{"id":"expansion-tank","version":"0.1.0","classification":{"uniformat":"D3040"},"names":["Expansion tank"],"aliases":["ET","bladder tank"],"service_life":{"median_years":20,"range_years":[20,20],"range_basis":"source_spread"},"pm_tasks":[],"basis":[{"type":"public_document","life_type":"design","title":"Design standards: employer's requirements – Technical Manual (ER-DFE-XX-XX-T-X-0201, revision A-C01)","by":"Department for Education (England)","url":"https://assets.publishing.service.gov.uk/media/6971f649d8adeaf266040501/ER-DFE-XX-XX-T-X-0201-Technical_Manual-A-C01.pdf","page":245,"code":"5.5.4","label":"Pressurisation units and expansion vessels: 20 years","years":20,"note":"Printed page 245. Expansion vessels. Minimum life expectancy (design requirement) for DfE-funded school buildings. Minimum design requirements placed on contractors for school buildings, not observed replacement ages. Section 5.1.4 (sanitaryware) refers to CIBSE Guide M Appendix 12.A1 'in general'."}],"confidence":{"grade":"C","sample_size":null},"open_questions":["Every source here is a published planning, design or accounting life. None is observed replacement data.","No preventive maintenance tasks are sourced yet."],"contributors":["unfinished.one editors"],"last_reviewed":"2026-10-22","canonical_url":"https://unfinished.one/c/expansion-tank","versioned_url":"https://unfinished.one/c/expansion-tank/v/0.1.0","licence":"CC-BY-4.0","citation":"unfinished.one (2026). Expansion tank, v0.1.0. https://unfinished.one/c/expansion-tank/v/0.1.0"}