within the 77 tender documents supplied to the contractor. The contractor was ... Acquisition (SCADA) software development of the port facilities. A close ...
Implementing Innovative Ideas in Structural Engineering and Project Management Edited by Saha, S., Lloyd, N., Yazdani, S., and Singh, A. Copyright © 2015 ISEC Press ISBN: 978-0-9960437-1-7
PRE-CONTRACT EVALUATION OF TENDER DOCUMENTATION: THE CASE FOR SYSTEMS INFORMATION MODELLING Peter E.D. Love1 Jingyang Zhou1 and Jane Matthews2 1 Department of Civil Engineering, Curtin University, Perth, WA, Australia Department of Construction Management, Curtin University, Perth, WA, Australia
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The quality of tender documentation provided to an electrical engineering contractor for the control system expansion for an Iron Ore port facility is analyzed according to the errors and omissions that materialized. A total of 426 errors and omissions were found within the 77 tender documents supplied to the contractor. The contractor was required by the Engineering, Construction, Procurement and Management contractor to provide a lump sum bid and also ensure schedule would be met. The electrical engineering contractor decided not to submit a bid due the inaccuracy of tender information supplied. In addressing the issue of information errors and omissions contained within the electrical and instrumentation (E&I) documentation, the use of a Systems Information Model (SIM) is propagated and described. While a SIM is akin to the object-orientated representation inherent within the construction of a Building Information Model, the mining sector has yet to effectively embrace this approach, particularly within the context of E&I systems. The research concludes that the economic performance and productivity of mining projects can be significantly improved by using a SIM to engineer and document E&I systems. Keywords: Electrical and Instrumentation, Errors, Omissions, Productivity, Mining
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INTRODUCTION
The quality of tender documentation provided to an electrical engineering contractor for the control system expansion for an Iron Ore port facility is analyzed. Notably, such information is rarely made available for analyses due to commercial sensitivity and therefore, a detailed insight of practitioners operating in the mining sector is presented. Noteworthy, the participating contractor is hereafter referred to as ‘Contractor A’ to preserve confidentiality agreements made between both parties. Thus the aim of this paper is to examine the nature of errors and omissions that were presented in the tender documents and the potential risk exposure that the contractor would have faced in the field should they have been awarded the project. To address the deficiencies contained within the drawings provided in tender documents, it is suggested that the use of a Systems Information Model (SIM) to design and document the electrical and instrumentation (E&I) systems instead of Computer-Aided Design (CAD) would significantly reduce the occurrence of errors and omissions. A SIM is akin to the objectorientated representation inherent within a Building Information Model (BIM), yet the use of software applications by E&Is to produce object models are rarely used in the
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Australian mining sector. This is in stark contrast to recent studies in North America where electrical contractors have begun to embrace software that enables the construction of a BIM (Hanna et al., 2013; Hanna et al., 2014). 2
CASE STUDY
The E&I tender documentation for a control system expansion for an Iron Ore port facility provided to several electrical engineering contractors are examined. Those contractors invited to prepare a ‘bid’ were given three weeks to produce their tender. A lump sum bid was required for the control system by ‘Company IO’ and all work specified in the contract was required to be completed by the specified date. In addition, it was explicitly stated that any cost overrun incurred by latent uncertainties and insufficient information contained within the contract documents were at the contractor’s risk. 2.3 Tender Documentation The tender documents comprised of 126 files, containing a total of 1687 pages. The tender documents studied in this research described the requirements of the control system installation, Programmable Logic Controller (PLC) and Supervisory, Control and Data Acquisition (SCADA) software development of the port facilities. A close investigation of tender documents revealed numerous errors and omissions: the date required to produce a tender was considered unachievable by the electrical contractors. In particular, designing and constructing the project’s first switch room within seven weeks would be an impossible task considering the paucity and inaccuracy of information provided. Contractor ‘A’ decided not to risk submitting a tender due to the gravity of commercial risks posed. In trying to decipher and comprehend the scope and nature of work contained within the tender package, a principle engineer stated: “The documents contained many internal conflicts and omissions so we failed to understand the required scope. The work required was not sufficiently defined for a lump sum contract. Offering a bid, at its present form, would be an unacceptable commercial risk to us.’ The overall structure of the control system as defined in the tender documentation was not clearly specified. The typical process within ports for exporting iron ore consists of unloading (from trains or trucks), transporting and sampling and loading (to ships). Often (depending on the size and capacity of port), a number of devices and facilities are involved i.e. train unloaders, conveyors, shuttles, stackers, reclaimers, sample stations, ship loaders and other miscellaneous equipment. To achieve a safe and environmental friendly production process, all the devices were required to conform to a robust safety control system; where number of risk controls must be implemented i.e. dust suppression, structural anti-collision, materials route sequencing and stockpile management. Several environmental auxiliary systems such as oil water separation, sewerage treatment and potable water generation, also needed to be integrated into the plant to facilitate production. All the systems are controlled by the PLCs and supervised via the Central Control Room (CCR) through SCADA networks. It was implied that the process and safety control system would be designed together to maximize productivity by being capable of immediate fault detection and diagnosis so as to minimize system down time.
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However, tender documents did not provide a clear structure for how the control system would be achieved, or how contractors could integrate such into the existing system. 3
RESEARCH FINDINGS
A total of 77 E&I drawings were provided in the tender package. These drawings included 60 single line diagrams to illustrate how various configurations of the HV, VSD and motor control panels were to be constructed, and eight Piping and Instrumentation Diagrams describing the process flows and installed instruments. When examining the information presented in the 77 drawings provided to produce a tender, the cables, components and their corresponding relationships were extracted and inputted into a SIM using the software Dynamic Asset Documentation (DAD). Tender documents did not include a cable schedule and as a result, designs had to be manually transferred from CAD drawings into a SIM; this established a 1:1 relationship between designs to be constructed in the real world and their digital realizations. Each piece of equipment was created with ‘Type’ and ‘Location’ attributes; where: the ‘Type’ attribute defined equipment functionalities; and the ‘Location’ attribute described the physical position of equipment within a plant. Such classifications, enabled engineers to browse the SIM model and locate information as required. For example, a conveyor drive motor (CV915EM01) can be found under the folder ‘Type\Motor’ as well as the folder ‘Location\CV915’. As each cable or component is only modeled once, errors and omissions contained within the CAD drawings were identified and rectified during the SIM conversion process. 3.1
Errors and Omissions
The completed modeling process identified a total of 1545 cables and 1518 components within the 77 drawings. Numerous errors and omissions found would have hindered the engineers’ ability to interpret the information contained within these tender documents. These errors and omissions were classified as follows: 1. Incorrect labeling: Cables or components are labeled with incorrect names; 2. Inconsistent labeling: Cables or components are named differently within various contractual drawings; 3. Incorrect connection: Cables or components were connected to wrong connections; 4. Drawing omission: Cables and components were missing from some drawings; 5. Missing label: Cables or components are drawn on drawings but are not labeled; 6. Incomplete labeling: Labels of cables or components are not completely shown. A total of 426 errors and omissions occurred within the 77 drawings. A total of 244 errors and omissions (i.e. 57.28% of all problems identified) were attributed to cables. 182 (42.72%) errors and omission were associated with components. Noteworthy that the classification of ‘Missing Label’ was the most prevalent accounting for 59.86% of all issues identified. A total of 84 omissions (65 cables, 19 components) were identified on drawings; these drawings were CAD generated, so information within them was not
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dynamically linked thereby reducing information traceability. Thus, there is a propensity for omissions to occur when the same information is repeated on several drawings especially when produced by different draftsmen Considerable amounts of cross coupled reference drawing numbers were identified in contract drawings. Notably, 70 of the drawings referred to were not made available to the applicants at the tender package and three drawings were mistakenly referenced. For example, a reference drawing was labeled as 505P-10016-DR-EL-×××× where the last four digits were replaced by ‘××××’ instead of a specified drawing number. Given such an obscure expression, it proved impossible to locate the drawing where the reference information resides. In the case of electrical engineering projects, there is a proclivity for cable schedules to be used to document inter-connections between components and cables, and to estimate the quantity of materials used to form the control networks. If the information extracted from cable schedules is different from that expressed on a drawing, then the risk of an error or omission arising is elevated. However, no cable schedule was provided in the tender documents and so consequently, contractors tendering for the project could not check information conveyed on the drawings against the cable schedule. Moreover, to take-off the quantities, the contractors would have had to examine all the contract drawings, which would have been an unproductive process. 4 SYSTEMS INFORMATION MODEL To effectively and efficiently address errors and omissions that were found in the E&I documentation in the case study, it is suggested that there needs to be a switch from a 1:n drawing based documentation process, inherent within CAD, to a 1:1 that utilizes a SIM. In contrast to conventional CAD software, a SIM can be applied to projects where a system’s design describes the interrelationships of the connected components that exist within the system. For example, in a SIM based electrical control system, all the interconnected equipment and cables are digitally modeled in a single database that can be accessed through specific software such as DAD. The model created replicates the design to be achieved in the ‘real world’ and each physical object only needs to be modeled once. Therefore, a 1:1 relationship is achieved between the real world and the model. Information stored in the database is dynamically linked to enable future access via the model directly. During the design phase, all engineers can collaborate on the same model concurrently. Components and relationships among them can be modeled and a SIM can be obtained. Duplicated modeling of an identical device can be detected and avoided automatically. Because each object modeled is allocated with a unique tag number, the problem of ‘missing label’ is eliminated. Attributes, (such as material types, number of connections, and equipment dimensions) can be attached to the model for each individual object. These attributes and associated functions enable the SIM to be applied to activities in engineering, procurement, construction, commissioning and maintenance. A SIM model database can be accessed either locally or remotely via a local workstation (Personal Computer (PC)) or a remote server, which can be accessed online (via mobile device). The PC version is compatible with a ‘Windows’ operating systems whilst the mobile version can be installed on industrial tablets and used in the field. Once design is complete, the model is encapsulated to protect the data stored in case of any unauthorized
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changes. The design can then be exported and issued to other users as a read only copy called ‘Kernel’ (Figure 1).
. Figure 1. Kernel revision process (Adapted from Love et al. 2013)
Users can import and access all or part of the design information within the Kernel, depending on their authorization level. Private user data can be established and managed via a portal such as editing attributes for the components or attaching additional documents to the model. To guarantee that all users are working on an identical Kernel, users are not authorized to change the design. However, if users find conflicts or design errors in the Kernel, they can identify them and create a specific RFI folder within the user portal. A spreadsheet can be automatically generated containing all the information for those objects either in Microsoft Excel or portal document format (pdf.) file format. On receipt of the spreadsheet, the design team can review the design and rectify problems immediately before generating and exporting a new ‘revised’ Kernel to users for further application. By adopting a SIM, the need for drawings can be eliminated and error rectification becomes a straightforward process as all modifications can be undertaken within the digital model. This approach eliminates the need for an engineer to identify all other relevant drawings and manually revise them. Consequently, time and cost can be reduced and productivity increased (Love et al., 2013). When CAD drawings are used, relationships between components contained within various drawings are denoted by reference numbers, which is time consuming and prone to errors. The complexity of the linkages significantly increases as the size of the project expands. Any incorrect or incomplete labeling invariably reduces information traceability and a considerable amount of effort is required to recover the missing information. A SIM can overcome this issue as all the components modeled in within it are dynamically interconnected. A SIM can also perform quantity take-offs. Interpreting and recovering information presented on several drawings is an unproductive process whilst, errors and omissions contained within drawings can adversely impact a contractor’s procurement process (e.g. material waste, rework). As all the components modeled within a SIM are categorized
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according to ‘Type’ and ‘Location’ classes, users are able to identify and locate the required equipment. Equipment numbers are made available to users directly through a ‘Quick Spreadsheet’ function provided. Cost information for these items can also be acquired through the cost attribute assigned to each individual component. The number of equipment and the associated cost can be automatically calculated, which enables users to estimate the overall cost and the man-hours to complete the job at hand. The culmination of research presented here suggests that if a SIM model was adopted, the port expansion project could have been designed and progressed more efficiently because less errors and omissions would have occurred. Essentially, a SIM based design can assist the tenderers to evaluate and prepare a competitive bid for scheduled works. A reliable and reasonable bid can reduce ‘risk’ to the contractor but also facilitate the progress of downstream activities through informed decision-making and therefore mitigate against project delays and cost overruns. 5 CONCLUSION A detailed analysis of omissions and errors was undertaken for the E&I tender for upgrading a control system. An analysis of 77 drawings provided in tender documentation revealed 426 errors, and 70 drawings that were referenced had been omitted. Yet, the Contractor A was bound by a fixed lump sum price and rigid project schedule for completion. Contractor A decided not to submit a bid because the risks of financial loss outweighed the opportunity to generate a profit. The rationale for EPCM contractor providing contractors with such poor quality documentation was unclear because the researchers could not gain access to those who prepared the documentation, but it was suggested that there was a requirement by the client to be producing Iron Ore by a fixed date. In addressing the issue of information errors and omissions contained within the E&I documentation, the use of a SIM has been propagated and described. A SIM is a generic term used to describe the process of modeling complex systems using appropriate software such as DAD. When a SIM is applied to design a connected system, all physical equipment and the associated connections to be constructed can be modeled into a database. Each object is modeled once. Thus, a 1:1 relationship is achieved between the SIM and the real world. As a result, information redundancy contained within traditional CAD documents is eliminated. Productivity is subsequently improved and the economic performance of mining projects significantly augmented when a SIM is used engineer and document E&I systems. References Hanna, A.S., Boodai, F., and El Asmar, M. State of Practice of Building Information Modelling in Mechanical and Electrical Construction Industries. ASCE Journal of Construction Engineering and Management, 139(10), 2013 Hanna, A., Yeutter, M., and Aoun, D. State of Practice Building Information Modelling in the Electrical Construction Industry. ASCE Journal of Construction, Engineering and Management, 140(12), 2014 Love, P.E.D. Zhou, J., Sing, C-P. and Kim, J.T. Documentation Errors in Instrumentation and Electrical Systems: Toward Productivity Improvement using System Information Modelling. Automation in Construction, 35, 448-459, 2013
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