What this is
What is a written scheme of examination?
What is a written scheme of examination?
A written scheme of examination is the document that identifies the parts of a pressure system needing periodic examination, specifies the nature and extent of each examination, and sets the interval that must not be exceeded. It is drawn up or certified by a competent person before the system is used, and it is the instrument against which every subsequent examination is judged.
Who can write a pressure system scheme?
A person with the practical and theoretical knowledge to judge what examination a given system needs, and, critically, someone independent of the operation of the system. Independence matters because the scheme sets the standard the operator will later be examined against, and a scheme written by the same function that runs the plant tends to under-specify.
Is a scheme the same thing as an inspection?
No. The scheme is the plan: what to examine, how, and when. The inspection is the event carried out against that plan on a specific vessel, on a specific date, by a specific inspector, producing a pass or fail. A site can have an excellent inspection record sitting on top of a scheme that no longer describes the plant.
Scope
When is a pressure system written scheme required?
This scheme is the governing document for a site's pressure systems. Confusing it with the examination carried out against it, or with the safety checks that sit alongside it for related plant, produces a record that answers the wrong question when someone asks for it.
Use this template when
- A pressure system is being brought into use and needs its scope, method and intervals defined before the first examination
- An existing system has been modified in a way that could change what needs examining or how often
- The scheme is due its own periodic review, independent of any single vessel's examination date
- A competent person is being appointed or changed and the scheme needs re-certifying against the plant as it stands
- A linked examination record needs a current scheme to be tested against
Do not use it for
- Pressure Vessel Inspection, which is the actual examination event carried out against this scheme for one vessel, not the scheme itself
- Steam System Safety Check, which covers boiler operation, water treatment, blowdown, relief devices and steam trap condition as a routine safety check rather than a statutory scheme
- Boiler Attendant Log, which records the periodic checks an attendant makes through a shift, not the examination regime
- Ammonia System Safety Review, which addresses the ammonia-specific safety position rather than the pressure examination scheme
- Anything outside KnowSafe, which belongs in the workspace that owns that process
Compliance mapping
Which ISO 45001 cl.8.1 requirements does this satisfy?
Most regimes that regulate pressure systems require a written scheme as a precondition of use, and then leave the content of the scheme to the competent person's judgement, which is why the scheme's defensibility rests on its scope rather than its format.
| Clause | Requirement | Where it lands |
|---|---|---|
| PSSR 2000 reg.8(1) | A written scheme of examination must be drawn up, or certified as suitable, by a competent person before the system is used | Header |
| PSSR 2000 reg.8(3) | The scheme must specify the parts to be examined, the nature and extent of each examination, and the interval | Parts covered |
| PSSR 2000 reg.9 | Examination must be carried out in accordance with the scheme, at intervals the scheme sets and does not exceed | Parts covered |
| PSSR 2000 reg.7 | Safe operating limits must be established for the system and not exceeded | Scheme quality |
| ISO 45001 cl.8.1 | Operational controls established, implemented and maintained for processes needed to meet requirements | System scope |
| PSSR 2000 reg.10 | Action to be taken on receipt of the examination report, including where imminent danger is identified | Scheme quality |
| PSSR 2000 reg.13 | Records of the scheme and examination reports kept and available to those operating the system | Scheme quality |
What it does not cover
- Pressure Vessel Inspection, which is the examination event carried out against this scheme for a specific vessel, not the scheme itself.
- Steam System Safety Check, which checks boiler operation, water treatment, blowdown, relief devices and steam trap condition as an operating safety check.
- Boiler Attendant Log, which records the periodic checks a boiler attendant makes through a shift, with readings and any action taken.
- Ammonia System Safety Review, which addresses ammonia-specific containment and detection, not the general examination scheme.
- Confined space entry permit, which is required separately whenever an internal examination under this scheme needs entry into a vessel.
Global
Pressure System Written Scheme requirements by country
The written scheme is a distinctly regulated instrument in some regimes and an implied consequence of a general management-system duty in others, and that difference decides how much the scheme's content is prescribed.
Pressure Systems Safety Regulations 2000, regs.7-13
A written scheme is a named legal requirement, drawn up by a competent person, with specified content and examination against it.
Operating a relevant system without a current, adequate scheme is a straightforward offence, independent of whether the system is actually in poor condition.
State boiler and pressure vessel laws, generally incorporating the National Board Inspection Code
No single federal written-scheme requirement; jurisdiction sets the inspection regime, most adopting NBIC in-service inspection intervals and scope.
The functional equivalent of a scheme exists state by state, and the safe answer is to hold one even where the state does not name the document.
ISO 45001 cl.8.1
A management-system requirement to establish and maintain operational controls for processes with OH&S risk, without prescribing scheme content.
Certification auditors will ask whether the scheme exists and is followed, not whether it takes a particular form.
How to complete it
How to complete a pressure system written scheme, step by step
The scheme template prompts for a list of parts and intervals. What makes the resulting document defensible is judgement the template cannot force.
A design drawing and an as-built system diverge the moment site engineering adds a bypass or re-routes a line. The scheme has to describe what is actually there, which means walking the system rather than working from the original specification.
A scheme written by the operations function has every incentive to set intervals that fit the production schedule rather than the risk. Independence is what the record needs to show, and it is checked directly by this template's own field for it.
An interval tells you when to look. A limit tells you what the system must never exceed in the meantime. A scheme with intervals but no stated limits has defined the schedule without defining the boundary the schedule exists to protect.
The review date on its own guarantees the scheme is looked at once a year and nothing about whether it still matches the plant. Linking the scheme to the change process, so a re-pipe or a new branch raises the review as part of the change, is what actually keeps it current.
What auditors find
Most common pressure system written scheme findings
A scheme almost always exists somewhere in the file. The findings concern whether it covers the right parts, was written by the right person, and has kept pace with the plant.
| Finding | Clause | What fixes it |
|---|---|---|
| Scheme does not name the safety devices or state their protective settings. | PSSR 2000 reg.7 | Add every relief device and gauge to the scheme with its stated setting, not only the vessel it protects. |
| Scheme not reviewed after a plant modification such as re-piping or a new branch. | PSSR 2000 reg.8(1) | Link the scheme to the change process so a modification raises the review automatically. |
| Scheme was drawn up or certified by someone not independent of operations. | PSSR 2000 reg.8(1) | Appoint a competent person independent of the plant's day-to-day operation to write or certify the scheme. |
| An examination interval in the scheme has been exceeded before the next examination occurred. | PSSR 2000 reg.9 | Restrict use of the affected part immediately and escalate; do not treat an overdue interval as a paperwork gap. |
| Scheme is not available to the operators of the system it covers. | PSSR 2000 reg.13 | Hold a current copy, or a working summary of parts and intervals, where operators can reach it. |
| Parts covered list stops at the vessel and omits the pipework and safety devices around it. | PSSR 2000 reg.8(3) | Extend the scope to every part that stores or releases energy, not only the parts that look like vessels. |
Case in point
Case in point: the scheme that only covered the vessel
A dairy site's ammonia plant had a written scheme covering the two ammonia receivers, each examined externally and internally on a defined interval, both passing every examination for six years. The scheme did not mention the relief valves fitted to those receivers, on the reasoning that the valves were part of the vessel and therefore implicitly covered.
A relief valve failed to lift at its set pressure during an unrelated process upset, and the subsequent investigation found the valve had never been tested against a stated interval, because no interval for it existed anywhere in the scheme. The vessels had a flawless examination history and the part that was supposed to protect them had never been examined at all. The corrective action was rewriting the scheme to name every safety device as a separately scheduled part, not a detail assumed inside the vessel's own entry.
The template
The template, field by field
The form exactly as it installs. Every field, option, score and conditional rule is editable, and the links to other templates come with it.
4 sections
- Reference
- SAF-163
- Archetype
- Plan
- Record ID
- PWS-2026-000
- Scoring
- Scheme current
- Direction
- High is good
- Singleton
- No
- Basis
- ISO 45001 cl.8.1
- Links
- Links Vessel inspections, Permits
- Tags
- Pressure
- Sections
- 4
- Fields
- 41
- Follow up fields
- 3
- Repeating sections
- 1
- Links out
- 4
Header
10 fieldsScheme ID*
Auto sequence. Format PWS-2026-000.
The record's own ID. Other templates point at this value.
Status*
Drives who this goes to next.
- Planned2 pts
- In progress2 pts
- Complete3 pts
- Deferred0 pts
- Open0 pts
- Closed3 pts
- Overdue0 pts
Version*
Issue Date*
Next Review Due*
Site*
Site ID*
Format SITE-000.
Links to FDN-001 Site ID
Owner*
Approved By*
Operating Without One Is A Breach
A written scheme of examination is a legal requirement for relevant pressure systems. It must be drawn up by a competent person and name the specific parts, methods and intervals.
System scope
6 fieldsSystem Description*
System Type*
Stored Energy Category
- Low3 pts
- Medium1 pt
- High0 pts
Scheme Drawn Up By*
Competent Person Verified*
- Yes3 pts
- No0 pts
Independent Of Operations*
- Yes3 pts
- No0 pts
Parts covered
Repeats9 fieldsComponent*
Vessel, pipework, safety device, gauge, or ancillary.
Reference*
Examination Type*
Interval Months*
Preparation Required
Draining, cleaning, insulation removal and confined space entry all need planning weeks ahead.
Last Examination
Next Due*
Within Interval*
- Yes3 pts
- Overdue0 pts
Inspection ID
Links to MNT-036 Inspection ID
Scheme quality
16 fieldsAll Relevant Parts Included*
- Yes3 pts
- Partly1 pt
- No0 pts
Safety Devices Included*
- Yes3 pts
- No0 pts
Protective Devices Setting Stated*
- Yes3 pts
- No0 pts
Scheme Reviewed After Modification*
- Yes3 pts
- Not needed3 pts
- No0 pts
Operating Limits Stated*
- Yes3 pts
- No0 pts
Scheme Available To Operators*
- Yes3 pts
- No0 pts
Scheme Document
Document ID
Format DOC-0000.
Links to FDN-008 Document ID
Action Required*
Raise the action record, then enter its reference here.
- No2 pts
- Yes0 pts
Priority
- High0 pts
- Medium1 pt
- Low3 pts
CAPA ID
Format CAPA-2026-00000.
Links to FDN-014 CAPA ID
Action Owner
Competent Person*
Signature*
Engineering Manager*
Second Signature*
SAF-163 · record IDs look like PWS-2026-000 · Links Vessel inspections, Permits
Open in KnowellaRun it with agents
From a document you fill in to a programme that runs itself
The scheme is a document. What fails around it is the mechanism that should keep it matched to the plant: the modification that never reached it, and the interval that lapsed unnoticed on a part nobody was watching.
Holds the scheme against the register of pressure systems and their parts, and flags entries whose subject has been modified since the scheme was last reviewed.
Feeds each examination result back against the scheme's stated interval, so an overdue part is visible before it becomes an unexamined one.
Verifies that the competent person certifying the scheme, and any inspection body examining against it, holds current, checkable accreditation.
Watches modification, incident and inspection records for events that should trigger a scheme review, and raises it rather than waiting for the stated date.
This template lives in KnowSafe — safety and compliance. Incidents, hazards, permits, inspections and the critical controls behind them.
Meet KnowSafe→Glossary
Pressure System Written Scheme definitions and key terms
- Written scheme of examination
- The document specifying which parts of a pressure system are examined, the method and extent of each examination, and the interval that must not be exceeded.
- Competent person
- Someone with the practical and theoretical knowledge to draw up or certify a scheme, and, for that role, independent of the system's day-to-day operation.
- Safe operating limits
- The boundaries, typically pressure and temperature, that the system must not exceed between examinations, set alongside the examination interval rather than instead of it.
- Protective device
- A relief valve, bursting disc or similar fitting that limits pressure in the system, whose setting must be stated and examined in its own right.
- Statutory interval
- The maximum period between examinations of a given part, fixed by the scheme and not extendable on the basis of a clean examination history alone.
FAQ
Frequently asked questions about pressure system written scheme
Does the scheme have to be written by someone outside the company?+
Not necessarily outside the company, but independent of the operation of the system. An in-house engineer who does not run the plant can qualify; the person who operates it day to day should not be the one certifying the scheme they will later be examined against.
What must the scheme cover beyond the vessel itself?+
Every part with the potential to fail dangerously: pipework carrying stored energy, protective devices and their settings, and gauges, in addition to the vessels. A scheme that only lists vessels has left out the parts most likely to fail without warning.
What happens if the system is modified after the scheme is written?+
The scheme should be reviewed, because a modification can change what needs examining or how often. A scheme that has not been revisited since a re-pipe or capacity change is describing a system that no longer exists.
Can an examination interval be extended because the last examination found nothing?+
Only if the scheme itself is formally revised to extend it, by the competent person, on stated reasoning. A clean history is evidence to weigh in that revision, not a substitute for it.
Who is responsible if a system is used outside its scheme?+
The duty holder, typically the user or owner of the system, and the breach exists independent of whether the system happens to be in good condition. A scheme is a precondition of use, not a formality that trails behind it.
What is the difference between this scheme and an inspection record?+
The scheme is the plan: what gets examined, how, and how often. The inspection record is the event carried out against that plan for one part on one date. A site can hold a strong inspection record sitting on top of a scheme that has stopped describing the plant.
Keep going
Related templates and programmes
Industries this is written for
Programmes this belongs to
Used together in Pressure Systems and Refrigeration
Refrigeration Contractor Verification
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Environmental Aspects Register
Lists how your activities interact with the environment and how significant each interaction is
Refrigeration Unit Service Record
Records service and performance testing of a transport refrigeration unit, including temperature pull down and refrigerant
Boiler Operation Record
Records boiler operating parameters, water treatment results and blowdown through a shift
Refrigeration Plant Log
Records suction and discharge pressures, temperatures, oil levels and run hours across the refrigeration plant
Water Treatment Record
Records dosing, testing and results for boiler, cooling and process water systems
More in Pressure Systems
Steam System Safety Check
Checks boiler operation, water treatment, blowdown, relief devices and steam trap condition
Boiler Attendant Log
Records the periodic checks a boiler attendant makes through a shift, with readings and any action taken
Compressed Gas Cylinder Check
Checks cylinder storage, securing, segregation, valve protection and test dates
Ammonia System Safety Review
Reviews the refrigeration system against its safety requirements, covering detection, ventilation, relief, isolation, machinery room condition and emergency arrangements
Written and reviewed by
Siddarth Singh
Founder & Chief Executive Officer, Knowella
Certified Safety Professional and industrial and systems engineer with more than a decade inside food supply chain, freight and manufacturing operations. This page was written against the current text of the standards it cites, not against secondary summaries of them.
- Certified Safety Professional (CSP), Board of Certified Safety Professionals
- MBA, University of Chicago Booth School of Business
- MS and BS, The Ohio State University, Industrial and Systems Engineering
- Six Sigma Black Belt
Sources and last review. Reviewed 16 August 2026 against:
- Pressure Systems Safety Regulations 2000, regulations 7 to 13 (UK)
- ISO 45001:2018 clause 8.1, operational planning and control
- National Board Inspection Code, Part 2, in-service inspection (US)
- HSE guidance on written schemes of examination for pressure systems
This page is general guidance, not legal advice. Confirm requirements with your jurisdiction’s regulator.