Schematics and drawings represent the most important facet of engineering data; they bring in a new quality by adding relationships between pieces of information. CP links the primary data to the following interrelated schematics.
- Process Flow Diagram (PFD)
- Piping and Instrumentation Diagram (P&ID)
- Plant Layout (PL)
This collection of schematics void of any meaningful textual data is an input to Crenger collectively called Primary Schematics (PS).
Being part of the data rights sales every schematic has its unique role in the project scope. These roles and interrelationships are underestimated by the traditional engineering school. For example, PFD is defined as being used in “… process engineering to indicate the general flow of plant processes and equipment” [Wikipedia]. Such loosely defined PFD does not add any value to the project.
CP considers PFD as declaration of the constituent processes functionality and processes sequencing necessary to guarantee the required product quality. PFD should be generic enough not to show implementation details. In that, PFD and its annotation are similar to the method patent claims (US patent law).
PFD is a synopsis of the project and the definition of the design targets set. It is a first deliverable to the client and naturally, it is interpreted by the client as a set of guaranteed figures for the whole plant and its subsystems, and battery limits.
In defining the constituent process, CP shifts the focus from trivial process parameter description like flow rate, pressure, etc., to the product functionality and quality – categories easily grasped by the client. They include process dependability, flexibility, controllability and maintainability, and potential risks and environment impact. CP entirely substitutes ambiguous “process” for the equipment module or group term with precisely defined bounds and properties. By definition, each module or group shall be expanded into appropriate PI&D piece. Such rigorous approach to PFD allows identifying many design flaws at the earliest stage of the project. What other purposes does PFD serve?
- It is a basis for the Functional Requirement Specification as the major equipment modules or subsystems of the plant are already there.
- It is a starting point for Plant Layout development.
- It is auto-transformed by CP into Control Flow Diagram – basic document for the Plant Control Philosophy.
- It is a basis of the Reliability Block Diagram auto-generated by CP.
- It is a basis for the control Factory Acceptance Tests (FAT) and Commissioning Sequence auto-generated by CP.
- It is an input to the Work Flow Diagram - the sequence of the project major activities auto-generated by CP.
P&ID is a network of graphically linked symbols denoting pieces of equipment, instruments, piping, etc. Each of them has class-specific geometry, design and construction, materials, control and electrical data, related product information, etc. As it was mentioned previously, P&ID is an expanded view of the PFD elements or blocks, their implementation.
Traditionally P&ID has been regarded as the project main data repository, which may contain the pump performance data, piping and fitting sizes, ground and water levels, valve design details (rotary valve of ball type or butterfly one), number of solenoids in the pneumatically actuated valves, and even the assembly drawings of the injection nozzles for chemical solution. Some engineering companies include control-related information like generic discrete and analog signals to/from the instruments, analog signal processing steps, control loops information, etc.
Given the P&ID limited space, engineers struggle to strike the true balance between the P&ID readability and the information completeness. To extend P&ID capability to store data, multiple symbols and rules for composite symbols creation are being introduced (by ISO14617) to encode critical design and construction attributes.
This trend continues with introduction of multi-part classified tags for P&ID items (ISA, KKS, PIP naming standards), offering quick tip on the item service or design. Such information is of little practical use as the decoding rules are not intuitive and difficult to memorize. Manually maintaining the data placed on such P&ID diagrams and their synchronization with the accompanied documents like the Piping Schedule, Equipment List, and Instrument Index requires a lot of time and effort. For instance, the typical time allocated to the P&ID sheet containing from 40 to 60 items and accompanied documents preparation is about 150 person-hours. Worse, this data cannot be effectively searched and sorted by a computer.
CP considers P&ID a roadmap of the project; therefore, P&ID shall be simple enough for any member of the project team – engineers, managers or QA supervisors - to be capable of understanding it.
Implemented by CP multilayered approach to P&ID-linked data storage and retrieval turns every P&ID symbol into navigation shortcut. This drastically simplifies P&ID graphics (by a factor of 10) and makes CP insensitive to differences in and deficiencies of the international and local standards for the P&ID graphical symbols – ISO14617, IEC 60617, ANSI ASA Y32.11, E04-202(France), BS 1192, DIN 2429-2 and others. In addition, such approach makes P&ID truly non-dimensional and reusable in all projects – the dream of all the process engineers.
CP solves the problem of legacy P&ID diagrams: they are processed no different from new ones. In that respect CP is indispensable for small companies having no sufficient resources for maintaining high graphics standards; any diagram from very sophisticated to simplified one may be used.
CP preserves P&ID item tagging as a bridge to the legacy projects and to ease plugging the projects into already established P&ID naming systems (like KKS one).
CP generates smart tag, reuses it if the item is deleted, reorders and redefines tags according to the designer preferences, navigates the user from tag to item and from item (of the equipment list) to its location on P&ID.
Water treatment and desalination projects are a collection of subsystems (like dosing ones) and complex equipment pieces (like the high pressure pumps and centrifuges); all being supplied with P&ID diagrams often differing in graphical standards and P&ID symbols. Their direct integration into the project without re-drafting will simplify communication with the subsystem contractors and shorten the project schedule.
CP solves the problem of foreign P&ID integration by introducing a set of abstractions like symbol overriding and overloading, symbols aggregation, phantom symbols and a class of the P&ID virtual items having no associated symbols at all.
Another cornerstone concept underlying CP development is “recurring item patterns (RIP)” first introduced by ISA-5.1-1984 standard. It states that identical combinations of P&ID items shall not be shown on P&ID to make it more generic and readable. (CP enhances the latter by prohibiting the splitting of RIP between two P&IDs.) Such P&ID diagrams have no one-to-one correlation between the symbol depicting an item and its plant layout location.
This logical requirement has been never turned into industry guiding principle. It is partially explained by the adopted WISWIG - "What I See What I Get" - architecture of commercial graphics-driven programs inherited from the piping CAD software.
CP introduces the notion of P&ID items explicit and implicit grouping (Fig.1).
An explicit or static group is a finite number of items of the same project, having common attribute. Examples are items supplied by the client, items implementing the PFD node or block, pending items, UPS powered items, items connected to the same motor control center (MCC), etc.
An implicit or dynamic group may be created before the P&ID development; it is applicable to all projects executed under the same project context. Instead of group, special selector (IS) is created, which upon request groups items of the same project. This group type is extensively used for auto-mapping P&ID items to the company internal standards concerning inspections and testing. For example, only large-capacity motors shall be type-tested. Impact test is usually requested for centrifugal pumps of above 800 kW. Another example is an association of the equipment paint color with the process fluid type.
The third type of grouping is through directed links built by the designer. They go from a secondary item (child) to a primary item (parent). For example, the flow meter and the pipe fitting (expansion joint, reducer, etc.) shall always be linked to the piping (parent). VFD shall be linked to a motor, which, in turn, is pointing to the pump (parent). Another example is links between the P&ID connectors. These links are used for the P&ID auditing, the item procurement automation, and navigation between the P&ID sheets.
CP departs from traditional “A-size-framed” mindset tiling the plant layout with the P&ID sheets of the standard (A3, A2, A1) paper sizes. Besides the “tile” type, CP introduces “zoom-in” P&ID which substantially eases integration of purchased subsystem P&ID into the plant one.
CP requires that all the project areas, P&ID sheets, their items and item groups be mapped to the plant layout (PL). This mapping is turned by CP into bi-directional navigation links. On printed version of P&ID stripped of any hyperlinks, CP pastes the scaled down layout with highlighted P&ID contour at its upper right corner. Plant Layout is a basis for the following Secondary Schematics.
- Underground drainage piping layout and civil guide (UDL)
- Noise map auto-generated by CP
- Plant Control and Power Wiring Diagram, auto-generated by CP
UDL is erroneously not addressed during the bidding phase and even after P&ID completion; besides costs implication, important data about battery limits is missed (which may require extra permits). Often such an attitude leads to the project schedule slips and massive re-work due to underground piping clashing with the process equipment or civil works.
UDL is intended to convince the client that any emergency situation which may lead to the process equipment flooding, is thought of by the plant designer. (Otherwise the client may request the IP67 ingress protection, which may double the motor costs.)
CP maps the overflow points (which define the bounds of critically important Operation Modules discussed below), to the plant layout and links them to its battery limits. In addition CP auto-sizes and auto-costs underground piping based on the emergency scenarios provided by the designer. It may be said that UDL is a documented library of feasible emergency scenarios.
Recent years have been marked with growth of interest to the work safety on the desalination plants. Its first practical result was introduction of the noise pollution limitations inside the shop and on the plant boundary. The most effective way of the noise mitigation is putting the noisy equipment behind the walls or its isolation with specially designed enclosures. Both methods substantially affect the plant layout. Given the plant layout, CP auto-generates the noise map showing location of the noisy equipment and the levels of noise. This map is a standard input to the noise mitigation analysis. It will be added to the next version of CP.
CP generates Plant Control and Power Wiring Diagram defining the following points.
- Locations for instrumentation junction boxes, local control cabinets, local electrical panels/boards and UPS panels
- Instrument, control and power cables and wires instruments, junction boxes, local cabinets and electrical panels/boards
- locations for Motor Control Centers (MCC), switchgear and UPS (uninterrupted power supply) sources
- Power and control cables and wiring to MCC, switchgear and UPS sources
- Interactive One Line Electrical Diagram
- Cable BOM and MCC BOM (bill of materials).