舷側(cè)管壁厚及通風(fēng)筒透氣管加強(qiáng)

Amended January 2013, see page 3 Rules for Ships, July 2012Pt.3 Ch.3 Sec.6 – Page 105shear stress:τ = 110 f1 N/mm2

σ+3τ=200f1e N/mm22equivalent stress:σe=

H. Ventilators

H 100Coamings and closing arrangements

101

1)Ventilators in position 1 or 2 to spaces below freeboard deck or decks of enclosed superstructures shall havecoamings of steel or other equivalent material, substantially constructed and efficiently connected to thedeck. Where the coamings of any ventilators exceed 900 millimetres in height it shall be speciallysupported.

2)Ventilators passing through superstructures other than enclosed superstructures shall have substantiallyconstructed coamings of steel or other equivalent material at the freeboard deck.

3)Ventilators in position 1 the coamings of which extend to more than 4.5 metres above the deck, and inposition 2 the coamings of which extend to more than 2.3 metres above the deck, need not be fitted withclosing arrangements unless specifically required by the Society.

4)Except as provided in (3) ventilator openings shall be provided with efficient weathertight closingappliances. In ships of not more than 100 metres in length the closing appliances shall be permanentlyattached; where not so provided in other ships, they shall be conveniently stowed near the ventilators towhich they shall be fitted. Ventilators in position 1 shall have coamings of a height of at least 900 millimetresabove the deck; in position 2 the coamings shall be of a height of at least 760 millimetres above the deck.

5)In exposed positions, the height of coamings may be required to be increased to the satisfaction of theSociety.

(ICLL Reg.19)

102 Reduced coaming height may be accepted for vessels trading in domestic waters only, in accordance withPt.1 Ch.1 Sec.2 A 300.

H 200Thickness of coamings

201 The thickness of ventilator coamings shall not be less than given in the following table:

LocationExternal diameter in mm

≥≥ 230Wall thickness in mm6.0Position 1 and 2Above Position 2

For intermediate external diameter the wall thickness is obtained by linear interpolation.

(IACS UI LL36)

H 300Arrangement and support

301 Where required by 101, weathertight closing appliances for all ventilators in positions 1 and 2 shall beof steel or other equivalent materials.

Wood plugs and canvas covers are not acceptable in these positions.

(IACS UI LL52)

302 The deck plating in way of deck openings for ventilator coamings shall be of sufficient thickness, andefficiently stiffened between ordinary beams or longitudinals. Coamings with heights exceeding 900 mm shallbe additionally supported.

303 Where ventilators are proposed to be led overboard in an enclosed superstructure deck house or shipsidethe closing arrangement shall be submitted for approval. If such ventilators are lead overboard more than 4.5m above the freeboard deck, closing appliances may be omitted, provided that satisfactory baffles and drainagearrangements are provided.

304 Ventilators necessary to continuously supply the machinery space shall have coamings of sufficientheight to comply with H101 (3), without having to fit weather tight closing appliances. Ventilators necessaryto continuously supply the emergency generator room, if it is considered buoyant in the stability calculation,or protecting openings leading below shall have coamings of sufficient height to comply with H101 (3), withouthaving to fit weather tight closing appliances.DET NORSKE VERITAS AS

Amended January 2013, see page 3 Rules for Ships, July 2012Pt.3 Ch.3 Sec.6 鈥? Page 106Alternatively, depending on vessel's size and arrangement, lesser coaming heights may be accepted if weather-tight closing appliances are provided, in accordance with H101 and in combination with suitable meansarranged to ensure uninterrupted and adequate supply of air to these spaces.

305 The height of ventilators may be required to be increased depending on where these flooding points arein relation to the damaged waterline in the stability calculation.

Guidance note:

The term suitable means is meant e.g. that direct and sufficient supply of air is provided through open skylights,hatches or doors at a higher level than the heights required by 101.

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H 400Strength requirements for fore deck ventilators

401 For vessels with L > 80 m:

The ventilators located on the exposed deck over the forward 0.25 L, where the height of the exposed deck inway of the item is less than 0.1 L or 22 m above the summer load waterline, whichever is the lesser, shallcomply with the requirements given in 402 to 408.

(IACS UR S 27)

402 The pressures p, in kN/m2 acting on ventilator pipes and their closing devices to be calculated from:

p = 0.5 蟻 V2 Cd Cs Cp

where:

V=velocity of water over the fore deck (13.5 m/sec)

Cd=shape coefficient:0.5 for pipes, 1.3 for ventilator heads in general, 0.8 for an air pipe or ventilator head of cylindrical form with its axis in the vertical direction

Cs =slamming coefficient (3.2)

Cp=protection coefficient:0.7 for pipes and ventilator heads located immediately behind a breakwater or forecastle,1.0 elsewhere and immediately behind a bulwark.

403 Forces acting in the horizontal direction on the pipe and its closing device may be calculated from 402using the largest projected area of each component.

404 Bending moments and stresses in ventilator pipes shall be calculated at critical positions: at penetrationpieces, at weld or flange connections, at toes of supporting brackets. Bending stresses in the net section shallnot exceed 0.8 蟽y, where 蟽y is the specified minimum yield stress or 0.2% proof stress of the steel at roomtemperature. Irrespective of corrosion protection, a corrosion addition to the net section of 2.0 mm is then tobe applied.

405 For standard ventilators of 900 mm height closed by heads of not more than the tabulated projected area,pipe thicknesses and bracket heights are specified in Table H1. Where brackets are required, three or moreradial brackets shall be fitted. Brackets shall be of gross thickness 8 mm or more, of minimum length 100 mm,and height according to Table H1, but need not extend over the joint flange for the head. Brackets toes at thedeck shall be suitably supported.

406 For ventilators of height greater than 900 mm, brackets or alternative means of support shall be fittedaccording to the requirements in 302. Pipe thickness shall not be taken less than as required in 201.

407 All component parts and connections of the ventilator shall be capable of withstanding the loads definedin 402.

408 Rotating type mushroom ventilator heads are unsuitable for application in the areas defined in 401.(IACS UR S27)Table H1 900 mm ventilator pipe thickness and bracket standards

Minimum fitted Maximum Nominal pipe gross projected Height of bracketsdiameterthickness, LL36(c)area of head (mm)(mm)2(mm)(cm)

80A6.3鈥?60

100A7.0鈥?80

150A8.5鈥?00

200A8.5550鈥撓?density of sea water (1.025 t/m3)

DET NORSKE VERITAS AS

絎? / 9欏?/p>

Amended January 2013, see page 3 Rules for Ships, July 2012Pt.3 Ch.3 Sec.6 – Page 107Table H1 900 mm ventilator pipe thickness and bracket standards (Continued)

250A8.5880–

300A8.51200–

350A8.52000–

400A8.52700–

450A8.53300–

500A8.54000–

Note: For other ventilator heights, the relevant requirements of 401 to 407 shall be applied.

I. Tank Access, Ullage and Ventilation Openings

I 100General

101 The number of hatchways and other openings in the tank deck shall not be larger than necessary forreasonable access to and ventilation of each compartment.

102 Hatchways, openings for ventilation, ullage plugs or sighting ports, etc. shall not be placed in enclosedcompartments where there is a danger of accumulation of gases.

Ullage plugs or sighting ports should be fitted as high above the deck as practicable, for instance in the coverof access hatches.

Access hatches to holds or other openings, for example for tank cleaning devices, shall be of substantialconstruction, and may be arranged in the main hatch covers.

I 200Hatchways

201 The thickness of the hatch coaming shall not be less than given in Ch.1 Sec.10 for a deckhouse in thesame position.

202 The thickness of covers shall not be less than:

—12.5 mm for cover area exceeding 0.5 m2

—10.0 mm for cover area less than 0.25 m2.

For intermediate areas the thickness may be linearly varied.

203 Where the area of the hatchway exceeds 1.25 m2, the covers shall be stiffened.

204 Covers shall be secured to the hatch coamings by fastenings spaced not more than 380 mm apart and notmore than 250mm from the corners. For circular covers the fastenings shall not be spaced more than 450 mmapart.

205 Other types of covers may be approved, provided their construction is considered satisfactory.I 300Air Pipes

301 Where air pipes to ballast and other tanks extend above the freeboard or superstructure decks, theexposed parts of the pipes shall be of substantial construction; the height from the deck to the point where watermay have access below shall be at least 760 millimetres on the freeboard deck and 450 millimetres on thesuperstructure deck. Where these heights may interfere with the working of the ship, a lower height may beapproved, provided the Society is satisfied that the closing arrangements and other circumstances justify alower height. Satisfactory means permanently attached, shall be provided for closing the openings of the airpipes.

(ICLL Reg.20)

302 Air pipes shall be provided with automatic closing appliances.

(ICLL Reg. 20 (3))

303 Pressure- vacuum valves (PV valves) may be accepted on tankers.

Wooden plugs and trailing canvas hoses shall not be accepted in position 1 and position 2.

Guidance note:

The member Societies in formulating this interpretation realise that pressure-vacuum valves (PV valves) presentlyinstalled on tankers do not theoretically provide complete watertightness. In view, however, of experience of this typeof valve and the position in which they are normally fitted it was considered they could be accepted.

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(IACS UI LL49)DET NORSKE VERITAS AS

Amended January 2013, see page 3 Rules for Ships, July 2012Pt.3 Ch.3 Sec.6 – Page 108

304 The thickness of air pipe coamings in steel other than stainless shall not be less than given in thefollowing table:

Location

External diameter in mm

Wall thickness in mm

Position 1 and 2Above Position 2

For intermediate external diameter the wall thickness is obtained by linear interpolation. Coamings withheights exceeding 900 mm shall be additionally supported. (IACS UI LL36)

305 Above the deck the thickness of air pipe coamings made of stainless steel shall not be less than given inthe following table:

External diameter in mm

d ≤ 6060 < d ≤ 120120 < d ≤ 200200 < d ≤ 250250 < d ≤ 300300 < d ≤ 350350 < d ≤ 500d > 500

Wall thickness in mm

2.73.03.43.74.14.54.75.5

Note:The external diameters and thickness have been selected from ANSI B36.19M Schedule 10S.

For pipes covered by other standards, thickness slightly less may be accepted.

306 In cases where air pipes are led through the side of superstructures, the height of their openings to be atleast 2.3 metres above the summer water line. Automatic vent heads of approved design shall be provided.307 The height of air pipes may be required to be increased on ships of type "A", type "B-100" and type "B-60" where this is shown to be necessary by the floatability calculation.

308 The automatic closing appliances are to be permanently attached and of approved design. The closingappliances shall be so constructed that damage to the tanks by over pumping or occasionally possible vacuumby discharging is prevented.

309 All air pipes in cargo spaces shall be well protected.

310 For arrangement and size of air pipes, see also Pt.4 Ch.6 Sec.4 K.I 400

Strength requirements for fore deck air pipes

401 For vessels with L > 80 m:

The air pipes located on the exposed deck over the forward 0.25 L, where the height of the exposed deck inway of the item is less than 0.1 L or 22 m above the summer load waterline, whichever is the lesser, shallcomply with the requirements given in 402 to 407.For tankers:

The requirements given in 402 to 407 are not applicable for cargo tank venting systems and the inert gassystems.

(IACS UR S 27)

402 The pressures p, in kN/m2 acting on air pipes and their closing devices shall be calculated from:

p = 0.5 ρ V2 Cd Cs Cp

where:

V=velocity of water over the fore deck (13.5 m/sec) Cd=shape coefficient:

0.5 for pipes, 1.3 for ventilator heads in general,

0.8 for an air pipe or ventilator head of cylindrical form with its axis in the vertical directionCs =slamming coefficient (3.2) Cp=protection coefficient:

0.7 for pipes and ventilator heads located immediately behind a breakwater or forecastle,1.0 elsewhere and immediately behind a bulwark.

DET NORSKE VERITAS AS

ρ=density of sea water (1.025 t/m3)

Amended January 2013, see page 3 Rules for Ships, July 2012Pt.3 Ch.3 Sec.6 鈥? Page 109

403 Forces acting in the horizontal direction on the pipe and its closing device may be calculated from 402using the largest projected area of each component.

404 Bending moments and stresses in air pipes shall be calculated at critical positions: at penetration pieces,at weld or flange connections, at toes of supporting brackets. Bending stresses in the net section shall notexceed 0.8蟽y, where 蟽y is the specified minimum yield stress or 0.2% proof stress of the steel at roomtemperature. Irrespective of corrosion protection, a corrosion addition to the net section of 2.0 mm is then tobe applied.

405 For standard air pipes of 760 mm height closed by heads of not more than the tabulated projected area,pipe thicknesses and bracket heights are specified in Table I1. Where brackets are required, three or more radialbrackets shall be fitted. Brackets shall be of gross thickness 8 mm or more, of minimum length 100 mm, andheight according to Table I1 but need not extend over the joint flange for the head. Bracket toes at the deckshall be suitably supported.

406 For other configurations, loads according to 402 shall be applied, and means of support determined inorder to comply with the requirements of 404. Brackets, where fitted, shall be of suitable thickness and lengthaccording to their height. Pipe thickness shall not be taken less than as required in 304.

407 All component parts and connections of the air pipe shall be capable of withstanding the loads definedin 402.

(IACS UR S27)

Table I1 760 mm air pipe thickness and bracket standards

Minimum fitted gross Nominal pipe diameter (mm)thickness, LL36(c) (mm)

40A6.0

6.050A65A6.080A6.3100A7.0125A7.8150A8.5175A8.5200A8.5250A8.5 300A8.5 350A8.5 400A8.5 1)

2)3)

Maximum projected area of head (cm2)

鈥撯

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