Ultrasonic Thickness Gauge Explained

Ultrasonic thickness gauge
Cygnus Dive ultrasonic thickness gauge

An ultrasonic thickness gauge is utilised by professional engineers to undertake sub-sea surveys and carry out maintenance inspections.

What is an ultrasonic thickness gauge?

An ultrasonic thickness gauge is a non-destructive testing device utilised for acquiring an accurate thickness measurement of solid materials such as steel and other metals.

These types of gauges allow reliable measurements to be taken in a non-destructive manner, and without requiring access to both sides of the material. For example, they can be used to measure the thickness of a pipe without needing access to the inside of the pipe.

Available in a selection of models for differing circumstances and environments, ultrasonic thickness gauges measure the amount of time it takes for sound to travel through a material, and this information is then used to calculate the material's thickness.

Ultrasonic measuring gauge facts

  • Non-destructive measuring device
  • Able to read through protective coatings such as paint
  • Utilised for determining corrosion and wastage
  • Readings are taken from one side only
  • Highly accurate and error-checked readings
  • Lightweight and portable for easy handling
  • Simple operation
  • Reduces inspection times and costs
  • Reliable and robust construction with stringent IP ratings

How does an ultrasonic thickness gauge work

The digital multiple echo technology in an ultrasonic thickness gauge.  It sends a short pulse of high-frequency sound through the material.  However, unlike single echo technology, the multiple echo unit measures the time delay between 3 consecutive back wall echoes, and it is the distance between the 2nd and 3rd echoes that gives a true and accurate reading of the material thickness only, ignoring any paint or coating.

Ultrasonic thickness devices save time and money

Measuring pipeline thickness with ultrasonic gauge
Measuring pipeline thickness with an ultrasonic gauge

When performing industrial surveys and maintenance checks the ultrasonic thickness gauge has become a necessity.  Cutting down the time taken to complete the task and negating the need for expensive removal and reinstatement of coatings, the device enables engineers to easily and efficiently obtain accurate readings highlighting any current flaws or upcoming problems that could occur in a structure.

Types of ultrasonic gauges

Portable and hand-held devices are currently available on the market, these allow industrial engineers to perform vital predictive maintenance in situations that require rope access, in hazardous environments, offshore, and for ship survey projects as well as for divers on deep-sea exploration assignments.

Industries Currently Utilising the Ultrasonic Thickness Gauge

  • Civil Engineers & County, Borough and District Councils :
    Used in the assessment of the metal thickness of bridges and other large structures
  • Chemicals:
    Used for inspection and maintenance of hazardous material vessels and storage tanks
  • Food & Other Processing Plants:
    Used to provide maintenance testing for Food production plants, pipe and storage tanks
  • Oil & Gas:
    Used to perform maintenance testing for internal corrosion of oil and gas pipelines and storage tanks
  • Shipping & Marine:
    Used to obtain regular preventative maintenance readings for shipping companies and marine leisure craft from hull and bulkhead
  • Underwater:
    Used in hazardous environments to perform regular maintenance readings on underwater pipelines and oil rigs. The device is often referred to as an underwater ultrasonic thickness gauge
  • Water Treatment Facilities:
    Used to perform regular maintenance checks on water treatment plants, pipes and storage.

Underwater Thickness Gauges

Utilised by professional divers and engineers to undertake sub-sea surveys, the underwater thickness gauge is commonly used to carry out maintenance inspections and corrosion checks on metal structures in the ocean, such as ships' hulls, underwater pipelines, offshore structures, piers and bridges.

Many ultrasonic thickness gauges ignore surface coatings which allow for a more accurate measurement to be acquired. Some models have the added convenience of calibration buttons and can be used to a depth of 300 metres, enabling them to be employed for a wide range of sub-sea tasks without the need for complex and time-consuming setups.

Ultrasonic thickness testing data

Once surveys have been carried out, the collected data can be transferred to an external device to allow for in-depth analysis of the results. The results of the survey are used to analyse the damage and assess reconstruction work that may be required. The underwater thickness gauge has become an essential piece of testing equipment that greatly reduces time spent on inspection and allows regular ongoing maintenance cost-effectively.

Utilising high-quality ultrasonic testing equipment is essential

Using good quality equipment is essential for recording accurate information when conducting underwater surveys. The technology used in underwater thickness gauges is specially designed to carry out incredibly precise measurements, allowing one to work to the highest standards in hazardous, unpredictable environments such as structures at sea, protecting both the structure and the surrounding environment from unnecessary, costly disasters.

Cygnus Instruments has three decades of experience in the field of ultrasonic measurement and is the leading manufacturer of multiple echo digital ultrasonic thickness gauges.


  1. The article is useful because it gives brief information about ultrasonic thickness gauge, how it works and its types. The ultrasonic gauge helps reduce inspection times and costs. Thanks.


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