涂层破损面积计算.doc

ASSESSMENT AND CALCULATION METHOD OF COATING DAMAGED AREAS FOR BALLAST TANKS OF SHIPS

Foreword
MSC.215(82) prescribes the preparation of steel substrates before application of paints and related products for ballast tanks of ships:

o Sa2½ with abrasive blasting during block coating;

o surface treatment of butts (after erection) shall be carried out by means of tool grinding,
o small damages up to 2% of total area: St 3.
o Contiguous damages over 25 m 2 or over 2% of the total area of the tank, Sa 2½ should be applied.

This guidance notes is drawn in order to satisfy with the demands of modern shipbuilding and standard of IMO due to there is no assessment and calculation method of coating damaged areas for ballast tanks of ships all over the world.
MSC.215(82)对船舶压载舱涂覆涂料前钢材表面处理规定：
² 分段涂装时必须采用喷丸（砂）处理达到Sa2½级；
² 合拢后表面处理允许合拢对接缝采用工具打磨，
² 小范围破损面积总和不超过全舱面积2％：St3级，
² 紧邻破损区域的总面积超过25 m2或超过全舱面积2％：Sa2½级。
由于均没有涉及压载舱涂层破损面积的评估与计算方法标准，为满足现代造船的需求，适应IMO标准规定，特制定本指导性文件。
Scope
This guidance notes prescribe the sorts, definitions of coating damages for ballast tanks of ships and the assessment and calculation method of defective areas of coating for ballast tanks of ships, etc.
This guidance notes are prepared to apply the dedicated seawater ballast tanks of new ships and double-side skin spaces of bulk carriers. Also uses for reference to other tanks.
本指导性文件规定了船舶压载舱涂层破损的分类、定义及相关涂层破损区域面积的评估与计算方法等。
本指导性文件适用于新建船舶的专用海水压载舱和散货船的双舷侧处所。也可供其它舱室参考。
Normative reference
The following referenced documents are indispensable for the application of these documents. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ASTM D 610-01 Standard Test Method for Evaluating Degree of Rusting On Painted Steel Surfaces.
下列文件中的条款通过本指导性文件的引用而成为本指导性文件的条款。凡是注日期的引用文件，其随后所有的修改单（不包括勘误的内容）或修订版均不适用于本指导性文件，然而，鼓励根据本指导性文件达成协议各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本指导性文件。
ASTM D610-01 涂覆涂料前钢材表面锈蚀等级评定方法（Standard Test Method For Evaluating Degree Of Rusting On Painted Steel Surfaces）
Terms and definitions
For the purpose of this Standard, the following definitions apply:
下列术语和定义适用于本指导性文件。

Coating damages
The phenomenon of coating damages goes to the steel which is caused by weld, fire, machinery crash and so on.
涂层破损
在船舶建造过程中因焊接、火工、机械碰撞等原因引起涂层损坏抵达钢材的现象。

Butts (after erection)
Erection butts between the blocks
合拢对接缝
分段间的合拢接缝。

Butts coating damages
Coating damages of double-side butts after erection, the width is usually not to be more than 200mm. For the fillet weld (the reserved weld is usually not to be more than 300mm on one side) relate to double-side areas is usually not to be more than 100mm. The figure of butts coating damages sees the shadow of figure 1.
合拢对接缝涂层破损
合拢对接缝两侧的涂层破损，其宽度通常应各不大于200mm。对于为合拢而预留的角接缝(预留焊缝一般单边不超过300mm)涉及区域为两侧一般各不大于100mm。合拢对接缝涂层破损示意图见图1阴影处所示。

Non-butts coating damages
Damages other than butts coating damages.
非合拢对接缝涂层破损
除合拢对接缝涂层破损以外的涂层破损。

Lumpish coating damages
Coating damages which length-width ratio is less than 3.
片状涂层破损
长宽比小于3的涂层破损。

Linear coating damages
Coating damages which length-width ratio is not less than 3.
线状涂层破损
长宽比不小于3的涂层破损。

Grade 1 coating damages
The piece coating damages which maximum diameter is less than 10cm or the line coating damages which length is less than 20cm.
1级涂层破损
最大直径小于10 cm的片状涂层破损或长度上小于20 cm的线状涂层破损。

Grade 2 coating damages
The piece coating damages which maximum diameter is not less than 10cm or the line coating damages which length is not less than 20cm.
2级涂层破损
最大直径不小于10 cm的片状涂层破损和长度上不小于20 cm的线状涂层破损。

Contiguous damages
Which edge distance of two coating damages areas is less than 10cm.
紧邻涂层破损
两破损涂层区域的边缘距离小于10 cm的相邻涂层破损
Types
Coating damages of ballast tanks of ships can be divided into two sorts in accordance with the difference of damaged method:
A) Butts coating damages
B) Non-butts coating damages
船舶压载舱涂层破损按破坏方式的不同分为以下两类：
A)合拢对接缝涂层破损
B)非合拢对接缝涂层破损

Non-butts coating damages can be divided into grade 1 coating damages and grade 2 coating damages in accordance with the difference of damaged grade.
非合拢对接缝涂层破损按破损程度的不同又分为1级涂层破损和2级涂层破损
Can be divided into piece coating damages and line coating damages in accordance with the length-width ratio of coating damages areas.
按涂层破损区域的长宽比的不同又可分为片状涂层破损和线状涂层破损。Assessment and calculation of non-butts coating damages areas非合拢对接缝涂层破损面积的评估和计算
Calculation of grade 1 coating damages areas1级涂层破损面积的估算
Confirm the percentage of damaged areas refer to ASTM D610-01 of annex 1.
对照附录1所引用的ASTM D610-01的图片确定破损面积百分比。

Calculation of grade 2 coating damages areas2级涂层破损面积的计算
Calculation of grade 2 coating damages areas: separate calculates by each ballast tank. 2级涂层破损面积计算：以每个压载舱单独计算
Each coating damages area can be calculated from similar figure area, refer to figure 2, also can be confirmed by using Photograph Crossing method. 单个破损涂层面积可由近似规则图形面积计算得出，参见图2，也可采用照片划格法确定。

Figure 2 Similar calculation of coating damages
Coating damages area≈a*b
图 2 涂层破损近似计算
破损涂层面积≈a×b
Calculate each coating damages area and accumulate, then will get the coating damages areas.
Percentage of grade 2 coating damages areas=grade 2 coating damages areas/whole area of each coating ballast tank* 100%
计算出各个破损涂层的面积，然后累加起来，就可得到破损涂层面积。
2级涂层破损面积百分比=2级涂层破损面积/单个压载舱涂层总面积×100%

Calculation of non-butts coating damages area
Percentage of non-butts coating damages areas=percentage of grade 1 coating damages areas + percentage of grade 2 coating damages areas
非合拢对接缝涂层破损面积的估算
非合拢对接缝涂层破损面积百分比为估算的1级涂层破损面积百分比与计算的2级涂层破损面积百分比之和。

Statistics of coating damages areas涂层破损面积的统计

Statistics of grade 1 coating damages areas according to Table 1. 1级涂层破损面积的统计按表1规定。
Table 1
Project No.

Ballast Tank No.

Location

estimate value1of grade 1 damages areas （%）

estimate value1of grade 1 damages areas of the tank （%）（arithmetic mean）

Note： Locations to be estimated are same in area.

Statistics of grade 2 coating damages areas according to Table 2

Table 2
Project No.

Ballast tank No.

Whole areas of ballast tank

No.
1
2
3
4
5
6
Location

Area

No.
7
8
9
10
11
12
Location

Area

No.
13
14
15
16
17
18
Location

Area

Whole areas of damages

estimate value1of grade 1 of damages areas of the tank（%）=damage of the total area ÷the total area of the tank ×100%

Percentage of whole coating damages areas= percentage of grade 1 coating damages areas + percentage of grade 2 coating damages areas涂层破损总面积百分比=1级涂层破损面积百分比+2级涂层破损面积百分比

Appendix 1 Annex A
(Informative annex)