GB142-2013
Logs for pit-props
坑木
GB 142-2013 is a current mandatory Chinese national standard for Logs for pit-props. It appears in the Machinery compliance cluster with a product safety focus and has an implementation date of Sep 11, 2014.
Applicability depends on product scope, certification route, competent authority notices and transition rules. Requst for the translation or verify source before using this record in a compliance decision.
Compliance overview
Scope and applicability
This standard applies specifically to logs for pit-props used as pillars and support structures in coal mine shafts. It is relevant for the forestry and mining industries supplying round wood for underground mining support. It does not apply to sawn timber or logs intended for general construction purposes. The standard replaces the previous version, GB 142-1995, updating the scope to clarify prohibited tree species and defect tolerances.
Technical requirements
The standard specifies the tree species permitted for use as pit-props, primarily allowing Pinaceae and hardwood species, while explicitly listing prohibited species such as A. holophylla and Paulowniaspp. It defines strict dimensional requirements and grading rules for log lengths and diameters, including specific progression increments and allowable deviations for length measurements. A core component of this standard is the defect allowable limits outlined in Clause 3.3, which is a mandatory section. Manufacturers must ensure that critical defects such as heart rot, sap rot, and severe bending do not exceed the strict thresholds defined in the standard. The standard also introduces requirements for longitudinal cracks, specifying the maximum allowable ratio relative to the log's total length. Additionally, the document provides specific volume calculation formulas for different diameter classes, including the newly added 13cm diameter class. Compliance requires accurate volume measurement according to the prescribed formulas and the reference volume table provided in the appendix.
Testing methods
Evaluation and measurement procedures rely on referenced national standards. Sampling methods are executed according to GB/T 17659.1, ensuring statistically valid batch inspections. Dimensional measurement and quality assessment of the logs are conducted following the methodologies outlined in GB/T 144. Finally, volume calculation is performed using the formulas and tables specified in GB/T 4814, with specific adaptations for the 12cm and 13cm diameter classes detailed within this standard.
FAQs
What products are regulated under GB 142-2013?
GB 142-2013 applies to logs specifically used as pit-props, pillars, and support structures in coal mining operations. It replaces the previous version, GB 142-1995 (Direct-use logs for pit-props).
Are there any updates from the previous version of GB 142-2013?
The 2013 version changed the standard name to Logs for pit-props, clarified prohibited tree species, added longitudinal crack requirements, introduced the 13cm diameter class with its volume calculation formula, included a volume table in Appendix A, and added product sampling methods.
Is GB 142-2013 a mandatory standard?
Clause 3.3 regarding defect allowable limits is mandatory, while all other clauses are recommended. This means strict adherence to defect limitations is legally required for compliance.
The summary above provides a high-level overview of GB 142-2013. To ensure complete compliance for your products entering the Chinese market, a precise and professional translation of the full technical specifications is essential. Purchase our high-quality English translation of GB 142-2013 today to access all detailed parameters, defect limit tables, volume calculation formulas, and testing procedures.
Applicability hints
- Type
- Product
- CCS
- B68
- ICS
- 79.040
- Competent department
- National Forestry and Grassland Administration
- Technical committee
- National Technical Committee on Timber of Standardization Administration of China
Relationships
Replaces:GB 142-1995