Chemical Technology June 2015

Construction The first works will be civil works in the form of base camps, access roads, and laydown areas for materials. The Con- struction Management teamwill act for and on behalf of the owner and the team will usually consist of a Site Construc- tion Manager an HSE Manager, a Quality Control Manager and numerous Site Craft Supervisors and a site Planner. Quality Management System Construction quality systems usually follow the International Standards Organisation (ISO) 9001:2008 format [7]. The owners demand written documentation defining quality requirements of every aspect of the new pipeline. Scheduling of packages Contractor personnel will maintain a status of the prog- ress on the completion of package activities when overall construction progress reaches the 50 % milestone. These system handover packages will be used to track the comple- tion of various construction, inspection, or mechanical completion activities in order to be able to quickly determine the completion status of any given system. Punchlists System punchlists will list items that are incomplete, not in conformance with the construction documents, or that require modification. Contractor will sign-off and advise owner to verify that the punchlist items have been completed in accordance with the construction documents. Handover /Mechanical completion Handover is the sequence of events leading to transfer of custody of a system from contractor to owner. It is the demarcation between the construction phase and commis- sioning/Start-up operations. Pre-commissioning [8] Pre-commissioning activities are associated withmaking the system ready for operation and will include the following: • De-watering of residual hydrostatic test water in the pipeline • Flushing and dry air blowing of above ground piping and valve and pigging stations. • Swabbing of pipeline • Low pressure leak check (with air) for the above ground section of the pipelines. Commissioning procedure [9] Instrument controls and interlocks are functional as per the normal operating conditions. Utilities - Utilities such as power, UPS, water, air, instru- ment air and HVAC will be checked. Alarm systems - Setting off alarms and their functioning will be ensured. Safety - Identification of possible emergencies and pre- paredness for its mitigation will be checked. To clear the pipeline of metallic particles, magnetic clean- ing will be carried out using a train of brush magnetic pigs. An intelligent pigging survey will be carried out recording the

entire length in one single run. The report will include a de- tailed description of the type, size and location of individual mechanical defects. The repair of defects will be carried out in accordance with that specified in IS 15663 (Part 1) [9]. The pipeline system needs to be rendered inert using nitrogen. The system will be considered to have been commis- sioned successfully when the pipeline system has run suc- cessfully for a minimum period of 72 h at stable operating conditions and instrumentation/control systems, process utilities and support systems taken on line. Commissioning documentation records must be kept by the contractor. Start-up/Runtest Start-up begins when all system pre-commissioning and commissioning are completed and accepted by the owner. Performance guarantee Contractor will guarantee the performance of all equipment and material in his supply, based on the ability of the com- plete system to be able to flow the design volume of gas, at the design pressure to the discharge location Challenges involved in constructing a pipeline There are a significant number of challenges in the construc- tion of a pipeline [9], in particular: • Sustaining the project with the number of resources required over a long period of time • Permission from local authorities and construction notifications • EIA assessment approvals, in particular wildlife conserva- tion areas and mitigation plans • Different sections of a pipeline will have particular issues, eg, conservation areas • Pipeline safety can have special conditions that have to be agreed to as part of the EIA • During construction, local authorities need to be kept abreast of any issues that may arise • Directional drilling at water or road crossings will be necessary and can be difficult • Safety in the design of the pipeline is paramount and needs acute attention • Trained artisans can be a problem to locate but proper skills development is essential • Multiple construction offices and laydown areas along the pipeline are necessary • Vendors need to be aware of the importance of materi- als and equipment deliveries on time and at the right location. • Experienced project managers, engineering managers, construction managers and craft supervisors are essen- tial to enable a pipeline to be constructed under budget and on time. References A list of references for this article is available from the editor at chemtech@crown.co.za.

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Chemical Technology • June 2015