Friday, April 8, 2011

HAZID and HAZOP Study for Alumina Refinery

Hi Friends,

In present post, we will discuss in brief about HAZID and HAZOP study conducted for setting up Alumina refinery. HAZID and HAZOP are abbreviated terminology for "Hazard Identification" and "Hazard and Operability" study. 

As per regulatory authority, "A hazard means the potential to cause injury or illness". Any process, operation, plant, procedure, substance, situation or activity may have the potential to cause harm. Thus HAZID and HAZOP studies are essential for installation of new plant as well as existing operative Alumina plant to carry out modifications in process or equipment or both so as to minimize risks to personnel and equipment.

HAZID includes all possible kinds / likely hood of major accidents and their consequences as well. HAZOP study is the systematic study carried out by a team of experienced professionals at the design, engineering, execution, commissioning and normal operation of the plant to assess the areas of hazardous / unsafe operation of the plant & equipment and remedial measures with respect to process, design and operational improvements for safe operation of Alumina refinery mitigating consequences. HAZOP study is the widely used technique for identification of hazards and unsafe approach of operational, process and quality problems due to faulty design, failure of equipment / instruments & controls and human error. 

Generally, HAZOP study for greenfield Alumina refinery is conducted soon after the readiness of PFD and P&IDs. However, basic requirements for structured and detailed HAZOP study are listed in subsequent paragraph.

Basic Requirements for HAZOP Study:
Following are the basic requirements for HAZOP study of Alumina refinery-
  • Fixing up process and operating parameters,
  • Material and thermal energy balance,
  • Finalization of sizes and numbers of equipment,
  • Freezing of general layout of plant,
  • Equipment datasheets,
  • Material safety data sheets,
  • Plant start-up procedures,
  • Plant shutdown procedures and
  • Emergency shutdown procedures.
Steps Involved in HAZID & HAZOP Study:
The HAZID and HAZOP study involves the following steps-
  • Identification of hazards and effects,
  • Evaluation of risks,
  • Risk control by comparison with objectives and performance criteria,
  • Recovery by taking risk reduction measures well in advance.
Standards and Guidelines:
The International standards and guidelines followed for HAZID and HAZOP studies are broadly outlined below-
  • EP95-0312 : HAZID,
  • IEC 61882 : HAZOP study guidelines,
  • EP95-0313: Job hazard analysis,
  • EP95-0314: Physical effects modelling,
  • EP95-0352 : Quantitative risk assessment and
  • PR-1696 : HAZOP procedure.
HAZOP study is the assimilation of historical records, present activity and future possibilities in relation to safety, health and environment. It requires thinking out of the box.

Hope, I have broadly covered the HAZID and HAZOP study for Alumina refinery. Please put your views / remarks / suggestions / comments, if any.

Kunwar Rajendra


  1. What criteria are analysed for initial safety and design?

  2. Hi Win Thiha,

    It's a very question you have put before me. I would like to present the gist before you as outlined below which you can elaborate further afterwards.

    The effect of direct exposure of input materials, intermediate stream and product is the basic criteria for human safety. In addition, the impact of equipment failure due to malfunctioning of instruments & controls and wide deviations in process and operating conditions.

    Kunwar Rajendra