Highly Intelligent Combustible Gas Detectors Are SIL 3 Suitable for Hazardous Environment Processes in Demanding Industries

With their highly intelligent microprocessor based designs, the advanced S4000C and S4100C Combustible Gas Detectors from General Monitors (USA) are now suitable for use in Safety Integrity Level (SIL) 3 applications commonly found in a wide range of demanding industries where the potential presence of dangerous hydrocarbon based combustible gas is a threat to people, equipment and facilities. The global importance of the SIL standard has grown substantially in the oil/gas, petrochemical and other process industries over the last 10 years in response to the development of safety equipment designed with next generation electronics. SIL is a measure of process safety system performance, in terms of probability of failure on demand (PFD). This convention was chosen because it is easier to express the probability of failure rather than that of proper performance.

There are four discrete integrity levels associated with SIL: SIL 1, SIL 2, SIL 3, and SIL 4. The higher the SIL level, the higher the associated safety level, and the lower probability that a system will fail to perform properly. As the SIL level increases, typically the installation and maintenance costs and complexity of the system also increase.

The S4000C Detector is a hydrocarbon gas detector that is suitable for SIL Level 3 applications and is FM, CSA, ATEX, CE Marking and GOST approved. It features a threedigit display and an explosion proof housing, which allows all data to be processed locally at the sensor site. The S4000C is also available with an optional relay configuration that is appropriate for SIL Level 2 processes.

With its highly reliable catalytic bead sensor, the S4000C Detector monitors combustible gas and vapors within the lower explosive limit (LEL) and provides status indication and alarm outputs. When the sensor detects gas, it initiates a 420mA alarm signal that is proportionate to the 0 to 100% LEL gas concentration present and communicates the alarm notification to the safety system.

Designed for the European community, the S4100C Detector is a hydrocarbon gas detector that is suitable for SIL Level 3 applications and is ATEX, CE Marking, GOST and Kazakhstan approved. It features a three digit display and an explosionproof housing, which allows all data to be processed locally at the sensor site.

The S4100C also features a highly reliable catalytic bead sensor. It is designed to measure and display concentrations of combustible gases in the 0100% LEL range, but will continue to display concentrations up to 120% LEL. The sensing element may be incorporated in the transmitter housing or remotely mounted at distances of 600 meters.