MCS offers various Non-destructive tests that detect flaws to ensure quality control without damaging or altering the inspected material.

​

There are numerous NDT methods available. The selection of NDT method depends on the specific cases and purposes. For example, the materials to be inspected, the type of defects to investigate, or the determination of pipework thickness.

​

Here are the MCS's NDT approaches (currently, expanding soon):

​

• Visual inspection/testing on site (VT)

• Ultrasonic testing (UT)

• Dye penetrant testing (DPT)

• Damp testing of insulation

• Dew point testing

​

Visual inspection/testing on site (VT)

Visual inspection requires a qualified expert to carry out a visual check on site for different items such as the condition of pipework, fittings, valves, boilers and other components in water systems of buildings. The purpose is to discover out of ordinary signs of corrosion or other defects. Visual inspection is mainly carried out for the external condition of the components of different systems. 

​

The tasks of visual inspection include the use of a digital camera, measuring rulers, tapes, removing insulations, inspection of profiles and other adequate tools to reveal flaws that may or may not be detrimental to the system components. Visual inspection can offer corrosion pit depths measurements using MCS's in-house designed digital pit depth gauge. The pit depth measurements would provide indications of external corrosion of pipework.

​

Visual inspection can also involve water sample collection for water chemistry analysis. Visual inspection will help to recommend the points of pipe samples to be cut out for future lab inspection.

​

Ultrasonic inspection (UT)

Ultrasonic testing is a widely used method for NDT. The method is frequently employed for the following purposes:

• Thickness determination to check for any wall loss due to corrosion and provide a prediction/suggestion for item replacement or retainability.

• Thickness checking to provide internal corrosion condition in situ with system operation; hence, no requirement to shut down the system and cut pipes out.

• Joints (welds or press-fit) testing for any corrosion or other volumetric defects.

​​

The procedure of UT includes contacting the inspection targets with an ultrasonic transducer. It causes beams of mechanical waves (vibrations) of short wave length and high frequency to be transmitted through the targets. These waves are then measured and compared with existing standards and abnormal peaks to verify the targets being inspected.

​

The pulse waves, when able to transmit through the target, can reveal the thickness of the target as well as any likely internal corrosion or imperfections.

​

Dye penetrant testing (DPT)

Dye penetrant testing is widely applied to inspect defects of welds. In most cases, it is used for the detection of imperfections such as cracks, pitting or other types of defects that exist in weld joints of steel pipework.​

​

Dye penetrant testing requires undergoing a correct order of procedures:

• The surface of the object to be inspected needs to be thoroughly cleaned to remove all traces of dirt and grease.

• A brightly coloured or flurescent liquid is applied liberally to the object surface and allowed to penetrate any surface breaking cracks, cavities or other defects. 

• Wait for at least 30 minutes for the liquid to fully soak into the material's surface. After soaking, the excess liquid penetrant is wiped from the surface and a developer applied.

• The developer is usually a dry white powder, which draws penetrant out of any cracks, cavities or other defects by reverse capillary action to produce indications on the surface. The coloured indications are broader than the actual flaw so more easily visible. 

​​

DPT test can be provided on or off site.​

​

Damp testing of insulation

Insulation is a common material applied to the pipework of water systems. The purpose is to prevent thermal/energy loss as well as condensation with its induced external corrosion at the external surface of pipework.

​

When insulation gets damp, it can no longer provide the function as described above. Further, the damp insulation would soon corrode the external of pipewor,k leading to detrimental leaking damages.

​

Therefore, inspecting the dampness of insulation on site can help to identify the possible dampness level and provide advice on the replacement of insulation and external corrosion conditions. The test will also assess how well or bad the insulation resists moisture penetration. 

​

Damp/moisture metre is used with two probes to penetrate the insulation for the measurement of dampness.

​

Dew point testing

Dew point testing is a test method combining visual inspection, damp testing,  environmental temperature and relative humidity testing to estimate/calculate and model the dew point data. Dew point is a key indicator to provide tell-tale signs of condensation on the external surface of metallic pipework. 

​

Condensation often occurs when water vapour in the air cools and turns into liquid water, and the dew point is the temperature at which this transformation happens. 

Essentially, the dew point is the specific temperature at which condensation begins. It is the temperature at which the air becomes saturated with water vapour meaning it cannot hold any more moisture as a gas.

​

When condensation occurs, exteranl corrosion can be triggered such as formicary corrosion on copper pipes or corrosion under insulation on steel pipes.

​​

​

Site survey - endoscope survey

​

MCS offers an endoscope survey of copper pipework in all types of water systems of buildings. An endoscope survey of copper pipes involves using a small-sized camera on a flexible long cable to inspect the internal of the pipes for identifying possible corrosion conditions, leaks, blockages or other defects. 

​

The endoscope needs to be inserted into the pipe through different access points. The flexible cable allows the camera to navigate through the pipe's bends, joints, elbows or other turns.

Endoscope survey provides direct evidence of internal pipework condition, which can be used to estimate the corrosion extent and life span.  The inspection results can also provide suggestions for pipework replacement plan or retainability assurance.

​

Endoscope survey normally requires the water system to shut down and cut out access points; therefore, the preparation stage is slightly intrusive. However, apart from the access points to be cut, no other sections need to be cut down. Hence, it is part of NDT due to minimal disruption to the building's pipework structure.

​

​

​

​

​

​

​

​

​

​

​

​​​​