CODES AND STANDARDS
PIPING LAYOUT CONSIDERATIONS
Project Client and Owner Requirements
Hierarchy of Reference Design Information
System Piping and Instrumentation Diagrams (P&ID)
components, pipeline sizes, and overall system arrangement required for proper system function. Computer-aided P&IDs that link the schematic diagrams to electronic design data are preferred in order to perform computerized P&ID compliance checks.
P&ID Implementation and Physicalization
Project Piping Specifications
General Arrangements or Equipment Location Drawings
Collection of As-Built Information
Piping Layout Considerations and Planning Studies for Improved Piping Economics
check valves. In addition, the designer should be aware that this requirement can be as much as 10 diameters of straight pipe depending on the type of valve and the manufacturer.
Safety Relief Valves
● The vent stack entry diameter shall be maintained throughout the length of the vent stack; enlarged entry spools, later reduced in size to the calculated minimum flow diameter, are not acceptable.
Piping of Centrifugal Pumps
● All pump suction lines must be designed to accommodate a conical-type temporary strainer.
Vents and Drains
Buried Piping Systems
pipe support components and their application. Piping should be routed such that the support designer can make use of the surrounding structure to provide logical points of support, anchors, guides, or restraints, with ample space for the appropriate hardware. Banks of parallel pipelines at different elevations should be staggered horizontally and spaced sufficiently apart to permit independent pipe supports for each line. Piping on pipe racks should be routed using bottom-of-pipe (BOP) elevations. The piping designer should work closely with the structural engineer in the spacing of the pipe rack supports and the method of intermediate support to prevent pipe sagging.
Operability, Maintenance, Safety, and Accessibility
will concentrate on those requiring the most frequent operation. Safety-related equipment and valves that are required to be operated during an emergency or to perform critical system functions must be accessible without exception. To ensure success, the designer, system engineer, and operating personnel work out the final arrangement. Sometimes input from construction, start-up, and vendor personnel is needed. Formerly in difficult cases, models or even full-size mock-ups have been used as design aids. Today the trend is toward virtual reality. Under today’s conditions the whole process can be accelerated and, when done effectively, accomplished at lower cost than formerly. Additional considerations are discussed in other sections of this chapter. In general, an operable valve or instrument is one that can be readily reached when standing at grade or on an elevated floor or platform provided for that purpose. The position of the valve handwheel should be such that the force necessary to operate it can be applied without strain or undue contortions or interference from valves, lines, or other equipment. It is recognized that plant operating personnel will occasionally have to reach for a drain from a kneeling position or a vent valve from a ladder, but these are infrequent operations and as such can be tolerated.
Interfacing Disciplines and Organizations
support steel should be avoided. Pipes or electrical trays that twist and turn to avoid one another should be uniformly designed in a coordinated design effort which reduces congestion and reduces TIC. Most piping designs are not completed by a single designer or company, which makes the coordination between designers and different organizations critical. The best way to address this concern is to agree to specific divisions of responsibility in the planning phase of the project.
Electrical Tray and High-Temperature Piping Interfaces
SPECIFIC SYSTEM CONSIDERATIONS
Main Steam and Hot and Cold Reheat
Turbine Extraction Steam
Floor and Equipment Drains
Sump Locations and Pump Discharge
Cooling Water Systems
APPLICATION OF COMPUTER-AIDED DESIGN TO PIPING LAYOUT
User-Definable Symbols and Menus
Use of Standard Hardware.
Availability of Third-Party Software
Support of User-Developed Software
Support for Multiple Users
Training and Implementation
model. These drawings should be generated in the form of 2D CAD drawings so that they can be managed along with the 2D drawings not generated from the 3D model. For orthographic drawings, the system should be able to represent the piping in the format required by the user, e.g., single-line; it should be able to automatically remove hidden lines from the model; and it should have some basic capability to automatically place annotation, such as component callouts, into the drawing. For piping isometrics, it is not unreasonable to expect the software to generate the piping isometric automatically.
Bills of Material
Interface to Other Systems
systems. This could also include interfaces to fabrication equipment, such as numerically controlled pipe-bending systems.
Training and Implementation
learning curve. Also, these types of systems are more pervasive than simple 2D CAD drafting in that they require a higher level of integration between disciplines and departments and thus a higher level of management attention and support.