Risk Assessment techniques in the Process Industry

Risk Assessment is defined as the qualitative or quantitative determination of the degree of hazard (or threat) posed by a system, process, or any other entity. While risk assessment is a generic term which may apply to almost anything like the risk of an individual dying immediately after being insured to the probability of a car meeting with an accident while going on a highway, it means different things in the process industry. In the process industry, which can mean a wide variety of industrial sectors right from oil and gas, chemical processing to mining, risk assessment is the quantification or subjective assessment of the degree of hazards that could turn into accidents such as explosions, fire, leakages & spills and so on.
As you can imagine there are several different ways and methods of risk assessment in these industries and there are both quantitative as well as qualitative methods. Quantitative methods of risk assessments are known as QRA or Quantitative Risk Analysis. The subjective ways are many and they comprise of techniques such as HAZOP, HAZID, what if analysis and LOPA (which is also known as semi quantitative). Thus HAZOP is a kind of subjective risk assessment technique used mainly in the process industry (although reportedly some variants are also used in the software and allied sectors).
Among all these techniques, the most popular one today is HAZOP.

For example, consider the gas storage tanks (spheres) above. There is obviously a risk associated with this storage which is the risk of explosion and or fire or gas leak. Now to assess this risk we can use a variety of risk assessment techniques, the main one being HAZOP. We will break down the unit into logical nodes and each node will then be analyzed using the HAZOP technique to provide an estimate of the risk associated with the storage.

PHA-Process Hazard Analysis

Today, we will examine in brief what is referred to in industry parlance as PHA or Process Hazard Analysis. PHA refers to any technique that is used to identify hazards that may exist in any industrial, manufacturing or any such similar activity. More specifically it refers to the hazards that are to be identified in the process industry. As you know the "process industry" is a generic term that covers a wide range of industries such as chemicals, oil and gas, power generation, mining and the like. These industries have several hazards present due to the nature of their operations and they need to be identified, reduced to a safe enough level to minimize the risk of accidents and thus mitigate them. PHA thus refers to any technique that can reliably do so. There are several PHA techniques that are used in the process industry and they are HAZOP (Hazard and Operability Study), What-if analysis, HAZID, LOPA (Layer of Protection analysis) to name a few. Out of these HAZOP and LOPA are growing in popularity worldwide.LOPA as a PHA technique is also used as a SIL determination technique. SIL is an acronym for Safety Integrity Level and we will cover that in a separate post.

HAZOP-Hazard and Operability Study

Sep 19, 2013- HAZOP is an acronym for the popular Hazard and Operability Study. However the focus of most HAZOP studies seems to be more on the "Hazard" part rather than the "Operability" part. Did you notice it? The operability refers to how easy or how difficult would it be to operate the plant in its current form. For example, it is easy to say (and record) that in case of an upset the plant operator will close the Hand Valve HV101. However where is it located? Is it easy to close it? Is it accessible? What if it requires an effort just to reach it? Would the handle get jammed? These operability questions are very relevant in HAZOP studies and must be addressed. In recent years, almost nothing is discussed in HAZOP studies about the plant's operability. On hopes that in the coming years the operability factors will also play an important role. After all, a plant that is easy to operate and run should cause less stress amongst operating staff and thereby cause lesser dangerous incidents or accidents, is it not? One good move in recent years has been though that "human factors" are seen to be as important as the plant design factors and these would be given weightage in the new HAZOP studies. For an in-depth course on the Hazard and Operability technique, you can refer to the Abhisam training course on HAZOP.

HAZOP

Aug 9, 2013- HAZOP stands for Hazard and Operability Study. This acronym, HAZOP is used extensively to describe the HAZOP Study technique that is a very popular risk assessment technique in industries such as Oil and Gas, Chemical, Power, Mining and others, where there may be several hazards that need to be identified and risks mitigated. The following HAZOP YouTube video by Abhisam is useful to get an overview of the technique and how to learn more about it.


Of course, HAZOP is not the only Risk Assessment technique around, there are others such as Hazard Matrix, HAZAN and HAZID too. However over the years HAZOP has proved to be much more popular than any of the other techniques.

HAZOP Video-Training Course

Here's a great video about HAZOP training that is on Youtube. See it below for yourself. The video basically tells you about HAZOP and how you can learn it in the comfort of your own home or office. Attending classroom trainings can be a pain these days, as you will have to spare time as well as a great deal of money AND be away from work to attend it. At the end of the day you may forget everything!

So here's an alternate way to learn all about the HAZOP process and also get certified in HAZOP! Note that it is not just a HAZOP ppt, it is a complete course.

HAZOP Study

HAZOP Study- What is HAZOP?
(Note: To learn about HAZOP Study in detail and to get certified as a competent person, please download or enroll online in the Abhisam HAZOP training course)



HAZOP is an acronym which is short for Hazard and Operability study and it was first introduced many years ago by ICI, a multinational chemicals company, based out of the UK. ICI no longer exists today as ICI (various parts have been taken over by companies such as Huntsman and AkzoNobel), but the HAZOP study technique that they pioneered, continues to grow in importance.
HAZOP is a risk assessment technique, used mainly in the chemical  and process industries such as oil and gas, refining, petrochemical, heavy chemicals, pharmaceutical and power generation as well as industries such as mining too. HAZOP is one technique out of a group of risk assessment techniques that form part of PHA (Process Hazard Analysis) . Other techniques in PHA are FMEA (Failure Modes and Effects Analysis), LOPA (Layer of Protection Analysis), HAZID (Hazard Identification), What-If analysis and of course checklists. HAZOP is more subjective rather than quantitative.

The HAZOP technique is  designed to identify the intentions and deviations of a particular operation, called a node. For example, a node may be a section of a plant that pumps liquid from a storage tank to a reactor some distance away. Then in this node, the original intention is identified (transporting liquid from the storage tank to the reactor) and then all possible deviations are analyzed in detail. Some of these deviations may result in accidents (for example if there is a reverse flow of liquid from the reactor to the tank). This process (the HAZOP process) is known as a HAZOP Study.

You may now appreciate that a HAZOP study should be done only by skilled personnel. If an unskilled or untrained person carries out a HAZOP (using the best software or no software), the chances of doing a bad HAZOP increase manifold. Doing a bad HAZOP is worse than doing no HAZOP at all because a bad HAZOP lulls people into a false sense of security, that their HAZOP study is complete (and the recommendations are implemented and the plant is safe and everybody lived happily ever after) when actually the opposite is true.

HAZOP Process

HAZOP Process-what does it mean? The word HAZOP is an acronym for HAZard and Operability Study, which is a Risk Assessment technique used extensively in the process industries (such as Oil and Gas, Chemicals, Petrochemicals, Power, Pharma and others). The HAZOP Process is a structured method that is a part of a PHA (Process Hazard Analysis), in which one examines a small part of a plant or facility (called as a Node) using a set of Guide Words that seek to examine all the permutations and combinations possible in a particular plant operation. For example, if one is analyzing the flow of a liquid from say a day tank (lets call it Tank A) to another tank (say Tank B) then there are several things that can go wrong with this simple process, such as Low Flow, Reverse Flow, No Flow and so on. These guide words (Low, Reverse, No) are combined with a parameter (such as Flow) to generate possibilities of what could go wrong in the operation.
Then each combination gives us an opportunity to think what can happen. For example if the normal operation of the process is to transfer liquid from Tank A to Tank B, then Reverse Flow will be from Tank B to Tank A. Will this cause any problems? We then list all these problems under the heading of "consequences" and for each consequence we can think of a protective method by which this consequence can be avoided. Thus if we determine that reverse flow will have dangerous consequences, then we can prevent it by having a Non Return Valve in the line that connects Tank A to Tank B.
Thus each such condition will be evaluated for consequences and protective measures designed. If we do this diligently for the entire plant, we will have a much safer operation!
If you wish to know more about this HAZOP Process, you can download an excellent e-learning course here.