DL/T 1002-2022 in English

Core changes in the standard revision

Analysis of key calibration technologies

1. Zero value calibration operation specifications

When using sodium sulfite-cobalt chloride solution as the anaerobic medium, please note:

• The solution should be prepared and used immediately, and the validity period is ≤2 hours
• All bubbles should be removed during the sealing operation
• Verification standard: Fluctuation for 5 consecutive minutes <0.3μg/L

2. Atmospheric pressure correction for air calibration

For every 100 meters increase in altitude, the saturated dissolved oxygen concentration decreases by approximately 0.03mg/L. It is recommended to use the interpolation formula in Appendix B:

Cs = Creference + (Pactual-Preference)×0.0935

Implementation Difficulties and Solutions

Analysis of Standard Evolution

This revision reflects three major technical trends:

• Field applicability: Eliminate the gas calibration method that requires laboratory conditions
• Measurement accuracy: Increase the verification standard from 1μg/L to 0.5μg/L
• Intelligence: Appendix B provides the data basis for programmable calculations