Risk Assessment & Hazard Analysis Techniques in the Process Industry

Risk Assessment
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April 24, 2013 Miami FL– Todays informative post in the Industrial Plant Safety blog will give you an idea about Risk Assessment in industry, especially the process industry.

The Process Industry  covers a large range of industrial sectors such as  Petrochemicals, Chemicals, Oil and Gas, Fertilizers, Pulp and Paper, Food & Beverages, Pharmaceutical manufacturing and Power Generation.  Many of the Process Industry’s operations deal with large quantities of hazardous, toxic, or flammable raw materials, intermediates as well as finished goods. Although in industries such as Oil and Gas, the products are used domestically, they aren’t exactly safe (like water). Hence though gasoline and diesel are used in millions of passenger vehicles, they ARE flammable substances, that have to be handled carefully. The same goes for the chemicals industry or even power generation, where natural gas is explosive/flammable and has to be handled carefully.

In later years, the process industry operations became bigger and bigger leading to larger and larger quantities of these hazardous and/or flammable and/or toxic materials being handled in massive facilities. These were massive in order to reduce operational costs ( a 1000 Kl storage tank is not twice as expensive as a 500 Kl one and requires the same number of personnel to operate). However the consequence of a 1000 Kl tank blowing up  may be more than twice the consequence of a 500 Kl tank blowing up! This is exactly the conundrum that the process industry is facing today. Large capacities lead to large savings under NORMAL conditions-but what happens under ABNORMAL conditions (e.g. in an accident)? Why of course consequences way beyond imaginable! Hence the process industry is now realizing that the large capacities need better risk assessment and managing, to prevent accidents from happening at all. Once something blows up, the game is almost over. Mitigation is almost not 100% possible. Witness what happened with Deepwater Horizon, or the more recent West Fertilizer plant in Waco, Texas. Hence it is of utmost importance to use the best risk assessment  tools. The entire procedure of risk assessment in the process industry comes under the umbrella of a common term named Process Hazard Analysis or PHA for short. PHA consists of many techniques such as HAZOP, HAZAN, What-If, HAZID, LOPA, Risk Matrix, FMEA, FMEDA, some of which we will briefly examine here.

You can study the HAZOP technique in detail here. For a short description of HAZOP please refer to another post on this blog here. In short, HAZOP is HAZard and OPerability technique. In the process industry, much of the plant operational design is represented in Piping and Instrumentation drawings (P & IDs). In the HAZOP technique, these are broken down into nodes and each node is analyzed using various guide words.

In the What-If technique, group brainstorming is used. The group studies one node and asks questions such as “What if this vent valve did not open under overpressure?” or “What if the operator doesn’t notice the high temperature alarm?”. As you can see this technique requires a hell of a lot of experience to ask all the right questions.

LOPA stands for Layer of Protection Analysis. More about LOPA can be found in this post here. You can also get actual LOPA training if you download the e-learning course available here.

LOPA-Layer of Protection Analysis
LOPA Worksheet

Other techniques such as Risk Matrix and FMEA will be discussed in a separate posting.