Suvarnabhumi Airport

        Suvarnabhumi Airport is the new airport servicing Bangkok, Thailand and is a major gateway linking Europe to Asia and Australasia. In 2010 the airport handled 43 million passengers making it the third busiest airport in Asia. Bangkok Aviation Fuel Services PLC. (BAFS) through its subsidiary Thai Aviation Refuelling Co., Ltd. (TARCO, www.tarco.co.th/eng) operate the hydrant network with Siemens supplying the hardware and SCADA systems.

 

 

Project Overview

        In 2004 ATMOSi was commissioned to install a Statistical Tightness Monitoring System (STMS) on the hydrant network. At this time the airport was a large building site. The STMS was commissioned after the hydrant network had been commissioned in the weeks leading up to the first commercial flight at the airport (28 September 2006).

 

        The specification (based on API/IP 1540) requires that “Existing hydrant systems that use a detailed analysis of pressure measurement are able to detect leaks equivalent to about 0.04 litres/hour/cubic metre at a reference pressure of 7 barg, require a fuel hydrant shutdown period of about one hour and can be used on a regular basis (at least weekly) with a minimum disruption to the normal operation of the hydrant.”

 

        In addition to the API/IP specification ATMOSi implemented a leak location algorithm to detect leaks to within 100 metres. The location implementation required tight integration to algorithms in the PLC system.

 

        The hydrant network consists of over 22km of pipe work, with diameters ranging between 150mm and 600mm, split over 12 sections for isolation and testing purposes. The scope of supply included integration with the Siemens SCADA and a Graphical User Interface presenting a schematic of the hydrant network that includes the status of the STMS.

 

 

ATMOS STMS

        At the core of ATMOS STMS is the same statistical algorithm (the Sequential Probability Ratio Test, SPRT) used by ATMOS LDS; ATMOS’s established and successful leak detection system. For the STMS the key difference is that the test is a discrete static (or shut-in) test as opposed to a continuously monitored system. At Bangkok pressure and temperature is used to monitor the leak state over a 45 minute period with the pressure signature used to determine if there is a leak present in the system.

 

 

ATMOS Data Server

 

        It provides the connection point between the SCADA and ATMOS STMS. Using the OPC protocol it gathers real time data from the hydrant network provides scripting functionality and supplies the STMS with process data. It subsequently sends status information back to the SCADA for presentation to the operator.

ATMOS Trend

 

        It is a flexible data charting and trending tool. Suvarnabhumi personnel use ATMOS Trend to monitor the process data on the hydrant network and to interrogate the system in the event of a leak.

 

Integration with Siemens WinCC

ATMOS STMS is closely integrated with the Siemens WinCC SCADA system. The SCADA is the main operator front end for the STMS. In particular, the start and interrupt control handshaking from the SCADA are used to control the tightness monitoring system. All pressure and valve values are collected via the SCADA and the final output is set to the SCADA for presentation to the operator.

The leak location required even tighter integration, with some settings being set from the ATMOS STMS system, via the SCADA, to the PLC’s.

 

System Commissioning and Leak Trials

        The Site acceptance tests were made late summer of 2006. As sections were handed over to TARCO the tightness monitoring system was calibrated with a series of leak trials of various sizes and pressures.

 

        Several tests were made on each of the sections. The tightness monitoring was tested at both high and low pressures to confirm it functioned in both cases. Large leaks, near 0.8 litres/hour/cubic meter, were detected in less than 2 minutes. The smallest leak detected was on 21 August 2006 when ATMOS detected a 0.017 litre/hour/cubic metre leak on a 601 cubic metre section- well within the specification of 0.04 litre/hour/cubic metre.

 

        The final week of commissioning was the tuning of the leak location. Each section was tested and every leak location was found within 100 metres, with the closest estimate being just 7 metres from the leak point on a section length of 550 metres.

 

        Mr Id Sukapattee, Hydrant Pipeline Specialist at the Thai Aviation Refuelling Company said, “The ATMOSi Statistical Tightness Monitoring System has been online since commissioning. It has worked reliably and without fuss requiring minimal support from ATMOSi. We are very pleased with the results of this project and the the on-going benefits resulting from it.”