Excavación

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Rehabilitation Coatings in IOCL

COATINGS USED IN WRPL
1. COAL TAR ENAMEL COATING (CTE) 2. COAL TAR BASED TAPE COATING (Hot tape) Above two coatings stopped using for field application due toenvironmental issues 3. FUSION BONDED EPOXY (FBE) 4. 3LAYER POLY-ETHYLENE COATING (3LPE) Above coatings are suitable for plant coating only. 5. COLD TAPE COATING (Poly Ethylene) 6. POLY URETHENE (PU)Above coatings are presently being used for field applications
7. LIQUID EPOXY COATING- Under trial run for bulk use

DESIRED PROPERTIES OF COATINGS
  EASE OF APPLICATION GOOD ADHESION TO PIPE
        

GOOD IMPACT RESISTANCE
FLEXIBILITY RESISTANCE TO SOIL STRESS RESISTANCE TO FLOW (CREEP) GOOD ELECTRICAL RESISTANCE CHEMICAL STABILITY RESISTANCE TO SOIL BACTERIARESISTANCE TO MARINE ORGANISMS RESISTANCE TO CATHODIC DISBONDMENT WATER PROOF




PERTOLEUM RESISTANCE
ECONOMICAL

Cold Tape Coating

Instruments required at site
Ultrasonic gauge SurfaceProfile Gauge SA 2 ½ films  Coat meter for measurement of primer thickness/ Coating thickness Holiday Detector Adhesion Tester Thermometer

Mirror

EXCAVATION

Sand Blasting-cleaning of pipeRequirements of sand blasting

Inspect surface the pipe for pitting/ any defects Check compressor, requirement – 7kg/sq.cm, 5.6 to 7 Cubic m/min, swing 15m

Abrasive size 1mm ( max), nozzleangle 30 deg.
Cleaning of pipe: Inspect surface after blasting ( Ref SA 2 ½ visual standard of SIS05 5900 “ Pictorial surface prep…. Steel surface”.

surface profile:
50-75microns

SA 2 ½film-Before cleaning of pipe

SA 2 ½ film-After cleaning of pipe

3ply/2ply Cold tape
Inner PE
Outer-

Pipe
Butyl rubber

Inner two layer+Outer two layer

Butyl rubber

COLD TAPE COATINGAPPLICATION Primer:
 Primer is a mix, of butyl rubber, synthetic compound and solvent confirming to DIN-30672  Primer thickness shall requirement. (25 microns DFT) coat be as per

 Before...
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