1087 - Guidelines For Partially Weathertight Hatchway Covers On Board Containerships

 

Ref. T4/4.01 MSC/Circ.1087                                                                                                                                       18 June 2003

 

1 The Maritime Safety Committee, at its seventy-seventh session (28 May to 6 June 2003), recognizing the need to standardize the conditions for the fitting of partially weathertight hatchway covers on containerships and to develop recommendations on installation of such covers on containerships, and having considered proposals by the forty-fifth session of the Sub-Committee on Stability and Load Lines and on Fishing Vessels Safety (SLF), the seventh session of the Sub-Committee on Dangerous Goods, Solid Cargoes and Containers (DSC) and the forty-seventh session of the Sub-Committee on Fire Protection (FP), approved the Guidelines for partially weathertight hatchway covers on board containerships, as set out in the annex.

2 Member Governments are invited to bring the annexed Guidelines to all the parties concerned for their application, as appropriate, urging them, in particular, to apply the measures for construction and equipment contained in sections 1 and 2 of the Guidelines to ships constructed on or after 1 January 2004 and to implement the operational measures contained in section 3 of the Guidelines as soon as possible for all ships.

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Annex GUIDELINES FOR PARTIALLY WEATHERTIGHT HATCHWAY COVERS ON BOARD CONTAINERSHIPS Guidelines For Partially Weathertight Hatchway Covers On Board Containerships

GUIDELINES FOR PARTIALLY WEATHERTIGHT HATCHWAY COVERS ON BOARD CONTAINERSHIPS

1 Location Of hatchways, Height Of Coamings And Weathertightness Of Hatchway Covers

 

1.1 Introduction

Requirements relating to the height of coamings and to the weathertightness of hatchway covers located above the superstructure deck are left to the discretion of the Administration, pursuant to regulation 14(2) of the International Convention on Load Lines (LL), 1966. This section of the Guidelines is intended to serve as a guide when decisions are made on whether to accept partially weathertight hatchway covers on board containerships, in accordance with regulation 14(2) of the 1966 LL Convention.

1.2 Design Considerations And Criteria

1.2.1    Coamings   and   hatchway   covers   to   exposed   hatchways   situated   above   the   second superstructuretieroritsequivalent,orabovethethirdtieroritsequivalent,intheforwardquarterof theship'slength,mayberegardedasbeingsituatedabovethesuperstructuredeck,forthepurposeof givingeffecttoregulation14(2)ofthe1966LLConvention.Partiallyweathertighthatchcovers fittedtohatchwayssituatedinsuchlocationsmaybeacceptedsubjecttothefollowingconditions.

 

1.2.2    Coamingsandhatchwaycoversmaybefittedtohatchwayslocatedonexposeddeckssituated atleasttwostandardsuperstructureheightsabovetheactualfreeboarddeckoranassumedfreeboard deck,onthebasisofwhichacalculationofthefreeboardmaybemadecorrespondingtothedraught, whichshouldbenotlessthanthatwhichwouldcorrespondtothefreeboardactuallyassignedtothe ship.  Ifanypartofthehatchwayisforwardofapointlocatedaquarterof a ship's length (0.25L) fromtheforwardperpendicular,thishatchwayshouldbelocatedonanexposeddeckwhichis situatedatleastthreestandardsuperstructureheightsabovetheactualorassumedfreeboard.   It shouldbenotedthatuseismadeofanotionalfreeboarddecksolelyforthepurposeofmeasuringthe heightofthedeckonwhichhatchwaysarelocated;itmayconsistofanimaginaryoravirtualdeck which,  under  such  circumstances,  is  not  used  fortheactualassignmentofthefreeboard.   The freeboardoftheshipshouldbeassignedonthebasisofanactualdeck,referredtoasthefreeboard deck ,whichshouldbedeterminedinaccordancewiththeprovisionsofthe1966LLConventionand  of IACS Unified Interpretation LL39, as contained in LL.3/Circ.77.

 

1.2.3    The height of the hatchway coamings should not be less than 600 mm.

 

1.2.4    Non-weathertightgapsbetweenthehatchwaycoversshouldberegardedasunprotected openings  with  respect  to  the  requirements  relating  to  intact  stability  and  damage  stability calculations.  Thegapsshouldalsobeassmallaspossibleandproportionaltothecapacityofthe bilgepumpingsystemandtheestimatedamountofwaterpenetration,aswellastothecapacityand

theoperationalefficiencyofthefire-extinguishingsystem,andinanycaseshouldbenotmore than 50 mm.

 

 

 

 

 

 

 

1.2.5    Labyrinths,guttersorotherequivalentmeansshouldbefittedclosetotheedgesofeachhatch coveratrightangleswiththeopeningsinordertoreducetoaminimumthequantityof waterthat mightpenetrateintotheholdfromtheuppersurfaceofeachcover.  Figures1.2.5-1and1.2.5-2are examples of labyrinth and gutter arrangements.

 

 

 

 

 

 

 

 

 

 

 

1.2.6    Scantlingsforhatchwaycoversandthecomponentsofclampingdevicesusedtosecurethe coverstothestructuresupportingthemandthecoamings,shouldbeattheveryleastequivalentto thoseapplyingtoweathertighthatchwaycoversandbeinaccordancewiththerelevantprovisionsof a  recognized  organization   or  with  the  appropriate  national  standards  established  by  the Administration and which provide for an equivalent level of safety.

2 Increase Of Carbon Dioxide Fire-Extinguishing Media For Fixed Gas Fire-Extingguishing Systems

2.1 Introduction

This section of the Guidelines is intended to serve as a guide when decisions are made on whether to accept partially weathertight hatchway covers on board containerships in accordance with SOLAS regulations II-2/10.7.1.1 and II-2/20.6.1.1, and the relevant provisions of the Fire Safety Systems Code (chapter 5, paragraph 2..1), taking into account the leakage of carbon dioxide fire-extinguishing media through clear gaps between hatchway covers.

2.2 Increase Of Carbon Dioxide Fire-Extinguishing Media

If a container cargo hold fitted with partially weathertight hatchway covers is protected by a fixed carbon dioxide fire-extinguishing system, the amount of carbon dioxide for the cargo space should

be increased in accordance with one of the following formulae, as appropriate:

                  

 

Recognizedorganizationmeansanorganizationthathasbeenrecognizedinaccordance withSOLASregulationXI/1.

3 Stowage And Segregation Of Cargo Transport Units Containing Dangerous Goods

 

3.1 Introduction

This section of the Guidelines is intended to serve as a guide when decisions are made on the stowage and segregation of cargo transport units (CTUs) containing dangerous goods on containerships fitted with partially weathertight hatchway covers. For the purpose of the stowage and segregation of CTUs containing dangerous goods on containerships fitted with partially weathertight hatchway covers, the effect of clear gaps, as defined below, should be taken into consideration. The effects of other structures such as labyrinths are not considered, as no clear path exists into the hold.

3.2 Definitions

 

For the purpose of the application of this section of the Guidelines:

.1 "clear gap" means a clear unobstructed passage between hatchway covers that provides a path for dangerous goods to enter the cargo hold;

.2 "effective gutterbar" means a gutterbar the height of which is not less than 50 mm and also includes labyrinth bar; and

.3 "sensitive vertical line" means a vertical line under deck within one container space from a clear gap in athwartships direction(s) as specified by "C" in figures 3.2.3-1 and 3.2.3-2 below or equivalent.

                     

               

 

 

 

 

 

Note:            Verticalrowpositions"on-deck",notdirectlyabovecleargapsbetweenhatchwaycovers,arespecified

by"A".Verticalrowpositionswithlessthan50%footingonthehatch,arespecifiedby"B".Where containersareplacedintheoutermostverticalrowpositionswithmorethan50%footingonthehatch coveraredeemedtoqualifyasposition(s)"A".

3.3 Partially Weathertight Hatchway Covers Fitted With Effective Gutterbars

Partially weathertight hatchway covers fitted with effective gutterbars can be regarded as "resistant to fire and liquid" for the purposes of stowage and segregation of CTUs containing dangerous goods on containerships fitted with such hatchway covers. Therefore, no special provision, other than those set out in paragraph 3.4, applies to the stowage and segregation of CTUs containing dangerous goods on or under the hatchway covers fitted with effective gutterbars. Gutterbars showing any visible structural damage, which would reduce their effectiveness, do not meet the definition in paragraph 3.2.2.

3.4 Special Requirement For On-Deck Stowage

3.5 Special Requirement For Segregation

• Informatietype: Internationaal
• Documentsoort: Circulaire niet in wetten.nl
• Toegangsrechten: Extern
• Identificatie: PUC_1796_14
• Versie: 1
• Datum beschikbaarheid: 07-11-2007
• Geldigheid van: 17-06-2003
• Wijzigingsdatum: 24-11-2016
• Titel: 1087 - Guidelines For Partially Weathertight Hatchway Covers On Board Containerships
• Organisatie: International Maritime Organization (IMO)
• Taal: Nederlands
• Thema: 1000 until 1099