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As Nzs 2566.2 Free Download


AS/NZS 2566.2:2002 - What is it and why do you need it?




If you are involved in the design, installation, or maintenance of buried flexible pipelines, you may have heard of AS/NZS 2566.2:2002. This is a joint Australian/New Zealand standard that specifies the requirements for the installation, field testing, and commissioning of buried flexible pipelines with structural design in accordance with AS/NZS 2566.1. These pipelines rely primarily upon side support to resist vertical loads without excessive deformation by adopting an elliptical shape.




as nzs 2566.2 free download



But what are the benefits of using this standard for buried flexible pipelines? And how does it differ from other standards or pipe types? In this article, we will answer these questions and more, so you can make informed decisions about your pipeline projects.


Introduction




Buried flexible pipelines are pipes that can deform under external loads without losing their structural integrity or hydraulic capacity. They are commonly used for applications such as water supply, sewerage, drainage, irrigation, gas distribution, and cable protection. Flexible pipelines can be made of various materials, such as plastic, metallic, or composite.


AS/NZS 2566.2:2002 is a standard that provides guidance on how to install buried flexible pipelines in a safe and effective manner. It covers aspects such as site preparation, trench excavation, bedding and backfilling, pipe laying and joining, thrust restraint, trenchless installation methods, field testing, and commissioning.


Some of the benefits of using AS/NZS 2566.2:2002 for buried flexible pipelines are:



  • It ensures that the pipeline is installed in accordance with the structural design criteria specified in AS/NZS 2566.1.



  • It minimizes the risk of damage to the pipeline during installation or service.



  • It optimizes the performance and durability of the pipeline under various loading and environmental conditions.



  • It facilitates quality control and inspection of the pipeline installation.



  • It complies with the relevant regulatory and contractual requirements.



However, not all pipelines are flexible. Some pipelines are rigid, meaning that they do not deform significantly under external loads. They rely on their inherent strength and stiffness to resist loads without cracking or collapsing. Rigid pipelines are typically made of concrete or clay.


The design and installation requirements for rigid and flexible pipelines are quite different. For example:



  • Rigid pipelines require more careful handling and protection during installation to avoid damage.



  • Rigid pipelines need more precise alignment and leveling to ensure proper jointing and sealing.



  • Rigid pipelines need more rigid bedding and backfilling materials to support their weight and prevent differential settlement.



  • Flexible pipelines require more careful selection and compaction of bedding and backfilling materials to provide adequate side support and load transfer.



  • Flexible pipelines need more allowance for thermal expansion and contraction due to temperature changes.



  • Flexible pipelines need more attention to thrust restraint at bends, tees, reducers, valves, etc., to prevent pipe movement or separation.



Installation Installation requirements




The installation of buried flexible pipelines according to AS/NZS 2566.2:2002 involves several steps, such as site preparation, trench excavation, bedding and backfilling, pipe laying and joining, thrust restraint, trenchless installation methods, field testing, and commissioning. Each step has its own specific requirements that need to be followed to ensure a successful installation.


Site preparation




Before starting the installation, the site should be prepared to provide a safe and suitable working environment. This includes:



  • Obtaining all necessary permits and approvals from the relevant authorities.



  • Identifying and locating all existing underground services and utilities, such as water, gas, electricity, telecommunications, etc., and marking them clearly on the ground.



  • Removing any obstacles or hazards that may interfere with the installation, such as trees, rocks, debris, etc.



  • Establishing access routes and storage areas for the equipment and materials.



  • Setting up traffic control and safety measures to protect the workers and the public.



Trench excavation




The trench excavation should be done in accordance with the design specifications and drawings. The trench should have adequate width, depth, and length to accommodate the pipe size, jointing method, bedding material, backfill material, and compaction equipment. The trench should also have sufficient clearance from other underground services and utilities.


The trench walls should be stable and safe to prevent collapse or cave-in. If necessary, shoring or bracing systems should be used to support the trench walls. The trench bottom should be smooth and level to avoid uneven settlement or stress concentration on the pipe. Any soft or unsuitable soil should be removed and replaced with suitable material.


Bedding and backfilling




The bedding and backfilling materials are crucial for providing side support and load transfer for the buried flexible pipeline. They should be selected and placed in accordance with AS/NZS 2566.2:2002 and the manufacturer's recommendations. The bedding material should have adequate strength, stiffness, durability, permeability, and compatibility with the pipe material. The backfill material should have similar properties as the bedding material, as well as good compaction characteristics.


The bedding layer should be placed on the trench bottom with a minimum thickness of 100 mm or 10% of the pipe diameter, whichever is greater. The bedding layer should be compacted to at least 90% of the maximum dry density (MDD) as determined by AS 1289.5.4.1. The pipe should be laid on the bedding layer with proper alignment and grade. The haunching layer should be placed around the pipe up to 75% of the pipe diameter or 300 mm above the crown of the pipe, whichever is less. The haunching layer should be compacted to at least 95% of the MDD as determined by AS 1289.5.4.1. The initial backfill layer should be placed above the haunching layer up to 300 mm above the crown of the pipe. The initial backfill layer should be compacted to at least 90% of the MDD as determined by AS 1289.5.4.1. The final backfill layer should be placed above the initial backfill layer up to the ground surface or as specified in the design. The final backfill layer should be compacted to at least 85% of the MDD as determined by AS 1289.5.4.1.


The compaction of the bedding and backfilling materials should be done using suitable equipment and methods that do not damage or displace the pipe. The compaction should be verified by field density tests or other approved methods.


Pipe laying and joining




The pipe laying and joining should be done in accordance with AS/NZS 2566.2:2002 and the manufacturer's instructions. The pipe laying should start from the lowest point of the pipeline and proceed uphill. The pipe should be handled carefully to avoid damage or contamination. The pipe ends should be inspected for any defects or foreign matter before joining.


The pipe joining method depends on the type and material of the pipe. For example:



  • Plastic pipes can be joined by various methods, such as solvent cementing, heat fusion welding, electrofusion welding, mechanical couplings, or rubber ring joints.



  • Metallic pipes can be joined by methods such as welding, brazing, soldering, flanging, threading, or mechanical couplings.



  • Composite pipes can be joined by methods such as those used for plastic or metallic pipes, depending on the composition and properties of the pipe.



The pipe joints should be watertight, airtight, and resistant to corrosion, abrasion, and stress. The pipe joints should be tested for leakage and integrity before covering with backfill material.


Thrust restraint




Thrust restraint is the method of preventing pipe movement or separation at changes in direction, size, or pressure in the pipeline. Thrust restraint can be achieved by various means, such as thrust blocks, anchors, tie rods, harnesses, or mechanical joints.


AS/NZS 2566.2:2002 provides guidance on how to design and install thrust restraint systems for buried flexible pipelines. The thrust restraint system should be able to withstand the maximum thrust force generated by the internal pressure and external loads on the pipeline. The thrust restraint system should also be compatible with the pipe material and jointing method.


Trenchless installation methods




Trenchless installation methods are techniques of installing buried flexible pipelines without digging a continuous trench along the pipeline route. Trenchless installation methods can reduce the environmental impact, cost, and time of the installation. However, they also require more careful planning, design, and execution to ensure a successful installation.


AS/NZS 2566.2:2002 covers two main types of trenchless installation methods for buried flexible pipelines: horizontal directional drilling (HDD) and pipe bursting. HDD is a method of installing a pipe by drilling a pilot hole along the desired pipeline route and then pulling the pipe through the hole. Pipe bursting is a method of replacing an existing pipe by breaking it with a bursting head and pulling a new pipe through the cavity.


Both HDD and pipe bursting have their own advantages and disadvantages, depending on factors such as soil conditions,


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