My company couldn't see all the fuss. There was been hired by Bechtel as a subcontractor for that ill-fated Goro project to refine nickel ore in New Caledonia. Bechtel wanted us in order to suit its pipe specifications. To us, evident than when you just another symptom of some bloated . We used to joke that Bechtel had two engineers for toilets: one for that men's room and one for the women's environment. Looking back, Bechtel's approach made sense: get the Stainless steel pipe specifications right or live along with a project fraught with headaches never mind other minor issues, my friends and i.e., safety, reliability and profitability.
The first decision in establishing a pipe standard is choosing whether it will depend on function or condition. A function-based specification would be something much like a sewer pipe or vent duct. A condition-based specification would discriminate between sewer pipe for corrosive versus sanitary assist. Usually, a condition-based specification very best.
Collecting the main the next phase. Pipe specifications often are presented in tables saved in massive volumes of prints. What's missing is supporting information explaining the cornerstone for decisions like picking out type 316 stainless steel over type 304L, or selection of Inconel 601 instead of Inconel 950. This omission in company records almost justifies the reluctance I've witnessed to challenge pipe features.
Once facts are collected, you should budget time for current debts by a consultant. The idea is to search for discrepancies in between your pipe specifications and for areas of improvement. For example, Trevor Kletz, component of his book 'Process Plants: A Handbook for Inherently Safer Design,' suggests eplacing fiber gaskets with spiral-wound gaskets because their leak rate is lower.
With the analysis complete, it's time for a gathering. Bring together maintenance staff, project engineers, vendors and contractors to pencil involving details within the new pipe specifications. Leave detailed discussion of any contentious give some thought to follow-up meetings. Rely on empirical data!
Sadly, plants seldom utilize one important associated with empirical data the corrosion coupon, the welded strip of metal designed for you to become inserted best process. Instead, they allow analysis from the effects of corrosion on parent metal and welds. Coupons, which also can be used for gasket materials in some applications, provide real data well beyond those associated with textbooks and from laboratory analysis, which seems artificial by variety. The downside is exposure time; material evaluation takes quite a few weeks. But, believe me, it's worth it.
Consider occurred on another project. There was to handle a feed stream of aluminum chloride added to be able to stream containing wet chlorine gas and vaporized titanium tetrachloride. A world-renowned valve material expert claimed that zirconium oxide would survive our routine. Being prudent, I suggested coupons but was overruled because of their time constraints. Automobile was dead-wrong! What we had was quickly dubbed 'the jawbreaker effect' by our operators. Over about six weeks, the balls within ball valves shrunk, flaking away from thermal worry. Coupons would have saved us very $1 million a/year in downtime your next years and justified a ball made for this more expensive ceramic.
With all basic facts now in hand, you need to schedule follow-up meetings to review the draft pipe specifications. The best format for these specifications consists of a single page summary followed by details, exceptions and individual references. The details should include gaskets, valves, fasteners (e.g., bolts), special fittings, construction aspects such as weld inspection and paint preparation, numerous others. If possible, review the specifications in your own mechanics. They may want to complete on their wisdom on construction features.
Exceptions may exist, and where they do, they must be clarified and documented. Sometimes exceptions arise because a vendor can't change a valve specification and a satisfactory alternative wasn't found in spite of that. In one company, we ordered a PTFE-lined plug valve and modified it to fit an actuator.
Keep the summary table relatively painless. It should include pressure rating; application, i.e., by which chemicals; connections, e.g., threaded or socket-welded; and material of engineering. It's best to isolate the summary table guarantee it's compact and usable by people in the sector.
References comprise of the ANSI number as well as the old pipe specification number it replaced if there is one. Clearly state temperature limits; separately cite test pressures for ambient pressure tests. In the event you must note vendor information, also one more thing include acceptable alternatives. Keep the options open with creates. Saving a little money now on a sole-source contract often isn't worth the headache later of employing a replacement when a part is not able to meet quality standards.
An often-overlooked item is the cross-comparison table, which matches the new specifications contrary to the old ones. This table is crucial for hiring old vendors and old inventories.
Stainless steel seamless pipe specifications are probably the keys to safe plant operation. By not keeping them current or allowing them to become confusing or tough to use, you could encourage deviation from good engineering exercises. Make specifications simple and easy adhere to.