Case study #109: National Physical Laboratory (NPL)

India’s premier research laboratory entrusts Adept with the responsibility of setting up Water Meter and Flowmeter Testing and Calibration facility

National Physical Laboratory (NPL) selected Adept to play a major role in this project due to our experience of more than 3 decades in Flowmeters manufacturing and calibration as well as our self-developed NABL accredited calibration facilities.

The National Physical Laboratory (NPL) is a National Metrology Institute (NMI) of India and premier research laboratory in the field of physical sciences. The NPL was conceptualised in 1943 by the Governing Body of Council of Scientific and Industrial Research (CSIR) and was one of the first National Laboratories to be set-up under the CSIR. Over the years, the Laboratory has fulfilled its primary mandate as the keeper of Measurement Standards for the nation. Over the years, it has also substantially expanded its research activities to emerge as a leading national institution for research in the areas of physical, mechanical, advanced materials and devices, environmental and biomedical sciences.

NPL also offers calibration and testing services, acting as an interface between all the calibrating and testing groups of CSIR-NPL with numerous customers from the industry, various laboratories and government organisations – locally and globally.

About the requirement

The Fluid Flow Measurement Standard Group of NPL wanted to revamp their Water Meter Testing and Calibration set-up and replace it with a state-of-the-art facility conforming to the global standards that befit an institute with NMI status in India.

The NPL invited bids from various laboratories, institutes and companies with proven expertise in designing and implementing such systems. Adept was awarded the contract after a thorough evaluation and comparison of various technical parameters of the proposed system vis-à-vis competitors. The competence acquired by Adept in Flowmeter manufacturing and calibration for over 3 decades, and establishing self-developed NABL accredited calibration facilities played a key role during the selection process.


The existing set-up at NPL was very old and challenging to maintain mainly due to non-availability of spares and absence of thorough documentation. Various modules were lacking integration and centralised control was not possible. Being an old generation technology, it was also lacking in delivering the performance that is necessary to address the needs of today’s industries. There were a few more drawbacks of the existing set-up.

  It was a fully automatic system but the automation was highly complex making it difficult to monitor and maintain

  Only pulse output type Flowmeters could be calibrated

  Straight length requirements were not met for Flowmeters of different sizes particularly when reducers were used

  It was a highly complicated system, making it difficult to operate and maintain

  No electronics or instrumentation engineer was available to maintain the set-up

  Weighing systems were not interconnected

  Large volume of water was required to be collected

  Being a load cell based weighing system, uncertainty was higher leading to less accuracy of readings


Before undertaking the design of the new facility, the Engineering Solutions team of Adept thoroughly inspected the existing set-up and interacted with the NPL team to understand their exact requirements and expectations from the new system.

Knowing this, Adept decided on the gravimetric-based flow calibration facility employing the latest in instrumentation and control. Adept successfully installed and commissioned it while adhering to proven and best engineering practices.

After installation, the NPL team closely monitored various trials, which were successfully concluded to their utmost satisfaction. The key features of the system are:

  Dedicated pipelines for five Flowmeter sizes from DN 25 to DN 200

  Provision for seven intermediate pipelines for Flowmeter sizes DN 15 onwards

  High performance weighing systems with exceptional repeatability and linearity

  Diverter, fishtail and nozzle subsystems to ensure extremely low diverter error

  Pumps with VFDs for precision flow control and energy saving

  Professional grade measurement instruments for accurate time totalising plus current and frequency averaging

  Segregated systems for power and instrumentation & control to achieve highest levels of operational reliability

  On-screen graphics to display the instantaneous status of all the field devices

  Inbuilt operational safety features

NPL, Delhi – The apex Indian institute selected Adept to design and deliver a new Water Meter Testing and Calibration facility.


NPL is experiencing multiple benefits while using the new facility delivered by Adept. Significant among them are:

  Capability to calibrate Flowmeters of 12 different sizes from DN 15 to DN 200, all under a single roof

  The uncertainty in Flowmeter calibration for totalized mass and totalized volume parameters is in the range of 0.01-0.02% (at k=2) whereas for mass flow rate and volume flow rate parameters is in the range of 0.03-0.05% (at k=2) which are at par with the international level

  Inbuilt mathematical and statistical functions completely eliminate human error

  Efficient and reliable operations

  Efficient and reliable operations

  Operation and monitoring from the comfort of the centralised control room

  Password protection to ensure only authorised person/s can access the system

This prestigious installation of Flowmeter Testing and Calibration facility at NPL, Delhi is a further attestation of our quality, reliability and capability in the flow instrumentation business.

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