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发表于 2010-8-15 20:50
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来自： 中国上海
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). |
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