Pressure testing insulated pressure vessels under API-510 involves several considerations to ensure that the insulation does not conceal leaks or damage. Before testing, inspectors typically require that sections of insulation be removed to expose the vessel surface, particularly in areas prone to corrosion or wear. The testing itself, whether hydrostatic or pneumatic, must be conducted at pressures specified by API-510 to simulate operational conditions accurately. After testing, the insulation must be carefully replaced and inspected to ensure that it maintains its protective properties. Documentation of the entire process is crucial for future inspections and maintenance records.