Chapter 05PreservationArticle 5.1
Preservation as an Operational Risk Control
Stored material is only valuable if it remains identifiable, protected, documented and fit for use when maintenance needs it.
- ProblemStock is recorded as available but is not ready for use.
- SignalsStorage condition, duration, inspection, condition, documents, criticality.
- DecisionFit for use, re-preserve, re-certify, restrict or escalate.
- ControlReadiness confirmed before maintenance relies on it.
01Business problem
Inventory quantity is not readiness. A spare can sit on the shelf for years, appear as available in SAP and still be unusable on the day maintenance needs it: corroded, with a perished seal, past its shelf life, or with a certificate that no longer matches the item.
The problem is invisible in the system and expensive in the field. It is discovered at the worst moment, when the equipment is already down and the replacement lead time only starts then.
02Core concept
Preservation is a risk control, not a housekeeping task. Its purpose is to keep stored material identifiable, protected, documented and fit for use until it is installed.
Not every item needs the same effort. The level of control depends, where relevant, on:
- the material type and its sensitivity to moisture, heat, UV or corrosion;
- the manufacturer's storage and preservation requirements;
- the storage environment: indoor, outdoor, climate controlled;
- the duration in storage and any shelf-life limits;
- the criticality of the equipment it serves;
- the validity of certificates and documentation;
- the integrity of packaging and sealing.
A critical spare with a near planned-use date deserves more attention than a common item that will be consumed next month, even if a calendar treats them the same.
03Decision rule
Release stored material as ready only when both its physical condition and its documentation support use. Set the preservation effort by risk: criticality, sensitivity, environment and time in storage, not by one calendar for everything.
When condition or documentation is in doubt for a critical item, restrict it and escalate, rather than let maintenance discover the problem at installation.
04Signals and inputs
- Storage duration
- Time since receipt or since the last preservation.
- Storage condition
- Indoor or outdoor, climate, exposure.
- Preservation requirement
- What the manufacturer or the specification requires.
- Last inspection
- When condition was last confirmed.
- Physical condition
- Corrosion, damage, packaging, seals.
- Shelf life
- Time-limited components and materials.
- Documentation
- Certificate validity and traceability to the item.
- Criticality
- Consequence if the item is not fit for use.
05Model
- 01MaterialItem, location and stock record.
- 02Storage conditionEnvironment, packaging, exposure.
- 03Preservation requirementManufacturer guidance, shelf life, protection method.
- 04InspectionPhysical condition and preservation status checked.
- 05Documents and certificatesValid, consistent and traceable to the item.
- 06Readiness decisionFit for use, re-preserve, re-certify, restrict or escalate.
06Worked example
Illustrative example
Available, and not ready
A critical valve actuator spare has been in outdoor covered storage for four years. SAP shows 1 EA available.
- Inspection: the outer packaging is torn, and light corrosion is visible on the machined sealing face of a flange.
- Requirement: the manufacturer requires dry indoor storage and periodic preservation of machined surfaces.
- Documents: the material certificate is on file and traceable to the serial number.
Readiness decision: restrict and escalate. Corrosion on a sealing surface is not a cosmetic finding: whether it affects the seal is a technical question. The item is restricted from issue, the condition is referred for an engineering opinion on whether re-preservation is enough, and the storage location is reviewed. SAP still says available. The control is what tells maintenance that it is not, yet.
07Professional judgement
Material availability is not useful if condition or documentation cannot be trusted.
Preservation programmes fail in two opposite ways: by treating every item the same and running out of capacity, or by maintaining the paperwork and never looking at the item. Risk-based preservation means deciding where the effort goes and accepting lighter control elsewhere.
A perfect part without valid documents can be as unusable as a corroded one. The readiness decision has to cover both, and it has to close: a finding that is recorded but never acted on is not a control.
08Failure modes
Calendar-only preservation
Effort goes to low-risk items while critical ones deteriorate.
ControlSet the frequency by criticality, sensitivity and environment.
Physical condition ignored
Preservation is recorded but the item is not inspected.
ControlInspect the item, not only the preservation record.
Documentation validity ignored
A sound part cannot be used for lack of valid documents.
ControlCheck certificates and traceability as part of readiness.
Identical frequency for all materials
Capacity runs out before the items that matter are covered.
ControlApply risk-based preservation categories.
Stock recorded available but unusable
Maintenance plans with an item it cannot install.
ControlRestrict unfit items in the system until they are corrected.
Findings not closed
The same defect is found at every inspection.
ControlTrack findings to closure with an owner.
09Field note
10Practical checklist
- The preservation category is set by risk, not by default.
- Manufacturer storage and preservation requirements are known.
- The storage environment suits the item.
- Physical condition is inspected, not only the record checked.
- Shelf life and certificate validity are confirmed.
- Unfit items are restricted until corrected.
- Findings are tracked to closure with an owner.
11Try the decision logic
Decision Lab
Preservation readiness
SAP says available. Is it ready for maintenance use?
Try the decision logic. There is no score: choose a decision and compare it with a professional review.
01Situation
Illustrative scenario
A spare has been in storage for some time. SAP shows it as available, and maintenance plans to install it at the next shutdown. Set what is known about its storage, condition and documents, then decide its readiness.
- System status
- Available, 1 EA
- Planned use
- Next shutdown
02Signals
- CriticalityCritical, no standby · Not critical
- Time in storageUnder a year · Several years
- Storage conditionMeets the manufacturer requirement · Does not meet it · Not known
- Last inspectionWithin the required interval · Overdue · None recorded
- Physical conditionNo findings · Minor findings: packaging, light surface corrosion · Damage affecting use · Not inspected
- DocumentationValid and traceable · Expired, or shelf life exceeded · Missing
03Decision
- Fit for use
- Re-preserve
- Re-certify
- Restrict
- Escalate
04Professional review
The interactive review needs JavaScript. Without it, the complete logic is in the rules below.
How the review is reached
The rules are checked from the top; the first one that matches the signals gives the professional position. Values in square brackets are filled in with the calculated numbers.
IfPhysical condition: Damage affecting use
Professional positionEscalate
ConditionalRestrict
Any other decision: escalation required
Damage affects use. Whether the item can be repaired or must be replaced is an engineering decision; it is restricted until then.
IfDocumentation: Missing
Professional positionRestrict
ConditionalEscalate
Any other decision: not supported by the signals
Documentation is missing. A sound part without its documents cannot be released for use.
IfPhysical condition: Not inspected · Criticality: Critical, no standby
Professional positionRestrict
ConditionalEscalate
Any other decision: insufficient information
Condition is unknown for a critical item. Availability in SAP does not prove readiness: inspect before maintenance relies on it, and restrict until then.
IfPhysical condition: Not inspected
Professional positionRestrict
ConditionalRe-preserve
Any other decision: insufficient information
Condition is unknown. The readiness decision needs an inspection; until then the item should not be planned as ready.
IfLast inspection: None recorded · Physical condition: No findings
Professional positionRestrict
ConditionalEscalate
Any other decision: insufficient information
Condition is recorded as good, but no inspection is recorded. The condition statement has no basis and should be treated as unknown.
IfDocumentation: Expired, or shelf life exceeded
Professional positionRe-certify
ConditionalRestrict
Any other decision: not supported by the signals
The documentation or shelf life has expired. The item needs re-certification, or replacement of its time-limited parts, before release.
IfPhysical condition: Minor findings: packaging, light surface corrosion · Criticality: Critical, no standby
Professional positionRe-preserve
ConditionalRestrict, Escalate
Any other decision: not supported by the signals
Minor findings on a critical spare. Renew the preservation now, record the finding and confirm the storage location, so the item is ready when it is needed.
IfPhysical condition: Minor findings: packaging, light surface corrosion
Professional positionRe-preserve
ConditionalRestrict
Any other decision: not supported by the signals
Minor preservation findings. Renewing the preservation keeps the item usable.
IfLast inspection: Overdue · Physical condition: No findings · Criticality: Critical, no standby
Professional positionRestrict
ConditionalRe-preserve, Escalate
Any other decision: insufficient information
Condition was recorded as good, but the inspection is overdue on a critical item. The record shows the item as it was at the last inspection, not as it is now, and maintenance would find out only at the shutdown.
IfLast inspection: Overdue · Physical condition: No findings · Time in storage: Several years
Professional positionRestrict
ConditionalRe-preserve
Any other decision: insufficient information
Condition was recorded as good, but the inspection is overdue after years in storage. Preservation wears out with time; an old record cannot show whether it still protects the item.
IfLast inspection: Overdue · Physical condition: No findings
Professional positionFit for use
ConditionalRe-preserve, Restrict
Any other decision: not supported by the signals
Good condition was recorded at an inspection, and the next one is now overdue. The item is not critical and has been stored for less than a year, so the record can still support this use.
IfStorage condition: Not known
Professional positionFit for use
ConditionalRe-preserve
Any other decision: not supported by the signals
The item is in good condition, inspected and documented, but it is not known whether its storage meets the manufacturer requirement. It is fit for use now; the storage condition still has to be confirmed.
IfStorage condition: Does not meet it
Professional positionFit for use
ConditionalRe-preserve
Any other decision: not supported by the signals
The item is in good condition and documented, but its storage does not meet the manufacturer requirement. It is fit for use now; the storage itself is the finding to correct.
IfAny other combination
Professional positionFit for use
ConditionalRe-preserve
Any other decision: not supported by the signals
Condition, documentation and storage support use. The item can be released as fit for use.
Illustrative scenario, not a record of a specific item. No inspection intervals are stated: they depend on the item and the manufacturer.
12Connected intelligence
Experience
See this principle in practice
- Preservation Governance and Storage ReadinessOperational experience
13Evidence and basis
The example is illustrative, not a record of a specific company item; no inspection intervals are stated because they depend on the item and the manufacturer. Basis: preservation requirements (Spare Parts Engineer) and preservation governance (Spare Parts Superintendent) in the CV, and training in material preservation, storage and corrosion protection.