Intrinsically safe cathodic protection systems for hazardous environments – how one of Australia’s key ports tackled corrosion

According to the press release, over the last decade, it has been established that chlorine-induced corrosion is affecting some of the major structures at NSW Ports, including Sydney Harbour and Port Botany, Australia’s largest container port.

As a result, NSW Ports commissioned Infracorr to design a CP system for use at BLB1, which is located at Port Botany and contains hazardous gas pipelines. The project also included the repair of defective concrete structures which were suffering from the effects of corrosion and concrete spalling in the many pre-stressed beams and headstocks of the various bridges and catwalks at the port.

The CP system needed to be designed to allow for tight control of the currents and voltages used across the site, due to the presence of hazardous materials in the environment on an ongoing basis, meaning that any stray sparks caused by excess voltages and currents could become an ignition source for a major fire or explosion, and that as many of the structures present are constructed using pre-stressed concrete, it was extremely important that all electrical currents applied were carefully controlled to avoid structural damage caused by over protection.
One of the big technical challenges for the project was that there was no off-the-shelf CP system available that had certification for use in zone 1 classified hazardous areas, which meant that a bespoke system had to be designed that met the cathodic protection objectives, including dealing with the challenge of prestressed concrete, and that could be certified to meet the necessary requirements under AS60079 regulations.

The system designed for use at BLB1 by Infracorr, was a hybrid CP system that combined the properties of both passive galvanic and impressed current cathodic protection. It works by inserting specially designed anodes directly into the structure in a matrix. A voltage is then applied to force salt migration from the steel to the anode and passivate the zone, and when the zone is sufficiently charged, the power source is disconnected, and the sacrificial anodes are left to operate galvanically, providing passive protection to the structure.

The system relies on remote monitoring technology to provide asset managers with ongoing reassurance that it is operating as intended, and corrosion levels are under control, and to deliver this, Omniflex were asked to advise on the remote monitoring aspects of the design.

Because this was the first large scale implementation of hybrid CP used in a working hazardous area anywhere in the world, some components needed certification for the design to meet the requirements of AS60079 as an intrinsically safe certified system, which was subsequently obtained.

System performance and corrosion levels are continuously monitored 24/7 using 24 remote monitoring units situated throughout the site, each with the capacity to monitor 16 structures. This should ensure that the integrity of BLB1 is maintained, and the berth remains reliable and available to handle NSW’s growing bulk liquid trade volumes for the next 50 years. For further information, visit www.omniflex.com

Intrinsically safe cathodic protection systems for hazardous environments – how one of Australia’s key ports tackled corrosion
Remote monitoring unit.

Follow us on social media

General Enquiries

Institute of Corrosion
Corrosion House
5 St Peters Gardens
Marefair
Northampton
NN1 1SX

tel: + 44 (0)1604 438222
e-mail: admin@icorr.org

Related News

ICorr MIC Training Course for 2023

ICorr MIC Training Course for 2023

ICorr Microbiologically Influenced Corrosion (MIC) Training Course Plan for 2023 The Institute of Corrosion (ICorr) is pleased to announce the plan for the MIC training course for 2023. Both the Awareness and Certified MIC Technologist proficiency levels are offered,...

President Handover –  Bill Hedges to Stephen Tate

President Handover – Bill Hedges to Stephen Tate

The Institute of Corrosion is very pleased to announce the successful election of Stephen Tate as its New President and Dr Yunnan Gao as its New Vice President. Stephen has worked with Aberdeen Branch Committee for the past 11 yrs in various roles and has twice been...

New ICorr MIC Training Course Available

New ICorr MIC Training Course Available

The Institute of Corrosion (ICorr) is delighted to announce that we have developed a Microbiologically Influenced Corrosion (MIC) course to meet the increasing demand from industry. MIC is the least understood phenomenon of corrosion despite the number of high-profile...

ICorr office will be closed from Thursday 22nd December 2022, and will reopen Tuesday 3rd January 2023

X