National Centre for NDT ready by October :

State-of-the-art technology in major construction projects

By Kurulu Kariyakarawana

It is not inevident how certain mega construction projects have come into effect as a result of the postwar development drive which is underway at present. A dozen or more high rise skyscrapers are being built by multinational private companies in Colombo and the suburbs along with the networking of the expressway projects utilising the latest technology in the world.

The new National Centre for Non Destructive Testing

Testing an engine part

Testing a huge pipe

But the strength and the durability of these colossal concrete and metal structures are questionable, as proper testing methods are not being used currently to check their quality. In other words Sri Lanka is yet to use sophisticated technology is in existence for over two decades.

Reveal

Non Destructive Testing or popularly known as NDT is the science of testing material to reveal hidden defects without making any damage to the material. These materials could be either metals like iron, steel and aluminium or solids like concrete. In simple terms NDT could be used to test the strength of a huge concrete beam of a skyrise building or a massive pillar of an expressway without causing any damage to that particular structure.

It could check whether the concrete mixture used in these pillars is up to the international safety standards and that it will remain for a long period. Instead of collapsing due to a dangerous crack or a hollow space within the structure.

This technology could also be used in many other areas where high-tech heavy machinery is involved. Like power stations where massive water and diesel powered turbines have been installed to generate electricity, the condition of these machines should be tested every now and then to have a flawless smooth operation. With the Non Destructive Testing methods these giant machinery can be examined to identify any defects and faults without dismantling them which could be a major time and money waste. The same goes for sophisticated parts and objects of an aircraft which has to be tested using radiographic substances like X-ray and Gamma ray.

The NDT technology is currently possessed by the Atomic Energy Authority (AEA) under the Ministry of Technology, Research and Atomic Energy, which has the sole authority in the country to conduct these testing methods and train people in certified courses for world recognised professions. The technology was introduced to Sri Lanka about three decades ago in mid eighties by the International Atomic Energy Authority (IAEA). Since the global super powers decided to use atomic and nuclear technology for the betterment of the humankind instead of creating devastating weaponry, this technology was introduced to developing countries to be used in the industrial activities.

The most experienced and skilled NDT scientist in the country cum AEA Director of NCNDT T M R Tennakoon explaining about the history of this technology told the Sunday Observer that a team of experts from the IAEA visited the country thirty years ago and initiated the first training programs to a selected AEA officials. After producing a batch of local teaching experts in the NDT technology the IAEA encouraged them to pass the science to more qualified people.

The AEA selected graduates who have mastered and exelled in Physics and Mathematics and trained them with the new technology. Having possessed a properly trained staff and experiments being conducted everyday, the unit became capable of rendering practical services to the required fields in no time.

Typical industries that benefited from NDT technology in the country include power generation, aerospace, chemical, heavy mechanical fabrication, automobiles, oil and gas, ship building, foundries and civil engineering.

With rapid development of the industrial sector such as petroleum, steel fabrication, power generation, pressure boilers, high roof building and future projects on oil exploration and construction of offshore oil wells, overhead bridges and highways will increase the potential uses of NDT technology.

The NDT operations were maintained within a small unit in the authority for a long time until today, it was recognised as a national requirement to establish a suitable centre for this technology. Like the recently established sophisticated Gamma Ray Centre, the necessity to set up a fully-fledged centre for NTD technology was felt both by the authority and the ministry.

As a result a proposal was made to the cabinet in 2009 by the then Minister of Technology and Research Professor Tissa Vitharana to establish a National Centre for Non Destructive Testing (NCNDT). The proposal was approved by the Parliament and the project was overtaken by the successive Minister Patali Champika Ranawaka.

With the Cabinet approval a one and half acre land was granted to the AEA in Kelaniya Bolugaha Junction for the establishment of the new centre. The foundation stone for the NCNDT was laid by Minister Basil Rajapaksa in 2011 and the construction work was commenced immediately.

The constructions were handed over to Sri Lanka Land Reclamation and Development Corporation to be handed over to the AEA under a Design, Built and Transfer policy.

Chairman AEA Dr. Ranjith Wijewardena told the Sunday Observer that 95% of the construction work of the building is completed by now and the centre will be opened for operations in October.

Spacious centre

The NCNDT project was allocated a sum of Rs.594 million and is facilitated with state-of- the- art equipment to carry out necessary testing.

The spacious centre built on a four storey building will house 16 laboratories, four lecture halls, an examination hall, an auditorium, three practical rooms, space for Certificate Body for NDT, a heavy machinery facility, a welder training and qualification facility, space for scientific and administrative staff.

A 45-strong qualified staff has been nominated for this centre of which 28 are already serving for the AEA including 18 graduates. The final preparations of this centre are being conducted these days with expectations of opening the centre under the patronage of President Mahinda Rajapaksa in mid October, Dr. Wijewardena said.

Once the centre is set up and started to function Sri Lanka is capable of carrying out high-tech laboratory tests related to the NDT field similar to the neighbouring countries in the region. At present India, Pakistan, Singapore, Malaysia and Vietnam is having this technology and utilising it for the respective development programs in those countries.

However in Sri Lanka the authority is currently faced with a minor challenge to continue the operations of the new NDT centre due to the non availability of the laws. It is globally accepted theory that once a major construction project is commenced the NDT programs should be used from the very beginning.

For an example the first phase of a skyrise building project is piling works to set up a deep foundation run many meters down until the bedrock is found.

This bedrock is also drilled another meter down where the huge concrete columns supported with large iron rods are placed.

Once this is done an NDT should be performed on the constructed concrete columns to realise their strength prior to proceed with the rest of the construction of the building.

And from storey to storey this testing should be followed according to the international standards. But to the amazement these guidelines are never being practised by the local construction giants involved in any of the skyscrapers at present.

It is also the formality to let a third party or an external party to conduct NDT on these construction projects concerning an independent and impartial test report on the strength and safety of a project.

But this also never been practised in Sri Lanka to date except for the government base projects.

Even the mega expressway projects being carried out by the Chinese companies would not let a third party to handle an NDT but they themselves issue a report.

This why the laws are extremely important to empower the AEA to act strict in cases where NDT is not done when it comes to major construction projects.

And a Cabinet decision was taken about two months ago ordering all the government institutes should seek NDT for their projects only from the National Centre in future.

It is learnt that most of the government corporations and some leading private sector companies are already consulting the AEA for NDT for the past decade including Ceylon Electricity Board, Sri Lanka Air Force, Colombo Dockyard Ltd., Shell Gas (Lanka) Ltd. and Unilever (Ceylon) Ltd.

Apart from conducting NDT on newly constructed projects it is widely used in the industry for checking quality of the production and also as a part of routine inspection and maintenance in services. Therefore NDT is a tool to assure the quality of industrial components, assemblies and structures and that these are free from dangerous defects.

Some areas of application are boilers and pressure vessels, oil/gas pipeline and storage tanks, electric power generation (hydro, thermal, gas and diesel turbine), aerospace, shipping and railway, chillers and heat exchangers, concrete structures etc.

The AEA during the past three decades through establishment of this technology in Sri Lanka has provided inspection services to government and private sector industries, trained qualified and certified NDT personnel up to Level 3 Qualification. Many trained NDT personnel are serving the country and some have found lucrative employment overseas. Qualified NDT personnel are paid salaries starting from $1500 overseas.

There is high demand for skilled personnel in the Middle East.

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[NDT Methods]

There are five basic NDT methods commonly used to examine materials. Those are Ultrasonic (UT), Liquid Penetrant Testing (PT), Eddy Current Testing (ET) and Radiography Testing (RT). Among these NDT techniques, Radiographic and Ultrasonic Testing techniques are used for detection of internal defects. Magnetic, Penetrant and Eddy Current Testing methods are commonly used for surface and just below surface defects.

In addition to these techniques there are some other NDT methods which have specific applications. These include Acoustic Emission, Leak Testing, Visual Testing, Strain Gauging, Thermorgraphy and Concrete Testing techniques. More advance NDT techniques which are coming to the industry are Digital Radiography, Phased Array Ultrasonic Testing and Computer Tomography.

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