Safety Integrity Level (SIL)
A common way of ranking the dependability of a Safety Instrumented Function (SIF) is to use a simple numerical scale from one to four, with four being extremely dependable and…
Flow Meter Characteristics
Different Types of Flow Meter Characteristics are Recommended Service, Rangeability, Pressure Loss, pipe diameters, Viscosity Effect and Cost of instruments
SIS Logic Solver
Control hardware for safety instrumented functions should be separate from the control hardware used to regulate the process, if only for the simple reason that the SIF exists to bring…
Pilot-operated Safety and Relief Valves
While many safety and relief valves actuate by the direct action of the process fluid forcing against the valve plug mechanism, others are more sophisticated in design, relying on a…
Direct-actuated Safety and Relief Valves
Pressure Relief Valves (PRVs) and Pressure Safety Valves (PSVs) are special types of valves designed to open up in order to relieve excess pressure from inside a process vessel or…
Rupture disks
A Rupture Disc, also known as a pressure safety disc, burst disc, bursting disc, or burst diaphragm, is a non-reclosing pressure relief device that, in most uses, protects a pressure…
Over Pressure Protection Devices
Fluid pressure exerts force on any surface area it contacts, as described by the formula F = PA. One practical consequence of this fact is that process vessels and pipelines…
Proof Testing of Safety Instrumented Systems
A reliability enhancing technique related to preventive maintenance of critical instruments and functions, but generally not as expensive as component replacement, is periodic testing of component and system function. Regular…
High Reliability of Safety Instrumented Systems
Instrumentation safety may be broadly divided into two categories: the safety hazards posed by malfunctioning instruments, and special instrument systems designed to reduce safety hazards of industrial processes. This section…
Concept of Redundancy in Control Systems
The Mean time between failures (MTBF) of any system dependent upon certain critical components may be extended by duplicating those components in parallel fashion, such that the failure of only…
