I am often asked about the difference between piping design and piping engineering design. There is much confusion between the two, particularly since the major piping codes and standards partially address them and certain actions performed by them fall under government licensing for professional engineers. The distinction is important as most engineering, procurement and construction (EPC) companies employ piping designers on engineering projects who are not qualified under codes or licensing to perform piping engineering without supervision.
I define design as the creation of highly quality-assured, product definition data. A drawing is little more than a sketch without the extra step of assuring the product will perform to expectations and defined requirements. Piping designers and piping engineers provide assurance from two different bodies of knowledge: Both perform design but in accordance with two sets of requirements.
ASME B31.3-2012 defines pressure piping engineer designers as 301.1 Qualifications of the Designer — The designer is the person(s) in charge of the engineering design of a piping system and shall be experienced in the use of this code. The qualifications and experience required of the designer will depend on the complexity and criticality of the system and the nature of the individuals experience. The owner’s approval is required if the individual does not meet at least one of the following criteria:
• Completion of a degree, accredited by an independent agency [such as ABET (U.S. and international), NBA (India), CTI (France, and CNAP (Chile)], in engineering, science or technology requiring the equivalent of at least four years of full-time study that provides exposure to fundamental subject matter relevant to the design of piping systems, plus a minimum of five years’ experience in the design of related pressure piping.
• Professional engineering registration, recognized by the local jurisdiction, and experience in the design of related pressure piping.
• Completion of an accredited engineering technician or associate’s degree, requiring the equivalent of at least two years of study, plus a minimum of 10 years’ experience in the design of related pressure piping.
• Fifteen years’ experience in the design of related pressure piping. Experience in the design of related pressure piping is satisfied by piping design experience that includes design calculations for pressure, sustained and occasional loads and piping flexibility.
I won’t presume to speak for the ASME code committee but my understanding of this paragraph is it applies to engineering design of pressure piping. Practitioners under this code use their knowledge of the underlying physics to correctly apply the equations and design checks of B31.3.
Generalizing further, piping engineering applies the principals of mathematics, physics and chemistry to assure the design. They would assure pressure integrity, flow rates, pressure drops, useful life under corrosion, etc. Many licensing codes say as much, such as the Texas Engineering Practice Act:
• § 1001.003. Practice of engineering — In this chapter, “practice of engineering” means the performance of, an offer or attempt to perform any public or private service or creative work, the adequate performance of which requires engineering education, training and experience in applying special knowledge or judgment of the mathematical, physical, or engineering sciences to that service or creative work.
The piping designer specializes in applied “ilities,” i.e., fabricatability, constructability, operability, maintainability, etc. It has a body of knowledge based in company standards, field experience, construction knowledge and applicable “ilities.” Beyond drafting and CAD tools, this knowledge is acquired by reading customer standards and specs, field visits, correcting the work of others, mentoring by checkers and managers, vendor presentations and other means.
Piping designers do require some knowledge of mathematics, physics and chemistry. In their assurance of other considerations, they need to preserve (design in accordance with) the intent of the engineer. They need to know when they are “driving outside the lines painted on the road” and obtain approval from engineering. As the final product is an engineered system, they must work under engineering supervision.
Both benefit from acquired knowledge from the other’s domain. Engineers benefit from awareness of the “ilities” and designers from applicable mathematics, physics and chemistry. As designers often create the “first draft” of the design, scientific awareness increases the chances of meeting engineering requirements without redesign. Both deserve a seat at the table.
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