Reducing Costs Associated with Mechanical Pipe System Design & Installation

Maximizing cost efficiency is a key focus for many building contractors, developers and engineers in today’s challenging construction market. Controlling project schedules and labor costs, while optimizing space and footprint through effective building structure and system design, are key considerations at the forefront of any project. In today’s construction industry, traditional pipe jointing methods no longer provide clear benefits when compared to alternative jointing technology.  

Combining material prices and volatile labor costs, the installation of mechanical piping components can represent a significant cost risk on complex commercial and industrial building projects. Contractors are eager to balance labor and material costs without sacrificing quality. Furthermore, they must also consider the factors that minimize future maintenance and servicing for the building operator. Pressure to reduce the cost impact of the mechanical piping phase of the project has led engineers and contractors to identify opportunities to minimize installation times, with a subsequent reduction of labor costs. Added to this drive for efficiency is the increased focus on system reliability as developers and owners factor the total operational cost of the building once the initial construction and fit-out phases are complete. These considerations take into account maintenance and service costs relating to critical mechanical services within the heating, ventilation and air conditioning systems, for example. The high cost and scarcity of building space is also leading architects and building engineers to design smaller plant and mechanical rooms in order to maximize footprint for the remainder of the building. This is evident on retrofits of older buildings where the mechanical system must work within existing structural constraints. Together these factors affect the design, engineering and specification of mechanical piping systems and the need for innovative solutions that mitigate the risks of project cost volatility.

The traditional approach to mechanical piping systems

Installing mechanical piping systems can be an intricate and labor intensive process. On complex commercial and industrial buildings, the installation of the main pipework and additional ancillary products can involve thousands of separate components. The traditional approach to installing these components typically uses welded, flanged or threaded connections. This approach requires extensive, on-site skilled installation and can also impact subsequent maintenance and service schedules once the building is in operation.

Welding produces a high-strength, permanent joint with a leak–tight seal. Often specified for industrial process piping under high pressure, there are several disadvantages to using this method in mechanical piping systems. Pipe welding can be a volatile and dangerous process, particularly in enclosed spaces, and represents greater risks to installers due to the hot works, sparks and fumes. The preparation of materials required for welding makes it time consuming and labor intensive. Welders must cut and bevel pipe lengths, clamp the joint and then finally weld the material together. Depending on the pipe diameter and material, this process can take several hours for each weld. Welded systems also create potential maintenance and service challenges. By connecting different pipe sections together with permanent joints, each component essentially becomes part of a sealed unit, making it more difficult to access and replace a specific point within the system.

Flanged mechanical jointing is another traditional method used to connect pipe, using a series of nuts and bolts to compress a gasket, or rubber seal, between two flanged pipe ends. Although this method produces a strong and leak-tight joint with the added benefit of easier system access compared to welded pipe systems, it also requires further maintenance to maximize joint integrity. The nuts and bolts used to connect the flanged pipe can loosen over time due to surges and expansion and contraction within the pipeline. This pipe movement, which occurs regularly, can eventually lead to potential leaks and gasket failure in a flanged system.

Threading is typically used to connect smaller diameter pipes and ancillary products, using a spiral thread that joins a male and female channel either inside or outside the pipe and mating component. Although quick and easy to assemble, this jointing method is regarded as the least reliable in terms of seal tightness and minimization of system vibration. Leaks can be a regular occurrence with threaded pipe joints as the seal can be compromised by poor thread cuts, system vibration and improper initial installation. Joints can also become fused over time, making system access difficult and leading to increased maintenance and service times which outweigh the initial time savings when first jointing the pipes together.

“Installing mechanical piping systems can be an intricate and labor intensive process”

The innovative approach to mechanical piping systems that will reduce costs

The most beneficial alternative to welded piping systems on today’s market is grooved piping components. Grooved mechanical piping systems is an innovative solution, offering a viable alternative to conventional pipe jointing methods. A grooved mechanical joint is formed with grooved-end pipes, fittings or valves, and a coupling. The coupling comprises of three elements in order to make a complete joint – housing, gasket, and nuts and bolts. Grooved mechanical piping uses standard pipes with a fabricated groove which is machined or cold-formed into the pipe end. The joint is sealed using a resilient rubber gasket around the two grooved pipe ends and is pressure responsive to accommodate degrees of expansion, contraction and movement within the pipeline. The coupling housing fully encloses the gasket and grips the pipe groove to create a leak-tight seal in a self-restrained pipe joint. The coupling housing is held together by the external nuts and bolts that connect the upper and lower housing segments. Grooved mechanical systems use either rigid or flexible couplings depending on the application. Rigid couplings grip the full circumference of the pipe grooves to create a rigid joint. When using rigid couplings, the piping is not subjected to axial movement or angular deflection during operation. Flexible couplings allow controlled linear and angular movement caused by thermal changes in the pipeline. This is particularly useful at locations in the piping system where there is a change of direction, helping to minimize stress on the pipework.

Optimizing project schedules and reducing risk are significant factors behind change and adopting new innovative solutions in the mechanical piping jointing market. When considering the industry drivers affecting the uptake of grooved mechanical systems, this solution offers substantial and compelling benefits to project engineers, contractors and facilities operators. Grooved mechanical pipe systems improve jointing time, health and safety through the elimination of hot works and welding, and reduce project timelines and labor costs in comparison to traditional methods. This enables installation of the mechanical piping and infrastructure of the building to be completed quickly and safely with a high degree of trustworthiness and resilience. Once installed, grooved mechanical couplings reduce maintenance time as they do not require regular tightening, unlike flanged connections. Access to the system is also simplified for maintenance or retrofit of additional components by removing the coupling quickly, without special tools. This ensures the system can expand and change as the building evolves. Over the service life, this represents significant advantages for building owners and operators by reducing complexity.

“Grooved mechanical pipe systems improve jointing time, health and safety”

Welded versus Grooved Installation

Grinnell Products detailed an installed labor cost analysis comparing GRINNELL Mechanical Grooved systems with conventional welded pipe jointing for a recent hotel project in the UK. The data analyzed the potential material cost and labor savings of GRINNELL Grooved Products used in both heat recovery pump sets and horizontal in-line pump sets for HVAC applications. Based on specific installation parameters, the cost analysis used labor times for grooving and welding from Luckins Mechanical Database 2004/2005. The results of the installed labor cost analysis provide compelling evidence for the use of GRINNELL Grooved Products over traditional pipe jointing methods:

  • 90 percent Cost Savings – In heat recovery pump set applications the total labor hours are reduced from 123.04 hours to 11.75 hours using grooved mechanical systems. This represents a 90 percent savings in labor cost when based on labor cost per hour of £22.00 (USD26.98) as identified by the Luckins database.
  • 92 percent Cost Savings – For horizontal in-line pump sets the savings are even greater. Switching from traditional welded pipe jointing to grooved pipe jointing reduces the total project cost in materials and labor by 92 percent.

The above results demonstrate that considerable labor cost savings can be made by using grooved pipe jointing techniques. When it comes to optimizing cost efficiencies on the most volatile elements of a project, grooved mechanical systems represent a significant reduction in labor hours and subsequent cost.

Paul Burke
Sales Director
Mechanical Products EMEA, Tyco