A design pack is not a working plant. Between the last approved drawing and the first litre of product sits a construction phase where most of the cost, programme and safety risk actually lives. Packages arrive out of sequence, a vendor skid does not match the P&ID, a tie-in point turns out to be live, and a decision is needed within the hour.

On a regulated process site the pressure is sharper, because production rarely stops for the builders. Construction traffic shares roads with tanker deliveries, hot work happens close to zoned areas, and shutdown windows are short. Projex Solutions manages that phase for process manufacturers, as CDM duty holder, as construction manager, or as an experienced presence on site for the client. We cover pre-construction planning through to commissioning and site acceptance testing, so the plant handed back is one your operators can run.

What we cover

  • Construction Design Management (CDM) – advising on your legal duties and driving the Pre-Construction Information, Construction Phase Plan and Health and Safety File to completion.
  • Principal Designer – planning and monitoring the pre-construction phase so risks such as work at height, confined space entry and hazardous materials are designed out before anyone reaches site.
  • Principal Contractor – legal responsibility for the construction phase, coordinating every contractor under a live Construction Phase Plan with site rules, inductions and permits.
  • Construction management – day to day leadership of site execution: sequencing works, coordinating subcontractors and suppliers, enforcing HSE standards and controlling cost and change.
  • Site-based client project management support – a project manager or engineer embedded on site to represent your interests, verify work against specification and escalate issues early.
  • Commissioning support – functional testing, loop checks, safe energisation and start-up trials so mechanical, electrical, control and process systems are proven together before handover.
  • Site Acceptance Test (SAT) support and management – developing SAT protocols, coordinating vendors, witnessing tests and tracking non-conformances to closure in real site conditions.
  • CompEx inspections – visual, close and detailed inspection of electrical installations in zoned hazardous areas, confirming equipment is correctly rated, installed and certified for its zone.
  • Equipment improvement – condition assessments and targeted upgrades such as control panels, variable speed drives, instrumentation and safety interlocks, extending asset life without replacement.

CDM duty holder roles

The Construction (Design and Management) Regulations apply to all construction work in the UK, including maintenance, modification and decommissioning, not only new build. Where more than one contractor is involved, the client must appoint a Principal Designer and a Principal Contractor. Projex Solutions takes either role, or both, on operating process plant.

As Principal Designer we plan, manage and monitor the pre-construction phase. On a live plant that means testing the design against the site as it actually is: where scaffold can stand and which lines can be isolated and drained. We prepare or review the Pre-Construction Information, coordinate designers on health and safety, keep the risk register current and build the Health and Safety File.

As Principal Contractor we own the construction phase as the single point of responsibility on site, maintaining the Construction Phase Plan, coordinating contractors so their activities do not create new risks for each other, and running inductions, permits, temporary works and welfare. Shutdowns and tie-ins get particular attention: isolation and lock-off, hot work controls near hazardous areas, the interface with your permit system, and a realistic sequence for breaking in, testing and reinstating inside the window. Where DSEAR areas are affected, zone classification and ATEX equipment suitability are confirmed in the plan, not at commissioning.

When clients typically call us

  • A capital project has reached procurement with no competent Principal Designer or Principal Contractor appointed.
  • A shutdown is fixed in the calendar and the tie-in scope, permits and contractor sequence are not yet worked out.
  • A packaged skid is arriving and someone independent is needed to run the SAT and hold the supplier to specification.
  • Installation is complete but commissioning has stalled, or start-up has exposed problems nobody planned for.
  • A hazardous area installation needs CompEx inspection ahead of an audit or a return to service.

Frequently asked questions

Can you act as Principal Designer and Principal Contractor on the same project?

Yes, where we hold the competence and resource for each, and on process projects it often gives a cleaner handover between design and construction. We keep the duties and records distinct, and can equally hold one role alongside a contractor you have appointed.

Does CDM apply to a small modification on an existing plant?

Almost always. CDM covers construction work generally, including alterations, installation of plant, maintenance and decommissioning. A single line diversion or a new pump skid can still carry duty holder obligations. If you are unsure, we will review the scope and say what is required.

Can you work on a live site without stopping production?

That is the normal case for us. Work is planned around production: segregated construction areas and traffic routes, permits aligned to your system, and isolation and hot work controls. Some tasks genuinely need the plant down, and we will say so early enough for that to be planned properly.

What is the difference between commissioning support and SAT?

Commissioning proves that systems work together as designed, covering energisation, loop checks, control logic and start-up trials. A Site Acceptance Test is the formal, witnessed verification that an installed system meets its Functional Design Specification, User Requirement Specification or tender requirements in real site conditions. Most projects need both.

Related: our site and construction management work is one of six areas covered under engineering services. We also work across a range of regulated sectors and industries.

Whether you need a duty holder appointment, a construction manager or commissioning cover, we will tell you plainly what the work involves and what we would do first. Talk to us about your site. Request a call