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A condition assessment is a structured inspection that documents current deterioration, quantifies defect severity, and rates overall asset condition against a defined framework. It gives the asset owner a defensible basis for maintenance planning, remediation prioritisation, and remaining service life projection.
| Industry | Water and wastewater infrastructure |
| Asset Type | Reinforced concrete water treatment tank |
| Asset Age at Time of Inspection | 8 years |
| Inspection Date | August 2025 |
| Design Service Life | 40 to 60 years (AS 3600 / AS 3735) |
RemedyAP holds NATA accreditation No. 20711 under ISO/IEC 17020 as a Type A inspection body. This means inspection findings are independently verified, traceable, and reproducible across future inspection cycles.
Condition assessments on water infrastructure require working knowledge of AS 3600, AS 3735, and WSA 201. RemedyAP’s inspectors apply these standards directly in the field, not retrospectively during report preparation.
The 3D laser scanning and photogrammetry capability deployed on this engagement is integrated into RemedyAP’s standard assessment methodology. It produces a spatial baseline record that supports quantitative monitoring of deterioration rates over the asset’s service life.
RemedyAP provides independent condition assessments for concrete, coatings, corrosion, and industrial infrastructure. Our technical investigations help asset owners understand asset condition, prioritise maintenance, and make evidence based decisions with confidence.
RemedyAP was engaged to conduct an independent condition assessment of a reinforced concrete water treatment tank at a Victorian treatment facility. The tank was 8 years old at the time of inspection, with a design service life of 40 to 60 years under AS 3600 and AS 3735.
The scope covered all internal and external reinforced concrete elements, metal elements across the aerobic, anoxic, anaerobic, and clarifier zones, and metal elements in the walkway and external wall zones. Dry film thickness surveys were conducted on accessible coated metal elements throughout.
A preliminary report was issued mid-inspection to flag items requiring immediate repair. Those findings were incorporated into this final condition assessment.
Inspectors conducted a systematic visual survey across all accessible concrete surfaces, internal and external, targeting spalling, cracking, efflorescence, rust staining, surface erosion, and metal corrosion.
Delamination mapping was performed by tapping concrete surfaces with a percussion tool and evaluating the audible response. A hollow sound indicates separation of a surface layer from the parent element. No delamination was detected across any zone of the tank.
The inspection incorporated 3D laser scanning and UAV-based photogrammetry. The field survey captured 34 high-resolution laser scans and over 8,000 images across two days on site, producing a combined dataset accurate to within plus or minus 2 mm.
The 3D model was delivered via an online platform that allows the asset owner to annotate defects directly to spatial coordinates. It provides a documented baseline condition record that supports monitoring of deterioration rates across future inspection cycles.
DFT surveys were conducted using a calibrated PosiTector probe on accessible coated metal elements in the walkway and external wall zones. Measurements were recorded across six coating batches covering pipework frames, mixer bodies, hose reels, and handrails.
Horizontal cracks of 0.1 mm width were typical across internal and external stitch pours, consistent with shrinkage behaviour in precast panel construction and presenting a low to medium durability risk. Internal wall and slab cracks up to 0.3 mm wide were also recorded, along with three external wall cracks ranging from 0.5 to 1.2 mm on separate wall segments.
All observed cracking is assessed as likely shrinkage-related. Cracks exceeding 0.15 mm on internal surfaces and 0.3 mm on external surfaces are recommended for epoxy resin injection within 5 to 10 years.
Surface erosion was observed on all immersed concrete surfaces. In the anoxic zones, erosion was minor, with no exposed coarse aggregate and an estimated rate of approximately 0.1 mm per year. In the aerobic and clarifier zones, erosion was more advanced, with exposed aggregates, estimated surface loss of up to 3 mm, and a rate of approximately 0.4 mm per year. This is consistent with the abrasive action of aerated effluent on the concrete matrix.
Based on these erosion rates, the durability risk to the concrete is assessed as low, and no immediate repairs are recommended for surface erosion at this time.
The concrete inspection findings were rated against the Institute of Public Works Engineering Australasia condition rating framework. All reinforced concrete elements across the anoxic, aerobic, clarifier, and external zones were rated 2-good.
Moderate to severe corrosion and pitting were observed on the immersed surfaces of universal beams supporting pipework in the anoxic and anaerobic zones. Pitting concentrated along beam edges is consistent with inadequate stripe coating and poor surface preparation at the time of installation.
Per WSA 201 Clause 5.2, the expected durability of an industrial coating system before major maintenance is 15 to 25 years. Coating degradation at 8 years is premature, and the durability risk for the affected universal beams is assessed as high. Spot repairs were recommended during the current shutdown period, and a structural assessment is required to determine the extent of section loss.
Loose and missing fixings were identified on pipework flanges, impellers, aerator struts, the perimeter gutter, and mixer skirts. Reinstatement of these fixings was also recommended during the current shutdown.
Coated pipework and stainless steel elements, including aerator struts and the perimeter gutter, showed no corrosion. The coating system on the pipework and the stainless steel grade selected for the immersed environment are both assessed as appropriate.
General corrosion was observed on galvanized handrails, grates, cable trays, valve wheels, hose reels, and canopy purlins. No severe pitting was detected, and corrosion on most elements is attributable to normal wear, localised poor surface preparation, or mechanical handling damage.
The tank environment is classified as C3 under AS 4312, indicating moderate aggressiveness towards metals. Routine maintenance of corroded walkway and external elements is recommended within 3 to 5 years.
The average DFT of the galvanized handrails measured 84 µm, meeting the requirements of WSA 201 Clause 10.3.10 referencing AS/NZS 4680 Table 1. The hose reel coating averaged 92 µm but showed severe delamination, attributed to UV exposure and mechanical handling damage during operation.
Element condition was rated using the Institute of Public Works Engineering Australasia five-point framework, where 1 is very good and 5 is very poor.
All reinforced concrete elements were rated 2-good, and joint plastic covers and pressure relief valves were rated 1-very good. Universal beams supporting pipework were rated 4-poor. Walkway zone elements, including valve wheels, hose reels, and canopy purlins and framing, were also rated 4-poor. Galvanized handrails, cable trays, and mechanical and electrical equipment were rated 3-fair.
Immediate works during the shutdown covered universal beam spot repairs and reinstatement of all loose and missing fixings. UB repair quantities were estimated at approximately 18 m², with an expected service life of 10 to 15 years following repair, dependent on workmanship quality.
Crack repairs on internal and external concrete surfaces are recommended within 5 to 10 years. Internal repair quantities are estimated at 24 lineal metres across the anoxic and aerobic zones, 13 lineal metres in the clarifier zone, and 1 lineal metre on the anoxic zone 1 slab. External wall crack repairs are estimated at 2 lineal metres.
Where the condition assessment identifies repair requirements, RemedyAP prepares a remedial specification defining repair materials, application methods, and quality inspection requirements as the next stage of the process.
This assessment was conducted under RemedyAP’s NATA accreditation No. 20711 under ISO/IEC 17020 as a Type A inspection body. Design service life requirements were assessed against AS 3600 and AS 3735. Coating durability benchmarks referenced WSA 201, published by the Water Services Association of Australia. Atmospheric corrosivity classification was assessed under AS 4312.
RemedyAP was engaged to develop a coating management plan for steel jetty at a coastal infrastructure facility operating in a C5-Marine atmospheric corrosivity environment. The C5-Marine classification, defined under AS 4312 and ISO 12944, represents the highest level of atmospheric aggressiveness for coastal and marine-exposed steel. The engagement combined condition assessment findings from multiple inspection […]
