Grooved Advantage in Cross -country Pipework
Pankaj Soni, Country Manager - India, Victaulic

Unpredictable conditions can make the outdoor installation of pipework more difficult than on construction sites. Grooved piping systems offer advantages in laying pipework cross-country that can make them a superior choice to traditional joining techniques. The article explains why mechanical joints are increasingly being used in the transport of water.

Installing pipework outdoors can create numerous difficulties for engineers. Many problems may be caused by harsh external conditions, including the weather, difficult terrain, ground swell and landslides. Access to basic amenities is also often an issue. It is not always easy to bring a generator to remote areas in tough climatic conditions, whilst ensuring maximum safety levels are maintained. Delays are a common outcome.

Grooved systems help alleviate many of the problems associated with using traditional joining methods in the field. Mechanical joints are perfect for outdoor, remote use as they can be hand assembled with no need for power tools and can be mounted under any weather conditions, unlike welds which need dry pipe.

Couplings provide visual confirmation of proper installation and there is no need for X-ray testing. With a union at every joint, they offer added flexibility and are more easily adjusted if alterations are needed.

Another benefit of using grooved mechanical piping systems is that their flame-free assembly reduces the risk of fire as well as other hazards during installation. This is very important in installations outdoors in the countryside where the risk of using hotworks in dry conditions is high.

In addition, a trench carrying a flanged or welded pipe must be nearly twice the width of a trench carrying a grooved line, so using grooved technology lowers labor and time requirements, as well as the environmental impact. At a recent penstock line installation, the use of the grooved system successfully narrowed the piping trench from 13m to 6m in the Pacific Rim Rainforest.

Speed and Flexibility
Whether the project owner is a public agency or a private company, the speed of implementation is a very important factor. Grooved systems are dramatically faster than conventional solutions even in perfect construction conditions, lowering costs and limiting exposure.

With measurable time savings between 35 per cent and 50 per cent as compared to welding, grooved systems can contribute significantly to meeting tough deadlines. In harsh climatic conditions the difference is even more dramatic . Also, pipe misalignments during installation are easier to resolve as angles can be changed more easily. In addition, the use of flexible couplings in grooved systems has other major advantages. Over a number of years, land may be subject to ground movements and displacement, which can create stresses on pipes and even lead to underground breakages. This is very difficult for engineers to control, but flexible couplings offer additional security and can accommodate these potential misalignments without the need to install expensive and delicate specialised equipment.

Using flexible joints with a grooved system can also allow for contraction and expansion of pipes and associated potential movements with temperature as well as angular deflection.

Maintenance is much easier with grooved joints, which are easily maintained and easily expandable. It can take all day to unbolt a flanged joint depending on the size. Compare this with only few minutes to unlock even a large diameter grooved coupling.

Joint Benefits
Grooved mechanical pipe joining is a no-flame joining technique of forming or cutting a groove in pipe ends and then joining them with bolted housings around a sealed gasket. It has become a preferred joining method on many piping applications when compared with welding, threading and flanging, and is commonly used in water systems technology projects.

A mechanical joint is comprised of four elements: grooved pipe, a gasket, coupling housings, and a pair of nuts and bolts. The pipe groove is made by cold forming or machining a groove into the end of a pipe. The key section of the coupling housings engage the groove and the bolts and nuts are tightened with a socket wrench or impact wrench and hold the housings together. The coupling housings engage in the groove around the circumference of the pipe and encase the gasket. A pressure responsive gasket then creates a seal unified joint that is enhanced when the system is pressurised.

For engineers, the benefits of the grooved system are many: the design versatility of the joint can allow both rigidity and flexibility, or a combination of the two, throughout a system when necessary; a mechanical joint provides noise and vibration attenuation, seismic relief, and accommodates for thermal expansion and contraction.

Added to these benefits, the system provides a union at every joint for ease of system maintenance and expansion.

Conclusions
Mechanical grooved pipe joining has been proven through research, testing and extensive evaluation. It has stood the test of time in some of the most impressive engineering feats of the last century, including the Hoover Dam, the Alexandria Library, and the Burj Khalifa.

Moreover, mechanical joining has been a reliable and rugged component of mission critical applications such as data centres, flammable chemical cleaning applications and has met the rigorous system demands required for high pressure applications in desalination plants, as well as mines, power applications and tunnelling

Summing up the benefits there is scope for significant financial savings by using mechanical grooved piping systems. Faster field installation, elimination of hotworks and reduced need for expansion joints all add up to advantages that are particularly important when choosing a system for a project in the current economic environment.

Choosing a high quality and innovative mechanical grooved piping system can bring improvements in productivity. In a sector where margins are increasingly tight, this is an increasingly attractive option for consultants, engineers and system designers alike.