The calibration specifications for concrete laboratory equipment mainly include five core aspects: calibration basis, personnel qualifications, environmental control, standard instruments, and specific calibration procedures.
1. Calibration Basis and Scope
- Basis: National Metrological Verification Procedures (JJG) or Calibration Specifications (JJF) should be followed first. If none are available, industry standards or instrument manuals should be consulted.
- Scope: Applicable to non-mandatory verification equipment that has a significant impact on test results, such as balances, pressure testing machines, and curing chambers. Mandatory verification equipment must be submitted for verification.
2. Personnel Requirements
• Calibrator: Must be trained and qualified, possess professional knowledge and operational skills, and be responsible for the authenticity of data.
• Technical Supervisor: Responsible for the formulation and revision of procedures and the review of calibration results.
• Laboratory Supervisor: Provides resource support and supervises the execution of work.
3. Environmental Requirements
Calibration must be performed in a stable environment: temperature and humidity must meet instrument requirements; the work area should be shockproof, dustproof, free from strong electromagnetic interference, and well-ventilated.
4. Standard Instrument Requirements
- The accuracy class of the standard instrument must be higher than that of the equipment being calibrated, and its error is generally no greater than 1/3 to 1/10 of the allowable error of the equipment being calibrated.
- It must be verified/calibrated by a legally authorized institution and used within its validity period.
5. General Calibration Procedure
• Before Calibration: Inspect the appearance and function of the instrument, and confirm that the standard instrument and environment meet the requirements.
• During Calibration: Operate according to the specific equipment's procedures and accurately record data. For example, the rebound hammer's indication error must be ≤±1.0, and the ultrasonic testing instrument's acoustic time measurement error must be <±0.1μs.
• After Calibration: Issue a record report and affix labels to qualified equipment.