Waitoa- D3 Dehumidification Process Ducting

Key Elements:
• Fabricate and install large diameter Stainless steel ducting
• Ducts were 1m and 1.8m in diameter
• Insulation and cladding added to outside of the duct.
• Structural truss supports on outside of building to carry the load of both horizontal and vertical ducts
• Detailed design based on consultants developed design

Challenges:
• Covid lockdown to level 4 stopped work in PFS shop. Once Fonterra obtained essential service status for the project, we were able to continue fabrication under stringent conditions. We created several small bubbles within the shop to keep people isolated and socially distanced by min 2m but more likely 5-10m
• Covid restrictions on site were significant and again had major impacts to programs and resources. Access to site and to the workface was tightly controlled restricting all to keep with in defined corridors.
• A condition of the consent was that noise be controlled and limited. This meant that the ducts had to be well clad and insulated. Double layers of insulation were required, and cladding was out of a comparative thick 1.2mm SS sheet. Outside Diameter of ducts therefore increased from 1.8m to 2 meters.
• Cladding joint as a result had to cater for movement, as well as be waterproof. PFS built a machine to create a swage lock joint suitable for this large diameter and
• Installation of riser to side of the building was a real challenge. Vertical riser had a horizontal section on the end which went through the side of the building. The long duct with bend on it was lifted and rotated in the air and the horizontal section threaded through structural truss and wall of the building.