Description about the question:
a development project is being considered at a location in the Liverpool area, where the existing site will be cleared to make way LPG storage and distribution facility. The site is shown below from Google map:
The storage centre is fed by three 150 mm diameter pipe lines roughly following the railway line easterly direction. Planned storage consists of 2 spheres, each of volume 400m3. And 24 horizontal cylinders with various dimensions with an overall storage capacity of 4000m3 of LPG. It is noted that the cylinders arrays and associated pipe work create a moderately confined region of dimensions approximately 50m50m10m
The storage location will be divided into 4 separate areas by concrete bund walls of 1m height. On the site there will be a fire protection system complete pond, and pumps and water spray distribution.
1.4) There are several elements should be considered in order to estimate the number of fatalities of the given scenarios the assumptions carried out as following:
The location of the industrial site occupies the space on the western side of the junction between the Ave and Wood road In the Liverpool area. Affecting areas offices, canteen, control room, maintenance room, security and neighboring the main roads, houses, restaurants, bars, here assuming the percentage of people at residential areas 55% the percentage of people at industrial areas 25%. Population density of 3 people for residential areas 3 people / 100 m2, and 1 person / 100 m2 for industrial areas
The area of the site is 29,716 m2, diameter 194.5 m
Assuming that the 25% of the employees of the plan are out of door
From Google earth, the site is located between the Ave and Wood road with distance of 350 m.
the main sources of uncertainty in the estimating of the number of fatalities in the above Q1 (a):
The estimated number of fatalities based on many some assumptions, how ever, there is uncertainty combines with those results.
- the percentage of people out of door is vary during a year because that the liver pool area people usually go out for jobs at the residential area. Furthermore, people usually presence at nights that will change the number of people out of door,
- the weather condition not considered, wind direction and speed would affect the thermal radiation, flame velocity, and missiles direction. In addition, the ambient temperature has an impact on the severity of the thermal radiation,
- the distances to targets calculated by deferent models, which have weakness points in their estimation,
- The estimated areas of 90% fatalities of BLEVE and torch fire scenarios interact with the industrial area. It creates accurate results of fatalities.
- There is no enough information about the temperature and pressure of the LPG in the tank and pipelines,
- the duration of exposing to the thermal radiation in case of torch fire will influence the number of fatalities.
- The delight ignition time of the vapour cloud can lead to a catastrophic explosion and more fatalities,
- The fireball changing its height with time and the changing of the position of people relative to the fireball. The horizontal view factor employed rather than vertical view factor, which might be more accurate for distances estimation,
- The assumed plant area also can affect the number of fatalities; and
- Using of Google Earth facilities to indicate some distance which located within the industrial area that may cause uncertainty of the fatalities result.
1. Casal, J. (2007) Evaluation of the Effects and Consequences of Major Accidents in Industrial Plants, Volume 8, ELSEVIER.
2. Lees, F. (1995) Loss Prevention in the Process Industries, Volume 2, 2nd edition, Butterworths, Oxford/ UK.
3. Perry, R.H. and Green, D.W. (2007) Perrys Chemical Engineering Handbook, 8th edition, McGraw -Hill, USA.
Additional site safety requirements, which you would require for such an installation and prepare an on-site emergency, plan which could be presented to the local authority to demonstrate competence in operating the facility:
Emergency plan objective: according to the earlier incidents, it is important to make emergency plans.
Moderating and control the incidents: to reduce the accidental incidents effects, and should defense the harm to the people and damage to the property and the environment
Implements and adequate protection measure: it is very essential to measure is employed to protect the people and environment from the major accidents
Communicating the information to the public and the local authorities: it is very essential to implement the communication to the public and the emergency services at the working area
Providing for restoration: should be provided restore the normal situation and to keep the environment neatly
[COMAH Regulations, Schedule 5 part 1 (Regulation 9(1) and 10(1))]
Top tier COMAH site:
The top tier COMAH site defined as an establishment with quantities equal to or greater than higher level or limit. For the establishments that become a top tier COMAH after the beginning of April 1999, the effective emergency plan should be prepared prior to starting process operation. [HSG191]
Emergency planning: emergency planning is a method to limit the risk of serious events procedure, this method will normally focus on hazard elimination(to make sure low risk using of safe substances), hazard reduction(hazards can be minimized), hazard containment and moderate the incident in order to of all fails
Emergency planning requirements and principles:
The main goal of the emergency plan is restore the normal situation, on the other hand there are facing some difficulties so to face this difficulties producing the effective plan.
The top tier COMAH site that processing or handling hazardous substances. They required notifying the competent authorities about installation of such site. The need of notification has significant effects:
b) Health & Safety Executive (HSE) attention It allows identification to emergency planners, the land- use, and emergency services.
It stimulates superior on- site consciousness of associated hazards and risks.
Assessment and Control: Operators of top tier establishment required to:
- Notify the HSE of any recent major accident that has occurred in the establishment and details of action taken to prevent to occur in future.[Gow and Key,1988]
- Prepare of essential information to an inspector, and produce documentary evidence, on request.
- Identify all necessary measures to control and limit any risk in the site. It is important for continues improvement,
- Submission of safety report (case) to the HSE (competent authority in the UK),
- Preparation of on- and off-site emergency planning requirements,
- information to public, and
- involvement of public
These duties are essential to intervene in any incident escalation.
c) Mitigation: There are three elements of potential mitigatory action: the location, information to public, and on- and off-site emergency plans a) Location:
Planning control of incompatible land uses plays a role in achieving an adequate mitigation of major accidents effects. There is an existing bequest to control permitting; so many hazardous installations are not superlatively located close to neighbouring developments.
b) Information to the public: The emergency planning depends on a correct response from people covered by the plan. This needs appropriate information to those liable to be at risk. On-site personnel can receive this detailing as part of their duties and preparation of the emergency plan. However, the off-site people will not often receive such information. For this reason, COMAH Regulation enforces an additional duty to inform people who are inside the vulnerable zone. The minimum information to public:
Notify public of hazardous installation, Description of the process operation on the establishment, hazards, and risk that might affect the persons within the area, and Emergency measures that taken in case of an incident. [Gow & Key,1988]
c) Emergency planning: COMAH requires adequate arrangements for both on- and off-site emergency plans. This necessitates an effective cooperation between the on-site operators, local
Authority, and emergency services. The guidelines on emergency planning is briefing in HSG 191 (HSE book)
On-Site Emergency Plan:
The operator of the company must cover the on-site emergency plan, minimum information required for on-site emergency plan:
- Checking of the key personnel of the company and their responsibilities and duties: in on-site emergency plan, it is very essential to provide the details of the persons like name and their position who are charge of and co coordinating the on-site mitigating activities. Additionally the names of the persons and their positions manage with the local authority in order to prepare the off-site emergency plan
- Procedures and instructions: major accidents may caused by the predictable events or conditions so planner need to out line the action, and should be carry out to control the conditions or events, and limit their consequences, warnings, alarms and communication very necessary tool for receiving clear instruction and reach their duties during the emergency periods
- Warning of accidents: local authority will provide earlier warning, which is in capacity for sitting the off-site emergency plan in motion.
- Training: training is very essential program for staff on duties they expected to reach in events of major accidents and where it is applicable coordinating those with the emergency services
- Participation to off-site emergency plan: the arrangements of the assistance to be provided off-site mitigation action
[COMAH Regulations, Schedule 5 part 2 (Regulation 9(1) and 10(1))]
It is required to the management of top tier site to produce a safety report, there is minimum information included in the safety report:
1. Description of the Major Accidents Prevention Policy (MAPP) and details of the Safety Management System (SMS) of the company which is implemented to prevent and mitigate major accidents:
- Information on company structure and personnel role and responsibilities, procedures, training to workers who involved at the working place
- For the identification and estimation of the major hazards procedures implemented
- Procedures and instruction which adopted to prevent the operational aspects in order to safe operation conditions
- Procedures which are adopted and implemented for planning design
2. Information on local environment of the establishment:
- Full description of the site and local environmental aspects including the geographical location, topographical, hydrographical, and its history if required
- Installation and activities which might cause or present major accident hazards
- Description of the areas with probability of major accidents occurrence
3. Description of installation: Information on the installation of the establishment including description of:
- Main activities and products of the sections of the establishment that are related to the site safety aspects.
- Processes, in particular operating approaches.
- Dangerous substances:
- the inventory of dangerous substances: -Dangerous substances identification including chemical name, classification,
Numbering according to Chemical Aspects Service (CAS), and maximum
Quantity of dangerous substance to be stored (II) Chemical, physical, and toxilogical data- the indication of hazards and effects on both people and environment. (III) Chemical and physical behavior during normal operation or under accidental
4. Information on Risk analysis:
- escription of possibility or conditions of major accidental occurrence
- Extent and severity of the consequences
- Technical parameters and equipment, which installed for safety purpose
5. Prevention and mitigation measures:
- Technical equipment installed to limit major accident consequences.
- Internal or external mobilisable resources
- Alert and intervention
- Summary of above points (a), (b), and (c) is on-site emergency plan must be drown up.
[COMAH Regulation1999, Schedule 2 (Regulation5 (3)), and Schedule 4 part 2 (Regulation 7 (1), (5), and (7))]
1. Gow, H.B.F& Key, R.W., 1988, Emergency Planning for Industrial Hazards, Elsevier, Brussels and Luxembourg.
2. Emergency planning for major accidents: Control of Major Accident Hazards Regulations 1999(COMAH), HSG 191, HSE Books 1999.
3. Statutory Instruments 1999 No. 743, The Control of Major Accident Hazards Regulations 1999