Hindustan Petroleum Corporation Limited (HPCL) has an existing installation at Suryapet Terminal, for the receipt, storage and dispatch of petroleum products (POL) such as Motor Spirit (MS), High Speed Diesel (HSD), Bio Diesel, Superior Kerosene Oil (SKO) and Ethanol. Overall pipeline inside the terminal is around 5 kms and the details of the tanks are as follows.
| S. No | Tank No. | Tank Details |
| 1 | 1A | HSD TANK (EXTERNAL FLOATING ROOF – 4280KL) |
| 2 | 1B | MS TANK (EXTERNAL FLOATING ROOF – 4280KL) |
| 3 | 1C | MS TANK (EXTERNAL FLOATING ROOF – 5000KL) |
| 4 | 2A | ETHANOL TANK (EXTERNAL FLOATING ROOF – 1000KL) |
| 5 | 2B | BIO DIESEL TANK (EXTERNAL FLOATING ROOF – 1420KL) |
| 6 | 3A | HSD TANK (EXTERNAL FLOATING ROOF – 19980KL) |
| 7 | 3B | HSD TANK (EXTERNAL FLOATING ROOF – 19980KL) |
iFluids Engineering has carried out inspection of Storage Tanks for Suryapet Terminal, Telangana, India. Inspection was carried out with the need for information of wall thickness and external condition of Product Storage tanks and storing class A/B/C products using paints through Ultrasonic testing gauge (UT).
Execution Methodology:
Visual and UT Inspection for Tanks and Pipeline as per OISD and API Standards
Codes and Standards followed:
- OISD-STD-129 Inspection of Storage Tanks
- OISD-STD-130 Inspection of Piping System
- API 653 Inspection of Aboveground Storage Tanks
- API 570 Inspection of Piping System
Technician Details:
Visual Inspection : API 653 ABOVEGROUND STORAGE TANK INSPECTOR
UT Inspection : ASNT Level – II Technicians (UT/MT/PT/RT)
Measuring Equipment Details:
- Calibrated Ultrasonic Thickness Gauge (Olympus 45MG)
Visual Inspection methodology:
- Detailed external inspection of following tank components for 26 tanks.
- Concrete foundations are checked for foundation slope and external settlements.
- Bottom plates are checked for Bitumen sealant void, painting condition, corrosion, pitting, scales and growth of weeds and plants.
- Annular plates are checked for Bitumen sealant void, painting condition, corrosion, pitting, scales and growth of weeds and plants.
- Name plates for readability and support condition.
- Earth connections are checked visually for discontinuity.
- Shell plates are checked for painting, welds in between shell courses, leakage, pipe supports, bugling or other shell course damages.
- Shell Plumbness testing was carried for angle deviation check.
- Stiffener ring plates are checked for weld connections, painting and other external abnormalities.
- Nozzles are checked for external conditions, welds and associated RF pads, paint conditions, Bolt and Nut painting and tight conditions, tank drain and associated pipes visual inspection for leakage.
- Drain collector are checked for visual condition and stagnant water.
- Staircase and handrail are checked for painting, stability, weld joints and support conditions.
- Top walkway and Roof plates are checked for painting, weld joints, leakage, pipe supports, bugling, blistering and Stagnant water condition.
- Pontoon plates are checked for painting, weld joints and other external abnormalities.
- Rolling ladder and Rolling ladder track are checked visually for external abnormalities.
- Wear Plates, Dip pipes, Deck Support leg, Secondary seals are checked visually for external abnormalities.
Visual Inspection Methodology for Pipeline:
- External On-stream Inspection of Above Ground Pipelines
- External Inspection of Fire water sprinkler & foam riser
- Leaks’ Visual inspection made to locate leaks. Particular attention were given to pipe connections, the packing glands of valves and expansion joints.
- Alignment of the piping were inspected for misalignment. Inspector made note of following indications in the inspection report for each pipeline section being inspected.
- Pipe dislodged from its support so that the weight of the pipe is distributed unevenly on the hangers or the saddles.
- Deformation of the wall of the vessel in the vicinity of the pipe attachment.
- Pipe supports forced out of plumb by expansion or contraction of the piping.
- Shifting of base plate or shearing of the foundation bolts of mechanical equipment to which the piping is attached.
- Cracks in the connecting flanges or pump casings to which the piping is attached.
- Pipe supports were visually inspected for the following:
- Condition of protective coating or fire proofing if any. If fire proofing is found defective, sufficient fire proofing should be removed to determine extent of corrosion.
- Evidence of corrosion
- Distortion
- General physical damage
- Movement or deterioration of concrete footings.
- Condition of foundation bolts.
- Free operation of pipe rollers.
- Secure attachment of brackets and beams to the supports.
- Broken or otherwise defective pipe anchors.
- Free operation of pulleys or pivot points of counter balanced piping system.
- Pipe network Vibrations
- Bulging, Bowing and Sagging Line were checked for bulging, bowing and sagging in between the supports.
- Mechanical Damage from External Forces Pipes were inspected for dents, scratched etc. from external sources.
- Paint and Protective Coating Conditions of paint and protective coating were checked.
- Pipeline was inspected for cracks. Particular attention was given to areas near the weld joints.
- Insulation Damage of insulation was checked.
- Lining Externally concrete lined piping was visually inspected for cracking and dislodging of concrete.
UT Inspection methodology for Pipeline:
- Data collection from site (previous inspection reports, piping isometric drawings and P&ID)
- Based on the line list categorization of pipelines with respect to material, design and operating conditions
- Assessment of damage mechanisms available for the equipment and piping items
- Ultrasonic Thickness Survey of the pipelines were carried out using calibrated UT kit to ascertain the wall thickness. The following procedure was followed for the aboveground pipelines.
- Minimum three readings were taken on the bends of the piping at the outer curvature. One reading shall be at the center of the bend and two readings on the same line on either side.
- Minimum one ultrasonic scan each on the straight pipes on upstream and downstream of the bend adjacent to welds of the bend to pipe. One ultrasonic scan consists of four readings (3, 6, 9 and 12 o’clock positions).
- For Fire Water Pipelines & other product lines in which there is a possibility of ballast water coming,
- Ultrasonic scan will consist of six readings (3, 5, 6, 7, 9 and 12 o’clock positions) to scan the bottom portions.
- Ultrasonic scan on the entire circumference (four readings) upstream and downstream of the weld joint.
- Ultrasonic scan (four readings) each on reducer/ expander and just downstream on the pipe.
- Ultrasonic scan on the pipe downstream of valves orifices, etc.
- Ultrasonic scan minimum on horizontal pipe for every three meters’ length at lower elevations where possibilities of collection and stagnation of carryover water exist.
- Branch connection, dead ends etc., were checked by ultrasonic thickness survey for corrosion and erosion.
- The details of thickness survey were maintained on inspection isometric drawing.
- The thicknesses measured are all listed in the spreadsheet and compared with previous inspection thickness values.
- Remaining life calculation was performed as per API standard with respect to estimated corrosion rate.
- Based on the severity of the equipment and piping items, further detailed inspection or recommendations were submitted as report.