TPi November 2013

Expansion loops The flexible mechanical joint can be used in expansion loops utilising a U-shaped pipe configuration while minimising the stresses in the pipes, elbows or joints. A total of eight flexible grooved mechanical couplings, four grooved end 90° elbows and three pipe spools are required to complete each expansion loop. As system temperatures fall and the pipe run contracts, the loop expands and the deflection capability of the couplings accommodates this movement. As system temperatures increase, the opposite effect occurs as the pipe run expands and the loop contracts with the couplings accommodating the deflection in the opposite direction. The chief advantages of using grooved expansion loops over welded loops are significant reductions in both the size of the loop and the residual stresses in the piping system, such as on anchor points to activate the loop. Efficient solution In summary, grooved mechanical systems offer a range of efficient solutions to pipework installation challenges in tunnels. ■ Durable joints The Queensway Mersey Tunnel near Liverpool, UK, opened in 1934 and was one of the earliest tunnels to use a Victaulic shouldered system on its original fire main installation. Remarkably, the couplings were still found to be intact when the system was recently refurbished, although pipe sections had disintegrated. This evidence of the durability of Victaulic products was the best possible reason for the contractor to specify its modern successor – the Victaulic grooved system – as a replacement. The fire main pipeline provides water to numerous fire hydrant stations along the entire length of the 3,428m tunnel. Grooved pipe joining was chosen for its ability to cater for curvature of the tunnel and thermal pipe movement due to fluctuations in temperature. Since all work was required to be

Grooved pipe joining provides effective, time-proven methods for accommodating tunnel curvature and thermal pipe movement, while at the same time reducing stresses on the piping system and decreasing system maintenance needs. Additionally, the method helps to accelerate tunnelling projects, reduce costs and minimise job site health and safety risks. Tunnels throughout the world are fitted with grooved piping systems – a testament to the practical engineering and economic benefits of this technology. About Victaulic Since 1919, Victaulic has been a leading producer of grooved mechanical couplings and pipe joining systems. Used in the most demanding markets, Victaulic’s piping technologies and services put people to work faster while increasing safety, ensuring reliability and maximising efficiency. The company has 15 major manufacturing facilities, 28 branches worldwide and over 3,600 employees. With more than 900 active global patents, Victaulic solutions are at work in 115 countries across diverse business lines including oil and gas, chemical, mining, power generation, water and wastewater treatment, military and marine, and commercial building and fire protection. Victaulic mechanical pipe joining systems can be found in projects including the retractable roof over the world-famous Wimbledon Centre Court at the All England Lawn Tennis Club, heating and cooling at the Airbus assembly plant in Wales, and fire protection in the Queensway Mersey Tunnel. Providing sustainable solutions, Victaulic is a member of BREEAM and the UK Green Building Council, and is involved with other international initiatives.

carried out at night, speed of installation was critical, so the steel pipework was supplied in sections of 3, 6 and 12m, pre-grooved and painted with a protective coating to maximise the limited time available for fitting on-site. The refurbished fire main pipeline in Liverpool’s Queensway Mersey tunnel is joined with grooved- end couplings; the original couplings had stayed intact for over 70 years

Victaulic – USA www.victaulic.com

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Tube Products International November 2013

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