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LIGHTNING PROTECTION ASSESSMENT STUDY AS PER OISD-GDN-180 & IEC 62305 FOR HPCL SECUNDERABAD TERMINAL

Hindustan Petroleum Corporation Limited (HPCL) has awarded iFluids Engineering to carry out a Lightning Protection Assessment Study for its Secunderabad POL Terminal. The Terminal, is used for the purpose of receipt, storage, and dispatch of petroleum products (POL) such as Motor Spirit (MS), Bio Diesel, High Speed Diesel (HSD), ATF (Aviation Turbine Fuel), Superior Kerosene Oil (SKO), Ethanol and Hexane.

The HPCL POL Terminal is spread across following areas .

  • Land Area – 58.59 Hectare
  • Plant Area – 40.47 Hectare
  • Green Belt – 12.82 Hectare
  • Truck Parking Area – 5.5 Hectare

Objective of the Study

To conduct Lightning Protection Assessment Study to ensure that the entire plant area including structures/buildings and tank farms are safe from lightning phenomena . This is to be done based on Lightning Protection Standard OISD-GDN-180 & IEC 62305. The LPS is installed throughout the plant site including structures/buildings and the tank farm area, by means of down conductors and earth pits.

Scope of work

  • The scope included the calculations of the existing LPS that was installed throughout the plant site.
  • To review existing lightning protection arrangements in all the structures/buildings and check adequacy
  • To review and assess necessity of lightning protection for all the Tank Farms
  • To review coverage of lightning protection provided by the high mast lighting poles with air terminals
  • To review the road Loading gantry sick tanker bay, ETP area ,and provide recommendations if any

Facilities to be covered under the study includes:

  • Motor Sprit 2
  • SLOP tank 1
  • Ethanol/MS tank 1
  • High Speed Diesel 3
  • Motor Sprit 2
  • Superior Kerosene Oil 1
  • Motor Sprit 1
  • Aviation Turbine Fuel 2
  • High Speed Diesel 2
  • Ethanol 1
  • Ethanol 1
  • SLOP tank 1
  • U/G ground vessels
  • Administration building
  • Amenities Building
  • Security office
  • Control Room cum Emergency control center
  • VVSPL control room
  • VVSPL Sulphur analyzer
  • Purfural dosing facility
  • DG set
  • Lab building
  • Foam shed (2 nos)
  • Warehouse-1,2
  • Fire pump house
  • Calibration tower
  • Fire tender shed
  • Calibration tower
  • Compressor shed
  • Terminal Substation
  • ETP
  • Product pump house
  • Bio diesel pump shed
  • Security ingate room

Codes & Standards

Standard Description 
OISD-GDN-180  Lightning Protection  
S/IEC 62305 Part-1: 2010 Reaffirmed: 2015 (Identical Standard: IEC 62305-1: 2010) Protection Against Lightning Part I – General Principles  
S/IEC 62305 Part-2: 2010 Reaffirmed: 2014 (Identical Standard: IEC 62305-2: 2010) Protection Against Lightning Part II – Risk Management  
IS/IEC 62305 Part-3: 2010 Reaffirmed: 2015 (Identical Standard: IEC 62305-3: 2010)  Protection Against Lightning Part III – Physical Damage to Structures and Life Hazard  
IS/IEC 62305 Part-4: 2012 Reaffirmed: 2015 (Identical Standard: IEC 62305-4: 2010)  Protection Against Lightning Part IV – Electrical & Electronic Systems within Structures

Methodology

A lightning strike is an electrical discharge between the cloud and the earth. It is a natural, unpredictable phenomenon having independent current source causing severe damage to life and property. Direct hits may cause structural failure whereas indirect hits, through inductive or capacitive coupling, may affect the reliability and integrity of electrical and electronic equipment within the structure.

Conventional method of lightning protection system consists of lightning masts / rods exposed and placed at the highest levels of structures and connected through downward conductors to a grounding system. A design method is normally used to identify the most suitable locations for the lightning masts / rods, based on the area of protection offered by each one

External lightning protection system

The external lightning protection system includes all those systems installed outside or inside the structure to be protected which intercept and discharge the lightning current to the earth-termination system. A lightning protection system for potentially explosive atmospheres is typically designed according to class of II. An- other class of LPS can be chosen in justified individual cases, in case of special conditions (legal requirements) or because of a risk analysis

Air-termination systems

To determine the relevant points of strike, the recommendation is to use the rolling sphere method with a minimum radius according to class of II. However, in case of a lightning strike to the air-termination system, sparking may occur at the point of strike. To prevent ignition sparks, the air-termination systems should be installed outside. Natural components such as metallic roof structures, metal pipes and containers can also be used as air-termination systems if they have a minimum material thickness of 5 mm

Down conductors

Down conductors are electrically conductive connections between the air-termination system and the earth-termination system. To prevent damage when conducting the lightning current to the earth-termination system, the down conductors must be arranged in such a way that from the point of strike to earth.

Surge protection in hazardous areas

The lightning protection and Ex zones are already harmonized at the design stage. This means that the requirements for the use of surge protective devices both in hazardous areas and at the boundaries of lightning protection zones must be fulfilled. Consequently, the place of installation of the surge arrester is exactly defined, i.e., the transition from unprotected zones to Level-1. This prevents dangerous surges from entering Ex zone 0 or 20 since the interference has already been discharged. The availability of the temperature transmitter, which is important for the process, is considerably increased. In addition, the requirements of IEC 60079-11, IEC 60079-14 and IEC 60079-25 must be observed.

RISK ASSESSMENT FOR THE BUILDING STRUCTURES

The design of a lightning protection system needs to

  • Intercept lightning flash (i.e., create a preferred point of strike)
  • Conduct the lightning current to earth Dissipate current into the earth
  • Create an equipotential bond to prevent hazardous potential differences between LPS, structure and internal elements/circuits.

In achieving this the lightning protection system must:

  • Not cause thermal or mechanical damage to the structure
  • Not cause sparking which may cause fire or explosion
  • Limit step and touch voltages to control the risk of injury to occupants
  • Limit damage to internal electrical and electronic systems.
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