What is often used to measure pressure in a system that requires isolation?

Pressure gauges are commonly used to measure pressure in a system that requires isolation due to their design and functionality. Pressure gauges are devices specifically formulated to provide accurate readings of pressure levels in various systems, often using a pressure-sensing element to convert the force exerted by the pressure into a readable format.

In systems that need isolation, pressure gauges can be fitted with valves or isolation techniques that prevent the medium in the system from affecting the measurement. This is vital in preventing contamination and ensuring accurate readings while still allowing the user to take measurements without interrupting the system operation.

The other options do not serve the same purpose effectively. Thermocouples are used for measuring temperature rather than pressure. Manifolds can assist in managing multiple pressure connections but are not direct measurement tools. Fluid flow sensors measure the rate of flow of a fluid, not the pressure.