HTLP-80 Application Procedure [PDF]

Zitiervorschau

Covalence Raychem Corrosion Protection Group

PROCEDURE FOR HTLP-80 HEAT SHRINK SLEEVES WITH S1301M EPOXY OVER 3LPE COATED PIPES

Raychem RPG Ltd

SCOPE 1. GENERAL 2. MATERIAL AND EQUIPMENT 3. BEVELING OF LINE COATING EDGES 4. SURFACE PREPARATION 5. CUTTING OF SLEEVE CORNERS 6. EPOXY PRIMER MIXING 7. PREHEAT OF GIRTH WELD AREA 8. PRIMING OF GIRTH WELD AREA 9. SLEEVE INSTALLATION & POST HEATING 10. VISUAL INSPECTION CRITERIA 11. HOLIDAY INSPECTION TEST 12. ADHESION PEEL STRENGHT TEST

Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 2 of 9

Raychem RPG Ltd

1. GENERAL This installation procedure details the application of Raychem HTLP-80 Heat shrink sleeve system. The HTLP-80 heat shrink sleeve system comprises of HTLP-80 sleeve applied over S1301M epoxy. 1A. Reference: EN 12068, DIN 30672. 2. MATERIAL AND EQUIPMENT

1. HTLP80 sleeve with closure patch suitable for required dia pipe. 2. S1301M Epoxy Part A. 3. S1301M Epoxy Part B 4. Applicator Pad with Mixing Cup & Stick. 5. Gas torch with LPG Cylinder 6. Straight Rollers 7. Wet Film Gauge 8. Pyrometer with flat surface probe 9. Peel Strength Gauge 10. Holiday detector 11. Hygro Meter 3. BEVELLING OF POLYETHYLENE COATING EDGES

If not factory beveled, bevel the line coating edges on both sides of the weld bead to approximately 15°.

The ends of existing mill coating shall be inspected. Unbounded portions of the coating shall be removed and then suitably trimmed. Portions where parent coating is removed shall be thoroughly beveled, and cleaned as specified.

Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 3 of 9

Raychem RPG Ltd 4. SURFACE PREPARATION

o Clean exposed steel area and adjacent pipe coating (100mm before shrinking) that will be covered by the HTLP 80 sleeve from all dust, dirt, moisture, grease or other contaminations. o

If Humidity is greater than 85 % and pipe temperature is below or equal to 30c compared to dew point than coating should be stopped. Also when design pipe Temperature goes below 10 0c, it shall be stopped.

o If necessary, use a non-contaminating solvent such as Xylene. o Using copper slag clean blast only the bare steel part of the girth weld area to SA 2½ and a roughness profile (anchor pattern) between 50 to 70 microns. o Sweep blast adjacent PE line coating up to 100 mm only to create a rough surface. o Abrade the R -95 Coated pipe with Emery Paper (50 mesh size) to create rough surface and adjacent PE coating upto 100mm on either side. Remove carefully all remaining abrasive dust and loose particles after blast cleaning. 5. CUTTING OF SLEEVE CORNERS The corners of the underlying end should be cut by ± 15 x 50 mm, prior to wrapping sleeve around the joint. 15 mm

Underlaying end

50 mm

6. EPOXY PRIMER MIXING 

The S1301M epoxy has to be applied only on the steel surface. (THE EPOXY HAS NOT TO BE APPLIED ON THE PE)

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Mix Part A and Part B in a cup. The mixing has to be done thoroughly for 30 -60 seconds till homogeneous mass is obtained i.e. the hardener shall mix completely with resin. The color of hardener shall not visible or float over the resin.

Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 4 of 9

Raychem RPG Ltd

7. PREHEATING OF FIELD JOINT 

Make sure that all necessary items are in close proximity before you start.

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Proper arrangements are to be made during windy and rain conditions to protect the field joint surface from moisture and dirt/ dust.

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Preheat the joint area with a slow flame moving in a paintbrush motion.

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Preheat the steel surface to between 70ºC to 80°C, & the adjacent PE line coating to between 60ºC to 70°. This is very important to bond properly to the PE line coating.

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Check the temperatures using a digital pyrometer with a flat temperature sensor.

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To avoid excessively fast curing of epoxy do not preheat the steel higher than 85°C.

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The sleeve needs to be shrunk while the epoxy is still wet.

8. PRIMING OF GIRTH WELD AREA  

Apply the S1301M epoxy on the steel surface and include a couple of mm of chamfered polyethylene edges, in order to cover all bare metal. In order to achieve the required wet film thickness, apply the S1301M epoxy primer over the weld seams first.

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Then apply the S1301M over the main steel body. S1301M epoxy should not be applied on the adjacent PE line coating

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The S1301M epoxy applied to the steel should be a wet.

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For field joint coating applications of S1301M Brush Grade, disposable tools such as applicator pads should be used to apply the coating.

9. SLEEVE INSTALLATION The following steps are to be followed while applying HTLP -80 sleeves over PE. 

The shrink sleeve shall be applied immediately after the S1301M application without waiting.

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Wrap the HTLP 80 sleeve centrally around the girth weld. Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 5 of 9

Raychem RPG Ltd 

Position the leading edge of the sleeve onto the pipe between the 10 and 2 O'clock position.

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Preheat the underside of the leading edge of the sleeve with a LPG / Propane flame, and press firmly down onto the top of the joint area.

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The sleeve should be wrapped loosely around the joint leaving a small gap of 30-40 mm between the bottom of the joint and the sleeve as indicated below. Sleeve overlap onto itself should be minimum 50 mm.

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Apply closure patch centrally over sleeve overlap area. While heating press down and smooth the closure patch with a gloved hand to ensure good bonding and eliminate air entrapment.

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Using LPG gas torches adjust flame length as required.

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Begin at one end of the sleeve and heat circumferentially all around the pipe until sleeve conforms to the pipe; then continue to the other end of the sleeve with a constant paint brush motion until the sleeve is fully recovered. Alternately, shrinking can be started from the middle and shrunk first towards one end and then towards the other, from the middle.

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The embossed pattern on the sleeve ( dimpled PCI – Permanent Change Indicator) of the backing should disappear and a smooth backing profile should be seen as illustrated below :

Dimples still visible = more heat Smooth profile = O.K 

Till 4” dia of pipe one insulator for heating the sleeve is recommended. Two insulators are required for pipe sizes > 4” dia.

Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 6 of 9

Raychem RPG Ltd 9.1. SLEEVE POSTHEATING 

Immediately after the sleeve has been fully shrunk, post heat the sleeve area overlapping the polyethylene line coating well with the LPG torch until it passes the finger test as indicated below. Adhesive not bonded yet = More heat

Adhesive does bond = OK

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After post heating and while the adhesive is still liquid, roll the entire sleeve with a straight hand roller to remove any air voids if necessary.

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Start rolling from the weld bead towards the ends, forcing possible air enclosures out of the sleeve.

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Special attention should be given circumferential weld beads, and also to transition to the mill coating and the patch area.

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When the adhesive is too viscous and rolling difficult, reheat the area again.

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Rolling does not affect the properties of the sleeve; it only helps to work out possible entrapped air.

10. VISUAL INSPECTION CRITERIA The inspection of the joint shall be done after the cool down of the sleeve and the substrate to ambient temperature. The sleeve shall be visually inspected for the following points. 

The weld bead profile contour shall be visible through the sleeve.

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The ends of the sleeve shall be firmly bonded to the mill coating.

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There shall be no upstanding edges.

Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 7 of 9

Raychem RPG Ltd 

Adhesive flow shall be evident at both edges of sleeve around entire circumference of pipe / sleeve.

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The sleeve shall be smooth; there will be no dimples, cold spots, bubbles, punctures, burn holes or any signs of holidays.

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There shall be no signs of entrapment of foreign materials in the underlying adhesive.

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Sleeve shall overlap minimum 50mm onto the adjacent PE line coating on each side of joint.

11. HOLIDAY INSPECTION TEST After complete cooling down, each sleeve shall pass holiday detection test. Holiday inspection shall be done using a voltage setting can go upto 25kv. The holiday test shall be carried out after 4 hrs. 12. ADHESION PEEL STRENGHT TEST 

One out of every 50 sleeves, or alternatively one out of each day’s production (whichever is lower) shall be subjected to a manual peel test. The peel test shall be done after 24 hrs.

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Peel strength inspection shall be done at a sleeve temperature of around 23°C or 60°C in order to compare with Owner’s specification; both the substrate and the sleeve shall be at this temperature.

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Strips of 25 mm x 200 mm shall be cut perpendicular to the pipe axis, either at 9 or 3 o'clock position as per EN12068, in the area between the circumferential weld bead and the line coating and on the line coating.

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Manually remove the first 20-30 mm of the leading edge of the strip by using a screwdriver or chisel, make sure that the initial adhesive bond line cut is essentially centered within the adhesive layer or towards the epoxy primer layer.

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Attach the peel gauge to the leading edge of the test strip and fasten clamp.

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Holding the test gauge with both hands exert a steady force with a pulling speed of approximately 100 mm/min, and an angle of 90° to the circumference of the pipe. Note the pull value on the Peel Test Gauge.

Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 8 of 9

Raychem RPG Ltd 

The peel strength of the coating in Newton’s / cm is the pull value in Kg x 9.81/ 2.5.

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The peel strength at 23°C shall exceed 35N/cm and at 60°C 5 N/cm

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For peel test conducted at different temperature between these two temperature values, the peel strength recorded will exceed the values given in the following table. PEEL VALUE Vs. TEMPERATURE CHART Temperature in (°C) 23 30 35 40 45 50 55 60

Peel Value in Kg 9.0 7.75 6.5 5.0 3.8 2.5 2.0 1

Peel value in ( N/cm) 35 30 25 20 15 10 7.5 5

13. SLEEVE REPAIR PROCEDURE Sleeves damaged during Adhesion (Peel) Testing shall be repaired as follows: 

Cut repair patch from a roll of PERP80, approximately 50mm larger in each direction than the area to be repaired.

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Lightly abrade the area all around the damage with a 60 mesh Emery paper.

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Abrade area extending at least 25mm beyond the area to be covered by the PERP repair patch.

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Preheat the damaged area with a propane torch with a gentle flame.

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If damage is deep down to the steel, the void area should be filled with S1137 PERP Filler Mastic.

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Preheat the repair patch with a LPG gas torch on the adhesive side till soft and shiny.

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While adhesive is still soft, apply the patch centrally over the damaged area.

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Carefully heat and roll the PERP80 patch with a roller until the surface becomes smooth, and the adhesive is visible all around the PERP80. Procedure: HTLP-80

Heat Shrink Sleeves with S1301M Epoxy over 3LPE Coated Pipes Sheet: 9 of 9