ATEX Trainings and presentations 

PHA (Process Hazard Analysis)

It involves a set of methodologies, such as Checklist, What if?, What if?/Checklist, Hazard and Operability Study, and Failure Mode and Effects Analysis. The PHA Must Address:

• Equipment in the process
• Hazards of the process
• Identification of previous incidents
• Engineering and administrative controls
• Consequences of failure
• Facility siting
• Human factors
• Qualitative evaluation of S and H effects
• Consequences of deviation
• Steps required to correct or avoid deviation
• Equipment in the process
• Hazards of the process
• Identification of previous incidents
• Engineering and administrative controls
• Consequences of failure
• Facility siting
• Human factors
• Qualitative evaluation of S and H effects
• Consequences of deviation
• Steps required to correct or avoid deviation

HAZOP (Hazard and Operability Study)

A hazard and operability study (HAZOP) is a structured and systematic examination of a complex planned or existing process or operation in order to identify and evaluate problems that may represent risks to personnel or equipment. HAZOP is used as part of a Quantitative Risk Assessment (QRA) or as a standalone analysis.

The intention of performing a HAZOP is to review the design to pick up design and engineering issues that may otherwise not have been found; to investigate how the system or plant deviate from the design intent and create risk for personnel and equipment and operability problems.

The technique is based on breaking the overall complex design of the process into a number of simpler sections called 'nodes’ which are then individually reviewed. It is carried out by a suitably experienced multi-disciplinary team (HAZOP) during a series of meetings.The HAZOP technique was initially developed in the 1960’s to analyze major chemical process systems but has since been extended to other areas, including mining operations and other types of process systems and other complex systems such as nuclear power plant operation and software development.

FMEA (Failure Modes & Effects Analysis)

Failure Mode and Effects Analysis (FMEA) is a structured approach to discovering potential failures that may exist within the design of a product or process.

Failure modes are the ways in which a process can fail. Effects are the ways that these failures can lead to waste, defects or harmful outcomes for the customer. Failure Mode and Effects Analysis is designed to identify, prioritize and limit these failure modes.

FMEA is not a substitute for good engineering. Rather, it enhances good engineering by applying the knowledge and experience of a Cross Functional Team (CFT) to review the design progress of a product or process by assessing its risk of failure.

There are two broad categories of FMEA, Design FMEA (DFMEA) and Process FMEA (PFMEA).

Process FMEA (PFMEA) discovers failure that impacts product quality, reduced reliability of the process, customer dissatisfaction, and safety or environmental hazards derived from:

• Human Factors
• Methods followed while processing
• Materials used
• Machines utilized
• Measurement systems impact on acceptance
• Environment Factors on process performance

SIL (Safety Integrity Level)

To what extent can a process be expected to perform safely? And, in the event of a failure, to what extent can the process be expected to fail safely? These questions are answered through the assignment of a target Safety Integrity Level (SIL). SILs are measures of the safety risk of a given process.

Historically, safety thinking categorized a process as being either safe or unsafe. For the new standards, however, safety isn’t considered a binary attribute; rather, it is stratified into four discrete levels of safety. Each level represents an order of magnitude of risk reduction. The higher the SIL level, the greater the impact of a failure and the lower the failure rate that is acceptable.

IEC61508-4 defines „fault tolerance” as the „ability of a functional unit to continue to perform a required function in the presence of faults or errors.” Therefore, hardware fault tolerance is the ability of the hardware (complete hardware and software of the transmitter) to continue to perform a required function in the presence of faults or errors. A hardware fault tolerance of 0 means that if there is one fault, the transmitter will not be able to perform its function (measure level).