Operating a chemical plant under COMAH means the maintenance system doesn't just support production — it underpins the safety case. When the Competent Authority arrives on site, the questions are direct: which equipment is safety-critical, when was it last inspected, who signed off, and where's the evidence. Oxmaint gives chemical operators a single CMMS for safety-critical asset registers, planned preventive maintenance, permits-to-work, inspection records and audit-ready documentation — designed for the demands of Upper Tier and Lower Tier COMAH sites operating across the UK. Book a demo to see COMAH-ready maintenance in action.
~950
COMAH establishments across Great Britain — chemical, oil & gas, LPG, explosives and specialty processes
£5m+
largest recent single COMAH-linked fines under the HSE definitive sentencing guideline
2 yrs
maximum imprisonment for individual directors on indictment under the Health and Safety at Work etc. Act
Lower Tier vs Upper Tier — What Your CMMS Has to Support
COMAH 2015 splits establishments into two tiers by the quantity of Schedule 1 dangerous substances held on site. Both tiers carry major-accident-prevention duties. Upper Tier carries an additional layer including a formal safety report to the Competent Authority. From a maintenance-system standpoint, the difference determines how much evidence you need to hold, how it's structured, and how quickly it has to be producible on demand.
COMAH Tier Duties — Maintenance & Documentation Impact
Lower Tier
Above lower threshold, below upper threshold
MAPP documentRequired
Safety Management SystemRequired · proportional
Notification to CARequired
Safety ReportNot required
On-site emergency planNot required (but often held)
Public safety informationNot required
CA inspection cadenceRisk-based, less frequent
Upper Tier
Above upper threshold — full Seveso III demonstrations
MAPP documentWithin Safety Report
Safety Management SystemRequired · detailed
Notification to CARequired
Safety ReportRequired · Schedule 3 content
On-site emergency planRequired
Public safety informationRequired
CA inspection cadenceMore frequent, deeper scope
Regardless of tier, the CMMS has to demonstrate that maintenance actually happens — programme in place, evidence of completion, defect close-out, and traceable engineer sign-off. Sign up free to configure your COMAH asset register in the first session.
Safety-Critical Equipment — The Register That Underpins the Safety Case
The safety-critical equipment (SCE) register is the single most-requested document in any COMAH inspection. Every asset with a role in preventing, controlling or mitigating a major-accident scenario has to be identified, its performance standard defined, and its maintenance regime evidenced against that standard. Oxmaint holds the SCE register at the heart of the platform — every work order, inspection and CAPA tied back to the specific SCE it services.
Typical SCE Categories Across COMAH Sites
Pressure containment
PSSR aligned
Vessels, columns, heat exchangers, high-pressure piping. PSSR written schemes of examination, statutory intervals, thickness surveys.
Safety instrumented systems
IEC 61511
ESD, HIPPS, trip systems, safety-rated PLCs. Proof-test intervals, SIL demonstration, functional-testing evidence.
Relief & venting
DSEAR context
PSVs, bursting discs, blowdown systems, flare stacks. Scheduled testing, calibration, set-pressure verification records.
Fire & gas detection
Life-safety
Detectors, alarm systems, deluge, foam. Functional testing, response-time validation, cross-referenced with emergency plan.
Bunding & containment
Environmental
Bunds, secondary containment, drainage interceptors. Inspection cycles, integrity tests, capacity verification records.
Rotating & mechanical
Process-safety critical
Emergency pumps, motor-operated valves, backup generators. Runtime testing, vibration monitoring, changeover verification.
The Regulatory Cross-Check Behind a COMAH Inspection
The COMAH Competent Authority isn't a single regulator — it's a joint body combining HSE with the relevant environmental regulator for each GB nation. That matters for maintenance-system design: the same asset can be under simultaneous scrutiny from multiple regulatory bodies, each looking for specific evidence categories. Oxmaint holds all of them against the same asset record, so a joint inspection doesn't require reassembly for each regulator.
| Regulator | Scope on a COMAH site | What Oxmaint holds |
|---|
HSE
Health & Safety Executive |
Process safety, SCE integrity, permits-to-work, competency records, MAPP implementation. |
SCE register, PPM history, permit workflow, engineer competence matrix. |
EA / SEPA / NRW
Environmental regulator |
Bunding, drainage, emissions, environmental containment integrity. |
Bund inspection records, containment integrity tests, environmental permits. |
Fire & rescue services
External emergency plan |
Emergency response infrastructure, fire-fighting systems, muster points. |
Fire system PPM, deluge test records, drill participation history. |
Insurer / auditor
Separate assurance |
SCE testing evidence, maintenance backlog reporting, incident learning close-out. |
One-click audit pack export per asset, per system, or site-wide. |
See a COMAH Audit Pack Assembled on Live Data
Walk through the SCE register, permit-to-work workflow, PPM evidence and CAPA close-out — all indexed against a real asset set. Thirty minutes with the Oxmaint team, focused on your specific COMAH tier obligations.
Permits, PPM and Process-Safety Workflow
Chemical plant maintenance isn't just PPM against a calendar. It's PPM tied to permits-to-work, tied to isolation procedures, tied to competency verification, tied to CAPA linkage back to the safety case. That interconnection is where paper-based systems fail — a permit issued without a linked isolation record, a PPM completed without a matching permit, a CAPA that never traces back to the SCE it was raised against. Oxmaint enforces the linkages at the point of data entry.
01
SCE identified
Asset flagged as safety-critical against the safety case. Performance standard documented. Inspection interval set per PSSR / SIL / OEM.
02
PPM raised
Work order generated on schedule. Competent-person requirement enforced. Isolation and permit-to-work prerequisites linked before job can start.
03
Permit issued
Hot work, confined space or general permit issued electronically. Isolation record attached. Contractor competence auto-verified.
04
Close-out & evidence
Sign-off captured on mobile with photo evidence. Any defect raised as linked CAPA. SCE record updated automatically.
Expert Perspective — Why COMAH Audits Fail on Documentation, Not Engineering
The pattern is consistent across enforcement action: sites don't get improvement or prohibition notices because their engineers can't maintain the plant. They get them because the maintenance evidence trail has gaps that undermine the safety case. A safety-critical inspection completed but not signed off. A permit issued without the linked isolation record. A CAPA closed without documented verification. Each individual gap looks minor. In an audit against a Regulation 8 safety report, they compound into a serious deficiency finding.
SCE performance standards
Every safety-critical asset needs a documented performance standard and evidence the maintenance regime meets it. Missing standards are a common finding.
Backlog visibility
Overdue safety-critical maintenance is one of the most reliable predictors of an improvement notice. The CA looks for the backlog before it looks at completed work.
Permit-to-work integrity
Permits issued without isolation verification, or without competency verification, undermine the whole safe-work regime. Digital enforcement closes the loop.
Incident learning
Every incident should generate a CAPA that traces back to an SCE, gets closed with evidence, and feeds into the safety case review cycle.
Who Uses Oxmaint on COMAH Sites
The platform is used by the roles that carry COMAH obligations day-to-day: process safety engineers responsible for the SCE register and performance standards, maintenance managers running PPM against safety-critical assets, HSE managers producing MAPP implementation evidence and Regulation 8 audit packs, permit coordinators managing hot-work, confined-space and isolation controls across shifts, and site directors accountable to the Competent Authority under Section 20 HSW Act powers. Each role sees the same underlying data filtered to their view — SCE dashboard, permit register, compliance calendar or backlog report. Sign up free to configure roles for your COMAH team in the first setup session.
Deploying on a Live COMAH Site — What the First 90 Days Look Like
Rolling out a new CMMS on a live COMAH establishment is not a "big bang" migration — regulatory continuity has to be preserved throughout. Existing safety-critical equipment registers, PPM schedules, and permit records import from spreadsheets, legacy CMMS exports and safety case documents in the first weeks. SCE performance standards are validated against the current safety report. Permit workflows are configured to match your existing site procedures rather than a generic template. Within the first 90 days the platform is running in parallel, then cut over as the primary system with full evidence continuity. Sign up free to start the scoping conversation, or book a walkthrough to see a live COMAH deployment with the Oxmaint team.
Keep Safety-Critical Maintenance Audit-Ready Every Day
Oxmaint gives COMAH operators one platform for the SCE register, PPM, permits, inspections and evidence packs. Built for the compliance load of Upper Tier and Lower Tier chemical, oil and gas sites operating across Great Britain.
Frequently Asked Questions
Does Oxmaint work for Lower Tier as well as Upper Tier COMAH sites?
Yes. Lower Tier duties are proportional to the site's hazard profile, but the underlying discipline is the same — MAPP implementation, safety-critical equipment identification, PPM against defined intervals, permit-to-work control, and evidence retention. Oxmaint handles both, with Upper Tier configurations layering in the additional Safety Report and internal emergency plan cross-references required under Regulation 8. Tier status is captured against the site record so audit-pack exports carry the correct regulatory context.
How does the platform handle safety-critical equipment performance standards?
Every SCE record holds its documented performance standard — the specific measurable outcome the equipment has to deliver (e.g. valve closure time under 3 seconds, deluge coverage at specified density, trip system response inside SIL-defined limits). The PPM regime is scheduled to demonstrate ongoing conformance with that standard, and every proof test, calibration or functional check writes back to the SCE record. When an inspector asks "how do you know this equipment still meets its performance standard?", the answer is one screen and one exportable pack away.
Does the permit-to-work workflow support hot work, confined space and isolation controls?
Yes. Permits are issued electronically against the specific asset or area, with the required isolation records, gas testing evidence, contractor competence checks, and PPE requirements enforced as prerequisites before the permit can be signed off as ready-to-work. Hot work, confined-space entry, high-voltage, breaking of containment and general permit templates are configurable to your site's specific procedures. Contractor access is scoped so external teams complete their portion of the workflow without needing full user licences.
Can it produce a COMAH audit pack on demand?
Yes — that's the specific use case for the audit-pack export. Selectable by asset, system, safety case demonstration reference or date range, the pack bundles SCE inspection history, PPM completion records, permit-to-work history, CAPA close-outs, engineer sign-offs and photo evidence into a single PDF ready for the CA, insurer or internal auditor. It runs in one click, in minutes — not days of manual retrieval from multiple systems.
How does Oxmaint integrate with our existing safety report and MAPP?
Oxmaint doesn't replace the safety report — it operationalises it. The SCE register, performance standards, PPM regime and emergency plan procedures documented in the safety report are configured into the CMMS so day-to-day maintenance activity generates the evidence the report commits to. When the safety report is revised (typically on a five-year cycle for Upper Tier), the corresponding CMMS configuration is updated so the operational reality stays aligned with the documented safety case.
