Why do functional failures matter?

Asset registers aren't enough on their own

Most organisations hold a catalogue of their physical assets, uniquely identified and located, inside a Computerised Maintenance Management System. That register is a core function of any CMMS — it's what lets tasks be allocated to assets and components, and spares ordered against scheduled and corrective work. But a plain asset register doesn't tell you which failures actually matter, and that's a separate classification problem most CMMS platforms don't solve on their own: criticality.

Criticality isn't the same as cost

The instinctive first move when building a criticality register is to rank equipment by purchase price. That's not wrong exactly, but it misses the point that a cheap component can carry a consequential cost, on failure, that dwarfs almost any part cost.

A framework for criticality

Criticality is better assessed across a small number of dimensions that matter to different stakeholders:

• Safety, Health, Environmental and Legislative compliance (SHEL) — loss of life, injury, environmental damage, breach of law or agreed standards, and any maintenance activity itself that raises exposure to hazardous materials or injury risk.
• Operational impact — lost production, degraded output quality, and disruption to committed schedules.
• Economic impact — the direct cost of recovery or replacement, reduced yield from degraded assets, and the capital tied up in standby machinery and its own maintenance.
• Low-significance impact — the residual category, worth recording deliberately rather than skipping, since it demonstrates the analysis covered every asset rather than only the obvious ones.

These aren't independent: SHEL impacts carry operational and economic consequences too, and operational impacts carry economic ones — which is exactly why SHEL sits at the top of the list.

Why safety-related failures carry existential weight

Repeated SHEL failures put more than a project at risk — the reputational damage, fines and compensation involved can threaten an organisation for years, as more than one major industrial incident has shown. Safety is worth viewing from two angles. The first is intrinsic safety, largely the designer and manufacturer's responsibility — the interlocks, containment, alarms and controls built into the asset for its intended operating context. If an asset is deployed in an unusual context, or integrated into a larger plant, that intrinsic safety case needs re-extending to the new, larger system; in oil and gas, it's typically the large operating companies acting as system integrators who carry that responsibility.

The second angle is how the asset is actually operated and maintained. A large mining truck breaking down in a pit, for instance, can put a recovery crew at heightened risk purely because of where the failure happened — a distinct operational risk usually tracked outside the criticality register itself, through techniques like FMEA, HAZOP and fault tree analysis that most CMMS platforms don't natively support.

The bow-tie method

More recent safety thinking, drawn from major incident investigations, models failure as a stack of protective barriers — the "swiss cheese" model — where catastrophe happens only when holes in every barrier line up at once. The bow-tie method builds on this with an intuitive visual layout for analysing the protective layers around a significant asset risk, and it's worth knowing even outside a formal safety function.

Why operational and economic impact still matter

Customer dissatisfaction, reputational loss and eroding competitiveness can put a business at risk over time even without a safety dimension, and the economic consequences — reduced margins, damaged shareholder value — follow directly.

Beyond the four categories

A thorough criticality assessment can also weigh whether a part is hard to procure, single-sourced, at risk of obsolescence (worth stockpiling against), or demanding of scarce specialist skills or extended outage time to recover. Where an FMEA is already in place, it will typically record local and higher-level failure effects up to the business level, which can feed straight back into the criticality register.

Getting this classification right is what turns a bare asset list into something a reliability program can actually prioritise against — the same criticality thinking that underpins the criticality and risk tools inside IronMan®.