Msc in Environmental Health & Safety
EHS Risk Management Assignment 2
Assessment Due Date: 15th April 2011
Student No: A00169067
Student Name: Loretta Kirrane
Lecturer: Dr Sean Reidy
In compliance to the SHWW Act 2005, it is the duty of the employer (section 8) to prepare a risk assessment as required by section 19 of the Act. It states that every employer must identify the hazards at the workplace, assess the risks from those hazards, and have a written risk assessment of those risks.
Examples of three Risk Assessment Techniques includes:
1. Hazard & Operability studies (HAZOP)
Hazard and Operability (HAZOP) studies is a qualitative risk analysis technique that is used to identify weaknesses and hazards in a processing facility. It is normally used in the planning phase (design).
This technique was developed in the early 1970s by imperial chemical industries Ltd. It has gained wide acceptance in process industries as an effective tool for plant safety & operational improvements. For example, it is widely used in Norway in the oil & gas industry.
This technique involves the application of a formal systematic critical examination of the process and engineering intentions of new or existing facilities. It assesses the hazard potential that arises from deviation in design specifications and the consequential effects on the facilities as a whole. This technique is usually preformed using a set of guide words: NO/NOT, MORE/LESS OF, AS WELL AS, PART OF, REVERSE, AND OTHER THAN.
From these guidewords, scenarios that may result in a hazard or an operational problem are identified. For example, when analysing a pipe from one unit to another in a process plant, it is defined the deviation “no throughput” based on the guideword NO/NOT, and the deviation “higher pressure than the design pressure” based on the guideword MORE OF. As a result the causes and consequences of the deviation are studied. This is done by asking questions: as per sample of the pipe: 1. What must happen to ensure the occurrence of the deviation “no throughput” cause? 2. Is such an event possible?
3. What are the consequences of no throughput (consequences)?
The principal that is used in a HAZOP study can be illustrated in the following way:
A HAZOP study is generally carried out by a small team of people with knowledge of the system, directed by a group leader experienced in HAZOP. Once the guide words appropriate to the system has been established, the team works through each combination of guide words, brainstorming to decide whether a deviation from the design intention could arise. Then they consider possible causes of this particular failure and the consequences if the failure occurred. A HAZOP study worksheet, considered as a type of FMEA form are used to document deviations, causes, consequences and recommendations/decisions. Through a HAZOP study, critical aspects of the design can be identified, which require further analysis. Detailed, quantitative reliability and risk analyses will often be generated in this way.
A HAZOP study is a time & resource demanding method. Nevertheless, the methods have been widely used in connection with the review of the design of process plants for a safer, more effective and reliable plant. 2. Failure Mode & Effect Analysis: (FMEA/FMECA)
This qualitative method was developed in 1950s by reliability engineers to determine problems that could arise from malfunctions of military system. It has gained wide acceptance by the aerospace and the military industries and is used in companies such as “Intel” and “national Semiconductor” to improve the reliability of their products.
It is a procedure by which each potential failure mode (component fail) in a system is analysed to determine its effect on the system and to classify it according to its severity. When the FMEA is extended by a criticality analysis, the technique is then called failure...