed.Speaking about the painting of the civil constructions, the same dangerous products may be used at several workplaces. This means that the assessment is done to cover different workplaces or work areas.

5.3 Measures for risk control and diminishingAccording with the general prevention principles, the order of the prevention measures is the next one: elimination of the risks the substitution with safer alternatives the isolation of the hazardous processes technical measures organizatoric measures (administrative controls) using of personal protective equipmentsSome situations require combination of 2 or more measures in order to ensure the risk elimination and reduction. The elimination, in the situation of the civil constructions painting means the renouncing at certain substances, the applying of the pellicle product by brushing or rolling instead spraying, the renouncing at each product with interdictions.The substitution means the replacement of a hazardous substance with another less dangerous.The isolation means the signalization of the workplaces where high risks painting operations are done. The method does not protect the workers but protects other persons in the working area.In order to determine the area of the isolated area and the duration after which access is permitted, the following factors must be considered: the nature of the products to be used; the working environment, including wind speed, air temperature and humidity; other people position

After the area is established, some procedures must be applied: physical barriers to stop the access of unprotected persons stopping the access of unprotected persons until the concentration of hazardous substances is less than a safe value. This period of time may be established during the evaluation process removal of the hazardous substances which are not immediately necessary for the working process in order to reduce the exposure, fire and explosion risk removal of the ignition sources.

For paintings inside buildings, the natural ventilation may be used, by creating air currents through doors, windows or other spaces of the building. In some situations local ventilators may be used if the substances or the applying process present risks.The employers must ensure proper ventilation and the absence of any ignition source in the paint preparation area, respectively the dilution to the prescribed viscosity. The area must be precisely designated and exclusively used for this operation. Before pouring the flammable liquids from a recipient to another, both containers must be electrical earthed and connected through a crocodile cable to avoid the sparks in an area where volatile solvent vapors exist.

Fig. 5. Pouring flammable liquids from one container into another

5.3 Review of the prevention measures

Periodically, it must be checked if the prevention measures are effectively applied, if are efficient and if they can be improved. This means the re-examination together with the employees of the 4 steps of the hazardous chemicals management. In order to review the prevention measures, it must be established a procedure for the frequency of these checks, and to determine the responsibility of the checks. In the same time it must be established the manner of correction of the defects, the criteria for the assessment of the performances and recordings, as well as the documents to be completed. The employers must verify if the implementation of the prevention and control measures do not create other risks.

6. Conclusions

Civil construction use a large variety of materials; Most of the surfaces are painted for aesthetic and protection reasons; The paints are hazardous chemical products, or products containing hazardous chemical substances; The paints based on water have the same components like the paints based on solvents, but the solvent ratio is smaller and this makes them less dangerous; The brushing and rolling painting have less risks then the spraying painting but is less productive; The air less spraying painting has less risks then the classical painting but requires higher investments and is recommended only for large surfaces. Because the painting requires the handling of hazardous chemical products, the assessment of chemical risks must be done, according to the legislation, even if water paints are used.

REFERENCES

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