Testing times

Testing of MEP installations is essential to ensure the safe and efficient operation of systems. MEP Middle East examines the changing role of this equipment and outlines some of the latest products that are becoming available in the marketplace.

ANALYSIS, MEP

Testing and instrumentation equipment is crucial to both the commissioning and operation of MEP systems. Inaccurate readings or a complete lack of testing may result in poor system operation and in some cases could have fatal consequences.

The use of such products is key at the commissioning stage of a system to ensure that it is correctly calibrated to meet safety standards and function as required in the original design. Throughout the life cycle of the system they should be used to ensure that it continues to function efficiently. Such products can also provide important information that is needed for preventative maintenance programmes.

Electrical installation

 

 
In this climate it is very important that cabling and electrical systems are installed correctly.

"In this climate it is very important that cabling and electrical systems are installed correctly. The heat can cause cables to expand and the wires become sticky and can quickly become a fire hazard," explains Debashish Mukherjee, technical manager of Dubai-based distributor Haris Al-Afaq.

In the Middle East, electrical testing is generally carried out to British and European standards; the UK's IEE Wiring Regulations 16th Edition providing a basis for safe installations. "The IEE Regulations spell out what is needed in terms of testing. Four main tests are prescribed: continuity, insulation, loop impedance and rcd (residual current device) tests," explains Mark Hadley, project manager for contractor products, Megger.

"In the Middle East, it is by no means unusual to find that continuity and insulation tests are the only ones that are routinely performed, probably because these are the tests needed to confirm that the installation will actually work. What they don't do is to confirm that it's safe," Hadley stresses.

To cater for the growing pressures on electrical contractors to reduce installation times and costs, products have been developed that enable several tests to be completed using the same unit and in a shorter time. Hadley reasons: "If you take a continuity tester for example, all it has to do is produce a resistance reading of a dead circuit. Some testers have a relatively slow response, which adds a few seconds to every test. When you are carrying out hundreds of tests days these seconds add up; a continuity test function with a fast response time is therefore highly desirable."

Residual current device (rcd) testing is another area where product improvements have been made. According to the IEE Wiring Regulations a sequence of five tests must be carried out on each rcd, which has to be reset after all but the first test. Normally this would mean performing the test, noting the result, then resetting the rcd before returning to the instrument to carry out the next test.

"It is often the case that the instrument is plugged into a socket some distance away from the rcd and walking to and fro can absorb a lot of time," explains Hadley. "[One way to reduce time] is to use an instrument like Megger's MFT 1552 that has automatic remote testing. The tester automatically carries out all five tests without user intervention and stores the results for later inspection."

The MFT 1552 is a combined product that can provide continuity testing with measurements up to 99.9kΩ; insulation testing at up to 1,000Vdc; non-tripping and high-current loop tests; three-phase loop tests and prospective short-circuit current measurements. Another product to provide several functions is Fluke's 1650 Series multi-function installation tester, which performs all the basic installation tests including continuity, loop impedance and rcd tripping time. But are these new combined testers proving as popular with contractors as the equivalent individual products?

"There is still the eternal question of whether or not individual instruments are better than combined products," says Hadley. "There are still those who favour separate instruments - arguing that these allow two or more people to share the testing work more easily - and those who favour the combined approach, which means less equipment to carry and that the appropriate instrument is always to hand."

The combined approach has still to catch on in the Middle East says Mukherjee: "Combined products have proved to be very popular in Europe. They are becoming slowly more popular in this region but have still to truly take off," he states.

Air control checks

Products that enable contractors to ensure the efficient operation of air conditioning units are becoming more popular with a rising emphasis on indoor air quality (IAQ) as well as energy efficiency. Air conditioning manufacturers are developing products intended to provide better IAQ, but to gain full benefits these must be correctly installed and various testers are now being launched on the market that enable this to be checked throughout the life cycle of a system.

The Particle Counter from Fluke is intended to test the air quality provided by air conditioning units. It measures particle size distribution, temperature and humidity and can store up to 5,000 records of date, time, relative humidity, temperature and sample volumes. "This is new technology and hasn't yet proved popular in the region because people still don't know about it," admits Mukherjee.
 

Another product about to be launched into the Middle East is the PPMonitor SAS from UK-based PPM Technology. Developed to enable flexible and accurate monitoring of IAQ levels, the portable, standalone system can be used to simultaneously measure up to eight parameters that can be pre-selected by the user. Built-in software can be used to generate graphs and calculate statistical data and enables users to instantly access results, reports and scheduling options.

The PPMonitor SAS can be used to measure air quality, evaluate air control measures and in investigations of building related illnesses such as sick building syndrome. It is designed to give a visual representation of indoor air quality and its real-time functions enable immediate warnings, while analysis of recorded data allows for efficient management of resources and energy use.

"A number of monitoring units could be networked and all data collected to a central point so that precise changes in the quality of air in one area can then be monitored," explains John Jones, managing director of PPM Technology. "If the system is then connected to the building's management system, action could then be taken to resolve any issue," he adds. Wireless and hard-wired versions of the product are currently being developed and are scheduled to be officially launched in the Middle East at the 2007 Big 5 Exhibition in November.

Non-invasive techniques

With most mechanical installations at high level or remote locations, how can testing be carried out after the system is in place?

"Instruments that are popular in the region are infrared thermometers and thermal imagers," states Mukherjee. "You can use the thermal imagers to pinpoint leakages in pipes as the imaging will appear cooler where the point of moisture is."

Thermal imaging is a non-contact technology that measures infrared wavelengths to determine the temperature ranges in a system. A thermal imager displays an image that uses different colours to represent different temperatures, which makes it quick to visually check surface temperatures and identify hot spots. Fluke's Ti Series of thermal imagers measure and store the temperatures of each point on an area being examined and graphically display temperature differences. The data points can be recalled and used to determine trends over time.

Also proving to be popular in the region is Fluke's 570 Series precision non-contact infrared thermometers. These products allow contractors to measure temperatures in hard-to-reach places such as air conditioning vents. By pointing the laser beam at the desired location a precise temperature reading can be taken. Products in this series also have a built-in digital camera that photographs the location once the temperature reading is made.

Huntingdon Fusion Techniques has launched several new products recently that provide an alternative means of testing in pipework installations. The firm's Pipestoppers Division manufactures a range of devices designed specifically to provide temporary sealing during leak and low pressure testing.

These can be used in applications ranging from domestic and industrial plumbing systems to foul water drainage pipes or air conditioning ductwork. Products available cover diameters of 12mm to 1.8m and include a selection of inflatable bags that can be used to seal circular and rectangular orifices, as well as expandable mechanical plugs. Two inflatable dams connected by a sleeve are positioned within the pipe then inflated by an inert gas supply on pulling of attached tags. The Argweld Quick Purge can typically purge a 914mm diameter pipe to below 0.1% oxygen in under ten minutes, with faster purging possible for smaller pipe sizes.

Future moves

Other product developments that have been made to ease the testing process include advances in the ergonomic design of equipment. As many MEP services are often installed in tight or difficult to reach spaces, this is important for on site work.

"Many older instruments are awkwardly shaped with small displays and complicated switching, making them difficult to hold and operate, particularly in cramped locations or at the top of a ladder," explains Hadley. "The more modern instruments have been designed from the outset with ease of use in mind. Larger instruments have a neck strap, they have large, often backlit displays, which are easy to read under any conditions and they have clearly marked, easy-to-operate switches for test selection."

Increased internal memory for storing test results and the ability to download readings to a computer are other areas of progress within the development of top-end instruments. With advances in technology, Bluetooth connectivity is now also being incorporated into some products, enabling data to be downloaded remotely and saving contractors further time.

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