Contract Applicator: Melchor Access
Application Date: Annex 1 August 2020 – January 2021. Annex 2 January 2021 –
The roof of Annex 1 had not been completely recoated for some time. Repairs to seam joints had been carried out as recent as 2019, but these repairs we insufficient to ensure that pressure testing of the storage facility conformed to CBH protocol. A costing and feasibility study was undertaken to replace the existing roof sheeting with new material. With fast turnaround time required, and cost being an important factor, CBH decided against the new roof option. Instead, it was decided to completely remove all of the existing coating and apply the Camelastic coating system, as per the CBH Sealed Storage Specification.
Camelastic CSE 729 was supplied in Grey and White for identification of the two coat process of the high film build required to provide long term elongation. The vertical and horizontal seams of every sheet was sealed using an approved mastic sealant (Fosroc Nitoseal MS400). 1500 micron DFT of Camelatic CSE729 was applied to every vertical and horizontal lap seal and every tek screw on the roof surface. 200 micron DFT of Camelastic Top Coat was applied over the entire roof area.
Image below shows different stages of application during the sealing process, to the left is first coat of Camelastic CSE 729; to the right is following application of the first coat of Camelastic Topcoat.
The surface preparation and removal of the old coating was completed for the entire roof area. The coating application which is a staged process was completed in sections. Testing of the coating system was carried out during the process to ensure that process complied with the required CBH protocol for Storage Sealing.
The image below, taken from the adjacent building, shows Annex 1 in the various stages of coating application after the surface preparation had been completed. The total roof area of Annex 1 is around 30,000 m2
When the coating application has been completed and the coating system has fully cured, the storage facility is subjected to a pressure test accordance with Australian Standards for Fumigation (AS2628-2010 – Sealed grain-storage silos –requirements for insect control).
The storage asset passed the requirements for sealed storage fumigation and achieved a projected half-life of 16 minutes at 200 Pascals, more than 3 times the requirement for a refurbishment scope. This was a 12.5-minute increase from the previous tests conducted.
In Early January, as Annex 1 had been completed, CBH decided to carry out remedial work on Annex 2, taking advantage of the contactors being on site. The existing Camelastic coating system was inspected and found to be in sound working condition. This meant that the existing coating did not require removal, simply a high pressure water wash, prior to application of the new coating system.