Speak to Adams at the Normandy's engineering deck. However, after Priority: Sur'Kesh, Mordin Solus and Eve will occupy the med bay, and Adams and the medical officer will be engaged in a conversation in the crew quarters. In this case, Adams will request to speak with you after N7: Cerberus Abductions and Tuchanka: Bomb — Adams and the medical officer will have returned to their stations.
There is some debate on at which point this quest can be acquired. It is possible it may be needed to pardon Engineers Donnelly and Daniels before it will become available. 
Alternately, if you have already previously visited the Elkoss Combine Arsenal Supplies kiosk, head to the Normandy's Shuttle Bay and access the Alliance Requisitions terminal. You can purchase the item with a 10% surcharge.
If you speak to Adams right after purchasing the item, he tells you that they are performing modifications for the installation. When you visit him again after a period of time, he tells you that the thermal pipe has been successfully installed, thus, completing the mission.