Saving time and money where it matters

McElroy Optimized Cooling™ is an ideal solution tailored to improving high-density polyethylene (HDPE) pipe fusion productivity in the field.

The field of HDPE pipe is rapidly expanding, especially in markets like Australia where municipalities and private companies are realising the advantages this piping material has over traditional metal or PVC pipe.

HDPE pipe, when fused according to an accepted standard using quality materials and equipment, is a piping solution that can last for a century with minimal corrosion, while also remaining durable and cost-effective.

But like any other job, the success of an HDPE project often comes down to efficiency, performance, and productivity. These standards must be met to consistently deliver quality results, whether working with a few metres of residential water line or a sewer line that stretches for several  kilometres.

During the fusion process, cooling time represents the largest time investment per joint. ASTM F2620 requires a cooling time of 11 minutes per inch of pipe wall, during which time the joint must remain under fusion pressure.

This allows the joint to gain enough strength to be removed from the machine. After removal, there is still a 30 minute “no rough handling” period that should be observed to allow the joint to cool and reach full strength.

McElroy Optimized Cooling can reduce the time investment required by using a real-time algorithm tailored to improving HDPE pipe fusion productivity in the field.

The hypothesis

Years ago, McElroy researchers determined there are four main factors at play when it comes to cooling time: ambient temperature, bulk pipe temperature, heat soak time, and wall thickness/OD (outer diameter).

Ambient temperature plays a significant role in HDPE cool times. When fusing in temperatures greater than 100 degrees Fahrenheit, the American Society for Testing and Materials (ASTM) notes that additional cooling time might be required to ensure joint integrity.

Working in partnership with the University of Tulsa, McElroy reexamined and tested standards for calculating cooling times. Using the DataLogger®, McElroy focused testing on fusion of pipe from 6 to 24-inch OD, with dimensional ratios (DR) ranging from 7 to 32.5.

During testing, pipe was fused under numerous conditions with instrumentation to measure the temperature of the core wall, using varying cooling times, then destructively tested.

The algorithm developed based on the results of those tests – McElroy Optimized Cooling – reliably predicts the optimal amount of time required to cool the core of HDPE pipe before moving on to the next fusion.

To test how temperature affects the cooling process, McElroy performed test fusions in a variety of ambient temperatures, ranging from 40 degrees Fahrenheit to 120 degrees Fahrenheit.

These tests involved 18-inch DR 32.5 HDPE and 18-inch DR 7 HDPE. All test fusions were performed in accordance with ASTM F2620.

McElroy Optimized Cooling calculates cooling times based on environmental conditions, pipe material properties and temperature, and heat soak time, while maintaining integrity of the joint itself.

The solution

McElroy Optimized Cooling can offer as much as a 55 per cent reduction in required cooling times, while still adhering to standards outlined in ASTM F2620.

Using Optimized Cooling is a simple process that utilises the DataLogger.

Before the fusion begins, the operator inputs the ambient temperature, the surface temperature of the pipe being fused, the DR of the pipe, the pipe material, and pipe diameter.

The DataLogger then provides graphical directions to the operator related to heat soak time and fusing/cooling times as calculated.

The first Optimized Cooling joint was recorded in October 2017. Shortly after, a company installing 16.3 miles (26 km) of DR 9 HDPE water line utilised Optimized Cooling and recorded its results.

Using standard cooling times per the ASTM F2620, the project would have required 1,850 hours in cooling time alone. This new algorithm cut that projected time down to 1,140 – a more than 700-hour reduction that could mean hundreds of thousands of dollars saved.

The results

Preparing for a joint using McElroy Optimized Cooling is simple. Before fusion begins, the operator inputs the ambient temperature, the surface temperature of the pipe to be joined, the DR of the pipe, pipe material, and pipe diameter into the DataLogger.

The DataLogger then provides graphical directions to the operator related to heat soak time and fusion/cooling time as calculated.

By reducing the amount of cooling time with each joint, operators and contractors are able to perform more fusions in less time while retaining the integrity of the fusion joint.

McElroy Optimized Cooling is a tested, proven, and efficient way to provide clients with an avenue to save both time and money.

For more information visit www.mcelroy.com.