关于甲板空气管壁厚的选取

chengx200

在《钢质海船入级规范2006》中有如下规定，具体我记不清了，反正大体是这样的。
问题1：
规定：“凡是涉及到船体结构的空气管、测量管的壁厚如下、、、、、、、、”（比一般情况下的要厚，具体在《钢规》中的一张表中，发帖比较唐突各位原谅！）
请问什么情况下我们的这些管子才算涉及到船体结构呢，还是只要它是空气管、测量管等后一律用这一栏的壁厚？
问题2
规定：“甲板上的空气管（包括艏艉楼）  通径小于80的壁厚至少为6，通径大于150的壁厚至少为8.5，通径在两者之间的用插值法”（大致是这个意思）
请问甲板上的空气管为什么要加厚？只是甲板上的那段空气管就要这么厚吗？然后插值法又做何解。
问题3
请问各位排舷外的管子的壁厚需要加厚吗？比如生活污水存储柜的排水口向舷外排水的管子。
谢谢各位船哥船姐的指点！

wangyongqi

有的，所有的甲板上的空气管的壁厚都要加厚，因为防止上浪把空气管打坏
bv规范里面也有PtC,Ch1，Sec10，[9.1.8]
9.1.8  Construction of air pipes
Where air pipes to ballast and other tanks extend above the freeboard deck or superstructure deck, the exposed parts of the pipes are to be of substantial construction, with a minimum wall thickness of at least:

6,0 mm for pipes of 80 mm or smaller external diameter

8,5 mm for pipes of 165 mm or greater external diameter,

Intermediate minimum thicknesses may be determined by linear interpolation
对于船长超过80m的船，在船首0.25L的长度之内的空气管头还有额外的强度要求，防止上浪
9.1.9  Strength requirements to resist green sea forces for the air pipes, ventilator pipes and their closing devices located within the forward quarter length
In addition to all other requirements specified before, the following shall apply on the exposed deck over the forward 0,25 L, applicable to:

All ship types of sea going service of length 80 m or more, where the height of the exposed deck in way of the item is less than 0,1 L or 22 m above the summer load waterline, whichever is the lesser.

For application to existing ships (that are contracted for construction prior to 1 January 2004), see Part A, Chapter 6.

The rule length "L" is the distance, in m, taken as defined in Pt B, Ch 1, Sec 2, [3.1.1].
The requirements do not apply to the cargo tank venting systems and the inert gas systems of tankers.

Generally, the bending moments and stresses in air and ventilator pipes are to be calculated at following critical positions:

at penetration pieces

at weld or flange connections

at toes of supporting brackets.

Bending stresses in the net section are not to exceed 0,8 of the specified minimum yield stress or 0,2% proof stress of the steel at room temperature. Irrespective of corrosion protection, a corrosion addition to the net section of 2,0 mm is then to be applied.
Relevant drawing and calculation shall be submitted.

For standard air pipes of 760 mm height closed by heads of not more than the tabulated projected area, pipe thickness and bracket heights are specified in  Tab 27. Where brackets are required, three or more radial brackets are to be fitted. Brackets are to be of gross thickness 8 mm or more, of minimum length 100 mm, and height according to  Tab 28 but need not extend over the joint flange for the head. Bracket toes at the deck are to be suitably supported.

For other configurations, loads according to item i) are to be applied, and means of support determined in order to comply with the requirements of item b). Brackets, where fitted, are to be of suitable thickness and length according to their height. Pipe thickness is not to be taken less than as indicated in [9.1.8].

For standard ventilators of 900 mm height closed by heads of not more than the tabulated projected area, pipe thickness and bracket heights are specified in  Tab 28. Brackets, where required are to be as specified in item c). See also Pt B, Ch 9, Sec 9, [8].

For ventilators of height greater than 900 mm, brackets or alternative means of support shall be fitted according to the arrangement acceptable to the Society. See also Pt B, Ch 9, Sec 9, [8]. Pipe thickness is not to be taken less than as indicated in [9.1.8].

All component parts and connections of the air pipe or ventilator are to be capable of withstanding the loads defined in item i).

chengx200

2楼楼主在甲板上空气管的厚度问题上说的非常清楚，非常感谢！不过还有两个问题没有解决，其次希望能引用CCS的规范，毕竟我这谈的问题就是CCS的规范问题。
再次感谢二楼楼主！

wangyongqi

其实问题1和问题2是同一个问题，对于空气管只要是伸出甲板的都需要加厚的，CCS规范上的3.10.4.4有明确要求的。另外CCS的结构规范里面1.12.7.5露天甲板的空气管的厚度有这个要求
关于问题3排舷外的加厚的管子是指阀到外板这段距离的一小段管，因为当阀关闭后，这段阀可能和海水接触，考虑海水的腐蚀情况因此要加厚

chengx200

谢谢你。

yrj200911

2楼所说的露天管子加厚可以防止海浪打坏管子是不是有点夸张了？感觉就是露天环境腐蚀会大些而已吧