TankRadar Rex Addresses the Weak Links in Your Safety Chain...
November 06, 2009
Protecting Your Plant
An undetected overfill incident at a fuel production or storage facility can have severe consequences for society, the environment and the companies involved. Thus, all refineries, tank farms and fuel depots have a huge responsibility to ensure that overfill incidents do not occur. In this context the most important job for an automatic tank gauging system is to provide reliable High-High level alarm functionality.
Designed to be a state-of-the-art level gauging transmitter, Rosemount TankRadar Rex is probably the safest overfill alarm sensor on the market. Quite uniquely, it is third-party assessed and considered to be SIL 2 suitable. Rosemount TankRadar Rex is also TÜV-tested for overfill protection. This helps you future-proof your investment in a Safety Instrumented System for your plant, already today.
Reliable Radar Gauging
The non-contact Rosemount TankRadar gauges generally perform more reliably than mechanical tank gauging sensors, such as float and tape gauges and servo gauges. Mechanical gauges are complicated devices, vulnerable to many failure modes. They also require inspection and service on a regular basis.
Radar gauges eliminate the failure occurrences associated with mechanical components. Therefore many tank gauging professionals, customers and other specialists agree that modern radar gauges may be more reliable and efficient than mechanical gauges.
This also means benefits in terms of safety. Reliable TankRadar gauges can complement a traditional High-High switch thereby introducing redundancy into the safety system, and improving your plant's safety level.
The Self-checking Alarm Switch
A conventional overfill alarm sensor in a storage tank, such as a float or a point switch, has one major weakness: the only time you really know it’s working is when you are actually testing it. Between tests, the switch just waits passively for something to happen. When an overfill occurs, who knows if it will work or fail?
With a Rosemount TankRadar gauge connected to your system, it’s the other way around. The gauge acting as a switch gives the operator continuous information about its status and performance, since it is being used in the everyday operations of the tank farm.
In the unlikely event of a gauge failure, detectable by its diagnostic capabilities, the operator will be immediately notified to take appropriate action under safe conditions.
SIL 2 System Safety
Rosemount TankRadar Rex has recently been assessed by a third party (Exida) and is considered suitable for use in SIL 2 safety functions in accordance with IEC 61508/61511. The safety function is based on the relay (switch) outputs. One relay, or a combination of two, can be used for overfill or dry run protection.
Although the decision to incorporate proven-in-use devices is always with the end user, the assessment by Exida provides a good basis for the implementation of a plant safety strategy in accordance with section 11.5.3 of IEC 61511.