Hindustan Petroleum Corporation Limited (HPCL) has an existing installation at Ghatkesar, Secunderabad Terminal, for the purpose of receipt, storage and dispatch of petroleum products (POL) such as Motor Spirit (MS), High Speed Diesel (HSD), ATF (Aviation Turbine Fuel), Superior Kerosene Oil (SKO), Ethanol and Hexane. Overall pipeline inside the terminal is around 10kms and the details of the tanks as followed.
| S. No. | Tank No | Product | Dimensions | REF Ht( cm) | SFH( cm) |
| 1 | lA | BS 4 MS | 46.5*18 | 2032.2 | 1670 |
| 2 | lB | BS 4 MS | 46.5*18 | 2023.2 | 1670 |
| 3 | lC | BS 4 MS | 22*16 | 1805.1 | 1450 |
| 4 | lD | SLOP | 22*16 | 1837.6 | 1450 |
| 5 | 2A | SKO | 22 .5*15 | 1754.5 | 1400 |
| 6 | 2B | SKO | 22 .5*15 | 1726.2 | 1400 |
| 7 | 3A | BS4 HSD | 51.5*18 | 2014.6 | 1670 |
| 8 | 38 | BS4 HSD | 51.5*18 | 2021 | 1670 |
| 9 | 3C | BS4 MS | 23*18 | 2039.1 | 1640 |
| 10 | 3D | BS4 HSD | 34*18 | 1963.6 | 1650 |
| 11 | 3E | BS4 HSD | 42*18 | 1959.5 | 1650 |
| 12 | 4A | ATF | 23*1s | 1919.8 | 1600 |
| 13 | 4B | ATF | 23*18 | 1924.9 | 1600 |
| 14 | 4C | BS4 MS | 34.0*18.0 | 1961.6 | 1650 |
| 15 | SA | BIO DIESEL | 13*9 | 998.5 | 892 |
| 16 | SB | SLOP | 13*9 | ||
| 17 | SC | ETHANOL | 13*9 |
| S.No | Tank | Service | Dia.Ht. | Gross Volume (kl) |
| 1 | 6A | Fire water | 16.5 x 13.5 | 2670 |
| 2 | 6B | Fire water | 16.5 x 13.5 | 2670 |
| 3 | 6C | Fire water | 24.5 x 13.5 | 5890 |
| 4 | 6D | Fire water | 23.5 x 13.5 | 5420 |
HPCL has entrusted iFluids Engineering to carry out NDT Inspection services for Tanks and Pipelines of their Secunderabad Terminal, which as used for receipt, storage and dispatch of petroleum products (POL) such as Motor Spirit (MS), High Speed Diesel (HSD), ATF (Aviation Turbine Fuel), Superior Kerosene Oil (SKO), Ethanol and Hexane. Other activities included As-Built P&ID preparation, Fire water and Foam network adequacy for the entire terminal and CAT/ DCVG inspection for underground pipelines.
Execution Methodology:
Activity – 1: Update of As-Built P&ID
- Data collection for existing P&ID
- Site visit for MOC register and details
- Perform Site Survey and make Redline mark up for additional changes in the plant and existing arrangement availability
- Validation of Equipment details and Tagging philosophy
- Preparation of Line list and Line numbering as per Company standard specification
- Drawing update as per Redline markup and verified with Site in charge for approval
- Submission of Final As Built P&ID both Softcopies and Hardcopies as per Client’s document standard
Activity – 2: Fire water and Foam Network Adequacy Calculation
Data Collection
- PFD & P&IDs of the Firewater and Foam arrangement including Fire Water and Foam bladder tanks.
- Fire water and Foam network system overall layout for the Process units.
- Isometric and Piping GADs for firewater network and foam network showing sprinkler system for each facility.
- Equipment datasheet for Water monitors, hydrants, deluge valves, HVLR’s, Foam Monitors, Foam pourers and orifice plate.
- Fire Water sprinkler system for storage tanks details including the K factor of sprinkler nozzles and number of water sprinkler rings in each area.
- Firewater pump datasheet including Main and Jockey pump.
- Fire Water and Foam Piping Material specifications.
- Operating philosophy of fire water system and foam network.
- Fire and gas philosophy and its cause and effect, showing fire zones with respect to their deluge valves opening.
- Existing Hydraulic analysis Report (if available)
Hydraulic Study Procedure
- Hydraulic analysis of firewater systems has been carried out through standard software, in compliance with NFPA13, NFPA15 and NFPA16 rules.
- This module is ideal for the design of systems used in critical applications such as offshore platforms, petrochemical plants, power plants, terminals and refineries.
- Fire water equipment such as Water monitors, hydrants, deluge valves, HVLR’s and orifice plate data were fed to Software.
- Fire water pump including main & jockey pump characteristic curve was incorporated for pressure and flow rate from the pump house.
- Fire water pipeline data was taken from piping class specification.
- Firewater flow line size and line length was incorporated from overall layout file or site survey report.
- Firewater model is primarily drawn from pump house and flow lines are extended to respected main headers & sub headers.
- Initially Firewater pumps are drawn from characteristic curve & optimized for BEP. Output pressure, flow rate & Efficiency was checked.
- Overall layout of the firewater network was drawn adding Water monitors, hydrants, deluge valves, HVLR’s and orifice plate in the main header and sub header flow lines.
- Fire water flow lines was then extended to each Process facilities and storage tanks. Similarly, Water monitors, hydrants, deluge valve, HVLR & orifice plate were added.
- Similar to fire water network, foam system was added to storage tanks along with the nozzles.
- While adding nozzles such as water monitor, hydrant, deluge valve, HVLR, should be checked for off position.
Software Modelling
- The modelling was run for two simultaneous fire and HVLR, Monitor, hydrants to be opened as per NFPA. All other sections of the facility nozzles were kept in off conditions or as per Client provided details for worst case scenario.
- Fire water pumps were checked for flow, pressure and the number of pumps to be line depends upon the fire water demand, pump capacity and the fire water flow line network.
- Iterations were done in flow line size i.e., main header or sub headers based on the required pressure and flow rate in a section.
- Flow lines must satisfy the velocity limit given in NFPA. Iteration was done in flow line size when velocity exceeded. Optimization was done, such that given pressure and velocity was achieved for a given flow rate.
- Following the iteration in Flow lines, iterations were done in Fire water main pumps and jockey pump, to be added even if required flow rate and pressure is not achieved.
- Fire water demand calculations were performed for each storage tanks, bullets, storage spheres & Process units as per NFPA.
- Minimum fire water storage should satisfy the fire water demand for fire fighting as per NFPA.
Outcome of the Study
- Pipe sizing for new and retro fire water pipe networks.
- Calculation of pressure drop in fire water pipes for existing piping networks.
- Calculation of velocity in fire water flow pipes.
- Selection of fire water main pump, jockey pump & restriction orifices.
- Ensuring that all consumers will get the demanded amount of fire water for distribution networks.
- Ensuring that all nozzles get desired water flow rate and pressure for fire-protection network.
- Fire water demand for fire protection.
- Hydraulic analysis.
Activity -3: 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 (Accuplus MT-180)
Visual Inspection methodology:
- Detailed external inspection of following tank components for 26 tanks.
- Concrete foundations, checked for foundation slope and external settlements.
- Bottom plates checked for Bitumen sealant void, painting condition, corrosion, pitting, scales and growth of weeds and plants.
- Annular plates 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 checked visually for discontinuity.
- Shell plates 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 checked for weld connections, painting and other external abnormalities.
- Nozzles 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 checked for visual condition and stagnant water.
- Staircase and handrail 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 given to pipe connections, the packing glands of valves and expansion joints.
- Alignment of the piping 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 will be inspected for dents, scratched etc. from external sources.
- Paint and Protective Coating Conditions of paint and protective coating will be checked.
- Pipeline will be inspected for cracks. Particular attention was given to areas near the weld joints.
- Insulation Damage of insulation were checked.
- Lining Externally concrete lined piping were 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 was 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 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 consisted 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., will be checked by ultrasonic thickness survey for corrosion and erosion.
- The details of thickness survey will be maintained on inspection isometric drawing.
- The thicknesses measured were 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 was submitted as part of the report.