1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-21107-3 SANS 38:2008Edition 3.3Any reference to SABS 38 is deemedto be a reference to this standard(Government Notice No. 1373 of 8 Novemb
4、er 2002)SOUTH AFRICAN NATIONAL STANDARD Metallic naphthenates for timber preservation Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 38:2008 Ed
5、ition 3.3 Table of changes Change No. Date Scope Amdt 1 1983 Amended to add a new requirement and to change the method for the determination of the acid value. Amdt 2 1983 Amended to change the methods for the determination of the zinc content, the copper content and the acid value of the naphthenic
6、 acids. Amdt 3 2008 Amended to change the designation from SABS to SANS, and to move reference to legislation to the foreword. Foreword This South African standard was approved by National Committee StanSA SC 5110.07C, Timber preservation Timber preservatives, in accordance with procedures of Standa
7、rds South Africa, in compliance with annex 3 of the WTO/TBT agreement. This document was published in April 2008. This document supersedes SABS 38:1976 (second revision, reprint 1983). In the note to 4.2 reference is made to “relevant legislation”. In South Africa this means the Fertilizers, Farm Fe
8、eds, Agricultural Remedies and Stock and Remedies Act, 1947 (Act No. 36 of 1947). A vertical line in the margin shows where the text has been modified by amendment No.3. SANS 38:2008 Edition 3.3 1 Contents Page 1 Scope . 3 2 Definitions 3 3 Physical and chemical requirements . 3 4 Packing and markin
9、g . 4 5 Sampling and compliance with the specification . 5 6 Inspection and methods of test 5 6.1 Inspection 5 6.2 Test samples . 5 6.3 Water plus sediment content . 6 6.4 Acid value of naphthenic acids . 7 6.5 Copper content 9 6.6 Zinc content . 10 6.7 Metallic naphthenate content . 11 SANS 38:2008
10、 Edition 3.3 2 This page is intentionally left blank SANS 38:2008 Edition 3.3 3 Metallic naphthenates for timber preservation 1 Scope 1.1 This specification covers metallic naphthenate concentrates and solutions of metallic naphthenate suitable for the preservation of timber. 2 Definitions 2.1 For t
11、he purposes of this specification the following definitions shall apply: lot that quantity of copper or zinc naphthenate concentrate or timber preserving solution of the same mix, from one manufacturer, submitted at any one time for inspection and test metallic naphthenate metallic salts of naphthen
12、ic acids naphthenic acids the group of cycloalkane carboxylic acids of varying molecular mass and molecular complexity as occurring in petroleum 3 Physical and chemical requirements 3.1 Concentrate 3.1.1 General The metallic naphthenate concentrate shall consist of copper or zinc naphthenate dissolv
13、ed in suitable organic solvents. All the metal present shall be in solution in the form of metallic naphthenate. The concentrate shall be a liquid, and it shall not be so viscous as to make its removal from the container difficult. 3.1.2 Dilution The metallic naphthenate concentrate shall, after dil
14、ution according to the manufacturers instructions as given on the container, comply with all the requirements laid down in 3.2. SANS 38:2008 Edition 3.3 4 3.2 Solution suitable for the preservation of timber 3.2.1 General The metallic naphthenate timber preserving solution shall consist of copper or
15、 zinc naphthenate dissolved in suitable organic solvents. All the metal present shall be in solution in the form of metallic naphthenate. 3.2.2 Detailed requirements The metallic naphthenate timber preserving solution shall comply with the relevant requirements given in table 1. Table 1 Metallic nap
16、hthenate solutions 1 2 Detailed requirements Metal contents, g/L, min. 4,1 Metallic naphthenate content, g/L, min. as copper naphthenate 36,8 as zinc naphthenate 34,7 Acid value of naphthenic acids, calculated on an oil-free basis 100-230 Water plus sediment content, % (V/V), max. 0,5 4 Packing and
17、marking 4.1 Packing Metallic naphthenate concentrates and metallic naphthenate timber preserving solutions shall be packed in containers that are strong enough to withstand normal handling and transportation and that will prevent leakage or contamination of the product in the containers. 4.2 Marking
18、 The outside of each container shall be legibly and indelibly marked with the following information: a) The manufacturers name or trade mark or both; b) the net volume of the contents, in litres; c) the copper naphthenate or zinc naphthenate content (as relevant) calculated as metal; d) in the case
19、of a metallic naphthenate concentrate, instructions for diluting; e) the nature of the solvent; f) the mix identification. NOTE Compulsory requirements for the labelling of receptacles containing timber preservatives are laid down in relevant legislation (see foreword). Amdt 3 SANS 38:2008 Edition 3
20、.3 5 5 Sampling and compliance with the specification NOTE This section applies to the sampling for inspection and testing before acceptance or rejection of single lots (consignments) in cases where no information about the implementation of quality control or testing during manufacture is available
21、 to help in assessing the quality of the lot. 5.1 Sampling The following sampling procedure shall be applied in determining whether a lot complies with the requirements of the specification. The sample so taken shall be deemed to represent the lot. NOTE When liquids in large containers are sampled,
22、a sampling device that will allow the withdrawal of a homogeneous sample from each container shall be used. a) From the lot draw at random 10 containers or all the containers, whichever is less. b) Mix the contents of the containers thoroughly (to ensure an even distribution of the sediment in the l
23、iquid). c) Take from them increments, proportional to the volumes of the contents of the respective containers, to make a composite sample of volume at least 1 L. 5.2 Compliance with the specification A lot shall be deemed to comply with the requirements of the specification if, after inspection and
24、 testing, the composite sample taken from the lot is found to comply with all the relevant requirements. 6 Inspection and methods of test 6.1 Inspection Inspect the lot for compliance with the requirements of section 4. 6.2 Test samples 6.2.1 Timber preserving solutions Mix the sample taken in accor
25、dance with 5.1 thoroughly, and immediately after that take just over 100 mL for the determination of water plus sediment (see 6.3). Then centrifuge the remainder of the sample, or allow it to stand, until the supernatant liquid is free from water and sediment. Carry out all other tests on the water-
26、 and sediment-free liquid. 6.2.2 Concentrates Dilute, according to the manufacturers instructions, the sample, taken in accordance with 5.1, then proceed as detailed in 6.2.1. SANS 38:2008 Edition 3.3 6 6 . 3 Water plus sediment content 6.3.1 Apparatus a) Centrifuge. A centrifuge capable of whirling
27、 two or more 100 mL centrifuge tubes at a speed that can be controlled to give a centrifugal acceleration of between 4 900 and 6 860 m/s2at the tip of the tubes. The speed of the centrifuge shall be calculated as follows: r/min = 13,5cadwhere ca is the centrifugal acceleration; d is the diameter of
28、swing, measured between the tips of opposite tubes when in rotating position, m. b) Centrifuge tubes. Pear-shaped centrifuge tubes that conform to the dimensions given in figure 1. Scale-error tolerances and the smallest graduations between various calibration marks are given in table 2 and apply to
29、 calibrations made with air-free water at 20 C. Table 2 Pear-shaped centrifuge tube calibration tolerances 1 2 3 Range Smallest scale division Maximum scale error mL mL mL 0 1,5 0,1 0,03 Over 1,5 3,0 0,5 0,20 Over 3,0 5,0 0,5 0,30 Over 5,0 10,0 1 0,50 Over 10 25 5 1,0 Over 25 100 25 2,0 c) Bath. A c
30、onstant-temperature bath maintained at 50 C and deep enough to allow the centrifuge tubes to be immersed in a vertical position up to the 100 mL mark. 6.3.2 Procedure Measure exactly 50,0 mL of the well-mixed test sample, taken as described in 6.2, into each of two centrifuge tubes. Fill the tubes t
31、o the 100 mL mark with 90 % benzol. Stopper the tubes tightly and shake vigorously until the contents are thoroughly mixed. Immerse the tubes to the 100 mL mark in the constant-temperature bath at 50 C for 10 min, shake vigorously for 10 s and immediately after that place them in holders on opposite
32、 sides of the centrifuge. Operate the centrifuge for 10 min at the speed required to give a centrifugal acceleration of between 4 900 and 6 860 m/s2, and then read the volume of water plus sediment to the nearest 0,1 mL. Whirl the tubes again in the centrifuge for 10 min, read the volume of water pl
33、us sediment, and repeat this cycle until the volume of water plus sediment remains constant for three consecutive readings. SANS 38:2008 Edition 3.3 7 Figure 1 Pear-shaped centrifuge tube 6.3.3 Calculation Water plus sediment content, % (V/V) = 100abwhere a is the volume of water plus sediment found
34、, mL; b is the volume of sample taken, mL. 6.4 Acid value of naphthenic acids 6.4.1 Reagents and solvents a) Alcoholic potassium hydroxide solution (c(KOH) = approximately 1 mol/L). Dissolve 56 g of potassium hydroxide in 1 000 mL of methanol or ethanol that has been allowed to age for a week over p
35、otassium hydroxide and then distilled. SANS 38:2008 Edition 3.3 8 b) Phenolphthalein indicator. Dissolve 1 g of phenolphthalein in 100 mL of ethanol and, stirring constantly, add 100 mL of distilled water. c) Standard potassium hydroxide solution. An aqueous solution of potassium hydroxide, of conce
36、ntration c(KOH) = approximately 0,2 mol/L, and that has been accurately standardized against potassium hydrogen phthalate. d) Dilute sulphuric acid. A 1:5 aqueous solution. e) Hydrochloric acid, concentrated (d at 25 /25 C = 1,16). f) Petroleum ether, of boiling range 40-60 C. g) Acetone. 6.4.2 Proc
37、edure Weigh accurately approximately 20 g of the test sample into a 350 mL flask that is fitted with a ground-glass joint. Add 25 mL of the dilute sulphuric acid, fit to an air condenser and heat in a boiling water bath for 1 h, shaking the flask frequently. After cooling, transfer the contents of t
38、he flask quantitatively to a separating funnel, using three 10 mL portions of distilled water followed by three 10 mL portions of the petroleum ether to rinse the flask. Allow the layers to separate and then run the lower layer off into a 400 mL beaker. Extract the contents of the separating funnel
39、three times with 20 mL portions of distilled water, allow to separate, and add these aqueous layers to the first one. Retain the 400 mL beaker containing the aqueous extract for the determination of copper content (see 6.5). Add 25 mL of the alcoholic potassium hydroxide solution and 25 mL of distil
40、led water to the separating funnel and its contents and shake carefully until the pentachlorophenol and naphthenic acids have been neutralized. Add 25 mL of the petroleum ether, shake the mixture and allow to stand. Run off the aqueous layer into a second separating funnel. Carry out two further ext
41、ractions of this aqueous layer with 25 mL portions of the petroleum ether to remove solvents and unsaponifiable matter. Combine the portions of petroleum ether used for the last two extractions. Extract the organic solvents in the first separating funnel with three 10 mL portions of distilled water
42、and use these three 10 mL portions of extract, successively, to wash the combined petroleum ether portions used for the last two extractions. Then discard the petroleum ether layers. Combine all the aqueous extracts, filter if necessary, and transfer to a third separating funnel. Make up to 75-100 m
43、L with distilled water, add 5 mL of the hydrochloric acid, and extract by shaking with two 50 mL portions and one 25 mL portion of the petroleum ether. Combine these petroleum ether extracts and wash with distilled water until free from mineral acid. Run the petroleum ether into a tared beaker, filt
44、ering if necessary, and wash the separating funnel with three 10 mL portions of the petroleum ether, adding the washings to the beaker. Distil off most of the petroleum ether on a water bath, add 2 mL of the acetone, and heat the extracted pentachlorophenol plus naphthenic acids to constant mass at
45、60 C (constant mass being indicated by the loss of not more than 0,1 % in 15 min of drying). Note the final mass of the contents. Dissolve the contents by adding 50 mL of ethanol that has been neutralized, to phenolphthalein and titrate the solution with the standard potassium hydroxide solution usi
46、ng phenolphthalein as indicator. 6.4.3 Calculation Acid value of the pentachlorophenol plus naphthenic acids, in milligrams of potassium hydroxide equivalent to 1 g of pentachlorophenol plus naphthenic SANS 38:2008 Edition 3.3 9 Acids = 56,1acmwhere a is the volume of the potassium hydroxide solutio
47、n used in the titration, mL; c is the concentration of the potassium hydroxide solution used in the titration, mol/L; m is the mass of pentachlorophenol plus naphthenic acids found, g. 6.5 Copper content 6.5.1 Reagents a) Standard sodium thiosulphate solution, 0,1N Preparation. Dissolve 25 g of pure
48、 sodium thiosulphate in 1 000 mL of recently boiled and cooled distilled water and keep the solution in an amber glass bottle. Standardization. Weigh out accurately approximately 0,18 g of pure copper turnings into a 350 mL conical flask and dissolve in a mixture of 3 mL of nitric acid and 6 mL of d
49、istilled water. Dilute to 25 mL with distilled water, heat the solution to boiling, add 0,5 g of urea, and boil the solution for 1-2 min. Cool, neutralize with ammonium hydroxide as described in 6.5.2, and complete the titration according to 6.5.2. Normality of sodium thiosulphate solution = 1000 63,54 Abwhere A is the mass of copper turnings taken, g; b is the volume of sodium thiosulphate titrated, m2. b) Starch solution. Make a paste of 1 g of soluble starch in a little distilled water and pour the paste, with constant stirring, into 100 mL of boili
