DRAFT TANZANIA STANDARD CDC 13 (4228) P 3 Bituminous paint for cold application excluding use in contact with potable water Specification TANZANIA BUREAU OF STANDARDS. 1 st edition TBS 2015
0. FOREWORD 0.1. This Tanzania Draft Standard was prepared by the Technical Committee CDC 13 - Paints and varnishes under the supervision of Chemical Standard Division Committee, and it is in accordance with the procedures of the bureau. 0.2. During the preparation of this standard reference was made to the following standards: MS 386:2014 Bituminous paint for cold application excluding use in contact with potable water Specification published by Malawi Bureau of Standards, and BS 6949:1991 Specification for bitumen-based coatings for cold application excluding use in contact with potable water published by British Standards Institute 0.3. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value observed or calculated expressing the result(s) of a test or analysis shall, be rounded off in accordance with TZS 4:1979 (see clause 2). The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. 1. SCOPE 1.1. This Draft Tanzania Standard specifies requirements and method of sampling and test for a range of bitumen-based solvent-borne paints. It covers paints for cold application by either brushing, spraying, rolling or dipping processes intended to give a coat for the corrosion protection and waterproofing of substrates including iron and steel. 1.2. Two types of bitumen-based solvent-borne paints each with three classes are included in this standard. All of these are suitable only for application where the coating will not be in contact with potable water. NOTE 1 These bitumen coatings are neither intended to withstand hot conditions, as on boilers, smoke stacks, etc., for which special paints should be obtained, nor to resist contamination with mineral oils or paint solvents, all of which conditions will cause softening of the film. NOTE 2 Guidance on the use of bitumen-based coatings is given in Annex A 2. Normative references The following normative references are indispensable for the application of this standard. For dated references, only the edition citied applies. For undated references, the latest edition of the normative references (including amendments) applies CDC 13 (4229) P 3 Solvent-based paint remover, non-flammable Specification CDC13 (4231) P3 Mineral solvents for paints, turpentine, white spirit and related products Specification CDC 13 (4606) P 3 /ISO 1514, Paints and varnishes Standard panels for testing CDC 13 (4607) P 3 /ISO 1516, Paints and varnishes Determination of flash/no flash Closed cup equilibrium method CDC 13 (4609) P 3/ ISO 2812-1, Paints and varnishes Determination of resistance to liquids -- Part 1: Immersion in liquids other than water CDC 13 (4610) P 3 /ISO 4628-2, Paints and varnishes Evaluation of degradation of coatings -- Designation of quantity and size of defects, and of intensity of uniform changes in appearance -- Part 2: Assessment of degree of blistering CDC 13 (4612) P 3/ ISO 6503, Paints and varnishes Determination of total lead -- Flame atomic absorption spectrometric method CDC 13 (4616) P 3/ ISO 15528, Paints, varnishes and raw materials for paints and varnishes Sampling TZS 4, Rounding off numerical values TZS 552/ISO 6860, Paints and varnishes Bend test (conical mandrel) TZS 587/ISO 9117-3, Paints and varnishes Drying tests Part 3: Print free test 1
3. Terms and definitions For the purposes of this standard, the following terms and definitions apply: 3.1. bitumen viscous liquid, or a solid, consisting essentially of hydrocarbons and their derivatives, which is soluble in trichloroethylene and is substantially non-volatile and softens gradually when heated. It is black or brown in colour and possesses waterproofing and adhesive properties; it is obtained by refinery processes from petroleum, and is also found as natural deposit or as a component of naturally occurring asphalt in which it is associated with mineral matter NOTE The international definition of bitumen relates its solubility to carbon disulphide but, in this Tanzania Standard, the safer material trichloroethylene is recommended for use as the test solvent. This recommendation is based on the experience of others, in particular, the United Kingdom, where it is said in BS 6949 that examination has shown no significant difference. 3.2. bitumen-based paint liquid mixture of bitumen in a carrier (solvent or solvent mixture), usually paraffinic hydrocarbons, chlorinated hydrocarbons and aromatic hydrocarbons, with or without fillers, to give a consistency suitable for brushing, spraying, rolling or dipping in accordance with the recommendations of the manufacturer. The coating may exhibit thixotropy 3.3. thixotrop phenomenon shown by some fluids in which the viscosity decreases as the shear rate increases 3.4. defective test sample or a container of the paint that fails in one or more respects to comply with the relevant requirements of this standard 3.5. thixotropic paint paint which exhibits thixotropy NOTE Thixotropic paints are firm on the brush but become thinner when worked 4. Requirements 4.1. General requirements 4.1.1. Classification the Bituminous paint shall be classified into the following two types: a) Type 1, without fillers b) Type 2, with fillers 4.1.2. Each type shall be further sub-classified as follows: 4.1.3. Finish a) Class A, using white spirit complying with CDC13 (4231) as the carrier b) Class B, using either a solvent other than white spirit, or a solvent mixture with a flash point of above 21 C and below 32 C as the carrier. c) Class C, using either a solvent other than white spirit, or solvent mixture with a flash point of above 32 C as the carrier. When tested in accordance with 8.2, the film shall be smooth, opaque and free from sags or runs or other surface imperfections. 2
4.1.4. Protection against corrosion 4.1.4.1. Resistance to potable water immersion 4.1.4.1.1. When tested in accordance with 8.3.1.1, the film shall remain completely adherent to the substrate. Any blistering shall not exceed rating 2 (S3) in accordance with CDC 13 (4610). 4.1.4.1.2. When tested in accordance with 8.3.1.2, the surface of exposed metal revealed shall show no visible rust or pitting. 4.1.4.2. Resistance to artificial sea water immersion 4.1.4.2.1. When tested in accordance with 8.3.2.1, the film shall show no signs of breakdown. Any blistering shall not exceed rating 2 (S3) in accordance with CDC 13 (4610). 4.1.4.2.2. When tested in accordance with 8.3.2.2, the surface of exposed metal revealed shall show no visible rust or pitting. 4.1.5. Bend resistance When tested in accordance with 8.4, the film shall show no signs of cracking or of becoming detached from the substrate. 4.2. Specific requirements The paint shall also comply with specific requirements specified in Table 1 when tested in accordance with the methods therein. Table 1 Table of specific requirements for bitumen-based solvent-borne paints S/ No. Characteristic Type I Type II Test method Drying time (i) Surface drying time at 25 o C, h, max. Hard drying time at 25 o C, h, max. 12 36 12 36 TZS 587 Flash point, ºC, min. (ii) For Class A and C 32 32 CDC 13 (4607) For Class B 21 21 (iii) Lead content, ppm, max. 90 90 CDC 13 (4612) 4.3. Storage stability The bitumen-based solvent-borne paints when stored in the original seal container at the room temperature shall retain its properties for the period of 12 months from the date of manufacturing. No separation shall take place which cannot be removed by stirring. NOTE In the case of thixotropic paints, sufficient time, as advised by the manufacturer, should be allowed after any stirring to redevelop the thixotropy. 5. Sampling Sampling shall be done in accordance with CDC 13 (4616). 3
6. Packaging, labeling and marking 6.1. Packaging The bitumen-based solvent-borne paints shall be packaged in a suitable container that prevents it from deterioration during storage, transportation and normal handling 6.2. Labelling and marking 6.2.1. The labelling shall be either in English or Kiswahili or in combination. Any other language shall be optional. 6.2.2. The paints shall be packaged in containers that are legibly and indelibly marked with the following information: a) the name of the product b) manufacturer s name, address and/or registered trade mark; c) date of manufacture; d) net content; e) batch/code number; f) country of origin; g) a statement that it is unsuitable for use in contact with potable water; h) expiry date or best before date; and i) instructions for use and safety. 7. Quality of reagents Analytical grade reagents and distilled water or deionized water of equivalent purity shall be used for the appropriate tests. 8. Methods of test 8.1. Preparation and coating of test panels 8.1.1. Material and dimensions Use test panels of the material specified in CDC 13 (4606) and of the specified dimensions. 8.1.2. Preparation and coating Prepare the test panels in accordance with CDC 13 (4606) and then coat by brushing, spraying, rolling or dipping as recommended by the manufacturer, to give a dry film thickness of 35 µm ± 5 µm for type 1 Paints or 75 µm ± 10 µm for type 2 Paints. 8.1.3. Drying of test panels Dry the test panels in a vertical position at a temperature of 25 C ± 2 C and a relative humidity of 50 % ± 5 % for the specified time. Allow the first coat to dry for 24 h before application of the second coat. For the tests required in 4.1.5 coat the backs and edges of the panels with a protective paint system. 4
8.2. Finish Apply a single coat of the paint as described in 8.1 to a burnished nominal 300 mm 300 mm steel panel to give the appropriate dry film thickness for its type given in 8.1.2. Inspect the resultant film visually by nominal or corrected vision. Record the observations and compare with the requirement. 8.3. Protection against corrosion 8.3.1. Resistance to potable water immersion 8.3.1.1. Apply two coats as described in 8.1 to a burnished nominal 150 mm 100 mm steel panel. Then 72 h after application, test in accordance with Procedure A, Method 1 of CDC 13 (4609) using potable water and an immersion period of 14 days. Inspect the film visually by normal or corrected vision. Record the observations and compare with the requirement. 8.3.1.2. Remove the film with a non-corrosive paint remover complying with CDC 13 (4229). Inspect the surface of the exposed metal by normal or corrected vision. Record the observations and compare with the requirement. 8.3.2. Resistance to artificial sea water immersion 8.3.2.1. Apply two coats as described in 8.1 to a burnished nominal 150 mm 100 mm steel panel. Then 72 h after application, test in accordance with Procedure A, Method 1 of CDC 13 (4609). Use artificial sea water complying with annex B, with an immersion period of 4 days for type 1 material and 14 days for type 2 material. Inspect the film visually by normal or corrected vision. Record the observations and compare with the requirement. 8.3.2.2. Remove the film with a non-corrosive paint remover complying with CDC 13 (4229). Inspect the surface of the exposed metal by normal or corrected vision. Record the observations and compare with the requirement. 8.4. Bend resistance Apply a single coat as described in 7.1 to a burnished nominal 100 mm 50 mm 0.3 mm thick tinplate panel. Allow to dry for 7 days. Test as described in TZS 552, using type 1 apparatus. For type 1 coatings use a 6 mm mandrel. For type 2 coatings use a 10 mm mandrel. Inspect the film visually by normal or corrected vision. Record the observations and compare with the requirement. 5
A.1 Safety instruction ANNEX A (normative) Guidance on the use of bituminous paint for cold application Consult the safety instructions of the manufacturer before application and, especially, before spraying these materials. A.2 General Properties Like other protective paints, bituminous paints are used to protect surfaces rather than to decorate them, their function being to exclude moisture or other corrosive agents. It is thus important that each coat is applied in a continuous manner, without holidays or misses. Bituminous paints have little power to inhibit corrosion. Hence, if ferrous surfaces are not adequately cleaned to be free from rust and mill-scale before these paints are applied, under-rusting may occur with consequent failure of the film. They have good adhesion to most surfaces commonly found in building, e.g. ferrous metals, slightly etched galvanized iron and steel, concrete and brick, and will withstand moderate concentrations of acids and alkalis. These bituminous paints are neither intended to withstand hot conditions, as on boilers, smoke stacks, etc for which special paints should be obtained, nor to resist contamination with mineral oils or paint solvents, all of which conditions will cause softening of the film. A.3 Precautions Provide adequate ventilation, particularly of closed vessels, while the material is being applied and until it is thoroughly dry. The use of air-fed masks for personal ventilation is recommended. When painting the interiors of tanks, use a forced air supply to disperse the solvent and prevent residual solvent condensing on the coating and washing it off. Avoid naked lights in or near the tanks or cisterns during these periods. Use appropriate barrier creams and protective clothing to prevent skin sensitization. Skin should be thoroughly washed and clothing removed and cleaned as soon as possible after the work has been completed. A4. Durability The durability of bituminous paints depends mainly upon (a) the thickness of the film and (b) the degree of exposure. It is important to apply the products liberally in a number of coats, as thick films give proportionately greater protection than thin ones, and to ensure that all areas of a surface are covered. The degree of exposure largely controls the rate of deterioration of the film surface. Bitumen is sensitive to sunlight and other strong light, which quickly cause complete loss of gloss, followed later by a form of chalking. This is, however, confined to the surface and provided that the film is of adequate thickness it will continue to give protection. In situations protected from such attack, the gloss is maintained longer. Crazing sometimes occurs with bituminous paints but bituminous-paint-coated ferrous metals are seldom subject to early corrosion from this cause. A5. Thinning Where thinning is necessary, e.g. as a first coat on very porous surfaces, only white spirit should be used in the case of class A paints. For class B and C paints, only the manufacturer s recommended thinners should be used. In all cases thinning should be kept to a minimum for the type of use required. 6
A6. Primer In order to prevent under-rusting on ferrous metals, a system of rust-inhibiting primer and bitumen is often advocated. Reference should be made to the bituminous-paint manufacturer. It is important to allow adequate time for the hardening of primers prior to the application of bituminous paint. A7. Preparation of surfaces Establish that the substrate and the bituminous paint are compatible and prepare the substrate according to its type as follows: a) Bare non-porous surfaces. All dirt, including loosely adhering rust and mill-scale, and grease should be removed. b) Surfaces previously covered with bituminous paint. All dirt, grease and loosely adhering coat of bituminous paint should be removed by washing or other suitable means. Any bare patches of metal should be spot-primed with bituminous paint before the general paint is applied. c) Porous surfaces. All dirt and dust should be removed by thorough brushing and any loosely adhering flakes of material should be detached. Washing of porous surfaces is not usually satisfactory unless adequate time is given for the water to evaporate. d) Other surfaces. Reference should be made to the manufacturer of the bituminous paints. A8. Painting All surfaces should be allowed to dry following the preparation. Painting during humid weather, or in other conditions giving rise to condensation, should be avoided. Further details of the establishment of conditions and appropriate applications of paints are given in (a) to (d) below. a) Application to non-porous surfaces. A full coat should be applied by the appropriate method taking care to obtain a uniform and continuous film at the recommended spreading rate. Particular care should be taken to coat thoroughly all recesses, edges, joints, intersections of members, rivet and bolt heads and nuts. No subsequent coat should be applied until the previous coat has dried thoroughly. b) System of bituminous paints and corrosion-inhibitive primer on bare steel. One or more coats of primer should be applied followed by at least two coats of bituminous paint. NOTE The final coat of bituminous paint may, with advantage, be one which contains leafing aluminium as an additive to minimize the effect of sunlight (see A.4) c) Systems of bituminous paint on cementitious surfaces. These surfaces should be sealed with a thinned paint of type 1 bituminous paint, (see A.5). If the original surface has a high degree of porosity a second thinned seal coating should be used. Two subsequent coats of non-thinned bituminous paint are usually necessary, all coatings to be applied after ensuring that the previous coating is thoroughly dry. The spreading rate of the material should be adjusted so as to give a satisfactory final film. If the original surface has a high degree of porosity, an additional thinned priming coat should be used. If the surface is rough, as with some concrete surfaces, or irregular or jointed, as with brickwork, the method and paint should be agreed with the manufacturer. d) Use of bituminous paint with other systems. Bituminous paints are unsuitable where it is desired to finish the work with many other types of paint, since bleeding of the bitumen through the top coat and crazing of the finish is likely to result. Where it is necessary to apply an oil paint over a coat of bituminous paint these faults may be mitigated by the use of a barrier coat of a preparation made especially for this purpose. 7
ANNEX B (normative) Test solution for resistance to artificial sea water immersion The reagents used shall be of a recognized analytical quality. Distilled water or water otherwise produced of equal purity shall be used. The composition of the test solution shall be as given below: Sodium chloride as NaCl Magnesium chloride as MgCl 2 Magnesium sulphate as MgSO 4 Potassium chloride as KCl Sodium hydrogen carbonate as NaHCO 3 Sodium bromide as NaBr Calcium chloride as CaCl 2 (to be added last) Water 26.5 g 2.4 g 3.3 g 0.73 g 0.20 g 0.28 g 1.1 g to 1000 ml NOTE The volume of solution used should be between 1 litre and 1.5 litres per 24 hours. 8