High Integrity Protection System
API 521 and Code Case 2211 of ASME Section VIII, Division 1 and 2 allow the use of a Safety Instrumented System (SIS) in lieu of a pressure relief device, as long as the SIS meets or exceeds the protection provided by the pressure relief device. As SIS, their design must follow the international standard IEC 61511. These systems are often called high integrity protection systems, because the SIS must achieve high safety availability. In most cases, the logic solver must be IEC 61508 compliant to Safety Integrity Level (SIL) 3.
The DIAMOND-SIS® is designed as a low-cost, stand-alone, non-PE logic solver certified as fit for use in HIPS applications up to SIL 3. The 2oo3 voting assembly provides the end user with a fault tolerant logic solver that it is physically and functionally independent from the process control and safety instrumented system. This complete independence mimics that of traditional relief systems, where the failure of one relief valve does not disable any other relief valve. By eliminating the common cause associated multiple HIPS implemented in one safety PLC, the random and systematic failures are significantly reduced.SIS-TECH takes a very serious and holistic approach to lifecycle documentation management and has developed a software program to help manage IPS lifecycle documentation across the lifecycle from the initial Process Hazard Analysis through IPS component test and repairs in the field.