A volume of liquid trapped within an enclosed piping system has the potential to expand following a corresponding rise in ambient temperature. Some liquids more than others have high coefficients of expansion and are particularly sensitive even to small temperature changes. Liquid hydrocarbons and derivatives thereof are the best examples. Volumetric expansion within a blocked in piping system means that the pressure in that line will also rise exponentially!
Considering the liability, both operational and safety, rigid piping systems have to be designed with rupture disks and/or relief valves to handle these over pressure conditions when they occur. When the frequency of occurrence exceeds reason, then maintenance costs become a nuisance. ANSWER: Thermal Volume Expansion Compensators. Simply stated, these devices can be sized to accumulate a predictable expansion volume and then limit the pressure rise to a predetermined set point somewhere below that of the rupture disk. The static pressure of the piping system becomes self-regulated. The operational cost savings, in many instances, are significant.