Failure Causes

The failure cause is the underlying cause of a failure; the circumstances during design, manufacturing or use which have led to a failure. The objective of specifying failure causes is to identify the initiating events (“root causes”) in the sequence leading up to a failure of an equipment item.

Failure causes are commonly not known in depth when the failure is observed and, in order to reveal the root cause of a failure, a specific root cause analysis can be useful. This is in particular relevant for failures of a more complex nature and where the failure is important to avoid due to its consequences. Examples are failures with serious safety and/or environmental consequences, abnormally high failure rates compared to the average and failures with a high repair cost.

Due care is required so as not to confuse failure mechanism (describing the apparent, observed cause of failure) with failure cause (describing the underlying or “root” cause of a failure).

ISO 14224 prescribes the following best practice failure causes:

Failure cause type	Failure cause	Description of the failure cause
Design-related causes	General	Inadequate equipment design or configuration (shape, size, technology, configuration, operability, maintainability), but no further details known
	Improper capacity	Inadequate dimensioning or capacity
	Improper material	Improper material selection
Fabrication or installation-related causes	General	Failure related to fabrication or installation, but no further details known
	Fabrication error	Manufacturing or processing failure
	Installation error	Installation or assembly failure (assembly after maintenance not included)
Operation or maintenance-related causes	General	Failure related to operation or use or maintenance of the equipment, but no further details known
	Off-design service	Off-design or unintended service conditions, for example compressor operation outside envelope, pressure above specification
	Operating error	Mistake, misuse, negligence or oversights during operation
	Maintenance error	Mistake, errors, negligence or oversights during maintenance
	Expected wear and tear	Failure caused by wear and tear resulting from normal operation of the equipment unit
Management-related causes	General	Failure related to management issues, but no further details known
	Documentation error	Failure related to procedures, specifications, drawings, reporting
	Management error	Failure related to planning, organisation, quality assurance

Also refer to Failure Cause Types.