[ Business case listing ](/case-studies " Business case listing") ### Execution and key achievements - **The gas holder was successfully dewatered and desludged before structural demolition** - **The steel roof and inner three steel walls were cut into sections and recycled** - **All work completed safely with no incidents** - **By working closely with stakeholders, there was minimal disruption to site work** - **Maintained strict PPE, site access, work permits and toolbox talks** ## Working with National Grid National Grid is a multinational energy company, focused on cleaner energy by investing in electricity networks and emerging technologies. Veolia was appointed to safely undertake the demolition and infilling of the below-ground gas holder for future redevelopment. The holder was flooded with 1,200 cubic metres of water, above a thick layer of sludge. This required dewatering and desludging by a subcontractor prior to any demolition works. ![Heavy machinery working on demolishing a gas holder at National Grid ](/sites/g/files/dvc1681/files/styles/crop_freeform/public/image/2026/10/NATIONAL%20GRID%2C%20BOLTON%20GASHOLDER%20DEMOLITION%20CASE%20STUDY%20%28V4%29.pptx_P3_IMG3.png.webp?itok=Jut6wWNS) #### Project highlights ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/10/KDC%20Decom%20icons%20%281%29.png.webp?itok=M4WstAyM) **Supporting the energy sector** ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/08/Workers%20icon.png.webp?itok=UfOdqAxe) **Partnership with National Grid in Bolton** ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/08/Money%20icon.png.webp?itok=yGLRSM5V) **Total project costing £1M+** ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/08/Calendar%20icon.png.webp?itok=-Ut426ft) **Executed over 16 months** ## How we demolished the gas holder and overcame challenges The demolition works included the removal of the steel roof, the central masonry pier, the existing redundant gas pipes and three internal steel walls. The backfill material was a specified mix, primarily consisting of 6A material for drainage, compacted shale clay and 2A grade stone with 0.10 metres of 20mm cobbles on top to match the existing ground of the site. ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/10/Lightbulb%20icon.png.webp?itok=xekk49sr) #### Demolition challenges There was a sensitive retaining wall on the southern boundary in close proximity to the gasholder and a public road. We closely monitored the vibration with action thresholds set at 2.5 mm/s and 5 mm/s and tilt monitors. A no-vibration drum was used for the 13-tonne roller to protect the wall. An adjacent Cadent Gas pressure reduction system requiring 24-hour access. We coordinated closely with Cadent Gas to schedule site visits at appropriate times, with no plant or wagon movement ensuring safe, uninterrupted access. ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/10/Lightbulb%20icon.png.webp?itok=xekk49sr) #### Dewatering challenges During the dewatering process, the pump could not reach the bottom of the holder to fully dewater it. We placed the pump between the inner metal walls, to reach the bottom of the gas holder. For the last 0.5 metres of water, we brought in a 6 foot 5 bulk import to create an access ramp for plant operations. We installed two access scaffolding, one for main use and emergencies within the gas holder. All workers were equipped with a gas monitor and signal to alert any dangerous gas levels, keeping workers and the air quality safe. An evacuation drill was timed to ensure any workers within the gas holder could safely leave within a reasonable time. ## National Grid gas holder demolition results ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/08/tick%20icon.png.webp?itok=J6OPgtye) **Completed within budget** ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/08/tick%20icon.png.webp?itok=J6OPgtye) **Removed site liability through the removal of a redundant structure** ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/08/tick%20icon.png.webp?itok=J6OPgtye) **Providing a usable asset for the client to divest** ![](/sites/g/files/dvc1681/files/styles/default/public/image/2026/08/tick%20icon.png.webp?itok=J6OPgtye) **Safe demolition of the gas holder with no incidents or accidents during works** #### Are you looking for expert demolition for your next project Learn more by contacting our specialised team. [Contact us](https://www.veolia.co.uk/kdc-veolia-home-new-wireframe-test#kdccontactform) ### Related case studies [ ![Veolia workers in PPE on the site for Imperial CONSORT reactor decommissioning](/sites/g/files/dvc1681/files/styles/media/public/image/2026/08/e2b8f07b-41f4-4611-aec2-a229e1106639.jpg.webp?h=b0ad284b&itok=khoz6ayy) ](https://www.veolia.co.uk/case-studies/imperial-consort-reactor-decommissioning)[Imperial CONSORT reactor decommissioning](https://www.veolia.co.uk/case-studies/imperial-consort-reactor-decommissioning) ### [Imperial CONSORT reactor decommissioning](https://www.veolia.co.uk/case-studies/imperial-consort-reactor-decommissioning) [ ![Veolia workers standing in front of machinery ](/sites/g/files/dvc1681/files/styles/media/public/image/2026/08/NRS%20HARWELL%2C%20BUILDING%20B401.8%20DECOM%20AND%20DEMO%20CASE%20STUDY%20%28WIP%29%20%282%29.pptx_.png.webp?itok=xDjK5Z9m) ](https://www.veolia.co.uk/case-studies/harwell-zephyr-building-decommissioning-and-demolition)[Harwell Zephyr Building decommissioning and demolition](https://www.veolia.co.uk/case-studies/harwell-zephyr-building-decommissioning-and-demolition) ### [Harwell Zephyr Building decommissioning and demolition](https://www.veolia.co.uk/case-studies/harwell-zephyr-building-decommissioning-and-demolition) /* Forcer couleur de fond pour le breadcrumb */ .breadcrumb--theme--veo-neutral-90 { background-color: #4C4C4C !important; } .container--breadcrumbs.theme--background-color--veo-neutral-90 { background-color: #4C4C4C !important; } /* Pictogramme bas droite - modifications */ body.bg-pictogram--bottom-right::after, body.bg-pictogram--bottom-right::before { width: 800px !important; height: 800px !important; right: 0 !important; left: auto !important; bottom: 0 !important; top: auto !important; margin: 0 !important; padding: 0 !important; z-index: 0 !important; background-size: contain !important; background-position: bottom right !important; background-repeat: no-repeat !important; position: fixed !important; } /* Footer au-dessus du pictogramme */ .footer { position: relative !important; z-index: 1 !important; } @media only screen and (max-width: 767px) { .carousel--content, .carousel__container, .carousel__slide, .container--media, .container--media-entity, .media-image, .media-image__picture { margin: 0 !important; padding: 0 !important; } .container--space-inner--v-m { padding-top: 0 !important; padding-bottom: 0 !important; } .carousel--content .slick-list, .carousel--content .slick-track { margin: 0 !important; padding: 0 !important; } .carousel--content img { display: block; width: 100% !important; max-width: 100% !important; height: auto !important; margin: 0 auto !important; } }