For operators of oil refineries, offshore platforms, gas pipelines, and petrochemical plants, lightning protection is not optional. It is a regulatory requirement, an insurance expectation, and most importantly, a matter of safety. Despite clear guidelines under IEC 62305, many facilities in Southeast Asia still operate with systems that are missing, inadequate, or never properly assessed.
This article explains what IEC 62305 requires, how it applies to electrical and instrumentation systems in hazardous areas, and why working with a qualified electrical and control specialist is essential to ensure proper compliance.
Understanding IEC 62305: The Standard in Full
IEC 62305 is the internationally recognised standard for lightning protection, published by the International Electrotechnical Commission. It replaces older national standards and provides a unified, risk based framework for all types of structures and industries. For oil, gas, and petrochemical facilities, where lightning can cause serious hazards, it sets the minimum level of protection required.
The standard is divided into four parts, each covering a different aspect of protection. Understanding how these parts work together is important for asset owners and engineers managing electrical and instrumentation systems in hazardous environments.
| Standard Part | Title | What It Covers | Relevance to E&I |
| IEC 62305-1 | General Principles | Defines the nature of the lightning threat, damage types, and loss categories. Sets the conceptual framework for all subsequent parts. | Establishes why E&I systems in hazardous areas require the highest protection priority. |
| IEC 62305-2 | Risk Management | Provides the methodology for conducting a Lightning Risk Assessment (LRA) to determine whether protection is required and at what level. | Mandatory for all facilities. Output determines the Lightning Protection Level (LPL) required for the installation. |
| IEC 62305-3 | Physical Damage to Structures | Covers the design and installation of External Lightning Protection Systems (ELPS) — air termination networks, down conductors, and earth termination systems. | Defines the structural protection around E&I equipment enclosures, cable routes, and instrument stands. |
| IEC 62305-4 | Electrical & Electronic Systems | Covers Internal Lightning Protection Systems (ILPS) — equipotential bonding and Surge Protection Devices (SPDs) to protect E&I systems from transient overvoltages. | Directly governs the protection of all instrumentation, control systems, PLCs, transmitters, and electrical panels. |
The Lightning Risk Assessment: Where Compliance Begins
Before any lightning protection system is designed or installed, IEC 62305-2 requires a formal Lightning Risk Assessment. This is not a desktop exercise or a checkbox on a maintenance form. It is a structured engineering calculation that determines the annual probability of lightning-caused damage to a specific facility, based on variables including geographic location, structure dimensions, occupancy type, contents, and the consequences of damage.
For oil and gas facilities in Malaysia and Southeast Asia — a region with one of the highest ground flash densities in the world — the outputs of a properly conducted LRA will almost always indicate a requirement for lightning protection at Lightning Protection Level I or II. These are the highest protection levels defined by the standard, demanding the most stringent design criteria for both the external and internal protection systems.
External Lightning Protection: Intercepting the Strike
IEC 62305-3 governs the external lightning protection system — the physical components that intercept a direct lightning strike and safely conduct the enormous energy of that strike to earth without causing damage to the protected structure or creating an ignition source within the hazardous zone.
A compliant External Lightning Protection System for a hazardous area facility requires all of the following components, engineered to the specifications dictated by the assessed LPL:
1. Air Termination Network
Franklin rods, catenary wires, or mesh conductors positioned to intercept lightning before it strikes protected areas. Placement geometry is calculated against rolling sphere, mesh, and protective angle methods depending on LPL.
2. Down Conductors
Dedicated conduction paths routing the intercepted lightning current from the air termination network to the earth termination system. Minimum conductor cross-sections, routing separation distances, and test joints are prescribed by LPL.
3. Earth Termination System
Ground electrode systems — vertical rods, horizontal rings, or foundation earthing — designed to disperse the lightning current into the earth without generating hazardous step and touch voltages in the surrounding zone.
4. Equipotential Bonding at Zone Boundaries
All metallic services entering the structure — pipework, cable armour, instrument tubing — must be bonded at the point of entry to prevent dangerous potential differences during a lightning event.
Internal Lightning Protection: Defending E&I Systems from Surges
IEC 62305-4 is the part of the standard that most directly governs the protection of electrical and instrumentation systems. Even when an external LPS successfully intercepts a direct lightning strike, the transient electromagnetic field generated by the lightning current induces dangerous overvoltages in all nearby electrical conductors — including the signal cables, power supplies, and data lines connected to every instrument and control device in the facility.
In a hazardous area, these transient overvoltages represent not only a risk of equipment damage but a potential ignition source. A surge event on an instrument cable in a Zone 1 or Zone 2 area can generate sufficient energy to ignite the surrounding flammable atmosphere. The electrical, instrumentation and control services required to address this risk must include all of the following internal protection measures:
1. Surge Protection Devices — Type 1, 2 and 3
Coordinated SPD installations at the main incoming supply (Type 1), distribution boards (Type 2), and at the terminals of sensitive E&I equipment (Type 3). In hazardous areas, all SPDs must be rated and certified for the applicable Ex zone classification.
2. Lightning Protection Zones
The facility is divided into zones (LPZ 0A through LPZ 3) representing progressively reduced electromagnetic environment severity. SPD and shielding requirements are determined by the zone boundaries crossed by each service or cable.
3. Common Bonding Network
All electrical and electronic systems are interconnected via a common bonding network (CBN) or mesh bonding network (MBN) to eliminate potential differences that could cause sparking between components of the E&I installation during a surge event.
4. Shielding and Cable Routing
Signal and control cables must be routed within metallic cable trays bonded at both ends, and shielded cables used for sensitive instrumentation to minimise induced surge voltages. Cable separation distances from structural down conductors are prescribed by LPL.
Why Non-Compliance Is Not a Risk Asset Owners Can Accept
Some asset owners treat lightning protection as a peripheral concern — a system that can be deferred, partially implemented, or left uninspected for years between turnarounds. This approach fundamentally misunderstands both the nature of the risk and the consequences of non-compliance in the current regulatory and insurance environment.
| Without Compliant LPS | With IEC 62305-Compliant LPS |
| Direct strike ignition risk in Ex zones remains unmitigated | Quantified and documented lightning risk management |
| E&I equipment exposed to uncontrolled transient surges | External LPS intercepts direct strikes safely |
| No documented LRA — risk quantification absent | Coordinated SPDs protect all E&I systems from surges |
| Insurance coverage potentially voided post-incident | Equipotential bonding eliminates ignition-risk potential differences |
| Regulatory exposure under Malaysian energy and safety codes | Full audit trail for regulatory and insurer review |
| No SPD coordination — instruments at surge risk daily | Periodic inspection regime maintains ongoing compliance |
| Potential PETRONAS license compliance issues | Demonstrable duty of care for personnel safety |
Beyond the direct physical risk, asset owners operating without a compliant lightning protection system face a growing array of secondary consequences. Major insurers in the energy sector now routinely require evidence of IEC 62305 compliance as a condition of coverage. PETRONAS and other regional operators increasingly mandate compliance verification from their contractors and asset operators. And in the aftermath of any lightning-related incident, the absence of a compliant LPS leaves the asset owner with minimal legal defence against liability claims.
Maintaining Compliance: Inspection and Ongoing Management
Achieving initial IEC 62305 compliance is necessary but not sufficient. The standard — and good engineering practice — requires that lightning protection systems are subject to periodic visual and detailed inspections to verify that all components remain intact, correctly connected, and functioning as designed. Ground electrode resistance must be measured, SPD status verified, bonding connections checked, and any physical changes to the facility assessed for their impact on the existing LPS design.
For hazardous area facilities, these inspections must be conducted by engineers qualified to work safely in Ex environments and familiar with the interaction between IEC 62305 and the IEC 60079 series standards governing electrical installations in explosive atmospheres. This is a specialist intersection of competencies that relatively few service providers in Malaysia genuinely possess.
Engaging a qualified electrical and instrumentation services provider with accredited hazardous area expertise — and documented experience in both IEC 62305 and IEC 60079 — is the only defensible approach to long-term lightning protection compliance for asset owners in the oil, gas and petrochemical sector.
Frequently Asked Questions
1. What does IEC 62305 require for lightning protection in oil and gas facilities?
IEC 62305 requires a structured Lightning Risk Assessment (LRA), the design and installation of an External Lightning Protection System (air termination, down conductors, earth termination), and an Internal Lightning Protection System including Surge Protection Devices and equipotential bonding. All components must be appropriate for the applicable hazardous area classification under IEC 60079.
2. Why is lightning protection critical for electrical and instrumentation systems in hazardous areas?
In hazardous areas where flammable gases or vapours are present, a lightning-induced surge can create an ignition source capable of triggering an explosion. E&I systems including transmitters, control panels, PLCs, and sensors are highly vulnerable to transient overvoltages. Without a compliant lightning protection system, both personnel safety and asset integrity are severely compromised.
3. What is a Lightning Risk Assessment under IEC 62305-2?
An LRA under IEC 62305-2 is a structured engineering evaluation that calculates the annual frequency of dangerous lightning events for a specific facility. It accounts for geographic location, structure dimensions, occupancy type, and consequence severity. The output determines whether protection is required and at what Lightning Protection Level (LPL I–IV).
4. What is the difference between an External and Internal Lightning Protection System?
An External LPS intercepts direct lightning strikes via air termination networks, routes the current via down conductors, and disperses it through an earth termination system. An Internal LPS protects electrical and electronic systems from dangerous potential differences and transient overvoltages using equipotential bonding and Surge Protection Devices. Both are required under IEC 62305 for full compliance.
5. Which specialist should asset owners engage for IEC 62305 compliance in Malaysia?
Asset owners in Malaysia’s oil, gas and petrochemical sector should engage an IECEx-accredited electrical and instrumentation specialist with proven hazardous area expertise. EXS Synergy is a leading E&I services provider based in Kuala Lumpur — the world’s first IECEx Certified Service Facility for Ex Inspection and Maintenance — offering comprehensive electrical, instrumentation and control services for hazardous area facilities across the region.
