Containerised modular units on external plinths

How does Containerised modular units on external plinths work, step by step?

1. 1

   Step 1: Fix the interface with the technology supplier

   Everything begins with the supplier's interface documents: module dimensions and weights, base frame and bolt geometry, lifting points, connection positions for power, water, gas, drainage, earthing and control, access and maintenance space, and the spacing between units. On most projects these are contractual documents and any change to them is managed as a formal revision. The civils and electrical packages design to those interfaces, and the sequence of the whole project is written around the supplier's delivery dates.

2. 2

   Step 2: Build and survey the plinths to the supplier drawing

   The plinths are built to the bolt geometry and level tolerance the supplier states. On most projects bolts are set in templates, surveyed before the pour and surveyed again after it, and the results issued to the supplier before the module is despatched. Level tolerance across the plinth matters because the module's internal alignment assumes a flat support. A plinth built to ordinary industrial tolerance is not necessarily good enough, and finding that out on the day of the lift is the expensive way to discover it.

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   Step 3: Plan the delivery route and the lift

   The module is an abnormal load with a fixed transport window. The route from the port or factory to the plinth is surveyed for width, height, turning and bridge capacity, and the on-site route is built as designed hardstanding. The lift is planned by the appointed person against the supplier's lifting points and weights, with crane positions on certified platforms. On most projects the lift plan is reviewed with the supplier, because using the wrong lifting arrangement on a tested process module can invalidate what the supplier has warranted.

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   Step 4: Receive, inspect and land the module

   The module is inspected on arrival for transport damage before it is accepted, with the supplier present or represented. It is then lifted, guided onto the bolt group and landed. Packing, shimming and levelling follow the supplier's procedure, and the final position and level are surveyed and recorded. On most projects the module is not released for connection until that survey is accepted, because a module out of position moves every connection that follows.

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   Step 5: Make the mechanical and electrical connections

   Power, water, gas, drainage, earthing, instrument air and control connections are made at the defined interface points. This is the field work that the modular approach exists to minimise, and it is done to the supplier's procedures under the site permit system. The technology supplier normally specifies the materials and methods for anything in hydrogen service, and the contractor follows that specification rather than substituting an equivalent, because material behaviour in hydrogen service is a matter for the supplier and the designer.

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   Step 6: Complete the external safety and detection systems

   Outside the enclosure the project installs whatever the safety design calls for around it: detection, alarms, emergency shutdown links, firefighting provision, signage, barriers and the arrangements that keep ignition sources out of the areas the designer has identified as hazardous. The extent, positions and settings all come from the designer, the technology supplier and the regulator. The construction team installs and proves what is specified and does not adjust it.

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   Step 7: Test the interfaces before energising anything

   Connections are tested to the specification before the system is brought into service - electrical, control, water and drainage first, with anything in gas service tested under the supplier's procedure. Earthing and bonding continuity is proved. Control and shutdown signals are verified end to end between the module and the site systems. On most projects this is a documented hold point, and the plant does not proceed to introduce gas until the interface testing is signed off.

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   Step 8: Hand the module to the supplier for commissioning

   Once the interfaces are proved the module is handed to the technology supplier to commission. Commissioning of the process itself belongs to the supplier and follows its procedures, with the operator's and the regulator's involvement as required. The construction team's role becomes support and access. On most projects the handover is documented item by item, and the construction contractor retains responsibility only for what it built outside the enclosure.