HAZOP manager: cost effective HAZOP study solution

A very often asked question is how many people and how much time is needed for preparing a given HAZOP study. Before we start analysing of how to reduce the number of people, and the time spent with preparing HAZOP study, it is important to determine the minimum technical and knowledge requirement of HAZOP study.

Minimum technical requirements are:

ƒ P&I diagrams

ƒ PFD diagrams

ƒ Licensor description and requirements

ƒ Technological description

ƒ Manuals and descriptions for the operators

ƒ Classification of the toxic and explosive material used in the technology.

Company safety policy including

ƒ Target risk matrices for the people

ƒ Target risk matrices for the environment

ƒ Target risk matrices for the business

ƒ Description of the Shutdown system

ƒ Alarm management system and alarm set points

ƒ Trip set points

ƒ Actual instrument list (tag list)

ƒ BPCS configuration and connection to SIS, control system topology.

The problems are arising from missing some of the above requirement. The reasons of not having the information are that either the HAZOP study is prepared in very early stage of the investment (like preliminary HAZOP) or when there is revamp of old plant, this documentation does not exist or not up to date at the given time. The more of the requirement of above listed is available, the better and more cost effective HAZOP study will be produced.

Other issue is the number and profession of people taking part in the HAZOP study. The HAZOP team has to be composed to match the Hazard problem to be analysed, ie. turbines, or compressor needs mechanical and instrument engineers, while a distillation tower needs chemical engineers. Also important

position would be the plant manager, but the better is the operators and shift leader. The HAZOP team leader has to build up an atmosphere within the team, where everybody has the freedom of saying his/her honest opinion based on his/her knowledge. The HAZOP team leader has to work like a reporter or even as a moderator at the HAZOP meetings. It is preferable to change the participant even day by day According to the problem to be analysed.

Functionality of the HAZOP study is clear for everybody but the HAZOP team leader shall take over the responsibility to structure the plant into HAZOP nodes in advance.

The preferable structure is:

ƒ Project, for example: HAZOP and SIL study of General Refinery

ƒ Project unit, for example: Hydrogen Plant of General Refinery

ƒ HAZOP study, for example: Furnace in the Hydrogen Plant of General Refinery

ƒ HAZOP Node, for example: Furnace 1 of Hydrogen Plant of General Refinery

ƒ HAZOP Sub-nodes for Furnace 1, for example: Fuel gas line of Burners of Furnace1 in the Hydrogen Plant of General Refinery

HAZOP Scenarios for Furnace 1, Fuel gas line of the burner with parameter and guidewords, for example:

ƒ Natural Gas pressure is low

ƒ Natural Gas pressure is high.

There are attempt of automating the HAZOP study. The question is what and why.

When building of a new chemical, petrochemical or refinery plant start, first the technology licensor is selected who will provide the basic engineering of the plant. The basic engineering never takes into consideration the local specialities and requests. For example, a Hydrogen plant in the world, even having the same licensor but different EPC partner and end-user never will be 100 % identical.

Question is how to automate the HAZOP study for a Hydrogen plant? Which part and why will be automated? And who will make this work?

At a given point of view a pump is everywhere is pump etc. but this approach drives us to a misinterpretation of the problem, since this is not automation, within a plants a copy and paste task and it is just not more.

Another “hot” question is who will automate the HAZOP and which part of the HAZOP shall be automated: HAZOP nodes, HAZOP sub-nodes, even HAZOP Scenarios? Who will take over the responsibility of the results? Who has the competence to decide that the result is good? Will it be good for all company?

Too much questions are to be an answered, and we feel that this solution will not drive to the future.

Another suggested solution when somebody (HAZOP leader or end-user?) draws schematics about the HAZOP nodes building up automatically the Hazard scenarios. That means that the complete plant has to be redrawn in a simplified mode again. Who will pay for this extra work? Drawing is much slower procedure

than the HAZOP meeting itself. What will happen if the drawing is not correct?

The HAZOP study also will be miss-interpreted too.

Other development direction is the adaptive HAZOP node. Behind this philosophy, there is an aim of building up a knowledge base and feedback into HAZOP nodes. The question is what the result of this feedback is. Who has the better answer for the Hazard scenarios and why? Who will decide about adapting or not adapting the new Hazard knowledge?

The above question leaded us to the following question: what does the knowledge-base mean? After preparing some 100 HAZOP studies in the Refinery Industry, we discovered and identified a lot of similarities in our work. However this was not more than only a copy and paste method, for handling the similarity.

Our conclusion was that the best way is preparing HAZOP node “template”, and using them to speed up our work and to make it more effective.

This solution will give the possibility of improving our knowledge-base philosophy and giving an editable template to the hand of HAZOP leader and HAZOP team, leaving the only work of filling up the template with the current actual tag names, and scaling the consequences According to the Company’s target matrices and checking the template’s IPL (Independent Protection Layers) with the realised ones and modify them accordingly.

A very minimum requirement of preparing HAZOP study is the availability of correct P&ID drawings. Without them this it is impossible to prepare HAZOP study. But if the P&ID drawings are correct, based on our template philosophy, the 90% of the Hazard scenarios would be prepared in advance. Sending this preliminary HAZOP study to the end-user in electronic form will give the possibility of reducing the time spent on the oral HAZOP study.

What is the advantage of this method?

ƒ The template is a knowledge based solution

ƒ The template is a context-independent method to solve the problem

ƒ Preparing a preliminary HAZOP needs only one person

ƒ Giving possibility for the end-user to study, ask questions, suggest modification of the preliminary HAZOP study before the oral HAZOP meeting;

ƒ In the oral HAZOP meeting there is no need of secretary since 90 % of the HAZOP study is in written form in advance and on the HAZOP meeting it shall be modified only

ƒ Save time of the end-user, since no need on site typing, it is not necessary at all, or just in small quantity, comparing to the traditional HAZOP studies.

We implemented this solution in our Tool4S (Tool for SIL) software as an option.

Using our program everybody can modify extent the Template Library and case by case supervise and modify it, feed back the experience of their company and even other companies.

What is the disadvantage of this method?

ƒ The knowledge base refers to our experience and practice in preparing HAZOP study and safety application in the Process Industry

ƒ Now, neither a forum nor competent authority exists to certify the correctness of templates.

In the next paragraph we will show an example how we built up a Burner Management template in the petrochemical Industry.