WEL Networks | 2018 Asset Management Plan 144 ASSET REPLACEMENT AND RENEWAL 8.2.2. MANAGEMENT OF SF6 Sulphur Hexafluoride (SF6 ) is a gas used in modern switchgear as an insulating and arc quenching material. We have initiated a review of equipment that could be used as an alternative to SF6 -filled switchgear. In the meantime we are required by law to disclose the quantity we have installed in our network. We record and monitor the volumes of SF6 gas installed, disposed and emitted into the environment. As at November 2017 the volume of SF6 installed by our switchgear was 1.35 tonnes. 8.2.3. VEGETATION MANAGEMENT Vegetation management is the process of managing vegetation in and around our assets that have the potential to interfere with the safe and reliable supply of electricity to our customers. We have increased our inspection rates and maintain a vegetation growth model to predict when future work will be required for different vegetation types. Vegetation operational expenditure is based on our vegetation growth model. Based on current cutting rates our model predicts expenditure will reduce towards the end of the AMP period as shown in Table 8.2.3. Defect Notifications Defects are identified during inspections. If an asset has a defect, the asset inspector will assess the severity of the defect and assign a defect rating as specified in Table 8.2.2 below. Defect Rating Defect Classification Delivery Period Definition 1 Red 2 days Faults / Urgent work required – immediate temporary repairs may be required to ‘make safe’. 2 Amber 2 weeks No customer outages or door knock for low volume of customers. 3 4 weeks Major customer consulted if outage required, typically Plant Maintenance will be priority 3. 4 12 weeks Long lead material consideration. 5 Green 12 months Typically asset replacement works or jobs which could be undertaken as part of capital projects. Table 8.2.2 Defect Classifications Vegetation Management Operational Expenditure (In Nominal Price $000) 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 Vegetation Management 1,360 1,399 1,107 1,130 1,153 823 840 858 875 893 TOTAL 1,360 1,399 1,107 1,130 1,153 823 840 858 875 893 Table 8.2.3 Vegetation Management Operational Expenditure