After passing the examination, the labor department will issue certificates. The witness must obtain the witness certificate and be authorized by the owner before undertaking the witness work of the authorized project. 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.

The quality of building materials is the basic element of building engineering quality, and the inspection of building materials is an important guarantee for the on-site quality control of building materials. Therefore, witness sampling and inspection are important means to ensure scientific, fair and accurate inspection. However, there are still many problems in witness sampling at present, mainly as follows: some workers' sampling is untrue and irregular;

Some field testers don't know much about construction testing, so they didn't do in-depth and detailed research. Some witnesses "testify" instead of "look" and practise fraud, resulting in the loss of representativeness and authenticity of the samples. Therefore, witness sampling directly affects the quality of building materials.

Extended data

approve

The engineering construction unit or supervision unit shall submit the Power of Attorney for Witness Units and Witnesses to the construction unit, engineering quality supervision station and engineering inspection unit. The power of attorney shall specify the names, certificate numbers and witness numbers of the witness unit and the witnesses of this project, and the number of witnesses shall not be less than 2.

sample

When sampling and making samples at the site, the sampling personnel of the construction enterprise must have witnesses present, monitor the samples, take effective measures to seal the samples together with the inspectors entrusted by the inspection, or send the samples to the testing unit.

check

When the inspection unit accepts the entrusted inspection task, it must fill in the entrustment form, and the witness shall produce the witness certificate and sign the inspection entrustment form. Testing units must implement a password management system.

laboratory report

The inspection unit shall affix the seal of "witness sampling inspection" on the inspection report. If there are unqualified samples, they should be reported to the quality supervision station within 24 hours, and the unqualified project account should be established. ?

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