Strength Requirements for Fore Deck Fittings and Equipment

Transcription

1 (Nov 2002) (Rev.1 March 2003) (Corr.1 July 2003) (Rev.2 Nov 2003) (Rev.3 July 2004) (Rev.4 Nov 2004) (Rev.5 May 2010) Strength Requrements for Fore Deck Fttngs and Equpment 1. General 1.1 Ths UR S 27 provdes strength requrements to resst green sea forces for the followng tems located wthn the forward quarter length: ar ppes, ventlator ppes and ther closng devces, the securng of wndlasses. 1.2 For wndlasses, these requrements are addtonal to those appertanng to the anchor and chan performance crtera of each Socety. 1.3 Where moorng wnches are ntegral wth the anchor wndlass, they are to be consdered as part of the wndlass. 2. Applcaton 2.1 For shps that are contracted for constructon on or after 1 January 2004 on the exposed deck over the forward 0.25L, applcable to: All shp types of sea gong servce of length 80 m or more, where the heght of the exposed deck n way of the tem s less than 0.1L or 22 m above the summer load waterlne, whchever s the lesser. 2.2 For shps that are contracted for constructon pror to 1 January 2004 only for ar ppes, ventlator ppes and ther closng devces on the exposed deck servng spaces forward of the collson bulkhead, and to spaces whch extend over ths lne aft-wards, applcable to: Bulk carrers, ore carrers, and combnaton carrers (as defned n UR Z11) and general dry cargo shps (excludng contaner vessels, vehcle carrers, Ro-Ro shps and woodchp carrers), of length 100m or more. 2.3 The shp length L s as defned n UR S Ths UR does not apply to CSR Ol Tankers. 2.5 The requrements of ths UR concernng wndlasses do not apply to CSR Bulk Carrers. 3. Implementaton 3.1 Shps that are descrbed n paragraph 2.1 that are contracted for constructon on or after 1 January 2004 are to comply by the tme of delvery. Note: 1. The contracted for constructon date means the date on whch the contract to buld the vessel s sgned between the prospectve owner and the shpbulder. For further detals regardng the date of contract for constructon, refer to IACS Procedural Requrement (PR) No Ths UR does not apply to the cargo tank ventng systems and the nert gas systems of tankers. Page 1 of 6 IACS Req. 2002/Rev

2 3.2 Shps descrbed n paragraph 2.2 that are contracted for constructon pror to 1 January 2004 are to comply: ) for shps whch wll be 15 years of age or more on 1 January 2004 by the due date of the frst ntermedate or specal survey after that date; ) for shps whch wll be 10 years of age or more on 1 January 2004 by the due date of the frst specal survey after that date; ) for shps whch wll be less than 10 years of age on 1 January 2004 by the date on whch the shp reaches 10 years of age. Completon pror to 1 January 2004 of an ntermedate or specal survey wth a due date after 1 January 2004 cannot be used to postpone complance. However, completon pror to 1 January 2004 of an ntermedate survey the wndow for whch straddles 1 January 2004 can be accepted. 4. Appled Loadng 4.1 Ar ppes, ventlator ppes and ther closng devces The pressures p, n kn/m 2 actng on ar ppes, ventlator ppes and ther closng devces may be calculated from: 2 p 0.5 V C C C d s p ρ = densty of sea water (1.025 t/m 3 ) V = velocty of water over the fore deck (13.5 m/sec) C d = shape coeffcent = 0.5 for ppes, 1.3 for ar ppe or ventlator heads n general, 0.8 for an ar ppe or ventlator head of cylndercal form wth ts axs n the vertcal drecton. C s = slammng coeffcent (3.2) C p = protecton coeffcent: (0.7) for ppes and ventlator heads located mmedately behnd a breakwater or forecastle, (1.0) elsewhere and mmedately behnd a bulwark Forces actng n the horzontal drecton on the ppe and ts closng devce may be calculated from usng the largest projected area of each component. 4.2 Wndlasses The followng pressures and assocated areas are to be appled (see Fgure 1): kn/m 2 normal to the shaft axs and away from the forward perpendcular, over the projected area n ths drecton, kn/m 2 parallel to the shaft axs and actng both nboard and outboard separately, over the multple of f tmes the projected area n ths drecton, where f s defned as: f = 1+ B/H, but not greater than 2.5 Page 2 of 6 IACS Req. 2002/Rev

3 B = wdth of wndlass measured parallel to the shaft axs, H = overall heght of wndlass Forces n the bolts, chocks and stoppers securng the wndlass to the deck are to be calculated. The wndlass s supported by N bolt groups, each contanng one or more bolts, see Fgure The axal force R n bolt group (or bolt), postve n tenson, may be calculated from: R P hx A x y x R P hy A y I I x y and R R x R y R s P x = force (kn) actng normal to the shaft axs P y = force (kn) actng parallel to the shaft axs, ether nboard or outboard whchever gves the greater force n bolt group h = shaft heght above the wndlass mountng (cm) x, y = x and y coordnates of bolt group from the centrod of all N bolt groups, postve n the drecton opposte to that of the appled force (cm) A = cross sectonal area of all bolts n group (cm 2 ) 2 I x = A x for N bolt groups 2 I y = A y for N bolt groups R s = statc reacton at bolt group, due to weght of wndlass Shear forces F x, F y appled to the bolt group, and the resultant combned force F may be calculated from: Fx ( Px gm) Fy ( Py gm) N N and F 2 2 F F 0. 5 x y α = coeffcent of frcton (0.5) M = mass of wndlass (tonnes) g = gravty acceleraton (9.81 m/sec 2 ) N = number of bolt groups Axal tensle and compressve forces n and lateral forces n are also to be consdered n the desgn of the supportng structure. Page 3 of 6 IACS Req. 2002/Rev

4 5. Strength Requrements 5.1 Ar ppes, ventlator ppes and ther closng devces These requrements are addtonal to IACS Unfed Requrement P3 and Unfed Interpretaton LL36 (Footnote *) Bendng moments and stresses n ar and ventlator ppes are to be calculated at crtcal postons: at penetraton peces, at weld or flange connectons, at toes of supportng brackets. Bendng stresses n the net secton are not to exceed 0.8σ y, where σ y s the specfed mnmum yeld stress or 0.2% proof stress of the steel at room temperature. Irrespectve of corroson protecton, a corroson addton to the net secton of 2.0 mm s then to be appled For standard ar ppes of 760 mm heght closed by heads of not more than the tabulated projected area, ppe thcknesses and bracket heghts are specfed n Table 1. Where brackets are requred, three or more radal brackets are to be ftted. Brackets are to be of gross thckness 8 mm or more, of mnmum length 100 mm, and heght accordng to Table 1 but need not extend over the jont flange for the head. Bracket toes at the deck are to be sutably supported For other confguratons, loads accordng to 4.1 are to be appled, and means of support determned n order to comply wth the requrements of Brackets, where ftted, are to be of sutable thckness and length accordng to ther heght. Ppe thckness s not to be taken less than as ndcated n IACS UI LL For standard ventlators of 900 mm heght closed by heads of not more than the tabulated projected area, ppe thcknesses and bracket heghts are specfed n Table 2. Brackets, where requred are to be as specfed n For ventlators of heght greater than 900 mm, brackets or alternatve means of support are to be ftted accordng to the requrements of each Socety. Ppe thckness s not to be taken less than as ndcated n IACS UI LL All component parts and connectons of the ar ppe or ventlator are to be capable of wthstandng the loads defned n Rotatng type mushroom ventlator heads are unsutable for applcaton n the areas defned n Wndlass Mounts Tensle axal stresses n the ndvdual bolts n each bolt group are to be calculated. The horzontal forces F x and F y are normally to be reacted by shear chocks. Where "ftted" bolts are desgned to support these shear forces n one or both drectons, the von Mses equvalent stresses n the ndvdual bolts are to be calculated, and compared to the stress under proof load. Where pour-able resns are ncorporated n the holdng down arrangements, due account s to be taken n the calculatons. The safety factor aganst bolt proof strength s to be not less than The strength of above deck framng and hull structure supportng the wndlass and ts securng bolt loads as defned n 4.2 s to be accordng to the requrements of each Socety. Footnote *: Ths does not mean that closng devces of ar ppes on all exstng shps subject to need to be upgraded to comply wth UR P3. Page 4 of 6 IACS Req. 2002/Rev

5 Table 1 : 760 mm Ar Ppe Thckness and Bracket Standards Nomnal ppe dameter (mm) Mnmum ftted gross thckness, LL36(c) (mm) Maxmum projected area of head (cm 2 ) 40A (3) A (3) A A A A A A A 8.5 (2) (2) 250A 8.5 (2) (2) 300A 8.5 (2) (2) 350A 8.5 (2) (2) 400A 8.5 (2) (2) Heght (1) of brackets (mm) (1) Brackets (see 5.1.3) need not extend over the jont flange for the head. (2) Brackets are requred where the as ftted (gross) thckness s less than 10.5 mm, or where the tabulated projected head area s exceeded. (3) Not permtted for new shps - reference UR P1. Note: For other ar ppe heghts, the relevant requrements of secton 5 are to be appled. Table 2 : 900 mm Ventlator Ppe Thckness and Bracket Standards Nomnal ppe dameter (mm) Mnmum ftted gross thckness, LL36(c) (mm) Maxmum projected area of head (cm 2 ) 80A A A A A A A A A A Heght of brackets (mm) Note: For other ventlator heghts, the relevant requrements of secton 5 are to be appled. Page 5 of 6 IACS Req. 2002/Rev

6 Fgure 1. Drecton of Forces and Weght Fgure 2. Sgn Conventon End of Document Page 6 of 6 IACS Req. 2002/Rev