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VISAKH MARKETING INSTALLATION

RESITEMENT PROJECT - WHITE OIL TERMINAL

Doc No:254624-400-SP-MEC-014 Rev: A Page 1 of 10

C:\Documents and Settings\sal51536\Desktop\Spec for Aluminium floating Roof_04Apr.doc

SPECIFICATION

FOR

ALUMINIUM FLOATING ROOF

Hindustan Petroleum Corporation Ltd

Visakha Dispatch Station

VR-ATP Area, Naval Base Post

Visakhapatnam - 530 014

Andhra Pradesh

Mott MacDonald Consultants (India) Pvt. Ltd.

Kothari House, CTS No. 185

Off Andheri - Kurla Road

Andheri (East)

Mumbai 400 059

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SPECIFICATION

FOR

ALUMINIUM FLOATING ROOF

Client HINDUSTAN PETROLEUM CORPORATION LTD.

MMCI Project No. 254624

Issue and Revision Record:

Rev Date Originator Checked Approved Description

A 02/03/12 RMN RMV MMS Issued for Tender

B 04/04/12 RMN RMV MMS Re-Issued for Tender

Group Disclaimer

"This document has been prepared for the titled project or named part thereof and should not be relied upon or

used for any other project without an independent check being carried out as to its suitability and prior written

authority of Mott MacDonald being obtained. Mott MacDonald accepts no responsibility or liability for the

consequences of this document being used for a purpose other than the purposes for which it was commissioned.Any person using or relying on the document for such other purpose agrees, and will by such use or reliance be

taken to confirm his agreement, to indemnify Mott MacDonald for all loss or damage resulting therefrom. Mott

MacDonald accepts no responsibility or liability for this document to any party other than the person by whom it

was commissioned.

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List of Content Page No

1.0 SCOPE 4

2.0 ABBREVIATIONS 4

3.0 DESIGN CODES 5

4.0 SITE CONDITIONS 6

5.0 MATERIAL 6

6.0 DETAILED ENGINEERING / DRAWINGS 6

7.0 DESIGN REQUIREMENT 6

8.0 ANNEXURE 1 10

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PWHT : Post Weld Heat Treatment

HAZ : Heat Affected Zone

DP : Dye Penetrant

3.0 DESIGN CODESDesign will be based on following codes and standards and their latest edition including

latest addenda as on date of finalisation of contract shall be followed unless otherwise

agreed. Sub-referenced codes within the following shall also be applicable.

SR.NO. CODES TITLE

1. API 650 Eleventh Edition Add 2 2009 Welded Steel Tanks for Oil Storage

2. API 2000 Fifth Edition 1998Venting Atmospheric and Low-Pressure Storage Tanks

(Non-refrigerated and Refrigerated)

3. ASTM / BISAmerican Society for Testing & Materials / Bureau of

Indian Standards for Materials

4. ASME Sec. IX 2007 Welding & Brazing Qualifications

5. ASME B16.5 2003Pipe Flanges and Flanged Fittings

(NPS 1/2 through NPS 24 Metric / Inch Standard)

6. ASME B16.47 2006Large Diameter Steel Flanges

(NPS 26 through NPS 60 Metric / Inch Standard)

7. ASME B16.20 2000Metallic Gaskets for Pipe Flanges

(Ring-Joint, Spiral-Wound and Jacketed)

8 OISD 129 - 2007 Inspection Of Storage Tanks

9 API MPMS Chaper 19 Section 2 -2003Manual of Petroleum Measurement Standards

Evaporative loss from floating roof tanks

10 OISD 105 -2004 Work Permit System

11 ASME B.96.1- 1999 Welded Aluminium Alloy Storage Tanks

12 ASME Sec II -2010 Materials

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SR.

NO.CODES TITLE

13 API RP 2016 - 2006Guidelines and Procedure for entering and cleaning

Petroleum Storage Tanks

14 API RP 2026 - 2006Safe Access/Egress involving Floating Roofs of Storage

Tanks in Petroleum Service

4.0 SITE CONDITIONS

5.0 MATERIAL5.1 Material used shall be as specified in Annexure 1. For Ethanol tanks floats shall be of

A312 TP 316Ti , Min 1.2 mm thk. End Plates shall be of A240 TP 316Ti, Min 1.5mm thk.

Deck skin for Ethanol tanks shall be min 1mm thk and seams exposed to vapour shall be

seal welded.

5.2 Tubular Floaters, Floating roof pipe supports and pipe sleeves shall be seamless.5.3 No substitution of material is to be made except in case of Ethanol tank for compatibility

with the service.

5.4 All materials by contractor shall be prime materials of new and first quality and of thetype and grade specified, with mill certificates for chemical analysis and mechanical

testing.

6.0 DETAILED ENGINEERING DOCUMENTS / DRAWINGS6.1 Requisite number of prints of all calculations, documents, detailed construction drawings

prepared by contractor shall be sent to Engineer for approval and one copy shall be

returned to contractor after comments/approval. No fabrication and erection shall becarried out without approved documents.

6.2 All drawing and documents shall have the name of OWNER (end user) Consultant workno., Consultant name and logo, contractor name no. and service of the item.

6.3 Drawing shall be prepared to scale and in third angle projection in the English languageand MKS/SI units.

7.0 DESIGN REQUIREMENT

Site Conditions are :

Wind Velocity 50 m/s

Rainfall (Max.) Hourly - 100

24 Hours 400

Seismic Zone II as per IS 1893-2002

Importance Factor 1

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7.1 ALUMINIUM INTERNAL FLOATING ROOF7.1.1 Floating roof shall be designed for a minimum of 100% excess buoyancy at the lowestexpected specific gravity, which shall not be more than 0.7 under conditions given in API

650 Appendix H.The design shall also cater for foam hold up near the seal area. Vendorshall provide suitable arrangement for holding the foam. Minimum heights of foam dam

shall be 75 mm above secondary seal.

7.1.2 For tanks provided with blanketing facility, the floating roof shall be designed foradditional load owing to blanketing (gas) pressure that acts on top of the roof. The actual

design blanketing pressure shall be as indicated in the Mechanical Datasheet.

7.1.3 The floating roof shall be designed such that the same shall remain afloat even in theevent of puncture in two adjacent pontoons. There shall not be any permanent damage to

the structure of the roof due its tilt on one side.

7.1.4 Floating roofs are to be designed to ensure that all stresses and deflections fall within theallowable limits for the material used when subjected to a load of 500 psf anywhere on

the deck's surface while floating or when suspended and receiving no buoyancy from the

pontoons.

7.1.5 The deck skin splices shall have a nominal lap of 45 mm with clamp beams to develop ametal to metal vapour tight joint, and full tear out strength. The clamp beams layout shall

be symmetrical in both the axis. The spacing between the fastening bolts shall not be

more than 300 mm. A diesel test shall be offered of the full length of all the seams to

confirm leak tightness. Seams in skin of Ethanol Tank exposed to product vapour shall be

seal welded.

7.1.6 The attachment between the floatation tubes and clamp beam shall be by a loaddistribution saddle or rigid construction. The saddle shall be minimum 50 mm wide with

a contact angle of minimum 100o. The end caps shall be mechanically rolled inward prior

to welding.

7.1.7 The leg supports shall be of adjustable type for providing a normal operating level of 1400mm and maintenance level of 2000 mm for the deck skin, when the roof is on its leg

support. The leg support shall be designed to permit drainage at the bottom. Teflon

insulators on the aluminium legs shall be provided to insulate from the carbon steel tank

floor. For Ethanol tank suitably designed cable suspended roof may be offered if the same

is economical.

7.1.8 Floating roofs legs are to be designed to ensure that all stresses and deflections fall withinthe allowable limits for the material used when subjected to the most severe combination

of loads as given in API 650 Appendix H. For calculating compressive stresses, the

effective length of the pipe shall be considered as twice the length of the pipe.

7.1.9 All weld joints in float shall be leak tested by detecting solution with minimum 1.4kg/cm2 air pressure.

7.1.10 The peripheral rim shall have sufficient rigidity to permit provision of specified seals. Therim shall extend below the liquid by at least 100 mm. All vertical roof penetration likeinstrumentation negotiators, gauge hatch, vertical ladder, etc. shall be surrounded by a

well extending 100 mm below the liquid level and 150 mm above deck. These shall be

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equipped with vapour mount seal of proven design compatible with stored product. The

lower end of peripheral rim and wells shall have a ramped edge.

7.1.11 Roof design shall be such that there are no hidden pockets for absorption/retention ofvapour/product during degassing. Each closed flotation compartment shall be capable ofbeing field-inspected for the presence of combustible gas. Closed compartments shall be

capable of being resealed in the field after periodic inspection (to prevent liquid or vapour

entry). Vendors Operating and Maintenance Manual shall give guidelines and training in

this regard.

7.1.12 The roof design shall prevent retention of product on top surface. Adequate number ofdrains shall be provided. Drains provided shall extend atleast 100mm into the product.

7.1.13 The floating roof design shall incorporate anti-rotation system with guide and cable, ifapplicable.

7.1.14 Aluminium load-carrying members, assemblies and connections comply with the designrequirements of the latest edition of the Aluminium Design Manual: Specifications forAluminium Structures, as published by the Aluminium Association, Inc. (Washington,

DC).

7.1.15 The floating roof shall incorporate standard accessories as Manways, Gauging nozzles,adequate Pressure Vacuum Bleeder vents, anti rotation device, earthing connections etc.

Ladder for Ethanol tank shall be provided. Elastomers or gaskets shall be compatible with

stored product.

7.1.16 Adequate means shall be provided to prevent electrical charge on the floating roof causingsparking in or above the seal. Shunts shall be provided on secondary seals, at maximum

spacing of 3 metres. Shunts shall be of austenitic stainless steel 50wide x 0.4thk x 400lg.All conductive parts of the internal floating roof shall be electrically interconnected and

bonded to the outer tank structure by cables from the external tank roof to the internal

floating roof.

7.1.17 Requirement of and sizing and location of inlet diffusers shall be advised by Vendor forfabrication and installation by client.

7.1.18 The construction of the floating roof shall be as per provisions of API MPMS Chapter 19Section 2 and all emissions from the sealed rim space, penetrations etc shall be within the

stipulations of notification GSR 186 E of Ministry of Environment and Forests.

Calculations corroborating the same shall be furnished.

7.2 SEALS

7.2.1 Space in between the outer periphery of the roof and the tank shell shall besealed by approved sealing devices consisting of double wiper seals. Sealing device

material shall be resistant to withstand product to be stored in the tank and also durable

against friction due to roof movement. At the same time the sealing system shall exertsufficient sealing pressure in all directions to prevent any evaporation leaks.

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7.2.2 The seals shall be installed and maintained from the top side of the floating roof anddesign should permit installation or maintenance while the tank is in service.

Guarantee of the seal for workmanship and materials shall be furnished for the period of 8

years. Periodic inspection shall be undertaken during the first two years to ensure

emission norms are not exceeded and train staff for further maintenance.

ANNEXURE 1

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MATERIAL OF CONSTRUCTION

N

o

ITEMS MINIMUM REQUIREMENT STANDARD

1 DECK SKIN Thickness- 0.7 mm U.S.Standard : AA 3003 H14

A.S.T.M.B 209

2 TUBULAR

FLOTATION

MEMBERS

Wall Thickness:1.3mm for upto 250NB Or

1.63mm for larger pipes

Outside Diameter:200NB,250NB,300NB as

per design

Welding Procedure : TIG

Quality Control : Leak testing at 1.4 kg/

cm2

End Cap : 2.5mm thk

Brackets: 2.0mm thk

U.S.Standard: AA 3004

H26(tube) 5052 H32 (End)

A.S.T.M. : B-209

3 DECKSKIN CLAMP

BEAMS/EXTRUSIONS

Thickness: 2.5 mm U.S.Standard: AA 6061 T6

A.S.T.M. : B-221 74

4 FIXED SUPPORT

LEGS AND

EXTRUDED

SECTION


A.S.T.M. : B-221 74

RIM EXTRUDED

SECTION


A.S.T.M. : B-221 74

5 SHEET FOR WELLS Thickness:1.52 mm U.S.Standard: AA 5052 H32

A.S.T.M. : B-209

6 STATIC GROUNDCABLES

Material: 18-8 Stainless Steel, 3.2 mm dia SS304

7 ANTI-ROTATION

CABLE

Material: 18-8 Stainless Steel, 6.4 mm dia SS304

8 FASTENERS BOLTS, NUTS & WASHERS

300 Series Austenitic Stainless Steel

A.S.T.M. A 193 B8 (Bolts)

A 194 Gr8 (Nuts)

9 FLOATING ROOF TO

SHELL SEAL

Composition: Compatible material as

specified in datasheets

10 SEAL FOR

APPURTENANCES

Composition: Foamed ionomer cross-

linked.Copolymer with special additives,

closed cell

Nominal density: 4 PCF(64 kg/m3)

Suitable for a broad range of chemicals and100% Aromatics

Colour-Black

* For Ethanol roof floats refer 5.1