After a pipeline is constructed and before it is put into service there are a number of key activities performed in order to ensure that the pipe meets the requirements of its owners or operators. These will vary to some extent depending on the service for which the line is intended, but as a minimum they will be looking for verification that the line has been laid without significant defects and is in a condition suitable to be filled with the intended product.
Pipeline Pre-commissioning is a series of activities performed to prepare it for receiving the product. SIS service line includes not only all stages of pipeline pre-commissioning but extends to pipeline regular maintenance via scheduled pigging, change of product, commissioning assistance.
Pipeline pigging has a significant role to play in meeting these conditions. Although each pipeline has its own set of characteristics which affect how and why pigging is used, there are basically three reasons to pig a pipeline:
The pigs which are used to accomplish these tasks can be divided into three categories:
The first operation during pre-commissioning is to clean and fill the pipeline.
The Purpose of this operation is to prove the continuous diameter of the pipeline.
Caliper-Tool is an intelligent inspection system which serves to measure diameter reductions.
The first operation during pre-commissioning is to clean and fill the pipeline. This is usually, though not always, performed as a single operation. The purpose of these activities is to prepare the line for hydrotesting and to ensure that the line is clean for the use of inspection tools, or that at least that debris left over from the construction phase (potentially damaging to the pipeline or associated process equipment) is cleared out. Progressive Pigging is generally run in a controlled manner with a number of pigs with increasing aggressive characteristics through a pipeline. The volume of material received/collected with each pig is carefully monitored at the receiving pig trap, pit (usually onshore), or tanks, and is used to guide the selection of the following pig types that are subsequently run.
The Purpose of this operation is to prove the continuous diameter of the pipeline, i.e. the absence of any significant dents, ovalities or defects caused during the construction phase. This phase gives a baseline for the pipeline at the date of construction. Gauging works usually carried out with 90% -97% of pipeline ID, 6-12 mm thickness Aluminium plate with redial incisions at 45⁰ intervals. Restrictions beyond the tolerance established by the disk size will manifest themselves as damage to the gauge plate, so that any damage to the gauge plate is an indication that there is a dent or other unwanted feature in the pipeline that will need further investigation. The nature of the damage can allow SIS skilled engineer to assess the probable nature of the defect. Beyond this the decision may be taken to run a caliper pig or similar geometry tool capable of providing more detailed information regarding the position and nature of the restriction.
Caliper-Tool is an intelligent inspection system which serves to measure diameter reductions in pipelines
– such as dents, ovalities, girth welds, and wall thickness changes – and to detect T-pieces, valves, and other installations. The basic body is the central mechanical element of the Caliper-Tool.All other components are fixed to the basic boxy.
The cup sleeves fill the cross section of the pipeline and enable the Caliper-Tool to be transported through the pipeline by the medium. The spider measures the inner pipeline diameter at every pipeline position. In addition to the measuring data from the spider, the distance data generated by odometer wheels is continuously acquired and stored together with the individual diameter values.
The internal locator unit transmits electromagnetic signals, which allows the Caliper-Tool to be located by an external inspection tool locator. Our tool works during the normal operation of a pipeline and is propelled through the line by compressed air / nitrogen gas / product of pipeline.
Flooding operation will start to facilitate following hydrotest operation. Fresh / brackish / sea water containing a corrosion inhibitor which meets the company’s approval shall be used for hydrostatic test purposes unless otherwise specified in Standards. Hydro pressure test is carried out to demonstrate and ensure the integrity, reliability, safety of the pipeline – Process is environmentally friendly in case of leakage or rupture during the test. The general sequence of hydrostatic testing operations for the main line shall be as follows:
If for any reason (product of the system, client specific requirement etc.) it is not practical to carry out a hydrostatic test, a pneumatic or partially pneumatic test may be substituted subject to prior agreement with the company. A pneumatic test poses a significant hazard due to the amount of stored energy in the compressed gas, however, it saves significant time. Pneumatic test can be performed by air or inert gas as medium. The testing medium should not adversely affect the material of the equipment or any process fluid for which the system has been designed. SIS experienced engineering team has developed its own methodology- complying with the specification, including risk assessment and provides to its customers practical, safe and efficient testing solutions adapted to all kinds of pipeline configurations.
Drying of pipeline is one of the critical activity to avoid formation of hydrate or corrosion. Hydrocarbon gas hydrate build-up in gas pipelines narrows the pipe profile and can cause as considerable loss of efficiency due to increased friction load. Conditions which cause formation of hydrates in gas pipelines exist mainly during or immediately after commissioning of new lines which have been hydrostatically tested. This is due to residual free water or moisture remaining in the line as a film 0.1-0.5 mm thick, after normal dewatering with or without single pig run. SIS used various methodologies for drying of pipeline such as drying with super dry air / nitrogen gas. Pig assisted drying is considered as the final cleaning works of the system. The advantages of super dry air process are low dew point, corrosion protection and economical, safe, non-hazardous cleaning action.
Pipelines that have been dried, planned to put into operation after a while and left packed with dry air, will protect the pipeline against corrosion. Although, it is a known fact that corrosion is slowed considerably or even halted at dew point below -10⁰C at atmospheric pressure, SIS recommend to purge the system with inert gas possibly right after drying works.
Process equipment in hydrocarbon services shall be subjected to periodic inspections and maintenance which may result in the pressure containment being broken. Such breaks in the pressure containment can result in explosive mixtures of air and hydrocarbon vapour being present. Therefore whenever pressure containment is broken measure must be taken to ensure that:
Nitrogen Purging and inerting process vessels, equipment, pipeline, piping system are two common, yet distinctive practices to control the concentration of oxygen, thereby reducing not only fire, explosion hazard but to preserve the system for longer duration.
Reliable flange joints are one of the vital ingredient of every industrial installation. SIS use the latest torque & tensioning technology to deliver safe, reliable flange management solutions to ensure quality of mechanical completion. Flange joints often leak due to incorrect assembly and inaccurate bolt loads. Using hydraulic bolt torques or tensioners, we provide controlled and optimum flange management services enhancing system integrity, safety and reducing costly unscheduled downtime. Bolts are used to affix two components so that they can resist tensile (pulling apart) and shearing (sliding apart) forces. After the nut has been turned onto the bolt, additional torque causes the nut to turn and stretch the bolt. When the bolt stretches it becomes a solid spring that clamps the components together. SIS range of services aren’t limited to bolt torqueing & tensioning or joint integrity only but extend to bolt protection, right application of thread lubricants, preservatives, installation of flange insulation etc.
SIS single-pass cold cutting using ultra-high pressure water jet technology for cutting storage tank floors, pipeline, side-shells etc. Cold cutting enables to carry out removal and modification work on site without having to shut down the production. SIS cold cutting methods are highly efficient compared to traditional torches and grinders, giving improved work environment for the workers and potential cost and time savings. When required, extreme accuracy and smooth cut surfaces can be achieved.
The process uses an Ultra high pressure abrasive water jet and will cut any metal, concrete or composite material that contains or is adjacent to highly flammable materials.
SIS uses portable, remote controlled, cold cutting system that pumps UHP water through a cutting head nozzle to produce a water jet at 3000 bar/ 45,000 PSI. The cold cutting machine has a split frame design which allows for easy installation and adjustments on any existing piping systems. Because the profile of the cold cutting machine is minimal, the machine only requires a small footprint to operate. The efficiency of this cutting method makes this an economical solution for de-commissioning works and other industrial cutting requirements.
