According to the notice of the Ministry of Construction (J&J (2000) No.211) on printing and distributing the Provisions on Implementing Witness Sampling and Inspection System for Housing Construction and Municipal Infrastructure Projects.
Article 3 stipulates that "witness sampling for inspection" as mentioned in these Provisions means that the on-site testers of the construction unit sample the test blocks, test pieces and data related to structural safety in the project under the witness of the personnel of the construction unit or the engineering supervision unit, and send them to the quality inspection unit certified by the construction administrative department at or above the provincial level and certified by the quality and technical supervision department.
Article 4 stipulates that the construction administrative department of the State Council shall implement unified supervision and management over the witness sampling and inspection of the national housing construction projects and municipal infrastructure projects.
The construction administrative departments of the local people's governments at or above the county level shall supervise and manage the witness sampling and inspection of housing construction projects and municipal infrastructure projects within their respective administrative areas.
Article 5 stipulates that the proportion of witness sampling and inspection of test blocks, test pieces and materials related to structural safety shall not be less than 30% of the number of samples specified in relevant technical standards.
(2) Witness sampling range:
According to the regulations, the following test blocks, test pieces and materials must be witnessed and sampled and submitted for inspection:
1, load-bearing structure concrete test block;
2. Load-bearing wall masonry mortar test block;
3. Specimens of steel bars and connecting joints for load-bearing structures;
4. Bricks and small concrete blocks for load-bearing walls;
5. Cement for mixing concrete and masonry mortar;
6. Admixtures used in load-bearing structure concrete;
7. Waterproof materials for underground, roof and bathroom;
8, used for road subgrade and pavement materials or specimens;
9, municipal engineering, the owner or the project director of the supervision unit that is closely related to the quality of materials or components;
10, other test blocks, test pieces and materials required by the state to witness sampling and inspection.
Extended data
Requirements for witness sampling:
1. Witness sampling involves three parties: the constructor, the witness and the tester.
2, laboratory qualification management:
① Engineering quality supervision and inspection institutions at all levels (stamped with CMA seal, i.e. metrological certification, and reviewed once every 1 year).
② The laboratory of the construction enterprise should be gradually transformed into the internal control organization of the enterprise, with 4 years 1 review.
Third-party laboratory inspection:
(1) measurement certificate, CMA seal.
② Check the attachment and record the certificate.
3. Metrology certification is implemented at two levels, one is the national level and the other is the provincial level, with the same effect.
4. The witness must obtain the witness certificate and be authorized by the construction unit. After authorization, it can only undertake the witness work of authorized projects. All building materials entering the construction site must undergo witness sampling and ex-factory test according to the specification requirements, and the test report should be included in the quality assurance data.
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