Seawater Pipe Penetration Seal Barangaroo
Barangaroo is a spectacular development located on the western waterfront of Sydney’s CBD and a challenge for this development was to seal the seawater pipe penetrations.
HDPE pipes (resistant to corrosion), were selected by engineers to be placed thorough core hole penetrations of varying diameters connecting the structure and the seawater of Sydney Harbour.
In order to seal the annular space between the HDPE pipes and the Pipe penetrations at the connection to Sydney Harbour seawater, a very interesting set of problems was identified:
1.Immersion in Seawater
3.Sunlight (UV radiation)
4.Rapid temperature variation
Due to tidal activity in Sydney Harbour the seawater pipe penetrations would be underwater at least 2 times a day. The remainder of the day these penetrations would dry out and be subject to direct sunlight (UV radiation) – and repeat!
This continuing cycle of conditions represents some of the harshest and most corrosive environmental conditions known to man.
Link-Seals are generally available with fasteners made from Stainless Steel Grade S316. S316 is a very high-quality stainless-steel grade, superior to the more common S-304. S316 stainless is able to withstand most normal salt and water spray (and also immersion in soil and mud). S316 stainless steel cannot be guaranteed to withstand the long-term cyclic immersion in salt water combined with UV radiation and temperature variations as required in the Barangaroo project.
We worked with the engineers at Barangaroo to develop a customised solution to this unique set of circumstances.
The pipe penetrations were sealed using LINK-SEALS combined with a specially created set of SAF 2507 grade stainless steel fasteners.
SAF 2507 grade of stainless steel is a more sophisticated compound than S316. It is a super-duplex (austenitic-ferritic) stainless steel for service in highly corrosive conditions. The SAF 2507 grade is characterized by:
- Excellent resistance to stress corrosion cracking (SCC)
- Excellent resistance to pitting and crevice corrosion
- High resistance to general corrosion
- Very high mechanical strength
- High resistance to erosion corrosion and corrosion fatigue**
**Information provided by Sandvik
The “SAF 2507” grade fastening system was custom made for the Barangaroo pipe penetration situation and it enabled the hardware to be immersed in sea water and then exposed to the UV and then sea water in regular cycles – with no adverse effect.
Once this problem was solved, we assisted the engineers with the required calculations to ensure permanent and watertight sealing of the annular space between HDPE pipe and core hole in each of the pipe penetrations. We supplied the required Link Seals with the custom-made fasteners.
These were installed on site and are providing a watertight seal to this very day!