The end-user has to balance technical and non-technical requirements in order to finalize on a particular selection. Non-technical requirements such as familiarity with the machine, delivery, costs, maintenance, parts, quality, and operability can make or break the project. The ability of the compressor selection to handle off-design operation (including startup and shutdown) has to be considered. How many times has the reader crossed their fingers and said “If we can just get it started, it will run great?”
Oversight of these nuances can have consequences, some not becoming apparent until the equipment is installed. It should be recognized that while technical requirements are critical for long term reliable service, the engineer may find themselves having to select a machine that is best for the project and not so much the application. The project always has technical constraints, but also commercial and schedule considerations to take into account. Also important are items such as availability of replacement parts, craft skills available for maintenance, repair facility options, staffing, and automation.
Ultimately, the end user has to make a technical compromise to select the best machine the project can bear that will be delivered and installed in the promised time, and without exceeding the budget. Everything about machinery selection can be lumped into one of these three categories: Quality, Delivery, and Price. Whether a technical or “soft” issue, quality, delivery, and price should always be brought into the discussion.