​Ocean Engineering Coating Warranty and Case Study

introduction

The components of marine engineering projects face corrosion risks, which are defined as high-level CX in the ISO 12944-2017 series of standards, which belong to the marine climate corrosion conditions.

1 Coating Warranty Procedure

The coating warranty period is different from the coating design life, which is usually shorter than the coating design life

Figure 1 Coating Quality Assurance Process

Figure 2 Typical diagram of coating process evaluation

1.

The coating quality assurance project requires the project participants to select a test reference surface for each specified coating system on the engineering entity before the project starts

Figure 3 Typical reference plane

The interested parties shall witness the surface preparation, coating mixing, coating application and performance testing of the coating applied to the test reference surface

Table 1 Test reference surface area and quantity selection

1.

Construction workers need to be trained and certified by the paint manufacturer before they can start work

2 Evaluation standard of paint coating aging

The coating evaluation is based on the warranty period, usually requires a certain period of time to make qualitative and Quantitative evaluation, including the evaluation of the number of defects, the evaluation of defect size, and the evaluation of the degree of color change
.

Table 2 Typical diagram of coating process evaluation

3 Coating Warranty Case Study

3.
1 Coating Warranty

Foreign offshore platforms and LNG module projects specify the coating warranty period and requirements in the specifications, and most of the enterprise standards of oil companies also propose coating warranty requirements, such as Shell Oil Company's engineering design standard DEP30.
48.
00.
31 Lu The quality assurance of the coating on the upper and the sea is 5a, the inner coating of storage tanks and pressure vessels is 10a, and the thermal sprayed aluminum coating is 10a
.
Table 3 shows the author's comparative analysis of the items involved in quality assurance.
The standard for coating defects is ISO 4628-2016 or ASTM D610; the maximum warranty period is 25a, and the minimum is 5a; Different grades are required for chalking, cracking, adhesion, color,
etc.

Table 3 Cases of project coating quality assurance requirements

3.
2 Fireproof coating warranty

The fire protection coating warranty generally requires that the "defective area" shall not exceed 0.
5% of the member area or length in the first and second years; the third, fourth and fifth years shall not exceed 1% of the member area or length; the sixth year and the 7th year cannot exceed 3% of the member area or length; the 8th, 9th and 10th years cannot exceed 5% of the member area or length
.
Defective area is defined as each discrete area or continuous occurrence of cracking or coating debonding shown by visual nondestructive examination where the fire protection coating system and the subject matter of the claim have been peeled off or at least as severe as the reference surface in comparison to the painted reference area.
The sum of the area size or length of the area: the coating is peeled off from the substrate with an area > 1 m2; the interlayer peeling with a coating area > 1 m2 or the substrate with a coating length > 1 m is cracked, and the degree of cracking of the fireproof coating is usually according to SY/T 7396-2017 "Recommended practices for passive fire protection of onshore production facilities in the oil and gas industry" section 9.
3 to deal with
.

3.
3 Repair

If quality problems occur during the coating warranty period, if the project stakeholders determine that the coating system has failed due to workmanship defects or coating manufacturing defects, the coating failure and corrosion areas shall be repaired in accordance with the original coating construction requirements used at the time of construction, including Surface preparation procedures and standards acceptable to the owner
.
In any case, the repair of the coating shall be completed before the expiry of the warranty period following the Interim Acceptance Certificate
.

4 Quality assurance risk response

The project requires coating quality assurance, and the general contractor or construction unit shall conduct on-site inspection of coating materials according to the contract requirements, including coating spectral fingerprints, solid content, mica content, zinc powder content, fineness and resin content.
Whether it is consistent with the parent composition provided by the coating company; keep the inspection and inspection records; process evaluation records; documents such as disclosure records during the construction process
.
At the same time, the general contractor or construction unit should sign a relevant material quality assurance agreement with the paint manufacturer; sign a quality assurance agreement with the construction manufacturer, and carry out engineering insurance for key projects to avoid contract quality assurance risks
.

5 Conclusion

At present, the domestic coating quality assurance system is not perfect, and it is easy to be ignored
.
If foreign-related projects fail to carefully understand the technical requirements, it is easy to have a coating quality assurance vacuum belt
.
Usually most of the guarantees provided by foreign coating manufacturers before the start of the project can protect the owner from common coating defects such as cracking, blistering, peeling and uneven fading that may result in a short period of time after the painting operation
.
The data shows that the long-term guarantee of paint and coating construction projects can ensure a certain level of quality.
The first maintenance time of the project coating is significantly longer than that of the project without warranty.
For the owner, it can save a lot of time and money, and it can also improve contracting.
Therefore, this article describes the coating quality assurance classification and area, in order to provide reference for domestic engineering projects to carry out coating quality assurance
.

References (omitted)

Author | Wan Juhui, Cheng Guodong

(Qingdao Lanshi Heavy Machinery Equipment Co.
, Ltd.
, Qingdao, Shandong 266426)

(Offshore Oil Engineering Co.
, Ltd.
, Qingdao, Shandong 266520)