Mechanical Integrity (MI): A Cornerstone of Industrial Safety and Insurability

14 January 2026

In high-hazard industries where even a single component failure can escalate into a catastrophic loss, Mechanical Integrity (MI) stands as one of the most critical pillars of industrial risk management. It is the systematic approach that ensures critical equipment and systems are designed, fabricated, installed, operated, and maintained in a manner that prevents failures, protects people and the environment, and sustains business continuity.

Authors: Jack Wishart Naveen Krishnan

For insurance and risk engineering professionals, MI is not just about engineering or compliance, it is about predictability. Predictable equipment behaviour translates to predictable operations, lower risk exposure, and stronger underwriting confidence. For operators, MI is safety assurance; for insurers, it is proof of control over physical risk.

Why MI matters

A corroded pipe can release flammable gas, a fatigued nozzle may rupture under stress, and an eroded pump casing can lead to a sudden loss of containment. Every such event poses a serious safety, environmental, and financial risk. A well-implemented MI program acts as a powerful barrier to such events, delivering four vital outcomes:

Loss prevention: Prevents leaks, ruptures, and mechanical failures that can lead to fires or explosions and safeguards people, environment, assets, and reputation
Operational reliability: Prolongs equipment life and minimises risks associated with transient operation by ensuring consistent uptime
Regulatory and insurance confidence: Demonstrates proactive risk control that earns trust from regulators and underwriters

Where MI applies

MI principles apply to any sector where asset performance directly affects safety or production continuity. Its relevance spans across:

Oil and gas, petrochemical, and chemical plants
Power generation and fertiliser industries
Metals, mining, and cement sector
Pharmaceutical, food processing, and pulp and paper facilities

Across all the industries, MI ensures equipment like pressure vessels, piping, tanks, heat exchangers, rotating equipment, and relief systems stay fit for purpose and within safe operating limits.

Common causes of MI losses

Even most mature organisations with a strong safety culture can experience MI lapses. Globally, insurers and engineers have identified recurring patterns that lead to costly incidents. Recognising these weak links helps organisations close the gaps before they escalate.

Incomplete or inaccurate asset registers

Outdated asset registers leave equipment untracked and unmanaged, with uninspected modifications like bypass lines often causing failures.

Example:

A drain bypass line in a crude unit, excluded from the asset register, corroded from stagnant hydrocarbons and failed, causing a flash fire and production loss.

Good practice:

Maintain live asset register connected to P&IDs and inspection databases
Tag all pressure boundary components, including vents, drains, and bypasses
Update registers immediately after turnarounds, or project modifications

Inadequate inspection coverage and technique

The MI program detects only what and how it inspects. Calendar-based schedules with limited inspection methods create blind spots, unlike a Risk-Based Inspection (RBI) approach that uses appropriate inspection techniques to detect degradation.

Example:

A refinery faced a piping rupture from erosion-corrosion under insulation, as inspections covered only straight runs, missing downstream elbows near a valve where turbulence was highest.

Good practice:

Implement RBI as per API 580/581 to prioritise assets by risk instead of a fixed schedule
Utilise targeted inspection techniques: Ultrasonic Thickness (UT) mapping for wall thinning, phased-array UT or radiography for weld degradation, and guided wave UT for inaccessible sections
Inspect small-bore and dead legs, often overlooked but common failure points

Lack of Corrosion Control Document (CCD) and circuitisation

Many sites lack CCD and circuitisation, leading to generic and reactive inspections. Circuitisation groups assets by metallurgy, operating conditions, and process fluids to identify the credible damage mechanisms (API 571).

Example:

In an amine treating system, piping fabricated from carbon steel (CS) failed due to amine stress corrosion cracking (ASCC). The circuit was never reviewed for SCC susceptibility.

Good practice:

Develop corrosion circuits linked to CCDs, detailing degradation mechanisms and inspection strategies
Update CCDs for process changes, feedstock variations, or temperature shifts
Monitor corrosion rates with real-time probes or coupon analysis to validate inspection intervals

Failure to act on inspection findings

Deferring action on identified anomalies is a common and risky behaviour. Without structured follow-up, flagged issues, including thinning, cracking, deferred repairs and unapproved clamps, can turn into major losses.

Example:

Deferred repair of the tank nozzle with local thinning caused product release two years after detection, as a "temporary clamp" was deemed acceptable until the next turnaround.

Good practice:

Establish an anomaly management workflow with risk categories and deadlines
Require engineering justification for any deferred action
Track findings on dashboards and link them to KPIs for visibility and accountability

Operating ageing assets without Fitness-for-Service (FFS) Assessment

Operating beyond design life without FFS evaluation risks the undetected cumulative degradation, including creep and fatigue in ageing components.

Example:

An old heat exchanger shell failed from thermal fatigue despite meeting thickness requirements, as prolonged high temperatures weakened its strength, overlooked without an FFS study.

Good practice:

Conduct Level 2 or 3 FFS assessments on ageing or degraded components and integrate them into RBI cycles
Maintain traceability of repairs, re-ratings, and replacement materials
Update inspection plans based on FFS outcomes

Weak integration with management of change (MoC)

MI failures often originate from uncontrolled changes, like altering process parameters or design limits, without assessing mechanical assumptions. Even minor changes, like increasing throughput or temperature, can impact corrosion rates or material suitability.

Example:

A refinery switched to high-tan crude without assessing corrosion susceptibility, accelerating naphthenic acid corrosion in furnace CS tubes. The change passed MoC but lacked an MI review, causing a tube rupture and fire.

Good practice:

Include MI approval in every MoC step involving design, materials, or process changes
Reassess damage mechanisms for changes in feed, temperature, or pressure

Fragmented data and lack of digital integration

Scattered inspection data across various sources prevents trend analysis and risk visualisation. Without integration, linking corrosion rates to history or system-level risks is impossible.

Example:

A plant had three separate databases for piping, tanks, and pressure vessels. A circuit experiencing corrosion was flagged in one system but never communicated to maintenance planning, leading to unmitigated thinning until failure.

Good practice:

Adopt Integrity Management Systems (IMS) that centralise inspection, maintenance, and process data
Use analytics to trend corrosion rates, remaining life, and trigger alerts when limits are exceeded
Digitisation allows faster decision-making, traceability, and audit readiness

A few examples of MI failures across industries

Facility	Industry	Cause	Estimated loss (US$ million)
Philadelphia Energy Solutions (PES) Refining Explosion (2019), USA	Oil and gas	A corroded pipe elbow failed, releasing hydrofluoric acid (HF), which ignited and exploded.	750
TPC Group Butadiene Plant Explosion (2019), USA	Petrochemical	Popcorn polymer formed in a dead-leg expanded rapidly, rupturing the pipe. This released flammable butadiene, which ignited and caused an explosion.	380
Sayano-Shushenskaya Hydroelectric Power Station Accident (2009), Russia	Power generation	Turbine failure occurred due to mechanical integrity issues, including fatigue cracks in bolts.	Multi-million

Gallagher's Mechanical Integrity Deep Dive

At Gallagher, we go beyond compliance checklists. Our MI Deep Dive gives operators and insurers a clear picture of integrity risks, system strengths, and improvement priorities.

Delivered by Gallagher engineers certified in API 510, 570, 653, 580, and 571, this program blends global insurance insight with hands-on engineering expertise. It benchmarks the facility's MI practices against international best standards and identifies opportunities for improvement.

For operators, it offers a pathway to safer, more reliable operations. For insurers, it enhances underwriting confidence and improves risk transparency, leading to better insurance outcomes.

To learn more about Gallagher's Mechanical Integrity Deep Dive

download our brochure

Final word

MI is far more than an engineering discipline. It is a strategic enabler that underpins safety, reliability, and insurability. By embedding MI into daily operations, organisations protect their people, environment, and profitability.

The best-performing facilities treat MI as a continuous improvement journey, not a compliance obligation. By transforming MI from a reactive necessity into a competitive advantage, companies build resilience and earn trust from lenders, regulators, and underwriters alike.

At Gallagher, our mission is to help clients connect technical reliability with financial resilience, empowering them to operate safer, insure smarter, and build a more sustainable industrial future.

Mechanical Integrity (MI): A Cornerstone of Industrial Safety and Insurability

14 January 2026

Why MI matters

Where MI applies

Common causes of MI losses

Incomplete or inaccurate asset registers

Inadequate inspection coverage and technique

Lack of Corrosion Control Document (CCD) and circuitisation

Failure to act on inspection findings

Operating ageing assets without Fitness-for-Service (FFS) Assessment

Weak integration with management of change (MoC)

Fragmented data and lack of digital integration

A few examples of MI failures across industries

Gallagher's Mechanical Integrity Deep Dive

Final word

Author Information

Jack Wishart, MA MEng CEng MIChemE MEI

Head of Risk Engineering

Naveen Krishnan, BE MSc CEng MIMechE MEI Cert CII

Risk Engineer