1、BSI Standards PublicationBS EN 252:2014Field test method fordetermining the relativeprotective effectiveness of awood preservative in groundcontactBS EN 252:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 252:2014. Itsupersedes BS 7282:1990 which is withdra
2、wn.The UK participation in its preparation was entrusted to TechnicalCommittee B/515, Wood preservation.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are r
3、esponsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 77751 6ICS 71.100.50Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStanda
4、rds Policy and Strategy Committee on 30 November 2014.Amendments issued since publicationDate Text affectedBS EN 252:2014EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 252 November 2014 ICS 71.100.50 Supersedes EN 252:1989English Version Field test method for determining the relative protectiv
5、e effectiveness of a wood preservative in ground contact Essai de champ pour dterminer lefficacit protectrice relative dun produit de prservation du bois en contact avec le sol Freiland-Prfverfahren zur Bestimmung der relativen Schutzwirkung eines Holzchutzmittels im Erdkontakt This European Standar
6、d was approved by CEN on 30 August 2014. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning suc
7、h national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own
8、 language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, G
9、reece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMU
10、NG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 252:2014 EBS EN 252:2014EN 252:2014 (E) 2 Contents Page Foreword 4 Introduction .5 1 Scope 6 2 Principle 6 3 W
11、ood specimens .6 3.1 Wood species .6 3.2 Wood quality 6 3.3 Characteristics and dimension of stakes 6 3.4 Number of Stakes 7 3.5 Labelling of stakes.7 4 Sample of wood preservative .7 5 Conditioning and treatment of the stakes .7 5.1 Conditioning .7 5.2 Treating process 7 5.3 Determination of retent
12、ion of wood preservative product 8 5.4 Range of preservative retention .8 5.5 Post treatment conditioning of stakes 8 6 Reference stakes .8 6.1 Reference preservative .8 6.2 Alternative reference preservative .9 7 Untreated control stakes .9 8 Condition of the test field .9 9 Installation of the sta
13、kes in the test field . 10 10 Inspections 10 11 Evaluation 11 11.1 General . 11 11.2 Attack by microorganisms . 11 11.3 Attack by termites . 11 11.4 Simultaneous attack by microorganisms and termites 12 12 Duration of the test . 12 13 Conditions for the validity of the test . 12 14 Test report . 12
14、Annex A (informative) Guidance for the testing of wood or wood based products that have not been treated with a wood preservative 15 Annex B (informative) Characterization of the field test site . 17 Annex C (informative) Example of pattern for setting up field stakes into the ground 18 BS EN 252:20
15、14EN 252:2014 (E) 3 Annex D (informative) Determination of strength characteristics in wood stakes through measuring Modulus of Elasticity . 19 Annex E (informative) Example of a test report . 21 Bibliography 24 BS EN 252:2014EN 252:2014 (E) 4 Foreword This document (EN 252:2014) has been prepared b
16、y Technical Committee CEN/TC 38 “Durability of wood and wood-based products”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2015 and conflicting na
17、tional standards shall be withdrawn at the latest by May 2015. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersede
18、s EN 252:1989. In relation to the previous version of the standard, the following main modifications have been made: change in the assessment criteria for fungal decay; minor changes in the description of termite attack; the addition of informative annexes concerning the determination of strength ch
19、aracteristics in wood stakes by measuring the modulus of elasticity; the characterization of field test sites and the setting-out of the test stakes in the field test sites. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound t
20、o implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, R
21、omania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 252:2014EN 252:2014 (E) 5 Introduction The method is primarily concerned with protection against microbial attack. However, it is also capable of being used in areas where a termite hazard exists. It should
22、also be noted that microbial decay may alter the resistance of a stake to termite attack and that termite attack may obliterate evidence of microbial decay. This field method provides one criterion by which the effectiveness of a wood preservative product can be assessed in a ground contact situatio
23、n (Use Class 4 according to EN 335). The main objective of the method described is to evaluate the effectiveness of a preservative relative to a reference material. For this reason permeable timbers are used throughout so that the protective efficacy of various retentions of wood preservative can be
24、 determined. NOTE Informative Annex A gives guidance for testing wood or wood based products in ground contact that have or have not been treated with a wood preservative. BS EN 252:2014EN 252:2014 (E) 6 1 Scope This European Standard specifies a field test method for evaluating the effectiveness of
25、 wood preservatives in a ground contact situation. Wood treated with a reference preservative is included for comparison. The protective effect of the test preservative is assessed in relation to the effect of a reference wood preservative applied by a specified treatment. 2 Principle Wooden stakes
26、are treated with preservative solutions to give a range of preservative retentions. After drying and, if necessary, an appropriate fixation period, the stakes are partially buried in soil in selected test fields in the open. The stakes are regularly inspected and their condition compared with that o
27、f untreated controls and that of a group of stakes treated with a reference preservative both of which indicate the aggressiveness of the individual field. The different agents of attack and their respective intensities are recorded. 3 Wood specimens 3.1 Wood species Susceptible wood species that ca
28、n be completely penetrated with preservative shall be chosen as follows: for every test the sapwood of Scots Pine (Pinus sylvestris (L), shall be used; it is recommended that a hardwood species of local importance is included if the preservative is expected to be used in this type of wood; if desire
29、d other wood species may be incorporated in the test. 3.2 Wood quality The wood shall be straight-grained and free from knots, cracks, stain, decay, insect holes, reaction wood or other defects. Test stakes with a resinous appearance shall be avoided. The wood shall not have been water-stored, float
30、ed, chemically treated or steamed or dried at a temperature above 60 C. The Scots Pine sapwood shall show an average rate of growth of 2,5 to 10 annual rings per 10 mm. If additional wood species are to be used the range in the number of annual rings per 10 mm for each species shall be mentioned in
31、the report. The test report shall also include the mean density and moisture content for the wood used in the preparation of the stakes. 3.3 Characteristics and dimension of stakes The boards shall be conditioned at (20 2) C, (65 5) % relative humidity. Stakes for test shall be cut from the test woo
32、d(s) as follows: BS EN 252:2014EN 252:2014 (E) 7 Each stake shall be planed to within the thickness tolerance indicated. When viewed at the cross-cut end, the rings shall be oriented tangentially to one of the 50 mm edges within the limits (0 25); The dimensions shall be: (500 2) mm x (50 1) mm x (2
33、5 0,5) mm when measured at a moisture content of (12 2) % (mass fraction). Each test shall be carried out with stakes of comparable density and any stakes in a test batch which have densities outside the range of 15 % of the mean density shall be rejected. Additional stakes of different dimensions m
34、ay also be included in the tests. 3.4 Number of Stakes At least 10 stakes per field for each wood preservative and retention shall be tested. A greater number of stakes shall be treated so that stakes with deviating retentions can be rejected (5.3). Additional stakes may also be included for chemica
35、l analysis, to aid determination of retentions and/or penetration/distribution (see 5.3). To assess the virulence of the field conditions a series of at least 10 untreated control stakes shall be included in each field (see Clause 7). Include in each field at least two series of 10 standard referenc
36、e stakes of Scots Pine treated according to 5.2 with a reference preservative (see Clause 6). 3.5 Labelling of stakes Each stake shall be labelled with an inert, long-lasting label or tag. NOTE A map of the position of each stake within the site is desirable. 4 Sample of wood preservative The sample
37、 shall be representative of the wood preservative to be tested. It shall be stored and handled in accordance with written recommendations from the manufacturer. It is recommended to chemically quantify the active ingredients content. 5 Conditioning and treatment of the stakes 5.1 Conditioning The st
38、akes should be conditioned in conditions to reach constant mass at (20 2) C and (65 5) %RH. The stakes shall be air-dried indoors, to a moisture content at which a good penetration of the wood preservative can be obtained. For vacuum / pressure processes the moisture content of the specimens shall b
39、e (12 2) % (mass fraction). 5.2 Treating process For the reference stakes and unless otherwise specified for the test stakes a full-cell process is to be used. A typical full-cell process has an initial vacuum which shall be less than 10 kPa (0,10 bar) and maintained for at BS EN 252:2014EN 252:2014
40、 (E) 8 least 30 min. Pressure of at least 1 MPa (10 bar) shall be applied for at least 90 min. Complete records of treatment shall be made for each charge. 5.3 Determination of retention of wood preservative product Calculate the volume of each stake before treatment from its dimensions (see Clause
41、3). If shaped to a point before treatment this shall be taken into account in the calculation. Determine the mass of each stake by weighing to the nearest 0,5 g. After treatment, allow the stake to drain for several minutes. Reweigh each stake to the nearest 0,5 g to determine the mass of treatment
42、solution absorbed. Calculate the retention value of each stake from the mass of treatment solution absorbed, the concentration of the treating solution and the calculated stake volume. Express the retention of the wood preservative product as kilograms per cubic metre of wood. Calculate the mean ret
43、ention for each series of test stakes. Stakes with individual retentions deviating by more than 10 % from the mean value shall be rejected. 5.4 Range of preservative retention Test each preservative with at least three and preferably five different retention levels. These different levels shall be a
44、chieved by using fresh preservative solutions at different dilutions and without varying the treatment conditions. Use a fresh solution at each dilution; the dilution of a quantity of solution which has been used already may be unsatisfactory because preferential absorption may have occurred during
45、the previous treatment schedule. 5.5 Post treatment conditioning of stakes For those products requiring a fixation period the recommendations of the wood preservative manufacturer should be followed. For the reference preservatives the stakes shall first be close-stacked, each retention group separa
46、tely, and kept wrapped for an appropriate period (at least 3 weeks) at room temperature (above 15 C) in polyethylene or similar non water permeable material to avoid rapid drying. For drying after fixation, make open piles protected from rain and frost, with inert spacers to allow air flow between t
47、he stakes. 6 Reference stakes 6.1 Reference preservative Stakes of Scots Pine sapwood shall be treated according to 5.2 using the reference preservative, with the following composition: CuSO4.5H2O 35,0 % mass fraction K2Cr2O745,0 % mass fraction As2O5 .2H2O 20,0 % mass fraction Chemical purity of in
48、dividual components should be at least 98 %. BS EN 252:2014EN 252:2014 (E) 9 Two dry salt retentions shall be used approximating to 2 kg/m3, and 9 kg/m3respectively. The precise retentions obtained will be dependent on the concentration and uptake of the treating solution. NOTE 1 Alternative raw mat
49、erials could be used providing the same metal balance is achieved. In terms of elemental metal these retentions equate to the following: 2 kg/m3dry salt retention: 0,18 kg/m3copper, 0,32 kg/m3chromium, 0,23 kg/m3arsenic; 9 kg/m3dry salt retention: 0,80 kg/m3copper, 1,43 kg/m3chromium, 1,02 kg/m3arsenic. NOTE 2 It is possible to use a third concentration at 6 kg/m3to provide additional information. As a result of the implementation of the Biocidal Products Directive 98/8/EC there are restrictions in the use of chromium- containing w
