Pipe Coating: Pipecoating Part 2

MODULE 4

APPLICATION of COATING

ELEMENTS IN THIS MODULE:

FBE Application

3 Layer Polyethylene and Polypropylene.

Application

INTRODUCTION PIPE COATING

Module “4” describes the process and the requirements for inspection and recording the identity of pipes when being processed in anti corrosion coating facilities. Coatings described within this module include Fusion Bonded Epoxy (FBE), 3 Layer Polyethylene and Polypropylene.

3.0 FUSION BONDED EPOXY COATING (FBE)

Fusion Bonded Epoxy (FBE) is a fairy hard thermosetting material that is commonly used for corrosion control of steel surfaces. For pipe coating the material can be used as a stand alone coating or it can be used as a primer for multi layer coatings. For greater protection (Mechanical) sometimes two layers of FBE are applied simultaneously, this is commonly known as dual coat FBE

FBE Coating

Prior to the commencement of FBE coating all incoming materials should be checked against the material manufacturer’s certification and any other specification requirements. The Incoming receipt form IRF stipulates the incoming material testing requirements that are to be verified prior to using the material. Incoming test that are typically Gel Time, Cure Time, Thermal Analysis and Moisture Content. "See section 3.11 off line tests"

3.1 INCOMING PIPE

Pipes are received at the incoming racks. Any contamination or pipe defects that prevents acceptable coating and cannot be repaired at the incoming rack or grinding area shall be cause to hold the pipe. The held pipe shall be removed from the process and clearly marked (HOLD or REJECT) and placed into an appropriate holding area for adjudication by the client representative as to its disposition.

The criteria for steel defects shall be generally in accordance with API (The practical detail to be agreed by both parties). See steel defects "Module 2"

Responsibilities:

The incoming Tally man shall be responsible for the recording and traceability of all the incoming bare pipes. He shall also be responsible in ensuring that the task is conducted in the safest possible manner.

The incoming Inspector shall be responsible for the release or quarantining of the incoming bare pipe.

3.2 COATING PROCESS

Preheat & Blast Cleaning:

Pipes are be placed onto the incoming blast line rack where bevel protectors (if fitted) are removed and end plugs fitted. The pipes are then be indexed and lowered onto a blast line conveyor and conveyed through a pre-heat oven set to allow for the required preheat temperature to be achieved.

The pipe surface temperature shall be monitored prior to blast cleaning using a hand held surface roller contact pyrometer, optical thermometer or melt sticks.

The preheat temperature shall be checked as a minimum each hour and the temperatures recorded. The steel surface temperatures for blast cleaning shall be above the required local dew point requirement, the dew-point should be checked twice per shift and recorded on an agreed Climatic Conditions Report.

After preheating he pipes are then progressed through the first centrifugal abrasive cleaning machine; the blast machine operator shall continually monitor the blast effectiveness via visual inspection. Abrasive samples (100 ml) shall be taken from the working mix(s) once per shift: the sample shall be passed through 1.18 mm & 0.425-mm mesh sieves. No more than 16% shall pass the 0.425-mm sieve.

Should the amount of fines exceed this figure, fresh grit shall be added to the working mix. Each abrasive sample shall be tested for chlorides and other contaminants. The results of the analysis shall be recorded on an agreed Abrasive Contamination Test Report

Responsibilities:

The Abrasive Line Supervisor shall be responsible for ensuring that the end plugs are positioned correctly and that the specified preheat temperature is constantly maintained. He shall also ensure that the conveyor line speed is constant and that the surface amplitude and pipe cleanliness is maintained within the specified tolerances. He shall also be responsible in ensuring that the task is conducted in the safest possible manner.

The QC Inspector/Auditor shall be responsible for verifying that end plugs have been positioned correctly and that the specified preheat temperature is maintained. He shall also perform climatic conditions testing at the specified intervals and review laboratory testing of abrasive materials.

The Laboratory Technician shall be responsible for taking samples of the abrasive and analysing.

3.3 Grinding Area:

On completion of the first abrasive blasting the pipes shall be indexed onto the transfer holding rack (grinding area) and inspected. All pipes are to be checked for any steel imperfections i.e. sliver, scabs, lamination's, burrs or bristles. Defects shall be repaired by grinding or by hand filing. Pipes that cannot be repaired and fail to meet the specified requirements shall be clearly marked (HOLD or REJECT), removed from the process and placed on a reject rack for adjudication by the client as to its disposition.

Details of pipe defects shall be recorded on an agreed Grinding Inspection Report.

A salt contamination check of the blasted pipe surface is checked using an SCM 400 salt contamination instrument and the results recorded. Typically the first pipe then further two pipes per shift are checked, the results are recorded on an agreed Salt Contamination Test Report.

On completion of surface defect and salt contamination checks, the pipes are lowered onto the second centrifugal abrasive cleaning line where the pipes receive a second blasting process.

After the second blasting operation the blasted surfaces are checked for surface profile (using Testex Press-O-Film) replicating tape or other agreed methods and the profile recorded. Typically pipes are checked at the commencement of each shift then twice more during the shift.

A surface contamination check is typically performed at the commencement of each shift and twice more during the shift.

To check contamination clear cellotape strips are used and compared against a contamination table. The results of both the surface profile and contamination checks are recorded on an agreed Surface Blast Cleaning Inspection Report. Both the Testex film and the dust contamination films are normally attached to the report.

The blasted surface shall meet or exceed the requirement of the blast grade as specified by comparing the blasted surface to a pictorial standard e.g. ISO 8501-1. The blast standard shall be monitored and recorded every 4 hours.

The elapsed time shall between surface preparation and the commencement of coating shall be monitored, the maximum elapsed time shall be 4 hours, no rust blooming shall be apparent prior to the application of the coating.

Responsibilities:

The Blast Line Supervisor shall ensure that all repairs grinding and filing is carried out under controlled conditions. If unsure about the disposition of pipe defects, the QA department should be contacted to assist with any queries. The supervisor should also ensure that the pipe has been cleaned of residue blasting matter both internally and externally. He shall also be responsible in ensuring that the task is conducted in the safest possible manner.

The QC Inspector/Auditor shall be responsible for recording disposition of pipe exhibiting defects and raising NCR report. He shall also perform periodic testing in accordance with the agreed project ITP.

The Tally Man shall maintain pipe traceability and ensure that correct records of defective pipe, movement and disposition.

3.4 Surface Conditioning

It is often a requirement that after abrasive blasting the pipe surfaces should receive a surface conditioning (chemical treatment), particularly for standalone FBE coatings.A typical chemical treatment is a Phosphoric Acid Treatment: below you will find a typical application procedure.

Note: Any chemical treatments must be applied strictly in accordance with the chemical supplier’s recommendations.

Phosphoric acid is applied immediately on completion of the blast cleaning; the acid is typically applied using an acid concentration of 10% ± 3% (by volume). The concentration is normally measured and recorded using a titration method.

Ideally the pipes shall be uniformly heated to between 40 and 70⁰ C. The heating is usually provided a residual heat from the blasting line preheating system.

The Phosphoric Acid solution has to be applied in a uniform manner: normally gravity fed from above the pipe and spread on the pipe surface using a brush arrangement. The acid has to remain on the pipe surface for a period of time (Dwell time) that allows the reaction process to take place.

It is critical that the dwell time is strictly adhered to and is related to the pipe temperature at the time of application. The acid manufacturer normally provides a dwell time table for this purpose.

Typical dwell time chart:

38⁰C - 37 sec’s

43⁰C - 27 sec’s

49⁰C - 25 sec’s

54⁰C - 21 sec’s

60⁰C - 17 sec’s

Note: It is essential that the pipe surfaces remain wet at all times during the Phosphoric Acid treatment.

After the dwell time has elapsed, the pipe surface shall be thoroughly rinsed with deionized water having a conductivity of 10µmhos/cm max.

The pressure of the water used shall be sufficient to thoroughly remove all acid residues. The minimum specified pH of the wet surface after rinsing shall be determined by directly touching the pipe surface with a pH paper. The pH paper shall have measurement units of 0.5 pH or less.

On completion of the surface conditioning the appearance of the steel substrate should be similar to that of the freshly blasted surface (apart from slight water streaking).

Note: Normally A maximum of four (4) is permitted between the acid pre treatment an the coating application

3.5 Preheat FBE:

Prior to FBE coating the previously installed end plugs should be removed and the internal bore of the pipes checked for contamination. The pipes are then preheated prior to the application of the Fusion Bonded Epoxy powder by passing through an Induction coil heating system.

Induction Heating Coils

The preheat temperatures are controlled so that the pipe is within the correct manufacturers recommended temperature range when the epoxy powder is applied. The pipe temperature is continuously monitored immediately prior to the powder application booth by using a calibrated surface temperature probe, infrared sensor or "Tempil" sticks. The latter however, may not be a permissible method due to oily residues left on the pipe surface.

Infra Red Thermometer

Infra Red Temperature Read Out

Tempil Stick

Responsibilities:

The Blast Line Supervisor should ensure that the induction heating equipment is maintained in satisfactory operating condition and that the settings are commensurate to the required heating range for the particular pipe size and wall thickness being heated. He should also ensure that the conveyor line speed is constantly maintained to allow even pipe preheat and coating to be achieved. He should also be responsible in ensuring that the task is conducted in the safest possible manner.

The QC Inspector is responsible for monitoring preheat temperatures at the specified periodic intervals.

The Tally Man should ensure that pipe traceability and correct records of pipe movement and disposition.

Coating Parameters:

It is always advisable that the production line operating parameters be recorded for internal analysis on an internal coating operations parameter report..

3.6 FUSION BONDED EPOXY POWDER INSPECTION

Each container of epoxy powder is inspected prior to loading into the powder delivery systems. (Where dual coat powders are used, the separate powders are loaded into the appropriate delivery systems, i.e. primer in one system and the top coat in the other. The powders shall not be mixed or interchanged).

Note: With FBE powder it is advisable to check production material for moisture content and gel time on at least a daily basis. A high moisture content can cause porosity and cure problems with the coating.

The inspection should also confirm that the epoxy powder is listed on the "Approved IRF". Only powder with current, valid approval shall be used. Batch numbers shall be recorded on all the relevant inspection and laboratory test reports. Once the approved status of the epoxy powders are confirmed, the powders are loaded into the delivery systems.

Reclaim:

Subject to client approval the amount of reclaim powder applied in any given interval shall not exceed 20 % of the total powder application. (When using dual coat the reclaim powders shall be controlled separately and blended with the top coat virgin powder. Reclaim shall not be blended with the primer powder).

FBE Reclaim

3.7 Coating Application

The Fusion Bond Epoxy Powder is applied to the heated pipe using a series of electrostatic spray guns. (When using a dual coat system using a single fluid bed, the primer and top coat guns should be set apart in a manner that allows the correct amount of separation of the two FBE layers. Alternatively two separate fluid beds may be used).

By balancing the conveyor line speed and the settings of the electrostatics and guns, flow rate and pressure of the material feed the material application is controlled to achieve the correct applied coating thickness. The coating should be continuous over the entire length (coating area) of each pipe joint. The minimum/maximum thickness shall be as indicated in the agreed Inspection Project ITP.

FBE Application

On completion of coating and allowing sufficient flow out and set up time of the powder, the coated pipes continue on through a water quenching station where the coating is cooled down using a continuously application of water. The pipes are cooled until the pipe is safe to be handled.

Typical FBE Quenching

Caution: The pipe coating should not be quenched to early or the FBE cure may be compromised.

Note; If and when required, a friction coating shall be sintered (Sinter coat) onto the FBE surfaces immediately after the FBE application process.

Responsibility:

The Coating Line Supervisor is responsible for maintaining the correct pipe preheat temperatures for the line speed being used and ensuring that the line speed is at an even rate. Information required to perform this function is obtained from the coating line controller. He is also responsible in ensuring that the task is conducted in the safest possible manner.

The QC Inspector/Auditor is responsible for monitoring of all the coating parameters.

The Powder Booth Operator is responsible for maintaining the application, gun settings, flow rates of materials, feed line pressures for the particular line speed and pipe diameter and the electrostatics.

The Coating Line Controller is responsible for all line activities for material coating line. This includes maintaining the correct line speed and pipe preheat by monitoring inspection reports, control room instrumentation and that all the powder coating parameters are maintained.

3.8 COOLING BOARDS & INSPECTION

Immediately after cooling the coated pipe is transferred to the outgoing "padded" pipe rack where the coating is visually inspected for any detrimental coating defects the pipes are then positioned on end cleaning rotators where the cutbacks are correctly established.

After end cleaning the entire coated surface of each length of pipe shall be inspected for holidays using a high voltage (pulse type) holiday detector that has been previously set and calibrated to the correct test voltage. The circumferential search electrode shall maintain intimate contact around the entire circumference of the coated pipe at all times. The voltage shall be checked and recorded hourly.

The travel speed for holiday detection is a rate of 300 mm per second maximum. Any holidays or surface defects are clearly marked on the pipe and details recorded on an agreed Coating Application Report.

Random adhesion testing are carried out using the St. Andrews cross method where coating is inscribed through to the metal substrate using a Stanley knife the coating is prized off to check the coating adherence to the substrate,

St Andrews Cross

The system coating thickness is typically determined by taking the 4 equidistant measurements, 3 on the body and 1 on the weld (if applicable) locations at the lead end middle and tail end of each pipe ( a total of 12 measurements). The measurement shall be conducted using an electromagnetic thickness gauge. Records of the thicknesses shall be recorded on an agreed Coating Application Report.

Thickness Check

Responsibility

The Cooling Board Supervisor is responsible for ensuring that the holiday detection of each pipe is carried out in a correct manner and at the correct voltage. Also he should ensure that the pipe cutbacks are correctly established and that the pipe ends and pipe internals are sufficiently cleaned. He should also be responsible in ensuring that the task is conducted in the safest possible manner.

The QC Inspector/Auditor should be responsible for visual inspection of the coating and physical testing, monitor the holiday detection and cut back length, calibration of the holiday detection equipment prior to the start of each shift. He shall also ensure that coating thickness checks are being carried out and being recorded correctly for each pipe

Note: In some coating facilities an "in line" holiday detector is used.

The Load Out Tally man is responsible for checking the pipe identity and maintaining pipe traceability on the computerized pipe tracking system (where used).

3.9 PIPE MARKING AND IDENTIFICATION:

The identity markings of each pipe shall be established and the details entered into the pipe tracking system such that traceability is maintained after which the accepted pipes are released for transportation to the stockpiles or other processes.

Responsibility

The Load Out Tally Man shall ensure that the correct pipe markings are applied in accordance with the agreed marking system. He shall also be responsible in ensuring that the task is conducted in the safest possible manner.

3.10 Repairs:

Repairs to the coatings are carried out in accordance with an agreed Repair Procedure. Coated pipes that cannot be repaired are rejected, stripped and re coated. Unacceptable pipe are marked up with Red/White hazard tape and recorded on the NCR system.

The maximum allowable holidays that may be repaired are to be agreed and should form part of the project ITP. Typically the allowable numbers of holiday repairs allowed is 1 per metre of pipe length.

Note: In the event that ongoing extensive numbers of holidays are apparent the coating line should be shut down and the cause of the problem investigated.

A typical FBE repair procedure:

Pin hole holidays should be repaired with a melt stick.

The coating surface must be abraded and clean. To ensure good adhesion, roughen area-using sandpaper and wipe to remove all dust.

Care must be taken when using hot melt sticks as preheat of the FBE coating surface is required. Heat should be applied to the repair area in a manner that avoids burning or charring of the epoxy coating. Slight browning of the parent coating is acceptable, but charring or blistering is not. The use of a noncontaminating heat source, such as portable hand held butane torch is required.

Holding the melt stick on or near the repair area continue to heat the cleaned area until the coating surface is at the desired temperature at which point the patch stick begins to melt. The heat source maintains the temperature of the coating and melts the stick. While continuing to expose the melt stick to the heat source, apply the patch material by rubbing the stick in a circular motion on the area to be repaired until the a thickness of the repair is at least 15 mils (380 microns) greater than the parent coating thickness. Allow the repair to cool before handling.

Larger repairs should be made using a 2 part liquid epoxy patching compound.

Larger defect repairs.

The defective area should be cleaned and abraded by using abrasive paper. The exposed steel surface should be power brushed to give a surface cleanliness equal to St 3 . All surface dust should be removed and the surface wiped with solvent saturated lint free cloth and the solvent allowed evaporate.

Using a 2-part epoxy repair material the two constituent parts should be thoroughly hand mixed in the correct proportions according to the manufacturers’ written instructions.The material shall be carefully applied to the abraded area of the steel and FBE. Finally, the surface of the repair should be allowed to cure. For neatness and containment of the repair area a masking tape border can be applied around the repair area that is removed prior to the repair compound curing

The repaired area should be visually inspected to ensure no voids and/or air entrapment.and shall be holiday detected using a portable holiday detector.

All repairs should be recorded on an agreed repair Quality form

Responsibility

The Repair Foreman is responsible for coating repairs and should ensure the correct equipment and repair method is used for coating repair. He should also be responsible in ensuring that the task is conducted in the safest possible manner.

The QC Inspector/Auditor is responsible for checking the preparation and the completed repairs.

3.11 OFFLINE TESTING

Besides online testing and inspection requirements there are a series of “Off Line” tests that have to carried out to confirm compliance of the coating system against the specified requirements which include the following practices:

Back Side Contamination Checks

Coating Thickness Measurement

Differential Scanning Calorimeter

Gel Time Determination

Holiday Detection

Thickness Measurement

Porosity both Inter facial and Cross Sectional

Flexibility (Bend) Test

Pull Off Adhesion Test

Cathodic Disbondment Test

Hot Water Resistance Test

Impact Resistance

Determination of Coating Hardness

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Back Side Contamination - CAN/CSA Z245.20-2

Scope

To determine the extent of backside contamination at the bottom side of an FBE coating chip sample.

Equipment

Sample freezer

Bending machine

40 X microscope

Procedure

A sample section of coated pipe shall be removed from a test ring. The sample section shall be approximately 200 x 50 mm

The sample cut out shall then be placed into a freezer and cooled down to near freezing point. After freezing the sample shall be removed from the freezer and rapidly bent around a suitably sized mandrel causing the FBE to flake off of the substrate.

Evaluation

Pry off the flake sample, The then examine the sample using a 40 X microscope and the percentage of contamination is rated

Acceptance criteria: The backside contamination shall be within the specified tolerance. Typically 30 % max.

Report

Record

Date

Time

Pipe number

Batch number

Backside Contamination expressed in %

Backside Contamination

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COATING THICKNESS MEASUREMENT BS 3900 Part C5 1992

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

Determine the coating thicknesses of anti corrosion coatings.

Equipment

Calibrated electronic Thickness Gauge

Procedure

The pipe should be suitably cooled immediately after anti corrosion coating before measuring the coating thickness.

The coating thickness of the coated pipe is checked by using a calibrated electronic thickness gauge. The checking position of the inspection probe should be in vertical position and at right angles to the coating being checked. The coating thickness is measured at the specified locations along the body of the pipe and on the weld seam where applicable.

Calibration of the measuring instrument

Switch on thickness gauge

Select "CAL" button

Place the probe on top of a certified standard thickness shim which has been placed on a blast cleaned bare steel area and read the measurement.

Adjust the up or down button to give the actual reading according the coating thickness standard or certified shim.

Press the "CAL" button again for confirmation calibration.

Report

Record

Date of coating

Pipe number

Thickness gauge reading

Report the individual coating thicknesses on both body and weld seam.

Report the minimum average thickness of the coating.

Record instrument calibration details

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DIFFERENTIAL SCANNING CALORIMETER - CAN/CSA Z245.20-2

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

This test is to determine the glass transition temperature (Tg) and the amount of exothermic heat of reaction (DH) of epoxy powder or fusion- bonded epoxy cured coating.

Equipment

Differential scanning calorimeter (DSC) and accessories

Analytical balance accurate to 0.1mg

Knife or file

Procedure

Obtain a 10+/-1-mg sample of epoxy powder or coating as applicable. Place the sample in a pre-weighed aluminum pan and put lid in place. Crimp the lid into place with the encapsulating press and obtain the sample weight by subtracting pan and lid weight from the total weight.

Place a small vent hole (pierce) in the lid without damaging the pan.

Place sample and reference (as suggested by the instrument supplier) in the DSC furnace.

Use nitrogen gas to purge the cell.

For epoxy powder sample, obtain thermal scans for the following cycles in order:

(a) heat the sample from 25 ± 5ºC to 70 ± 5ºC at a rate of 20ºC/min, then immediately cool the sample to 25

± 5ºC

(b) heat the sample from 25 ± 5ºC to 285 ± 10ºC at a rate of 20ºC/min, then immediately cool the sample to

25 ± 5ºC; and

scans for the following cycles in order:

(d) heat the sample from 25 ± 5ºC to 110 ± 5ºC at a rate of 20ºC/min, hold at 110 ± 5ºC for 1.5 min, then

immediately cool the sample to 25 ± 5ºC;

(e) heat the sample from 25 ± 5ºC to 285 ± 10ºC at a rate of 20ºC/min, then immediately cool the sample to

25 ± 5ºC; and

(f) heat the sample from 25 ± 5ºC to 150 ± 10ºC at a rate of 20ºC/min.

Evaluation

The Tg is taken as the point of intersection of the extrapolated baseline of the low temperature end and the tangents to the curve at the inflection point (onset) Calculate the residual exothermic heat of reaction (DH) following the instructions provided by the manufacturer of the DSC equipment.DTg = Tg4 – Tg3

Report

Record

Date

Date of coating

Product code for epoxy powder only

Batch number, and date tested.

Pipe number where applicable,

Report Tg1, Tg2 and DH, for epoxy powder

Report Tg3, Tg4, DTg and DH, for coating, including units

Indicate the type of differential scanning calorimeter.

DSC Sample Preparation

DSC Machine

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GEL TIME DETERMINATION - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine the gel time of fusion bonded epoxy powder coating material.

Equipment

Hot plate (accurate to ± 3° C)

Stopwatch or electronic timer

Spatula

Stiff wire

Procedure

Gel time shall be determined by placing approximately 1g of coating material in a hot plate stabilized at 205±3°C. In a smooth motion, deposit and draw the epoxy powder across the metal plate while holding the tool at an angle of approximately 45° to the metal plate. This motion will create a tongue of epoxy powder approximately 25mm wide. The target thickness of the cured film is 300 – 400µm. Start the time as soon as the coating material becomes molten. Stir the coating with a stiff wire or spatula, and stop the watch when the coating becomes resistant to stirring and gelatinous.

Evaluation

The elapsed time to reach this condition is the gel time.

Report

Record

Date

Product

Batch number

Gel time in seconds.

Testing Gel Time

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MOISTURE CONTENT - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

Determine the moisture content of FBE powder using the mass loss method

Equipment

Oven controllable within 3°C

Balance accurate to 0.001g

Desiccators; and

Sample container

Procedure

Weigh the sample container to the nearest 0.001g. Transfer approximately 10 g of epoxy powder into the sample container. Weigh the sample container and epoxy powder to the nearest 0.001g. Place the sample container with the epoxy powder into the oven for a maximum of two hours at 105 ± 3°C. Remove the container from the oven and place in the desiccators to cool. Weigh the sample container when it has cooled to 20 ± 3°C

Evaluation

Calculate the percentage of moisture using the following formula:

M = (B-C)/(B-A) x 100

Where

M = percentage of moisture

B = initial mass of sample container and epoxy powder, g

C = final mass of sample container and epoxy powder, g

A = mass of sample container, g

Acceptance criteria, Typically 0.5 % max
.

Report

Record

Date

Material Code

Batch number

Moisture expressed in %

Moisture Content

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POROSITY INTERFACE & CROSS SECTIONAL - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

a) To determine the extent of inter facial porosity at the bottom side of an FBE coating.

B) To determine the extent of cross sectional porosity within an FBE coating

Equipment

Sample freezer or dry ice & container

Bending machine

30-40 X microscope

Mandrel

Procedure

A sample specimen of coated pipe shall be removed from a test ring. The sample section shall be approximately 300 x 50 mm. The sample cut out shall then be placed into a freezer or dry ice and cooled down to near or below freezing point. After freezing the sample shall be removed from the freezer or dry ice and rapidly bent around a suitably sized mandrel causing the FBE to flake from the substrate. Pry off the flake sample of FBE coating to allow observation of both the cross section and underside of the coating sample to be examined.

Evaluation

The sample shall then be viewed both in inter facial and cross sectional elevations using a 40 X microscope and assessed for porosity.

Acceptance criteria, Typically rating 3 max.

Report

Record

Date

Pipe number

Interface Rating 1-5

Cross sectional rating 1-5

Ratings Chart

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FLEXIBILITY (BEND) TEST - NACE RP 0394-94 CAN/CSA Z 245.20-02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

This test is to determine the flexibility of coating for field bending.

Equipment

Hydraulic Press

Bending mandrels of fixed radii

Microscope

Freezer

Procedure

Specimens shall be removed from test rings (approx. 300mm long x 50mm wide x pipe wall thickness, with the 300mm dimension parallel to the axis of the pipe.

Ensure that the specimen edges have all stress raisers removed and that substrate is exposed along the edges. Test temperatures shall be 0ºC and 23ºC +/-2ºC. Typical, Calculate the required mandrel radius (R) using the following formula:

R= ((57.3)(t)/s))– t/2

Where:

R = mandrel radius, t= effective strap thickness, and

s = strain (deflection) in degrees per pipe diameter (°/PD).

Determine the effective strap thickness (t), which includes the specimen thickness and any curvature, by placing the specimen on a flat surface and measuring the thickness as shown in Figure K1 of NACE RP0394-94 Standard. Where a mandrel of the calculated radius is not available; the mandrel of the next smaller radius shall be used.

Bend the test specimens over the radius so that the uncoated side is in contact with the mandrel, completing the bend within 30 seconds. The bend test shall take a minimum of 10 seconds for completion.

Measure the residual bend radius by matching the outer curve of the test specimen to the nearest arc from Figures K2, K3, K4 or K5 of NACE RP0394-94 Standard.

Evaluation

Visually inspect the specimens for cracks, tears in the coating, and disbonding of the coating after the specimen has warmed to room temperature. The presence of any such defect within 2.5mm of the strap edge does not constitute failure. The presence of strain marks alone does not constitute failure.

Acceptance criteria, Typically equal to 2° PD (No cracking)

Report

Record

Date

Date tested

Manufacturer code

Batch number

Pipe number

Test Temperature

Defect {s} if any Specimen effective strap thickness, permanent (residual) strain radius, angle of deflection in degrees per pipe diameter for passing bend test.

Bend Test

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PULL OFF ADHESION TEST

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine either the greatest perpendicular force (intension) that a surface area can be bear before a plug of material is detached or whether the surface remains intact at a prescribed force (pass/fail)

Equipment

Hydraulic Adhesion Tester 108

Dolly/Loading Fixture

Adhesive

Procedure

The selected test area must be a flat surface to accommodate the specified numbers of replicate tests. (Test panel : 300 mm x 450 mm)

Loading fixture shall be detach with test panel using adhesive and hold for 1 day. After 1 day. Insert a decreased FE-fluorocarbon plug into the dolly until the tip protrudes from the surface of the dolly. When applying adhesive to the dolly, avoid getting adhesive on the plug. Remove plug after holding the dolly in place for 10 s. Ensure that the black needle of the tester is reading zero. Connect a test dolly to the head and increase the pressure by turning the handle clockwise until the pin protrudes from the dolly.

Decrease pressure to zero and remove the test dolly. Connect the head to the dolly to be tested, by pulling back the snap on ring, pushing the head and releasing the snap-on ring. Ensure the tester is held normal to the surface to be tested and that the hose is straight. Increase the pressure slowly by turning the handle clockwise until either the maximum stress or failure is reached.

Evaluation

Record the force attained at failure or the maximum force applied.

Report

Record

Date

Type and date coating

Sample ID

Maximum Pressure and thickness coating

Batch Number

Pull Off Adhesion Test

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CATHODIC DISBONDMENT - CAN/CSA Z245.20-02 & CAN/CSA Z245.21-02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To assess the comparative resistance of damaged coatings to loss of be performed on a test specimen taken from a pipe or pup piece previously subjected to holiday detection, and in which an artificial defect of a defined size has been drilled.

Equipment

Stabilized DC Power supply unit with controlled voltage output.

A Cathodic polarization potential of –1.500mV to a saturated calomel reference electrode (equivalent to UH = -1.260mV, where UH means the potential of the standard hydrogen electrode shall be maintained). “E” potential of the “working electrode” with regards to the “reference electrode”. “V” difference of potential between the “working electrode” and the “counter electrode”.

Electrolyte cell consisting of rigid plastic tube or PVC of with an internal diameter of 75 ± 3 mm. The height shall be 120 mm.

A rigid plastic cover in which 3 holes shall be drilled to allow the passage of the electrodes and any other measuring instruments deemed necessary, and to allow the escape of hydrogen.

Reference electrodes- the saturated calomel reference electrode or suitable type of reference electrode to give an equivalent potential shall be placed in an electrode holder situated in a glass tube with a porous end plug. The end of this assembly shall be placed approx. 10mm from the surface of the coating and approximately 20mm from the coating defect.

Counter electrode or platinum wire.

Working electrode (cathode)- is represented by the artificial defect, which shall be 3.2 mm in diameter for FBE & 6.4 mm in diameter for 3 Layer, which shall penetrate through the coating to expose steel substrate.

Calomel reference electrode

Utility knife

Test Specimen

Test- Ring Specimen

The test plate specimen shall be a 100mm x 100 mm (square) segment cut from the representative test ring.

Procedure

Drill a 3.2 mm (FBE) or 6.4 mm (3 Layer) diameter holiday through the coating at the center of the specimen.

Glue a plastic cylinder onto the specimen using a sealant to form a water resistant seal. Ensuring the pre drilled holiday is at the center of the cylinder.

Pour approximately 300ml of Sodium Chloride Solution into the plastic cylinder.

When testing specimens cut from the pipe, a heat- transfer medium shall be employed to provide uniform heating of the specimen.

Use a metal pan/tray partially filled with a heat transfer medium (sand) into which the specimen is implanted. Place on a hot plate or in an oven to maintain the test temperature as required according to the duration of tests specified in the specification.

Connect the negative lead (working electrode) from the power supply to the specimen ( Cathode) and the positive lead (Counter electrode) to the anode after the test temperature is reached.

Turn on the power supplies and applies voltage to the test specimen: negative 1.5V or 3.5V with respect to the calomel reference electrode for the 24 hr, 48-hr (only on accelerated production test) and/or 28-day tests.

Monitor the voltage, temperature and electrolyte level at the start and at every 24-hr interval thereafter.

For the 28-day test, the electrolyte level need not be monitored on weekends provided a cover plate is loosely fitted over the test cell. Distilled water shall be added as required to maintain the electrolyte level.

Evaluation

After 24hrs or 48 hrs (on accelerated production test), dismantle the test cell and remove the test sample cell from the hot plate or oven. Immediately drain the electrolyte and air-cool the sample to 20 ± 3° C. The evaluation shall be performed within one hour of removal from the hot plate. For 28 day test, remove the 28-day test cell using the same procedure.

Using a utility knife, make radial cuts from the edge of the holiday outward through the coating to the substrate. The radial cuts shall be at least 20mm in length from the centre of the holiday.

Insert the blade of the utility knife under the coating. Using a levering action, chip off the coating. Continue until the coating demonstrates a definite resistance to the levering action.

Measure the radius of the disbonded distance from the holiday edge along each radial cut and average the measured results. Maximum allowed CD radius as measured, is detailed in the controlled ITP drawn for this project.

Acceptance criteria:- Typically 3-4 mm radial disbondment for FBE

Report

Record

Date tested.

Pipe number

Coating date.

CD Equipment set up

Cathodic Disbondment sample

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HOT WATER RESISTANCE - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

Determine the hot water resistance (Adhesion) of FBE coating.

Equipment

Temperature controlled water bath

Tap water

Thermometer

Utility Knife

Procedure

A coated sample of approximately 100 mm x 100 mm removed from a pipe test ring be fully immersed in a tap water filled bath, previously warmed to the required test temperature of 75°± 3°C. The sample shall remain in the bath for a minimum period of 24 hrs and the test temperature of the water shall be controlled throughout the duration of the test.

After 24 hours the test sample shall be removed from the water bath and whilst still warm, a rectangle 30 x 15 mm shall be incised in the coating through to the steel substrate. The sample shall be air cooled to the test temperature of 20 ± 3°C

At the correct test temperature insert the tip of a utility knife under the coating at one of the corners of the incised rectangle. Used a continuing, levering action in an attempt to remove the coating. Continue the levering action until either all the coating is removed from the rectangle or the coating demonstrates a resistance to the levering action.

On completion of the test, record the rate of adhesion as follows:

Rating 1 Coating cannot be removed cleanly

Rating 2 Less than 50 % of the coating can be removed

Rating 3 More than 50 % can be removed, but the coating demonstrates a definite resistance to
the levering action.

Rating 4 The coating can be easily removed in strips or chips

Rating 5 The coating can be completely removed as a single piece.

Acceptance criteria, Typically rating 3 however sometimes rating 2 is required.

Report

Record

Date

Batch number

Rating 1-5

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IMPACT RESISTANCE - DIN 30670, DIN 30678 & CAN/CSA Z 245.20-02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine the impact resistance of coating (this practice can be adopted on both FBE & Three Layer coating systems). The test can be carried out both, in a controlled laboratory environment and as a field test (directly on test pipe surface).

Equipment

(Impact Tester having)

Falling masses 1-kg FBE, 3.5-kg 3LPE, 6-kg 3 LPP

15.8mm (FBE) or 25 mm (3 Layer) diameter ball bearing tup piece (tup shall have a

Hardness of 50 to 55 HRC)

1 meter long graduated slotted tube

A wood block measuring approx. 610mm on each side and have a top facing of

Hardwood (for laboratory controlled test procedure).

DC holiday detector

Test Specimens

(Laboratory test) Shall be approximately 25mm x 200mm x pipe W.T., with the 200mm dimension parallel to the axis of the pipe.(Field test) Test pipe.

Procedure

The impact test shall be carried at room temperature with the relevant weight housed within a 1-meter graduated slotted tube. The ball bearing shall be rotated every 10 impacts to a new location and replaced after 200 impacts. The distance between each impact shall be 30 mm minimum.

Evaluation

Each pipe shall receive 10 impacts, each impact indentation on the test specimen shall be checked for substrate exposure using a holiday detector set at 5V/micron (FBE) or 7900volts per mm (3 Layer).

Acceptance criteria, Typically the impact energy shall be 15 joules (For FBE)

Report

Record

Date

Batch number

Pipe number

Coating date.

The applied impact energy (joules)

Holiday detection voltage setting

Impact Resistance

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DETERMINATION OF HARDNESS - ASTM D 2240

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

Test to measures the coating hardness using a Shore D hardness gauge.

Specimen

Applied coating or a free film sample usually 3mm or more in thickness. The surface of the specimen shall be flat and parallel over a sufficient area to permit the presser foot of the gauge to suitably contact the test area.

Equipment

Shore D Hardness gauge.

Procedure

If a free film specimen is used, the specimen shall be placed on a hard, flat horizontal surface. The Shore D Hardness gauge shall be held in a vertical position with the point of indenter at least 12mm from any edge of the specimen. Apply the presser foot to the specimen as rapidly as possible, without shock, keeping the foot parallel to the surface of the specimen. Apply just sufficient pressure to obtain firm contact between presser foot and specimen.

Evaluation

When the presser foot is in firm contact with specimen, the scale reading is to be recorded within 5 seconds’

Note: The hardness reading may progressively decrease with any time delay.

Acceptance criteria, Typically Shore 60

Report

Record

Date

Manufacturer code

Batch number

Coating date .

Pipe Number or sample ID if applicable, shall be recorded

Record hardness value obtained.

Type and Serial Number meter

Shore D Hardness Test

4.0 POLYETHYLENE & POLYPROPYLENE COATINGS

Polyethylene and Polypropylene coatings are commonly used as an outer layer for multi layer coating systems. Due to the nature of these materials they are suitable for giving coated pipe added mechanical protection. Polyethylene and Polypropylene coatings are usually applied over an FBE primer and have a bonding material (Polymer Adhesive) between the primer and outer layer. (Three Layer System).

Typically Polyethylene is used for moderate temperature conditions and Polypropylene for higher temperature applications. Polymer coating are normally applied using a side extrusion method however, the cross head extrusion method can also be used for pipe diameters up to 26". In this module i will be describing the side extrusion method of coating.

Typical PE Coating

Typical PP Coating

Prior to the commencement of three layer coating all incoming materials are checked against the material manufacturer’s certification and any other specification requirements. The Incoming receipt form (IRF) should stipulate the incoming material testing requirements that are to be verified prior to using the material.

Incoming test are typically Gel Time, Cure Time, Thermal Analysis and Moisture Content for the FBE and Melt Flow Index MFI and moisture content for the Polymers."See off line tests section 4.5 below"

4.1 INCOMING PIPE

Pipes received at the incoming racks are checked for contamination or pipe defects that prevents acceptable coating and cannot be rectified at the incoming rack or grinding area. Any held pipes shall be removed from the process and clearly marked (HOLD or REJECT) and placed into an appropriate holding area for adjudication by the client representative as to its disposition.

The criteria for steel defects shall be generally in accordance with API (The practical detail to be agreed by both parties).

See steel defects "Module 2"

Responsibilities:

The incoming rack supervisor should ensure that pipe is handle in a manner that prevents pipe damage during the load in to the coating facility, he should also supervise any rectification work required. The supervisor is responsible in ensuring that tasks are conducted in the safest possible manner.

The incoming Inspector shall be responsible for the release or quarantining of the incoming bare pipe

The incoming Tally man shall be responsible for the recording and traceability of all the incoming bare pipes.

4.2 COATING PROCESS

Preheat & Blast Cleaning

Pipes are be placed onto the incoming blast line rack where bevel protectors (if fitted) are removed and end plugs fitted to the pipe internals to prevent the ingress of blasting media. The pipes are then indexed and lowered onto a blast line conveyor and conveyed through a pre-heat oven (Usually gas) set to allow for the required preheat temperature to be achieved. The pipe surface temperature shall be monitored prior to blast cleaning using a hand held surface contact pyrometer, optical thermometer or melt sticks.

The preheat temperature shall be checked as a minimum each hour and the temperatures recorded. The steel surface temperatures for blast cleaning shall be above the required local dew point requirement, the dew-point (typically 3 C above local dew point) should be checked twice per shift and recorded on an agreed Climatic Conditions Report.

After preheating he pipes are then progressed through the first of two centrifugal abrasive cleaning machine; the blast machine operator shall continually monitor the blast effectiveness via visual inspection.

Abrasive samples (100 ml) shall be taken from the working mix(s) once per shift: the sample shall be passed through 1.18 mm & 0.425-mm mesh sieves. No more than 16% should pass the 0.425-mm sieve. In the event that the amount of fines exceed this figure, fresh grit shall be added to the working mix. Each abrasive sample shall be tested for chlorides and other contaminants. The results of the analysis shall be recorded on an agreed Abrasive Contamination Test Report

See Module 2

Responsibilities

The QC Inspector/Auditor is responsible for verifying that end plugs have been positioned correctly and that the specified preheat temperature is maintained. He shall also perform climatic conditions testing at the specified intervals and review laboratory testing of abrasive materials.

(see Module 2)

The Laboratory Technician shall be responsible for taking samples of the abrasive and analysing.

4.3 Grinding Area:

On completion of the first abrasive blasting operation the pipes shall be indexed onto the transfer holding rack (grinding area) and inspected. All pipes are to be checked for any steel imperfections i.e. sliver, scabs, lamination's, burrs dents or bristles. Defects shall be repaired by grinding or by hand filing.

Pipes that cannot be repaired and fail to meet the specified requirements shall be clearly marked (HOLD or REJECT), removed from the process and placed on a reject rack for adjudication by the client as to its disposition. Details of pipe defects shall be recorded on an agreed Grinding Area Inspection Report.

On completion of surface defect and salt contamination checks, the pipes are lowered onto the second centrifugal abrasive cleaning line where the pipes receive a second blasting process.

A surface contamination check is typically performed at the commencement of each shift and twice more during the shift. To check contamination clear cellotape strips are used and compared against a contamination table.

See Module 2

The results of both the surface profile and contamination checks are recorded on an agreed Surface Blast Cleaning Inspection Report. Both the Testex film and the dust contamination films are normally attached to the report.

The elapsed time between surface preparation and the commencement of coating should also be monitored, the maximum elapsed time should be a maximum of 4 hours, or before any rust blooming apparent.

Responsibilities

The Blast Line Supervisor is responsible for ensuring that all repairs, grinding and filing is carried out under controlled conditions. If unsure about the disposition of pipe defects, the QA department should be contacted to assist with any queries. The supervisor should also ensure that the pipe has been cleaned of residue blasting matter both internally and externally. He shall further be responsible in ensuring that the task is conducted in the safest possible manner.

The QC Inspector/Auditor is responsible for recording the disposition of pipe exhibiting defects and raising NCR report if required. He shall also perform periodic testing in accordance with the agreed project Inspection Test Plan (ITP).

The Tally Man shall maintain pipe traceability and ensure that correct records of defective pipe movement and disposition.

4.4 Preheat FBE:

Induction Heating Coils

Infra Red Thermometer

Infra Red Temperature Read Out

Tempil Stick

Cutback taping

Cut back areas are sometimes applied to avoid excessive time on the end cleaning station after coating, the paper used must be flame resistant. Tapes have been known to inflame during pre heating and have the potential to cause a coating booth explosion?

Responsibilities:

The QC Inspector is responsible for monitoring preheat temperatures at the specified periodic intervals.

The Tally Man should ensure that pipe traceability and correct records of pipe movement and disposition.

Coating Parameters:

It is always advisable that the production line operating parameters be recorded for internal analysis on an internal coating operations parameter report.

4.5 MATERIAL INSPECTION

Fusion Bonded Epoxy Powder

Each container of epoxy powder is inspected prior to loading into the powder delivery system.

Note: With FBE powder it is advisable to check production material for moisture content and gel time on at least a daily basis. (A high moisture content can cause coating irregularities.

The inspection should also confirm that the epoxy powder is listed on the "Approved IRF". Only powder with current, valid approval shall be used. Batch numbers shall be recorded on all the relevant inspection and laboratory test reports.

Polymers

Each container Polymer shall be inspected prior to loading into the Extruder hopper systems.

Note: With Polymers it is advisable to check for moisture of the pellets every two hours when in production. A simple way to check for moisture is to push your bare hand into the box of pellets. If when you withdraw your hand you find pellets adhering to your skin it is an indication that excessive moisture is present.

The inspection shall also confirm that the Polymers are listed on the "Approved IRF. Only Polymers with current, valid approval shall be used. Batch numbers shall be recorded on all the relevant inspection and laboratory test reports.

Reclaim:

Subject to client approval the amount of reclaim powder applied in any given interval shall notexceed 20 % of the total powder application.

FBE Reclaim

4.6 Coating Application

Powder application

The Fusion Bond Epoxy Powder is applied to the heated pipe using a series of electrostatic spray guns. By balancing the conveyor line speed and the settings of the electrostatics, guns, FBE flow rate and pressure of the material feed the material application is controlled to achieve the correct applied coating thickness. The coating should be continuous over the entire length of each pipe joint. The minimum thickness shall be as indicated in the agreed Project Inspection Test Plan ( ITP.)

Polymer Application

Immediately after the FBE primer, the co polymer adhesive (intermediate coat) is applied. The application shall take place within the gel time window of the FBE to ensure adequate adhesion to the primer. The minimum thickness is as indicated in the agreed project Inspection Test Plan (ITP)

Following the adhesive side extrusion application, the Polyethylene or Polypropylene topcoat is applied by side extrusion process in a single sheet layer over the adhesive. Both polymer layers are applied with an overlap. During the application of the polymers, a pressure roller is applied against the pipe behind the polymer sheet that presses against the the applied sheet that eliminates air bubbles and ensures intimate contact between the layers. The minimum thickness of the PE/PP is as indicated in the agreed project Inspection Test Plan (ITP).

PE Application

PP Application

Responsibilities:

The coating line Supervisor shall be responsible for the strict control of all the heating to maintain the correct pipe preheat temperatures in accordance with line speed, pipe diameter and material preheat requirements. Information required to perform this function is received from the coating line controller. He shall also be responsible in ensuring that the task is conducted in the safest possible manner.

The QC, inspector/auditor shall be responsible for monitoring of the coating parameters.

The Powder booth foreman shall be responsible for maintaining the application, gun settings, flow rates of materials, feed line pressures for the particular line speed and pipe diameter and the electrostatics.

The coating line controller shall be responsible for all line activities for material coating line. This includes maintaining the correct line speed and pipe preheat by monitoring inspection reports and control room instrumentation and that all powder coating and Polymer extrusion parameters are maintained.

On completion of coating the coated pipe is progressed through a water quenching tunnel where copious amounts of water is sprayed onto the finished coating and to cool the pipe for safe handling.

Water Quench

4.3 COOLING BOARDS & INSPECTION

Immediately after cooling the coated pipes are transferred to an outgoing padded pipe rack where the pipes are positioned on end cleaning rotators The end cleaner brushes remove the coatings from the cut back areas of the pipe. The entire coating surface is visually inspected for coating quality and detrimental coating defects. The cutback distance at both ends of the pipe are also checked..

After end cleaning and visual inspection the entire coated surface of each length of pipe is inspected for holidays using a high voltage (pulse type) holiday detector previously set and calibrated to the correct voltage. The circumferential search electrode shall maintain intimate contact around the entire circumference of the coated pipe at all times. The voltage shall be checked and recorded hourly. The travel speed for holiday detection shall be at a rate of 300 mm per second maximum. Any holidays or surface defects shall be clearly marked and recorded on the agreed Coating Application Report.

Holiday Detector

The coating thickness is usually determined by taking the 4 equidistant measurements (3 on the body and 1 on the weld) at the lead end middle and tail end of each pipe (a total of 12 measurements). The measurement shall be conducted using an electromagnetic thickness gauge. Records of the thicknesses shall be recorded on the agreed Coating Application Report

Thickness Check

Responsibilities

Cooling board supervisor shall be responsible for ensuring that the holiday detection of each pipe is carried out in a correct manner and at the correct voltage. Also he shall ensure that the pipe cutbacks are correctly established and that the pipe ends and pipe internals are sufficiently cleaned. He shall also be responsible in ensuring that the task is conducted in the safest possible manner.

The QC, inspector/auditor shall be responsible for visual inspection of the coating and physical testing. He shall also monitor the holiday detection and cut back length. He shall also be responsible for calibration of the holiday detection equipment prior to the start of each shift.

Load out Tally man, shall be responsible for checking the pipe identity and maintaining pipe trace ability on the computerized pipe tracking system. He shall also ensure that coating thickness checks are being carried out and being recorded correctly for each pipe.

4.4 REPAIRS:

Repairs to the coatings shall be carried out in accordance with an approved Repair Procedure. Coated pipes that cannot be repaired shall be rejected, stripped and re coated. Unacceptable pipe shall be marked up with Red/White hazard tape and recorded on the NCR system.

Typical Repair Procedure

This procedure describes methods that enable repairs to be made to the 3 Layer Coating System after the completion of the in line process. This method statement describes three repair methods and is presented in three parts:

Part 1: - Repairs using a Hand Held Extruder Gun.

Part 2: - Repairs using Melt sticks.

Part 3: - Repairs using Sleeves.

Part 1: Hand Extruder

There are two types of repair

Type A: - Repairs to the total three layer system.

Type B: - Repairs to the Polyethylene layer only.

TYPE A - The defective area shall be removed and the surrounding sound coating shall be abraded to allow a "key" for the system repair material. An area of at least 50 mm diameter will be removed to facilitate the effective cleaning of the steel and FBE. The repair area substrate shall then be gently preheated to remove surface moisture.

The FBE shall then be feathered using abrasive paper at the FBE/substrate interface.The exposed substrate shall then be mechanically roughened, masking tape (if used) and surface dust shall be removed and two pack epoxy material applied. Mixing/application of the two pack epoxy shall be in accordance with manufacturer's data sheet and shall be applied to the prepared area using a clean brush (or pallet knife if compound is used).

After the Epoxy coating has cured, Polymer (as used in the parent coating) is then extruded from a hand held extruder onto the repair area taking care that no air entrapment at the FBE/Polymer interface occurs. The Polymer is extruded in layers to bring the repair thickness up to and in excess of the parent coating thickness. Once cool, the repair shall be blended with the parent coating, any excess Polyethylene removed by scraper and/or rasp. The completed repair areas shall then be holiday detected.

Hand Extruder

TYPE B - The damaged Polymer is removed using a chisel and the surrounding area roughened using a mechanical burr. Extruded Polymer (as used in the parent coating) is then introduced into the prepared area. Once cool, the repair area shall be blended with the parent coating and any excess removed by scraper and rasp. The completed repair areas shall then be holiday detected. For repairs of Pinholes and minor defects to the Polymer coating repairs shall be by using melt sticks.

Any loose or defective coating shall be removed from the damaged area and any sharp edges eliminated. The area and adjacent coating is then cleaned thus removing all foreign materials.

The prepared area is then preheated, at the same time the end of the melt stick is heated such that it becomes “glossy”. The molten adhesive is then spread onto the damaged area.

Melt stick

On hardening, the repair shall be smoothed with a rasp such that the repair area becomes flush with the existing parent coating.

Part 3: WPC Sleeves

Heat shrinkable sleeves shall be used as an alternative for larger repairs.

The defective coating area shall be removed from the defect area. The full circumference around the pipe at the defect locality shall be thoroughly cleaned of surface dust, grease, oil etc using Xylene or bio -degradable emulsifier. The full circumference of the pipe surface where the sleeve is to be applied plus 100 mm either side shall be abraded.

The steel substrate at the defect area shall be mechanically roughened and the repair area warmed slightly to drive off surface moisture. On completion of preparation a two pack epoxy shall be applied to the steel surface. Mixing and application of the two pack epoxy shall be in accordance with the manufacturer's data sheet. The epoxy shall be applied to the prepared area using a clean brush (or pallet knife if compound used).

When the Epoxy compound has cured, a filler shall be applied to the repair area to increase the coating thickness at the repair area location. A shrink sleeve shall be prepared to the correct dimensions and made ready for application. When prepared the protective release plastic shall be removed from the mastic coating and the sleeve centred over the repair area. The sleeve shall be loosely wrapped around the pipe with ends overlapping by approximately 75-100 mm. The overlap shall be in approximately the 11 o’clock position of the pipe with the edge of the overlap pointing downwards. The ends shall be aligned evenly.

Using a propane gas torch one end of the closure patch shall be heated until the reinforcing fabric is visible or the thermo-chromic paint has changed colour. With a gloved hand, the closure shall be patted down firmly to the pipe and any wrinkles or bubbles shall be smoothed out. This procedure shall be repeated moving across the closure until the opposite end is completed. Whilst the closure is still hot and soft, a hand roller shall be used to smooth out any trapped air and the edges and corners shall be firmly bonded down.

The heating procedure shall continue around the pipe by heating in the centre of the sleeve and continue towards the edges. Occasionally the adhesive flow shall be checked by using finger pressure. After the sleeve has shrunk and is still hot and soft, use a hand roller over the sleeve to remove any entrapped air. Re heating of the sleeve is permissible to complete the repair.

Responsibilities:

The repair foreman shall be responsible for coating repairs and shall ensure the correct equipment and repair method is used for coating repair. He shall also be responsible in ensuring that the task is conducted in the safest possible manner.

QC, Inspector/auditor shall be responsible for checking the preparation and the completed repairs.

4.5 OFFLINE TESTING

Back Side Contamination Checks

Coating Thickness Measurement

Differential Scanning Calorimeter

Gel Time Determination
Holiday Detection
Thickness Measurement

Flexibility (Bend) Test

Cathodic Disbondment Test

Impact Resistance

Melt Flow Index

Moisture content
Adhesion Test
Tensile Elongation Test

Determination of Coating Hardness

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Back Side Contamination - CAN/CSA Z245.20-2

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine the extent of backside contamination at the bottom side of an FBE coating chip sample.

Equipment

Sample freezer

Bending machine

40 X microscope

Procedure

A sample section of coated pipe shall be removed from a test ring. The sample section shall be approximately 200 x 50 mm

Evaluation

Pry off the flake sample, The then examine the sample using a 40 X microscope and the percentage of contamination is rated

Acceptance criteria: The backside contamination shall be within the specified tolerance. Typically 30 % max.

Report

Record

Date

Time

Pipe number

Batch number

Backside Contamination expressed in %

Backside Contamination

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COATING THICKNESS MEASUREMENT

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

Determine the coating thicknesses of anti corrosion coatings.

Equipment

Calibrated electronic Thickness Gauge

Procedure

The pipe should be suitably cooled immediately after anti corrosion coating before measuring the coating thickness.

Calibration of the measuring instrument

Switch on thickness gauge

Select "CAL" button

Place the probe on top of a certified standard thickness shim which has been placed on a blast cleaned bare steel area and read the measurement.

Adjust the up or down button to give the actual reading according the coating thickness standard or certified shim.

Press the "CAL" button again for confirmation calibration.

Report

Record

Date of coating

Pipe number

Thickness gauge reading

Report the individual coating thicknesses on both body and weld seam.

Report the minimum average thickness of the coating.

Record instrument calibration details

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DIFFERENTIAL SCANNING CALORIMETER - CAN/CSA Z245.20-2

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

This test is to determine the glass transition temperature (Tg) and the amount of exothermic heat of reaction (DH) of epoxy powder or fusion- bonded epoxy cured coating.

Equipment

Differential scanning calorimeter (DSC) and accessories

Analytical balance accurate to 0.1mg

Knife or file

Procedure

Obtain a 10+/-1-mg sample of epoxy powder or coating as applicable

Place the sample in a pre-weighed aluminum pan and put lid in place. Crimp the lid into place with the encapsulating press and obtain the sample weight by subtracting pan and lid weight from the total weight.

Place a small vent hole (pierce) in the lid without damaging the pan.

Place sample and reference (as suggested by the instrument supplier) in the DSC furnace.

Use nitrogen gas to purge the cell.

For epoxy powder sample, obtain thermal scans for the following cycles in order

(a) heat the sample from 25 ± 5ºC to 70 ± 5ºC at a rate of 20ºC/min, then immediately cool the sample to 25

± 5ºC

(b) heat the sample from 25 ± 5ºC to 285 ± 10ºC at a rate of 20ºC/min, then immediately cool the sample to

25 ± 5ºC; and

scans for the following cycles in order:

(d) heat the sample from 25 ± 5ºC to 110 ± 5ºC at a rate of 20ºC/min, hold at 110 ± 5ºC for 1.5 min, then

immediately cool the sample to 25 ± 5ºC;

(e) heat the sample from 25 ± 5ºC to 285 ± 10ºC at a rate of 20ºC/min, then immediately cool the sample to

25 ± 5ºC; and

(f) heat the sample from 25 ± 5ºC to 150 ± 10ºC at a rate of 20ºC/min.

Evaluation

Report

Record

Date

Date of coating

Product code for epoxy powder only

Batch number, and date tested.

Pipe number where applicable,

Report Tg1, Tg2 and DH, for epoxy powder

Report Tg3, Tg4, DTg and DH, for coating, including units

Indicate the type of differential scanning calorimeter.

DSC Sample Preparation

DSC Machine

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GEL TIME DETERMINATION - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine the gel time of fusion bonded epoxy powder coating material.

Equipment

Hot plate (accurate to ± 3° C)

Stopwatch or electronic timer

Spatula

Stiff wire

Procedure

Evaluation

The elapsed time to reach this condition is the gel time.

Report

Record

Date

Product

Batch number

Gel time in seconds.

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MOISTURE CONTENT - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

Determine the moisture content of FBE powder using the mass loss method

Equipment

Oven controllable within 3°C

Balance accurate to 0.001g

Desiccators; and

Sample container

Procedure

Evaluation

Calculate the percentage of moisture using the following formula:

M = (B-C)/(B-A) x 100

Where

M = percentage of moisture

B = initial mass of sample container and epoxy powder, g

C = final mass of sample container and epoxy powder, g

A = mass of sample container, g

Acceptance criteria, Typically 0.5 % max.

Report

Record

Date

Material Code

Batch number

Moisture expressed in %

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POROSITY INTERFACE & CROSS SECTIONAL - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine the extent of inter facial porosity at the bottom side of an FBE coating.

To determine the extent of cross sectional porosity within an FBE coating

Equipment

Sample freezer or dry ice & container

Bending machine

30-40 X microscope

Mandrel

Procedure

Evaluation

The sample shall then be viewed both in inter facial and cross sectional elevations using a 40 X microscope and assessed for porosity.

Acceptance criteria, Typically rating 3 max.

Report

Record

Date

Pipe number

Interface Rating 1-5

Cross sectional rating 1-5

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DETERMINATION OF HARDNESS - ASTM D 2240

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

Test to measures the coating hardness using a Shore D hardness gauge.

Specimen

Equipment

Shore D Hardness gauge.

Procedure

If a free film specimen is used, the specimen shall be placed on a hard, flat horizontal surface.The Shore D Hardness gauge shall be held in a vertical position with the point of indenter at least 12mm from any edge of the specimen. Apply the presser foot to the specimen as rapidly as possible, without shock, keeping the foot parallel to the surface of the specimen. Apply just sufficient pressure to obtain firm contact between presser foot and specimen.

Evaluation

When the presser foot is in firm contact with specimen, the scale reading is to be recorded within 5 seconds’

Note: The hardness reading may progressively decrease with any time delay.

Acceptance criteria, Typically Shore 60

Report

Record

Date

Manufacturer code

Batch number

Coating date .

Pipe Number or sample ID if applicable, shall be recorded

Record hardness value obtained.

Type and Serial Number meter

Shore D Hardness Test

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Melt Flow Index - (ASTM D1238)

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

This test is primarily useful to raw material manufacturers as a method of controlling material uniformity. While the data from this test is not directly translatable into relative end-use processing characteristics, the melt index value is nonetheless strongly indicative of relative “flow ability” of various kind and grades of Polymer. The property measured by this test is basically melt viscosity or rate of shear. In general, the materials that are more resistant to flow are those with higher molecular weight.

Equipment

Extrusion Plastometer (ASTM D1238)

Stopwatch or electric timer

Spatula

Thermometer

Procedure

The apparatus is preheated to 190°C . Material is put into the cylinder and the loaded piston is put into place. After 10-15 minutes, the extrudite dispensing from the orifice is cut off flush, and again one minute later. These cuts are discarded. Cuts for the test are taken at 1, 2, 3, or 6 minutes, depending on the material or its flow rate. The melt flow index is calculated and recorded in grams/10 minutes. For adhesive the test condition load is 2.16 kg test for 1 minute only at 230° C.

Calculation

Weigh 4 samples and take average reading; A

Melt Flow Index, g/10min = Ak

If test is 1 minute, the factor k is 10

If test is 3 minutes, the factor k is 3.33

If test is 6 minutes, the factor k is 1.67

Report

The following information shall be reported:

Manufacturer, product code, batch number, and date tested.

Pipe size identification

Report MFI results in g/10 min.

Indicate time, and weight used.

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HOLIDAY DETECTION - NACE RP 0188-99/DIN 30670/CAN/CSA 245.20+21-02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine the anti corrosion coating is without any coating defects that allow continuity between the test electrode and the substrate e.g. pinholes, voids, cracks and/or foreign matter inclusions.

Equipment

In-Plant Holiday Detector (e.g. SPY) which is an electrical device that locates discontinuities in the protective coating.

A calibrated Jeep meter crest-void meter which is used to calibrate the In-Plant Holiday Detector.

Calibration Procedure

The In-Plant Holiday Detector is connected to the Jeep meter. Then both holiday detector and jeep meter are switched on.

The In-Plant holiday detector is adjusted to the required test voltage and the voltage value on the Jeep meter checked. The readings shall be of equal value. Should the value on the jeep meter differ from that as set on the holiday detector, the holiday detector shall be adjusted to allow the jeep meter value to be obtained.

Calibration of holiday detector shall be performed at the beginning of each shift and after any long term pause in production.

Test Procedure

The pipe shall be in dry condition before holiday detection to avoid appreciable High Voltage DC leakage through the holiday detector circuit which can potentially produce a false signal.

The test voltage setting shall be dependant on the coating thickness. The minimum testing voltage for a particular coating thickness shall be in accordance with the specified requirements for the coating being tested, e.g. 3LPP/PE 5 Kv/mm and FBE 5 V/µm.

The holiday detector electrode shall travel along the pipe surface at a maximum travel speed of 300mm per/sec.

Where a holiday is detected, the defect area shall be clearly marked using a permanent marker and recorded on the appropriate inspection report.

Report

The following information shall be reported:

Date

Pipe Identification

Number and type of defect

Holiday detection speed

Calibration details

Holiday Detector

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FLEXIBILITY BEND TEST - NACE RP 0394-94 CAN/CSA Z 245.20-02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

This test is to determine the flexibility of coating for field bending.

Equipment

Hydraulic Press

Bending mandrels of fixed radii

Microscope

Freezer

Procedure

Specimens shall be removed from test rings (approx. 300mm long x 50mm wide x pipe wall thickness, with the 200mm dimension parallel to the axis of the pipe.

Ensure that the specimen edges have all stress raisers removed and that substrate is exposed along the edges. Test temperature shall be 23+/-2ºC.

Calculate the required mandrel radius (R) using the following formula

R= ((57.3)(t)/s))– t/2

Where

R= mandrel radius, t= effective strap thickness, and

s= strain (deflection) in degrees per pipe diameter (°/PD).

Measure the residual bend radius by matching the outer curve of the test specimen to the nearest arc from Figures K2, K3, K4 or K5 of NACE RP0394-94 Standard. Visually inspect the specimens for cracks, tears in the coating, and disbonding of the coating after the specimen has warmed to room temperature. The presence of any such defect within 2.5mm of the strap edge does not constitute failure. The presence of strain marks alone does not constitute failure.

Report

The following information shall be reported :

Manufacturer, product, batch number, and date tested.

Pipe number, coating date.

Specimen effective strap thickness, permanent (residual) strain radius, angle of deflection in degrees per pipe diameter for passing bend, and test procedure used.

Test Temperature

Defect {s} if any

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ADHESION TESTING - CAN/CSA Z245.20.02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine Peel Adhesion of Polyeofins (Constant rate of peel method)

To determine Peel Adhesion of Polyeofins (Hanging weight method)

Equipment (Constant Rate of Peel Method)

Tensile testing machine able to measure a load to an accuracy of 1%

Utility Knife

Attachment Clamp

Equipment (Hanging Weight Method)

Masses 0.3, 2.0, 15.3 kg

Attachment clamp

Utility Knife

Stop watch

Procedure (Constant Peel Method)

Cross head speed 10 +/- 1 mm/min

Normal specimen length of peel 75 mm for test

Normal specimen width 25 +/- 1 mm

Peel orientation shall be circumferential

Procedure

Prior to conducting the test condition the sample to test temperature for a period of 1 hour minimum. Cut the required dimension test strip through to the steel substrate. Make a cut at right angle to the test strip to enable lifting of the start tab. On the bonded area of the test strip mark the required test length

Attach the pull clamp to the tab of the test strip and proceed to peel the strip at the prescribed 10 +/- 1 mm/min. Record the load required to peel the sample. If more than 5 % of the total peeled length has a peeling load below the specified minimum value, the sample fails the test. If a small portion (less than 5 %) of the total peeled load is below the specified minimum, accept the test as satisfactory. If the polyeofin breaks more than three times during the test, terminate the test and accept as being satisfactory’

Calculate the minimum peel strength as follows:

P = Lp x 9.81

Where

P = minimum peel strength, N

Lp = minimum peel load, kg

Report (Constant Rate Test)

Sample ID

Test date

Minimum peel strength

Test temperature

Procedure (Hanging weight method)

Width of peel sample 25 +/- 1 mm

Peel orientation shall be circumferential

Make two cuts 25 +/- 1 mm apart through the coating to the substrate and circumferential from the 90° position to the 180° position. The coating shall be cut at right angle at the 90° position and the peel shall be down towards the 135° position.

The appropriate mass shall be attached to the free end of the peel strip

Mass for System

A1        0.3 kg
A2       2.0 kg
B         15.3 kg

The peeling time in minutes from the 135° position terminating at the 180° position shall be measured. The peeling may also be terminated when the test time calculated by using the following formula has been exceeded.

T = 0.125 x 3.14 x D ÷ 10

Where

T = test time in minutes
D = Nominal pipe outside diameter in mm

Measure the distance peeled in mm from the time the test was initiated until it was terminated. Calculate the peeling speed using the following formula;

PS        =          d ÷ t

Where

PS        =          peeling speed in mm/min
d          =         distance peeled in mm
t           =         peeling time in min

If the peeling speed is in excess of 10 mm/min at the test temperature the test shall be considered a failure.

Report (Hanging Weight Test)

Sample ID
Test date
Test temperature
Pipe OD
Mass used in kg
Distance peeled mm
Peeling time minutes
Peeling speed mm/min

   Peel Adhesion Machine

Peel Adhesion Sample

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TENSILE at BREAK & ELONGATION - ASTM D 638

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To assess of the tensile and elongation properties in material. The force necessary to pull the specimen apart is determined, along with how much the material stretches before breaking. The elastic modulus (modulus of elasticity or tensile modulus) is the ratio of stress to strain below the proportional limit of the material.

Specimen

Specimen can be machined from compression molded plaques or extrudate. Samples to be suitably conditioned prior to testing.

Specimen is typically 1/8” thick (3mm) and made up to a type 5 barbell configuration test piece.

Equipment

Universal Testing Machine, or equivalent
Computer complete with printer to plot graphical result

Procedure

Both ends of the specimen are firmly clamped in the jaws of a tensile testing machine. The jaws may move apart at rates of 5, 12, 50 or 500 mm per minute, pulling the sample from both ends.

Prior to starting the test, the original area (to be stretched) of the test specimen is measured and recorded.

The applied yield load is first recorded. After the yield load is obtained, the instrument is reset to get a second reading for the break point.

The stretched area of the sample is then measured to use in calculating the breaking or stress at break of the specimen.

For the elongation of specimen, the stress is automatically plotted against strain (elongation) on graph paper.

Note : In case there is no graphical plotter is available, the elongation shall be recorded as a percentage using the equation

A0, % = (L1 – L0)/L0 x 100

Where

L0 = initial free length between gauge length.
L1 = distance between gauge length at the time of breaking
The arithmetic mean of 5 results (A0) shall be determined.

Report

The following information shall be reported :

Manufacturer, product, batch number and date tested.
Pipe number, coated date.
Report Yield and Ultimate strength results in MPa.
Report Elongation in Percentage, %
Record results on relevant laboratory test report.

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CATHODIC DISBONDMENT- CAN/CSA Z245.20-02 & CAN/CSA Z245.21-02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To assess the comparative resistance of damaged coatings to loss of adhesion by disbondment when exposed to Cathodic polarization. The test shall be performed on a test specimen taken from a pipe or pup piece previously subjected to holiday detection, and in which an artificial defect of a defined size has been drilled.

Equipment

Stabilized DC Power supply unit with controlled voltage output.

A Cathodic polarization potential of –1.500mV to a saturated calomel reference electrode (equivalent to UH = -1.260mV, where UH means the potential of the standard hydrogen electrode shall be maintained). “E” potential of the “working electrode” with regards to the “reference electrode”. “V” difference of potential between the “working electrode” and the “counter electrode”.

Electrolyte cell consisting of rigid plastic tube or PVC of with an internal diameter of 75 ± 3 mm. The height shall be 120 mm.

A rigid plastic cover in which 3 holes shall be drilled to allow the passage of the electrodes and any other measuring instruments deemed necessary, and to allow the escape of hydrogen.

Reference electrodes- the saturated calomel reference electrode or suitable type of reference electrode to give an equivalent potential shall be placed in an electrode holder situated in a glass tube with a porous end plug. The end of this assembly shall be placed approx. 10mm from the surface of the coating and approximately 20mm from the coating defect.

Counter electrode or platinum wire.

Working electrode (cathode)- is represented by the artificial defect, which shall be 3.2 mm in diameter for FBE & 6.4 mm in diameter for 3 Layer, which shall penetrate through the coating to expose steel substrate.

Calomel reference electrode

Utility knife

Test Specimen

Test- Ring Specimen

The test specimen shall be a 100mm x 100 mm (square) segment cut from the representative test ring.

Procedure

Drill a 3.2 mm (FBE) or 6.4 mm (3 Layer) diameter holiday through the coating at the center of the specimen.

Glue a plastic cylinder onto the specimen using a sealant to form a water resistant seal. Ensuring the pre drilled holiday is at the center of the cylinder.

Pour approximately 300ml of Sodium Chloride Solution into the plastic cylinder.

When testing specimens cut from the pipe, a heat- transfer medium shall be employed to provide uniform heating of the specimen.

Use a metal pan/tray partially filled with a heat transfer medium (sand) into which the specimen is implanted. Place on a hot plate or in an oven to maintain the test temperature as required according to the duration of tests specified in the specification.

Connect the negative lead (working electrode) from the power supply to the specimen ( Cathode) and the positive lead (Counter electrode) to the anode after the test temperature is reached.

Turn on the power supplies and applies voltage to the test specimen: negative 1.5V or 3.5V with respect to the calomel reference electrode for the 24 hr, 48-hr (only on accelerated production test) and/or 28-day tests.

Monitor the voltage, temperature and electrolyte level at the start and at every 24-hr interval thereafter. For the 28-day test, the electrolyte level need not be monitored on weekends provided a cover plate is loosely fitted over the test cell. Distilled water shall be added as required to maintain the electrolyte level.

Evaluation Procedure

After 24hrs or 48 hrs (on accelerated production test), dismantle the test cell and remove the test sample cell from the hot plate or oven. Immediately drain the electrolyte and air-cool the sample to 20 ± 3° C. The evaluation shall be performed within one hour of removal from the hot plate. For 28 day test, remove the 28-day test cell using the same procedure.

Using a utility knife, make radial cuts from the edge of the holiday outward through the coating to the substrate. The radial cuts shall be at least 20mm in length from the centre of the holiday.

Insert the blade of the utility knife under the coating. Using a levering action, chip off the coating. Continue until the coating demonstrates a definite resistance to the levering action.

Measure the radius of the disbonded distance from the holiday edge along each radial cut and average the measured results. Maximum allowed CD radius as measured, is detailed in the controlled ITP drawn for this project.

Report

The following information shall be reported:

Date tested.
Pipe number and coating date.
Average disbonded radius.

PE CD SAMPLE

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IMPACT TEST - DIN 30670, DIN 30678 & CAN/CSA Z 245.20-02

Note: This practice may be modified by the requirements of the customer’s specification, see relevant Project Inspection Test Plan (ITP)

Scope

To determine the impact resistance of coating (this practice can be adopted on both FBE & Three Layer coating systems). The test can be carried out both, in a controlled laboratory environment and as a field test (directly on test pipe surface).

Equipment (Impact Tester having)

Falling masses 1-kg FBE, 3.5-kg 3LPE, 6-kg 3 LPP
15.8mm (FBE) or 25 mm (3 Layer) diameter ball bearing tup piece (tup shall have a hardness of 50 to 55 HRC)
1 meter long graduated slotted tube
A wooden block measuring approx. 610mm on each side and have a top facing of hardwood (for laboratory controlled test procedure).
DC holiday detector

Test Specimens

(Laboratory test) Shall be approximately 25mm x 200mm x pipe W.T., with the 200mm dimension parallel to the axis of the pipe.

(Field test) Test pipe.

Procedure

The impact energy shall be 15 joules (FBE) or 5 joules/mm (3 Layer)

The impact test shall be carried at room temperature with the relevant weight housed within a 1-meter graduated slotted tube. The ball bearing shall be rotated every 10 impacts to a new location and replaced after 200 impacts. The distance between each impact shall be 30 mm minimum.

Each pipe shall receive 10 impacts, each impact indentation on the test specimen shall be checked for substrate exposure using a holiday detector set at 5V/micron (FBE) or 7900volts per mm (3 Layer).

Report

The following information shall be reported:

Product batch number and date tested.
Pipe number and coating date.
The applied impact energy (joules)
Holiday detection voltage setting according to the type of coating being tested.

Impact Test

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Thursday, October 21, 2010

Pipecoating Part 2

To determine the impact resistance of coating (this practice can be adopted on both FBE & Three Layer coating systems). The test can be carried out both, in a controlled laboratory environment and as a field test (directly on test pipe surface).

6 comments: