Page 28 - Improving Machinery Reliability

Chapter 1

Reauirements Saecification

Long before machinery specifications can be prepared, the plant designers per-
form scoping studies encompassing a large number of options. Process and econom-
ic considerations are weighed, compared, and analyzed. Design philosophies are
debated at the highest levels of management, business forecasts are studied, and
thousands of questions are asked and answered before the machinery engineer is
given his first opportunity to prepare an inquiry document for major machinery or
detailed purchase specification packages for all the machinery in a process plant.
To the superficial observer, the job of specifying machinery would seem rather rou-
tine. But an experienced engineer knows that this is far from true. Ticking off a few
check marks on a form sheet may define the extent of supply, but it certainly cannot
pass as an adequate specification for major machinery. Then again, excessively bulky
specifications may have the effect of frightening the bidder into adding significant
extra charges for potential oversights, and badly worded specifications may prompt
cost escalation to cover potential misunderstandings. At times a combination of bulk,
cross referencing of many specification documents, and wording subject to misinter-
pretation has motivated vendors to decline to bid. As if this were not bad enough, an
ill-conceived specification may burden process plants with the perennial “bad
actor”-a piece of maintenance-intensive machinery not bad enough to replace with
something new or different, but bad enough to drive up maintenance costs, sap main-
tenance manpower, and cause feelings of resignation or demotivation in personnel.
A good specification, therefore, is concise and precise. It will have to define your
requirements in clear, understandable form. Yet it should encourage the vendor to
offer more than the bare minimum requirements. Your next process plant should
benefit from advances in the state-of-the-art of which the vendor may have knowl-
edge if your joint, conscientious screening efforts can certify these changes to be
safe, economic, and not prove to introduce downtime risks.

Industry Standards Available for Major Machinery in Process Plants
Table 1- 1 represents a listing of presently available API (American Petroleum
Institute) standards. These specifications were developed by panels of user engineers
to define petrochemical process plant machinery in a professional fashion. Wherever
possible, API standards should become the focal point document in machinery speci-
fications for process plants.

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