PRV for thermal expansion
PRV for thermal expansion
(OP)
The fuel oil line (pipe size 6") has steam tracing and insulation. The fluid temperature is greater than effect from direct sunlight. Do we need to install PRV for this application? Please comment.





RE: PRV for thermal expansion
Here is a solution I've seen on lines that can be blocked in and have some small thermal expansion that would cause an over-pressure. At the valve that can be closed, install a small (3/8") line around the valve. The small line will have a check valve in it such that if the line's pressure increases above the line on the other side of the shut valve, it will open and allow a small amount of liquid to pass into the other line and then to a PSV on that side of the shut valve. Of course, small valves can be placed on each side of the check valve to allow inspection of the check valve. This is a great way to remove all the thermal valves on meters, lines that have lots of headers and valves, ect... You can even limit the amount or rate that flows through the valve by adding a restrictive point in the tubing, these are commonally available by tubing fitting companies that normally size the restrictions to slowly bleed air on tubing vent lines.
RE: PRV for thermal expansion