Attachment-II to PR # 10-2453

Standing Order for Supply & Installation of Secondary vapour seal & Roof leg covers for Floating Roof Tanks in FR Offsite Area.

Item # 1 : Supply and installation of Secondary Seal for 8” Rim Gap Floating Roofs.

Scope of Job : Supply of Seal with all necessary accessories, Removal of weather shields from the existing tanks, shifting of scrap to the designated scrap yard, Installation of secondary seal, Inspection, Testing & Commissioning.

The specifications and necessary drawings for the seal are provided by HPCL. However the vendor should accept & return the HPCL dwg or submit the final dwg of the seal being supplied by them along with clear mention of deviations , if any & get its approval before supply.

Job scope includes Design, Preparation of Drawing for HPCL approval, supply, installation, & testing of Secondary Seal System. The removal of existing seal / weather shield is in vendor’s scope. Agency shall submit preliminary Seal Drawings, prepared in AUTOCAD (Latest version), in 2 Sets, individually for each Tank including Dimensions, Specifications and Bill of Materials, etc. for the specified Rim space - within One Week from the Date of advice. Agency shall provide the final approved Drawing in computerized form in a CD, with 1 full Set in non-degradable Sepia Tracings to HPCL.

Agency shall make necessary Mechanical modifications at Site, while fixing the Seals to the available Rim Angle, including Holes on the Rim Angle. All the arrangement is in the scope of the agency.

Design Codes shall conform to IS & API Codes.

As all jobs should be carried out in stage wise inspection, party must consult the HPCL

MI for all activity before they start.

1) MOC of all the seal components should be as per approved drawings.

2) Before installation, offer the material for visual & Dimensional inspection.

3) Offer Original test certificate of all the material for review.

4) In case of non availability of coordination marks on material, Samples will be tested at outside laboratory.

SPECIFICATIONS FOR SECONDARY VAPOUR SEALS

Material of Construction

# / Component / Material
1 / Secondary Seal Plates / SS 304 (Minimum 1.2mm Thickness), (1/4 Hard)
2 / Secondary Seal Tip / Extruded PVC/Nitrile
3 / Secondary Seal Vapor Barrier Fabric / Reinforced PolyUrethane (0.4mm thick) coated Fabric
4 / Seal Bolting Channels / SS 304
5 / Interface Channels / SS 304
6 / All Bolting Components / SS 304
7 / Hold down plate / SS 410

Secondary Seal

  1. Secondary Seal shall be designed to be mounted to the Floating Roof Rim Plate, and completely cover the annular space between the external Floating Roof and the Tank Shell Wall and provide contact against the Tank Shell Wall under all operating conditions. The Secondary Seal shall be independent of the Primary Shoe Seal in a manner that the Secondary Seal can be installed, repaired or removed without impairing operation of the Primary Seal. The Seal should be tight fitting against the Tank Shell at all levels of the Floating Roof. Any work carried out on the Secondary Seal shouldn’t affect the Primary Seal.
  1. The Secondary Seal Compression Plates shall be bolted to the Floating Roof Rim; each Plate overlapping the adjacent Plates by 40mm. The Width of the Compression Plates shouldn’t exceed 500mm, in order to obtain the maximum contact between Wiper Seal and Tank Shell Wall. The adjacent Secondary Seal Support Compression Plates are not to be bolted, welded or riveted together. They will be overlapped with each Compression Plate, free to expand and contract independent of the other Plates. All metallic Compression Plates should be independent and will not be riveted or bolted to each other. They will be bolted on the Rim Angle.
  1. Secondary Seal shall be designed and pre-tensioned to accommodate a variation in the annular space between the Floating Roof and the Tank Shell of +/- 100mm, while maintaining a Release Pressure of 15 Kg per Meter of circumference under normal operating conditions. Design of the Seal, especially size of the Compression Plates, is decided depending on the ACTUAL Rim Gap observed. Normally a Survey will be carried out and ACTUAL Rim Gap measurements will be taken at number of places on the periphery of the Deck at various levels of the Floating Roof. These readings are fed to the Computer and the Computer Program decides Height, Width and Bending Angle of the Compression Plate so that the Seal, when installed, will be always in contact with the Shell. The installed Seal will exert a pressure of 15 Kg per Running Meter on the Tank Shell with design Rim Gap.
  1. To prevent Vapor leakage between the Support Plates, a continuous Vapor Barrier of Elastometric material shall be installed under the Support Plates. Vapor Barrier material is designed for Chemical Resistance of the stored Product Vapor. Un-reinforced Fabrics will not be allowed. Vapor Barrier Fabric material shall be selected to be compatible with the stored Product. Vapor Barrier Fabric is installed inside the Compression Plates to make the Seal Vapor tight. The Fabric has to be compatible with the Product stored in the Tank. It is especially important that if joints in the Fabric, if unavoidable, should be Vapor tight. There shall be no holes, tears or other openings in the Seal Fabric.
  1. Secondary Seal Tip system will consist of a PVC/Nitrile extrusion, with an overall Width of not less than 20mm at the point of contact with the Tank Shell. The adjacent Tip sections are to be butted together with butt joints, protected by Stainless Steel Cover Strips. The Tip shall be bolted to the end of the Compression Plates, totally encasing the top 70mm of Plate, to provide Sealing at the point of contact between the Secondary Seal and the Tank Shell. The Seal Tip is wider at the point of contact with the Tank Shell. Minimum Thickness of the Tip at this point shouldn’t be less than 20mm. Minimum Length of the Seal Tip shouldn’t be less than 15 Meters. The Tip should be butt joint and protected with Stainless Steel Cover Strip to prevent Vapor through the joint.
  1. Secondary Seal shall be designed to be installed, repaired and replaced with the Tank remaining in service. No Hot Work is allowed during Secondary Seal installation. Hence, design of the Secondary Seal should be such that it can be installed with Tank ‘in service’ and without carrying any Hot Work.
  1. All the Secondary Seal Metallic Components, including Hold-down and Bolting Hardware shall be SS 304. Compression Plates shall be 1.2mm Thick, SS 304 Stainless Steel. Stainless Steel Compression Plates shall be fabricated from material to give adequate spring action. ‘C’ Channels are used to fix the Compression Plates on the Rim Angle for uniform Pressure on the Compression Plates. No Flats are allowed.
  1. Secondary Tip is to be attached to the Compression Plates by means of Thermoplastic Protection Device, with an internal Stainless Steel Bolt. In the event that Secondary Seal protrudes above the top of the Tank Shell (due to over-filling of the Tank), the Protection Device shall ensure that the Tip will not sustain damage when the Roof descends. Protector Clips are provided to fix the Seal Tip to the Compression Plates over Vapor Barrier Fabric. In an emergency, if the Roof needs to be taken above the Safe Filling Height, Secondary Seal may go beyond the Curb Angle. When the level is reduced and the Deck lowers, these Protector Clips guide the Secondary Seal safely back in to the Shell without causing any damage to the Seal.
  1. Maximum Spacing between Secondary Seal Tip Bolts shall be 127mm. The maximum Clips with Bolts are fixed at a maximum distance of 5 Inches. This reduced distance ensures proper shape of the Seal Tip and its contact with the Shell.
  1. Static Shunts shall be incorporated to operate above the Secondary Seal Tip at Spacing not greater than 3 Meters. These Shunts shall be fabricated from SS 304 Stainless Steel, The Shunts prevent built up of any Static charge. As the Shunts are made from Stainless Steel, SS-304 , they ensure contact with the Tank Shell. The Seal Tip is bolted to Compression Plate, using Protector Clip. No rivets are allowed.
  1. MATERIALS

A)  Metallic Components: The Secondary Seal Components shall be SS 304 Stainless Steel. Compression Plates shall be 1.2mm Thick SS 304 Stainless Steel.

B)  The Secondary Wiper Seal Electrometric Components shall be:

·  Secondary Seal Vapor Barrier Fabric

  1. Weld-able Polyester Poly-Urethane coated on both sides on a Polyester 500D Base Fabric. Total Finish Thickness shall be 0.4mm. Finished coated Fabric; weight approximately 500 gm per M2
  2. ALTERNATIVELY, TB.20 Reinforced Urethane coated Fabric, 20 mil Thick, with Aromatic Resistant characteristics, or Polyurethane coated Fabric.

·  Secondary Seal Tip

The Wiper Tip material shall be extruded PVC/Nitrile. The material is to have the overall characteristics of Aromatic and Abrasion Resistance, Tensile Strength and Weathering Resistance. No Foam type Wiper material or Urethane Wiper is allowed. Materials that grip the Tank Shell are not acceptable.

  1. Vendor to carry out own Inspection, and offer the Test Results/Certificates to HPCL Inspection/CES Section for review and approval, for the following –

A)  Vapor Barrier Fabric

B)  Wiper Seal Tip

C)  Compression Plate and other Hardware Chemical & Physical Test

D)  Inspection of installation at HPCL site by HPCL.

  1. Vendor to carry out measurement of the Tank for correct dimensions.
  1. Vendor to provide Sketch of assembly with cross-section view and material of construction indicating inter-distances, Shunt, Protector Clip, Liner Tap, etc.
  1. Maximum Width of Compression Plate is not to exceed 500mm. Minimum Thickness required is 1.2mm. Material shall conform to ASME SA240M Type 304, as per SA666.
  1. Joints for Vapor Barrier Fabric shall be minimum, depending upon the maximum available Size of Vapor Barrier Fabric available in the Market. Joining of small Lengths/Pieces of Fabric is not permitted. Also, Joints must be sealed with Corrections Solution.
  1. Vendor to confirm Test for Vapor Barrier Fabric, as follows:

·  For 100% Aromatic: Maximum 40% Volume swell is permitted for Seven Days. No Test Standard is required

·  Permeability under Toluene Vapor permitted is 0.2 Fl Oz per Ft2 per 24 Hours (Maximum). No Test Standard is required

·  Abrasion Resistance allowed is 50 mg loss per 1000 Cycles. No Test Standard is required

·  Finished Thickness: Minimum 0.4mm

·  Finished Weight: 500 gm per M2

18. Vendor to confirm Test for Wiper Seal Tip, as follows:

·  Hardness to be 75 +/- IRHD, as per BS 903 A26 Test Standard

·  Tensile Strength: Minimum 8 Mpa, as per BS 903 A2 Standard

·  Elongation at break: Minimum 250%, as per BS 903 A2 Standard

·  Tear Strength: Minimum 25 Nm, as per BS 903 A3 Standard (Angle Tear, Method B)

·  Ozone Resistance (50 pphm / 40OC / 72 Hours / 100% Strain). No cracks to be observed within 72 Hours. No Test Standard is required

·  Wear Resistance with H-18 Carbide Wheel: 1000 gm / 2000 Cycles, as per DIN 53516 Standard

·  Low Temperature Test is not required

·  Liquid immersion for 7 Days at 40OC as per BS 903 A16 for Toluene – Hardness: Maximum 20, Tensile Strength: Maximum 60%, Elongation at break: Maximum 65%, Volume Swell: Maximum 100%

·  Liquid immersion for 7 Days at 40OC as per BS 903 A16 for Naphtha – Hardness: Maximum 15, Tensile Strength: Maximum 50%, Elongation at break: Maximum 65%, Volume Swell: Maximum 100%

·  Liquid Immersion for 7 Days at 40OC as per BS 903 A16 for Fuel B – Hardness: Maximum 10, Tensile Strength: Maximum 35%, Elongation at break: Maximum 50%, Volume Swell: Maximum 50%

19. Protector Clip material is Thermo-Plastic Alloy of Poly-Propylene and Polyamide, with the addition of Glass Fiber suitable for Gasoline and Hexane.

PRODUCTION SPECIFICATION

Secondary Seal Vapor Barrier Fabric

Product Description : Weldable Polyster PU coated on both sides, on a polyester base fabric.

Base Fabric : Polyester 500 D mesh fabric.

Material : Poly Urethane coated Polyester Fabric

REQUIREMENTS COMMENT TEST METHOD/RESULT

100% aromatic 40% vol. Swell max. ASTMD 543

100% MTBE 11.70% ASTMD 471/14 days@ 50 Deg.C.

Conductivity Not applicable

Permeability 0.2 Fl.oz/Ft.Sq./24 hrs. Toulene Vapour

Fire resistance No data

Abresion Resistance 50 mg/1000 cycles DIN 53516

TUV Approval Yes

Recommended Use Standard Secondary

seal vapor barrier Fabric

SECONDARY SEAL

Tip Specification :

Value Test Standard

1. Hardeness (IRED) 75 +/- 5 BS 903 A26

2. Tensile Strength (Mpa) 8 min BS 903 A2

3. Elongation at break(%) 250%

4. Determination of Tear strength 25Nm BS 903 A3(Angle

tear) (Method B)

5. Ozone Resistance

50pphm/40C/72 hrs/100% extn. No Cracks

6. Wear resistance – weight loos (%) 2% Max. BS 903 A9

H-18 acrbide wheel, 1000 grams, weight loos

2000 cycle

7. Low Temperature : 5 hours@-20C No. Cracks

with 180 deg.bend.

8. Liquid Immersion : 7 days at BS 9030 A16

temperature indicated and tested

for hardness, tensile strength,

elongation and volume swell.

TOULENE 40 deg.C

NAPTHA 40 deg.C

Fuel B 40 deg.C