GB/Z 41367-2022Wood piles and poles - Preservative treatment by pressure process (English PDF)

Foreword

This document was drafted in accordance with the rules given in GB/T 1.1-2020, Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.

This document is under the jurisdiction of the National Technical Committee on Timber of Standardization Administration of China (SAC/TC 41).

The drafting organizations of this document are the Wood Saving Development Center, Jingjiang Guolin Wood Industry Co., Ltd., Fujian Zhangping Kimura Forest Products Co., Ltd., Dehua TB New Decoration Material Co., Ltd., Zhejiang Shiyou Wood Industry Co., Ltd., Jiusheng Flooring Co., Ltd., Zhejiang Haiyue Green Building Technology Co., Ltd., Dacheng County Zitan Jiayuan Classical Furniture Co., Ltd. and the China Wood Protection Industry Association.

The main drafters of this document are Dang Wenjie, Liu Nengwen, Yao Yuping, Li Huiming, Zhan Xianxu, Wu Zheyan, Dou Qingqing, Sun Longxiang, Yu Xiaoxi, Cao Changkun, Zhang Shaofang, Li Zhao, Yan Jingqi, Liu Xingcai and Li Guangjin.

1 Scope

This document specifies the wood species selection, preservative requirements, preparation before preservative treatment, requirements for the use of treatment equipment, treatment process, quality requirements and test methods for the preservative treatment of wood piles and poles by pressure process.

This document applies to the preservative treatment of wood piles and poles for outdoor use.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 1931, Method for determination of the moisture content of wood; GB/T 14019, Wood preservation - Terminology; GB 22280-2008, Code of practice for the production of preservative-treated wood; GB/T 23229, Analytical methods for waterborne wood preservatives; GB/T 27651, Use category and specification for preservative-treated wood; GB/T 27654, Wood preservatives; LY/T 2374-2014, Test method for penetration of active ingredients in preservative-treated and fire-retardant-treated wood; SB/T 10404, Determination of the main components of waterborne preservatives and fire retardants; SB/T 10440, Wood preservation equipment units for vacuum and/or pressure impregnation (treatment); TB/T 3172, Preservative-treated wooden sleepers.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in GB/T 14019 and the following apply.

3.1 wood piles: wood embedded in soil, immersed in seawater or fresh water, or embedded in masonry or concrete, performing a fixing or supporting function.

3.2 wood poles: wood of round cross-section used for utility poles, agricultural supports, municipal facilities and the like.

3.3 wood preservative working solution: a working solution obtained by diluting a wood preservative to a given concentration, used for the preservative treatment of wood.

4 Selection of wood species

The wood species for piles and poles should be selected from Mongolian Scots pine, southern pine, radiata pine, Scots pine, Masson pine, slash pine, larch, Norway spruce, Japanese cedar (Cryptomeria), spruce-pine-fir, Douglas fir, Canadian hemlock, Chinese fir, river red gum (Eucalyptus camaldulensis) and the like.

5 Preservatives

5.1 The manufacturer may select the preservative and determine the retention in accordance with GB/T 27651, according to the intended use of the treated wood.

5.2 The quality of the preservative shall comply with GB/T 27654.

5.3 The storage and use of preservatives shall comply with 5.3 of GB 22280-2008.

6 Preparation before preservative treatment

6.1 Before preservative treatment the moisture content of the piles and poles shall be lower than 30%.

6.2 Before preservative treatment the piles and poles shall be machined to final dimensions, so as to avoid mechanical processing such as sawing and drilling of the treated wood.

6.3 The heartwood of the piles and poles shall not be exposed.

6.4 The piles and poles shall be debarked; the area of residual bark shall not exceed 5% of the total surface area.

6.5 Incising requirements: a) refractory species such as larch, Douglas fir and spruce, and species with exposed heartwood such as Mongolian Scots pine, slash pine and Scots pine, shall be incised before preservative treatment; b) incising methods include laser incising, milling (routing), pressing of incisions and the like; c) the spacing of incisions is 35 mm to 55 mm along the grain and 16 mm to 20 mm across the grain; the incision depth is greater than 3 mm and does not exceed 15% of the thickness in the depth direction; d) the mechanical strength of the wood after incising shall meet the application requirements.

7 Preservative treatment equipment

7.1 The preservative treatment equipment shall comply with the relevant requirements of SB/T 10440.

7.2 The treatment equipment unit shall be installed on a leak-proof concrete floor foundation.

8 Preservative treatment process

8.1 The preservative working solution shall be prepared at a concentration corresponding to the solution uptake of the wood to be treated; its concentration shall be monitored during production and adjusted promptly.

8.2 The full-cell process should be used for the pressure treatment of piles and poles; the treatment process flow is given in Annex A of GB 22280-2008.

8.3 Drying methods after treatment: a) air drying: treated piles and poles may be air dried in a ventilated place sheltered from rain; b) kiln drying: treated piles and poles may be kiln dried after standing for 24 h; the dry-bulb temperature of the kiln shall not exceed 70 degrees C.

9 Quality requirements

9.1 Appearance. After preservative treatment the surface of the piles and poles shall be free from clearly visible preservative deposits.

9.2 Moisture content. After preservative treatment the moisture content of the piles and poles shall not exceed 25%.

9.3 Retention and penetration. The retention and penetration of the treated piles and poles shall comply with Table 1 and Table 2.

Table 1, use categories and retention requirements (retention in kg/m3 for use categories C4.1 / C4.2 / C5; NR = not recommended). Ammoniacal (amine) copper quaternary (ACQ) and micronized copper quaternary (MCQ): MCQ (copper oxide 66.7%, DDACO3 33.3%): >= 6.4 / >= 9.6 / NR; ACQ-2 (copper oxide 66.7%, DDAC 33.3%): >= 6.4 / >= 9.6 / >= 24.0; ACQ-3 (copper oxide 66.7%, BAC 33.3%): >= 6.4 / >= 9.6 / NR; ACQ-4 (copper oxide 66.7%, DDAC 33.3%): >= 6.4 / >= 9.6 / NR.

Table 1, copper azole (CuAz): CuAz-1 (copper 49.0%, boric acid 49.0%, tebuconazole 2.0%): >= 6.5 / >= 9.8 / NR; CuAz-2 (copper 96.1%, tebuconazole 3.9%): >= 3.3 / >= 5.0 / NR; CuAz-3 (copper 96.1%, propiconazole 3.9%): >= 3.3 / >= 5.0 / NR; CuAz-4 (copper 96.1%, tebuconazole 1.95%, propiconazole 1.95%): >= 2.4 / >= 4.0 / NR. Chromated copper arsenate CCA-C (copper oxide 18.5%, chromium trioxide 47.5%, arsenic pentoxide 34%): >= 6.4 / >= 9.6 / >= 24.0. Copper citrate CC (copper oxide 62.3%, citric acid 37.3%): >= 6.4 / NR / NR. Creosote (100%): >= 160 / >= 160 / >= 400. Footnotes: DDACO3 is didecyldimethylammonium carbonate; DDAC is didecyldimethylammonium chloride; BAC is dodecylbenzyldimethylammonium chloride.

Table 2, penetration required in treated piles and poles: C4.1 - used outdoors, exposed to all weather conditions and in contact with the ground or permanently immersed in fresh water: sapwood penetration >= 90%, penetration depth in exposed heartwood >= 5 mm; C4.2 - used outdoors, exposed to all weather conditions and in contact with the ground or permanently immersed in fresh water, for components that are difficult to replace or are critical structural members: sapwood penetration >= 95%, heartwood penetration depth >= 5 mm; C5 - permanently immersed in seawater (brackish water): sapwood penetration >= 95%, heartwood penetration depth >= 10 mm.

10 Test methods

10.1 Appearance quality. The appearance is inspected visually.

10.2 Moisture content. The moisture content is determined in accordance with GB/T 1931.

10.3 Retention and penetration. 10.3.1 Copper, copper oxide, didecyldimethylammonium carbonate (DDACO3), didecyldimethylammonium chloride (DDAC), dodecylbenzyldimethylammonium chloride (BAC), tebuconazole (TEB), propiconazole (PPZ) and boron are determined in accordance with GB/T 23229. Chromium trioxide, arsenic pentoxide and citric acid are determined in accordance with SB/T 10404. Creosote is tested in accordance with TB/T 3172. 10.3.2 Penetration is determined in accordance with LY/T 2374-2014.