Our refinery is planning to have a spare LPG loading pump with API seal plan 53B. With this seal plan, the barrier fluid will leak to LPG as part of the seal plan design. The concern is, the LPG will be loaded to tank trucks and no testing will be done once LPG was transferred so monitoring of the LPG quality after loading will not be done. With this, what barrier fluid will be compatible with LPG that will have no effect on its purity and might not cause any problems like clogging of pipelines due to propane vaporization?