OCSomewhere over the Atlantic, the engineer sitting beside me showed me photographs of repairs his team had carried out on machinery that, in some cases, was never expected to fail.
The engineering was fascinating. The operational question was more interesting.
If a critical machine fails tomorrow, can you actually get it out?
Assets are commonly designed to perform a duty. Far less consistently are they designed around the full intervention that follows failure: safe access, isolation, inspection, lifting, repair, replacement, recommissioning and the effect on everything around them.
By the time maintenance inherits the asset, many of those decisions are already fixed in steel, concrete, pipework, layouts and contracts.
01Maintainability is an investment decision
Maintainability is not a request for more space around every machine or unrestricted redundancy. It is the deliberate consideration of how an asset will be kept safe, available and economically productive across its life.
That consideration starts during concept selection and design. The latest edition of ISO 20815 places production assurance and reliability management across the lifecycle of oil, gas and lower-carbon energy assets. It connects design, project control, risk, maintenance and operations rather than treating reliability as a concern that begins at handover.
That matters commercially. A lower capital option can still be the more expensive decision if it creates:
- longer and more frequent shutdowns;
- restricted access to inspect or repair equipment;
- a need to remove unrelated systems before intervention;
- dependence on one specialist supplier or scarce lifting arrangement;
- long lead times for critical parts;
- unsafe or impractical maintenance tasks;
- production loss that was absent from the original comparison.
The cheapest asset to build is not necessarily the cheapest asset to own, operate or recover.
02The removal route is part of the design
The United States National Institutes of Health makes this unusually explicit in its design requirements. Its guidance requires service clearances, routes for oversized equipment, turning radii, rigging clearances and any modifications needed to move equipment through a building to be considered during design.
The rationale is simple: costly building changes and disruption to operations should not be necessary every time large equipment must be installed or replaced.
This is not a specialist lesson for laboratories. The same logic applies to compressors, pumps, transformers, generators, packaged units and critical rotating equipment. A component can be reliable and still create severe operational risk if the intervention route is impossible, unsafe or dependent on assumptions nobody tested.
03Repair capability changes the option set
Specialist repair techniques can recover equipment that might otherwise be written off. Cold metal stitching, for example, is used to repair damaged castings and engine blocks without the heat and distortion associated with welding. In-situ machining and restoration can also reduce the need to remove very large assemblies.
These capabilities matter, but they should not become the operating model. A difficult rescue is not evidence that the original maintainability assumptions were sound.
The stronger question during design and due diligence is: what credible intervention options will exist after failure, and what conditions must be present for each to work?
04Critical infrastructure makes the principle visible
Healthcare infrastructure shows the human consequence of availability. University College London Hospitals says its proton beam therapy department can treat up to 650 NHS patients each year at full capacity. In that setting, access, isolation, redundancy, spares and recovery planning are not abstract engineering preferences.
Lifecycle support can also preserve major capital assets. In 2023, IBA announced an US$80 million to US$100 million restoration of its first proton therapy installation at Massachusetts General Hospital. The system had treated its first patient in 2001. The restoration demonstrates the long operational life and renewal choices that can follow the original investment.
Pharmaceutical regulation reaches a similar conclusion from a quality perspective. EU GMP requires premises and equipment to be designed, located and maintained for the intended operations, with layouts that allow effective cleaning and maintenance. US FDA requirements likewise connect equipment design, location, cleaning and maintenance to preventing malfunction and contamination.
The sectors differ. The governing logic does not: intervention has to be designed into the system.
05Project trade-offs can transfer risk to operations
Designers, project teams and equipment suppliers are not usually ignoring maintainability. They are balancing capital, footprint, programme, safety, efficiency, constructability and many other constraints.
The problem arises when the trade-off is not made visible. A decision that improves the project case may transfer cost, downtime or complexity to the operating phase. If operations is not present, or the assumptions are not quantified, the investment committee sees only one side of the decision.
Recent pharmaceutical facility design offers a useful illustration. AstraZeneca's 2026 award-winning commercial cell-therapy facility treated 100 per cent operational uptime as a non-negotiable design requirement because patient-specific products cannot be stockpiled. That is maintainability and resilience expressed as a business requirement before the asset enters service.
06The Oclas Intervention Test
Before approving a design, acquisition or major modification, leaders should be able to answer ten questions:
- What happens when this fails? Define the credible failure, consequence and operating response.
- Can we safely reach it? Test access with the people, equipment and protective measures the task requires.
- Can we repair it where it stands? Understand inspection, tooling, environmental and specialist constraints.
- If it must come out, what is the removal route? Check clearances, loads, lifting points, turning radii and temporary works.
- What else must stop while we intervene? Identify common systems, isolations, permits and collateral downtime.
- Who has the specialist capability? Test market capacity, mobilisation, geography and single-supplier exposure.
- What are the lead times for critical parts? Connect spares policy to consequence and obsolescence risk.
- What does failure cost per hour, day and week? Quantify production, service, quality, contractual and reputational impact.
- Has operations validated the assumptions? Bring maintainers and operators into the decision before the design is fixed.
- Is the evidence available to decision-makers? Make trade-offs visible in the investment case, not buried in a workshop record.
07What AI cannot fix
Digital monitoring and AI can improve warning time, diagnosis and planning. They can help teams detect deterioration earlier, connect evidence and choose the right intervention.
They do not remove physical constraints.
AI may tell you that a bearing is deteriorating. It cannot make a three-tonne component fit through a doorway that was never designed for its removal.
The operational intelligence that matters is the connection between condition, consequence, intervention and decision. That connection should exist before technology is added and before capital is committed.
08Design the recovery, not only the operation
The strongest asset decisions do not assume failure away. They test how the organisation will detect it, reach it, isolate it, repair it, replace it and return the asset to service.
Maintainability is therefore not a downstream maintenance issue. It is part of design assurance, operational due diligence and the investment decision itself.
Assets should be designed to operate. They should also be designed to recover.
Sources: ISO 20815:2026, Production assurance and reliability management; NIH, Design for Maintainability; NIH Design Requirements Manual; Metalock Engineering, cold metal stitching repairs; UCLH, Proton Beam Therapy; IBA, Massachusetts General Hospital system restoration; European Commission, EU GMP Chapter 3; US FDA, CGMP equipment requirements; ISPE, AstraZeneca 2026 Facility of the Year Award.