Semi-submersible production facilities in harsh environments operate in a heavily regulated segment of the oil and gas industry. Every decision taken around modification or intervention must be thoroughly reviewed from a safety critical perspective. The North Sea is a high-cost environment where robust, timely and efficient solutions are essential. Hot work carries additional risks, cost and complexity offshore, and can be avoided using Izomax mechanical isolation systems. In this instance, the passing valve between the process plant and the high pressure flare system needed urgent maintenance. There were no suitable means for isolation near the maintenance point, so intervention with alternative technology was a must to minimize or negate production delays. During the site survey, the Izomax team identified the requirement for a specially designed lower integrity clamp to fit between the valve housing and pipe spool flange. The ultimate challenge was to avoid a full production shutdown which would be necessary using conventional intervention technologies.