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 978-0-626-20327-6 SANS 457-2:2008Edition 6.2Any reference to SABS 457-2 is deemedto be a reference to this standard(Government Notice No. 1373 of 8
4、November 2002)SOUTH AFRICAN NATIONAL STANDARD Wooden poles, droppers, guardrail posts and spacer blocks Part 2: Softwood species 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.c
5、o.za Standards South Africa SANS 457-2:2008 Edition 6.2 Table of changes Change No. Date Scope Amdt 1 2002 Amended to change the definitions of “lot” and “top diameter”, and to change the method of measurement of top diameters. Amdt 2 2008 Amended to change the designation of SABS standards to SANS
6、standards, to update the definitions of “acceptable“ and “approved”, to remove reference to the certification mark, and to update referenced standards. Foreword This South African standard was approved by National Committee StanSA SC 5110.07B, Timber Preservation Preservative treated timber products
7、, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This document was published in March 2008. This document supersedes SABS 457-2:2000 (edition 6 as amended 2002). A vertical line in the margin shows where the text has been modified by ame
8、ndment No. 2. SANS 457 consists of the following parts under the general title Wooden poles, droppers, guardrail posts and spacer blocks: Part 2: Softwood species. Part 3: Hardwood species. Annexes A, B, G, H and I form an integral part of this document. Annexes C, D, E and F are for information onl
9、y. SANS 457-2:2008 Edition 6.2 1 Introduction Different species of timber vary in natural durability. Practical experience has shown which species have the longest life in their untreated state under normal conditions. Even if these species are readily obtainable, their use is not always economical
10、or practicable. The use of timber properly treated with timber preservatives suited to the specific purpose is of great importance in prolonging the service life and thus putting available supplies of timber to the maximum use. In order to provide as wide a range of treated poles, droppers, guardrai
11、l posts and spacer blocks as possible, provision has been made for the use of a variety of timber preservatives divided into three classes (see SANS 10005). Timber treated with creosote or a mixture of creosote and waxy oils suffers less damage from grass fires than does untreated timber (which pres
12、ents a serious fire hazard). After re-drying, timber treated with a mixture of copper-chromium-arsenic compounds is, owing to “afterglow“, more susceptible to damage by fire than timber treated with creosote or a mixture of creosote and waxy oil. Users of poles, droppers and guardrail posts will rea
13、lize the difficulty of prescribing and working to precise requirements for a natural product such as timber, especially when it is used in the round form in which it grows. Treated timber should neither be cross-cut nor be sawn lengthways because untreated wood will be exposed to fungal and insect a
14、ttack. Where fabrication takes place after treatment, the exposed wood must be liberally coated with the same type of preservative at the recommended treating temperature and, in the event of drilling, a post-hole treater must be used. The grading in this part of SANS 457 is based on the assumption
15、that the poles, droppers, guardrail posts and spacer blocks are to be used in the dimensions in which they were graded. Conversion of any kind after preservative treatment will reduce the expected service life. This part of SANS 457 applies to the condition of the timber at the time of despatch and
16、does not cover deterioration brought about during transportation and storage. Units will generally give the projected service life only if a long period of storage before installation is avoided. Temperatures as high as 60 C have been recorded on a creosoted pole lying on the ground and exposed to d
17、irect sunlight. Because water-borne preservative-treated units will tend to develop checks and splits if left exposed to the sun for long periods, they should be used as soon as possible after treatment. Storage in a horizontal position combined with exposure to direct sunlight causes degradation of
18、 creosoted timber and, in addition, creosotes tend to migrate because of gravitational forces, thereby reducing the amount of creosote on the upper side of the unit. Where long periods of storage of creosoted units are unavoidable, these units should be close-stacked clear of the ground and under a
19、waterproof cover that also affords protection against the sun. This part of SANS 457 should be read and applied in conjunction with current Government regulations concerning the combating and the prevention of the spread of certain timber-attacking insects in proclaimed areas. SANS 457-2:2008 Editio
20、n 6.2 2 Contents Page Foreword Introduction 1 1 Scope 3 2 Normative references 3 3 Definitions . 4 4 Requirements 7 5 Preservative treatment 14 6 Inspection and methods of test . 17 6.1 Inspection . 17 6.2 Measurement of defects. 17 6.3 Dimensions. 18 6.4 Net retention. 19 6.5 Depth of penetration o
21、f preservative 19 6.6 Moisture content. 19 7 Marking . 20 Annex A (normative) Notes to purchasers. 21 Annex B (normative) Strength test for poles Midpoint loading test. 22 Annex C (informative) Modulus of elasticity (MOE). 27 Annex D (informative) Mean annual equilibrium moisture content of timber.
22、28 Annex E (informative) Typical top diameter classes and lengths 29 Annex F (informative) Marking methods . 30 Annex G (normative) Colour coding. 30 Annex H (normative) Quality verification of wooden poles, round droppers, guardrail posts and spacer blocks 31 Annex I (normative) Average volumes of
23、softwood poles, round droppers and guardrail posts 33 Bibliography. 35 SANS 457-2:2008 Edition 6.2 3 Wooden poles, droppers, guardrail posts and spacer blocks Part 2: Softwood species 1 Scope This part of SANS 457 specifies requirements for preservative-treated softwood poles, droppers, guardrail po
24、sts and spacer blocks. The poles are intended for the erection of fences and vine trellises, for general use in orchards and for structural purposes. The droppers are intended for fencing. The posts and spacer blocks are intended for the erection of steel guardrails at the sides of roads. Timber use
25、d in ground contact and exterior above ground contact, should have an expected life span of at least 20 years when treated in accordance with the requirements applicable to the exposure classes (see table 3). Timber treated for the interior above ground exposure class should have an expected life sp
26、an equal to that of the structure it is used in. NOTE 1 Assessment of compliance with the requirements of 5.2 to 5.6 (inclusive) and, except in the case of units treated with creosote or a creosote and waxy oil mixture, 4.4, requires special agreement between the supplier and the purchaser. Amdt 2 N
27、OTE 2 Steps should be taken to prevent the “mushroom top phenomena“ (cutting of wire into the pole) in poles to be used as straining poles, as in vineyards. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of
28、SANS 457. All standards are subject to revision and, since any reference to a standard is deemed to be a reference to the latest edition of that standard, parties to agreements based on this part of SANS 457 are encouraged to take steps to ensure the use of the most recent editions of the standards
29、indicated below. Information on currently valid national and international standards can be obtained from Standards South Africa. SANS 280, Hole location in fencing posts and droppers. SANS 2859-1/ISO 2859-1, Sampling procedures for inspection by attributes Part 1: Sampling schemes indexed by accept
30、ance quality limit (AQL) for lot-by-lot inspection. SANS 5967 (SABS SM 967), Retention of preservative in timber (volume method). SANS 5985, Moisture content of timber (extraction method). SANS 5986, Moisture content of timber (electric moisture-meter method). SANS 457-2:2008 Edition 6.2 4 SANS 5987
31、, Depth of penetration of preservative and detection and depth of sapwood in timber. SANS 5988, Retention of preservative in timber (sample method). SANS 5989, Retention of preservative in timber (weighbridge method). SANS 5995 (SABS SM 995), Retention of boron in timber (colorimetric method). Amdt
32、2 SANS 5999, Heartwood detection in timber of the Pinus species. SANS 6238, Retention of boron in timber (analytical method). SANS 6303, Depth of penetration of borate preservatives in timber. SANS 10005, The preservative treatment of timber. 3 Definitions For the purposes of this part of SANS 457,
33、the following definitions apply: 3.1 acceptable acceptable to the authority administering this standard, or to the parties concluding the purchase contract, as relevant Amdt 2 3.2 approved approved by the authority administering the standard Amdt 2 3.3 butt the thick end of a pole, guardrail post or
34、 round dropper 3.4 centre the part of a pole, guardrail post or round dropper that consists of the first years growth 3.5 class C preservatives coal tar creosote and timber preservatives that have a coal tar creosote basis 3.6 class O preservatives timber preservative solutions of organic compounds
35、in organic solvents 3.7 class W preservatives water-borne timber preservatives 3.8 core a cylindrical piece of wood extracted by means of an increment borer 3.9 crook a natural curvature or kink that extends over not more than one-quarter of the length of a pole, guardrail post or round dropper (see
36、 figure 2) SANS 457-2:2008 Edition 6.2 5 3.10 defective a unit that fails in one or more respects to comply with the relevant requirements of this part of SANS 457 3.11 diameter class the class as defined by means of the permissible minimum and maximum values of the top diameter of a pole, guardrail
37、 post or round dropper 3.12 effective length in the case of a structural pole, the total length of the pole; in other cases, 75 % of the length of a pole, measured from its thin end 3.13 end check a separation along the grain of the wood and across the annual rings, and that occurs at the end of a p
38、ole, guardrail post or round dropper 3.14 face check a separation along the grain of the wood and across the annual rings, but not extending to the end of a pole, guardrail post or round dropper 3.15 guardrail post a post intended for the erection of steel guardrails at the side of a road 3.16 incre
39、ment borer an auger-like instrument that has a hollow bit used to extract cores from wood 3.17 knot group three (or more) knots so close together that they all fall within any 150 mm length of a pole 3.18 lot not less than 50 and not more than 10 000 units of the same type, the same botanical group
40、(i.e. pine), the same nominal dimensions or length and top diameter class (as relevant), and treated with the same class of preservative, from one manufacturer, submitted at any one time for inspection and testing Amdt 1 3.19 machine peeling the removal, with the use of a lathe-like machine, of bark
41、, inner bark and a limited amount of sapwood from a pole, guardrail post or round dropper in such a way as to produce an acceptable finish 3.20 mechanical damage a defect caused by mechanical means, by excessive charring or by other means 3.21 pine timber derived from trees of the species Pinus radi
42、ata, Pinus pinaster and Pinus canariensis grown in Southern Africa SANS 457-2:2008 Edition 6.2 6 3.22 pole an upright or a line pole or straining pole used for structural, agricultural or fencing purposes 3.23 post-treatment defect a defect that has developed after treatment and that results in the
43、exposure of untreated wood 3.24 resin pocket a cavity that contains or has contained resin 3.25 resin scar a resin occlusion on the surface of a pine pole, guardrail post or round dropper 3.26 reverse crook crook in two directions in one plane 3.27 reverse sweep sweep in two directions in one plane
44、3.28 ring shake a complete separation of the wood fibres that appears as an arc or a complete circle, that occurs between the annual rings and that is a natural defect present in some trees 3.29 round dropper a short length of round timber that is intended for use as a support in fences and that has
45、 a top diameter of between 25 mm and 50 mm 3.30 seasoning end-check a check that appears on an end of a pole, guardrail post or round dropper, as a result of seasoning, and that follows an annual ring 3.31 slab-gaining the removal of timber to a specified depth (measured radially) from the top end o
46、f a guardrail post (or, in the case of a machine-peeled post that has a uniform diameter, from one end), resulting in an area on the face of the post that lies in one plane, extends from the end of the post for a specified length, is parallel to the general longitudinal axis of the post, is free fro
47、m unacceptable undulations, and terminates, at the bottom, in a bevel (see figure 1) 3.32 solid penetration presence of preservative (where relevant, as indicated by an acceptable chemical test) in all or in a specified portion (as relevant) of the sapwood, to an extent that causes complete colorati
48、on of that area of the sapwood 3.33 spacer block a piece of timber that is used as a spacer between the guardrail posts and steel guardrails at the side of a road SANS 457-2:2008 Edition 6.2 7 3.34 spiral grain an arrangement of the wood elements in which they follow a spiral course round the stem 3
49、.35 sweep a natural curvature that extends over more than one-quarter of the length of a pole, guardrail post or round dropper (see figure 3) 3.36 theoretical ground line TGL the position that is 25 % of the length of a pole or guardrail post, from the butt, with a maximum of 1 m 3.37 top diameter the diameter at the thin end of a pole, guardrail post or round dropper, as measured with a diameter tapeAmdt 1 3.38 treated/treatment impregnated/impregnation with an acceptable preservative 3.39 unit a pole, guardrail post, dropper or spacer block 3.40 volume the mean of the cross-sect
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