CB/T 3718-2016 in English

Key points of standard changes

Analysis of key technical requirements

1. Film thickness distribution control

The standard adopts a three-level control system:

• Liquid cargo tanks of finished oil tankers implement the special requirements of CB/T 3367
• Specific areas apply the 90/10 rule (90%≥NDFT, the rest ≥90%NDFT)
• Conventional areas implement the 85/15 rule (85%≥NDFT, the rest ≥85%NDFT)

2. Wet film construction control

Innovatively introduce the theoretical coating amount calculation formula:

V = α×β×S Wherein: α=loss coefficient (1.3-2.0), β=theoretical coating amount (L/m²), S=coating area (m²)

Typical application case: In the coating of a VLCC ballast tank, the paint loss was reduced by 18% through real-time control of wet film thickness.

3. Dry film inspection specification

Inspection points:

1. Use a calibrated dry film thickness gauge
2. For single-point measurement, take the average value of 3 readings within a circle with a diameter of 4cm
3. For complex structures, inspection points are set every 10m², and additional measurement points are required on the surface of profiles

Implementation suggestions

1. Equipment management

It is recommended to establish a thickness gauge calibration ledger, and the recommended calibration cycle is:

• Magnetic thickness gauge: quarterly
• Eddy current thickness gauge: every six months

2. Data traceability

Use a triple record system:

1. Spreadsheet archive (see Appendix C)
2. Site marking (use weather-resistant marker)
3. Photographic images to record special areas