The assumption
The assumption is that the site visit is the assessment, and everything else is paperwork around it.
It isn't. The design pressures, materials of construction and capacities that drive rebuild cost are confirmable from documents, before anyone travels.
Getting this the wrong way round is challenging for a specific reason: it means you can't make full use of the visit. Time on site is finite, and it's the only opportunity you get to understand what is particular about this facility: how it is laid out, how it fits together, what makes it unlike the last one. Spent recovering information that was always going to sit in a datasheet, that opportunity is gone.
Where to start
Equipment datasheets. They give materials of construction, design pressure and temperature, duty and dimensions. That is what determines the cost of a vessel or an exchanger. Not that it is a vessel, but that it is a vessel of a particular material at a particular design pressure and size.
From there the set builds outwards. P&IDs and PFDs for configuration. Plot plan and general arrangement drawings for footprint, spacing, elevations and rack runs, from which the civil and structural quantities follow. Piping layout and arrangement drawings for routing, and the line list where one exists, for sizes, classes and design conditions. Single line diagrams and cable schedules for the electrical bulks. Design basis for capacity, feedstock and utilities.
None of that requires standing on the asset. It requires the documents, and the ability to read them.
What the visit is for
Done in the right order, the visit stops being a data-gathering exercise and becomes a verification one. That is a better use of it.
- Confirming the assets are as documented, and that the as-built drawings actually hold
- Picking up recent major projects that haven't been handed over from the contractor to the plant owner. These are frequently absent from the owner's own document set, and you can only flag and request them once you've seen them standing there
- Confirming overall design capacities
- Building an appreciation of how the process areas connect to each other
- Manual take-offs on anything the documentation doesn't cover
- Insulation extent, which on cold-climate sites is a significant quantity in its own right
Every one of those is something presence resolves and paper can't. None of them is what the time on site is for, if you're still trying to establish what material the vessels are made of.
The actual bottleneck
The thing that genuinely slows this work down isn't reaching the plant. It's the information request, and specifically what happens at the other end of it.
The client receives a long list and is overwhelmed by it. Worse, the terms don't survive the journey. When I ask for equipment, I mean major static and rotary equipment. To someone on the receiving end it can reasonably read as every single valve on the plant. Faced with what looks like an unbounded task on top of their actual job, the rational response is to put it aside. And that's where the assessment stalls.
The obvious fix is a clearer, shorter, better-defined list. That helps. But it can't be the whole answer, because the problem isn't really the document. It's that a list arriving cold asks somebody to do work they don't understand the purpose of.
It has to be humanised. Talk it through rather than sending it. Define what you mean in their terms, not yours. Explain what each item unlocks, so the person retrieving it can make sensible judgements about substitutes when the exact document doesn't exist. And take the translation burden yourself rather than passing it across.
The visit was never the constraint. It's getting the information that takes months.
If you have a renewal coming
The practical consequence, for anyone working to a renewal date: the information gathering takes longer than almost anyone plans for, and how much longer depends on the facility. An older plant, one that has changed hands, or one with recent project work not yet handed over will take considerably more time than a recently commissioned facility with an intact document set.
Work backwards from the renewal date rather than forwards from when the assessment is commissioned. As a rule, allow a month between issuing the information request and the site visit. That month is what turns the visit into a verification exercise rather than a data hunt, and it is almost always the first thing compressed when the timeline slips.