OVERVIEW
ON MAJOR HAZARD INSTALLATIONS
Venugopala rao.V CSA ,WSO-CSS Principal Consultant NAGACONSULTANT&ENGINEERS,VISAKHAPATNAM,INDIA
venu@nagace.com
Abstract
Fears generally prevail
among public on environmental and personnel safety whenever any major hazard
factory is planned to be set up. While this was the situation during yester-years,
but with the stringent statutory controls and risk control measures and
methodologies prevailing in all countries ; thanks to the initiatives of ILO and other international agencies
in this regard, these fears are being gradually nullified .A close look at some
of the controls these hazardous factories are subjected to is focused here for
the general information of the WSO readers.
1.
Preface:
Among
various categories of factories across the world, industries handling, storing
and processing hazardous chemicals are well known for causing serious accidents
resulting heavy loss of life. The disastrous accidents in Flexiborough (UK),
Seveso, Italy and Bhopal, India, prompted European Union consisting of member
nations & ILO to look into the problem and evolve suitable control measures
to prevent any possible accidents in the industrial sectors.
Accordingly the EU issued directives referred as Seveso Directives I, II & III.
(Please see attachment 1) ILO in conjunction with UNEP( UNITED NATIONAS
ENVIRONMENTAL PROGRAMME,WHO-IPCS (International Programme on
Chemical Safety) published MAJOR HAZARD CONTROL SYSTEM-A
PRACTICAL MANUAL in 1988.
2.
Toxic
Substances
(very toxic and toxic) [1]
Substances with the following
toxicity values, physical and chemical properties which are capable of causing
major accident hazards are brought under the purview of major hazard substances
depending upon their storages.
|
|
LD50
Oral ln Rats LD50
Mg
/kg body weight
|
LD50
Cutaneous in rats
or
Rabbits Mg/kg body weight
|
LC50
inhalation (4 hours
In
Rats mg/l (inhalation)
|
|
1
|
LD
≤50
|
LD50
≤5 10
|
LC50
≤ 0 .1
|
|
2
|
5
< LD 50 ≤ 25
|
10
< LD50 ≤5 50
|
01
<LC50 ≤ 0.5
|
|
3
|
25
< LD 50 ≤ 200
|
50
< LD50 ≤ 400
|
05
< LC50 ≤ 2
|
Table-1: Toxicity Values
1.Flammable Chemicals: Flammable
gases ; chemicals which in the gaseous state at normal pressure and mixed with
air become flammable and the boiling point of which at normal pressure is 200C
or below;
2. Highly flammable liquids; chemicals which have
a flash point lower than 210 C and the boiling point of which at
normal pressure is above 200C;
3. Flammable liquids: chemicals which have a
flash point lower than 550 C and which remain liquids under
pressure, where particular processing conditions, such as high pressure and
high temperature, may create major accident hazards.
3.
Explosives: chemicals which may explode under the effect of flame, heat
or photo-chemical conditions or which are more sensitive to shocks or friction
For the properties
and threshold capacities of hazardous substances please refer to the respective
country legislation or refer Major
Hazard Control-Practical Manual ILO publication1988for guidance.
3.
Typical Major Hazard Installations
As per Major Hazard Control-Practical
Manual ILO publication, the following installations generally possess hazardous
substances beyond the stipulated threshold quantities classifying them under
MHI.
·
Petrochemical
works and Refineries;
·
Chemical works and Chemical production
plants;
·
LPG storage and terminals;
·
Stores
and distribution centers for chemicals;
·
Large
Fertilizer Stores;
·
Explosives
factories;
·
Works
in which Chlorine is used in bulk quantities
4.
Statutory Requirements
Because of the severe consequences arise due
to accidents in major hazard installations,in order to get ensured that the
occupier of the MHI , is properly taking effective control over storages and
manufacturing operations, the local Statutory Authority governing factories requires essential documents as detailed below
at certain intervals.
Table 2: Regulatory Compliance Schedule for MHI
|
Rule
|
Requirement
|
Frequency
|
Applicability
|
Required
documents
|
Time
to comply
|
Authority
|
|
Relevant Local Statute
|
Approval of facility& obtaining license
|
|
New projects
|
1.Safety report
2.On-site Emergency Plan
|
6 months before construction
commences
|
Local Regulatory Authority
|
|
|
Carrying out safety audit & submission of
safety report
|
yearly once
|
New &Existing units
|
1.Safety audit report
2 Updated safety report
3.On-site emergency plan
|
1 month of completion of audit
|
|
|
|
Advance intimation
|
Existing units: in case of changes, decrease or
increase in thresh hold quantity of
hazardous chemical
|
1.Updated Safety Report
2.Updated On-Site Emergency Plan
|
Before 3 months of making changes
|
||
5.
Safety Report
Safety Report is one among the 3 important documents
to be submitted by the Occupier to the statutory authority. It is a
comprehensive document with plant layout, process description, and construction safety features of plant, Safety
Management system, Employee training, Onsite Emergency Plan details, general
operational hazards, inventory of hazardous substances, loading & unloading
operations and not the least complete details on Preliminary Hazard Analysis
(PHA) on use of the hazardous chemicals.
6.
Identification of Hazards.
In order to have
an effective study on PHA, methodologies like HAZOP, HAZID, Accident consequence,
Fault Tree Analysis, FMEA etc. will have to be employed depending on the
operational status of the installation.
If MHI is in
project stage Hazard Operability (HAZOP) Study verifying with those of P & I
diagrams and arriving at the Action Plan as per HAZOP Table 3. is a must
identifying hazards during process operation through pipelines &Equipment s
level with appropriate control Operations Stage:
HAZOP
TABLE-3
|
Node:
Drawings
|
||||||
|
Sl.No
|
Guide Word
|
Causes
|
Consequences
|
Safeguards (Existing and Approved)
|
Further Mitigating Actions
|
Remarks
|
|
|
|
|
|
|
|
|
Risks generated
out of HAZOP, HAZID can be further evaluated as per 8 Step Risk Assessment
Process is given vide figure1 Risk
Assessment Process
Figure -1
8 STEP RISK
ASSESSMENT (RA) PROCESS
Risk Matrix (Combining Impact and Likelihood
QUALITATIVE RISK
CRITERIA
Table.4
|
LIKELYHOOD
LEVELS
|
RISK/IMPACT LEVELS
|
||||||||
|
1
|
2
|
3
|
4
|
6
|
|||||
|
MINOR
|
MODERATE
|
SEVERE
|
MAJOR
|
CATWSTROPHIC
|
|||||
|
6
|
LIKELY
|
6
|
12
|
18
|
24
|
30
|
|||
|
5
|
OCCASSIONAL
|
5
|
10
|
15
|
20
|
25
|
|||
|
4
|
POSSIBLE
|
4
|
8
|
12
|
16
|
20
|
|||
|
3
|
UNLIKELY
|
3
|
6
|
9
|
12
|
15
|
|||
|
2
|
RARE
|
2
|
4
|
6
|
8
|
10
|
|||
|
1
|
REMOTE
|
1
|
2
|
3
|
4
|
5
|
|||
|
|
|
1
|
First Aid Injury
|
Minor Injury
|
|
Fatality/Multiple Fatalities
|
|||
|
|
EXAMPLE
:Likelyhoodof2(Possible)x Impact of (Minor)2=3x2=6 Dark Blue
|
||||||||
|
|
RISK
& PLANNED CORRECTIVE ACTION
|
||||||||
|
|
RISK LEVEL
|
|
CATEGORY
|
TOLERABILITY
|
|||||
|
|
1-2
|
|
VERY LOW
|
ACCEPTABLE
|
|||||
|
|
3-9
|
|
LOW
|
ACCEPTABLE
|
|||||
|
|
4-12
|
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MEDIUM
|
TOLERABLE
|
|||||
|
|
15
|
|
HIGH
|
UNACCEPTABLE
|
|||||
|
|
16 &ABOVE
|
|
VERY HIGH
|
UNACCEPTABLE
|
|||||
TABLE:5
LEGEND: RISK LEVELS
Requires
Priority Action
Must
be brought down to ALARP LEVEL
Acceptable
Financial
Risks/Impacts are not calculated in this Matrix levels
The Risk Matrix Diagram [2] given below is indeed a very useful tool in
quickly assessing the severities and consequences.
Risk Matrix Nomogram: Figure.1.
SFAP in the above chart stands for: `So Far As Practicable’ term
used by (Victorian Australia Occupational Health and Safety Regulations).Equally
ALARP a term used in majority in UK and
in other countries, can also be used alternatively.
Once the hazard assessment
for all the hazardous substances during the process and bulk storage is
completed, the information may then be tabulated as per the Table 6
|
Sl.No
|
Incident
|
Scenario
|
Likelihood
|
Consequences
|
Risk Level
|
Correction Measures
|
Target Date
For
completion
|
Responsibility
|
|
|
|
|
|
|
|
|
|
|
RA CORRECTIVE ACTION TABLE -6
This complete study Report with graphical
representation viz. risk curves and threat
zones with calculation of individual and societal risks is called as
Quantitative Risk Assessment and is an important document to be submitted to
the Regulatory authority. (RA) along
with Safety report.Inorder to map the effects and risk curves, software models
will be necessary .
An example of gas release giving the accident
scenarios and the effects thereon to the individual fatalities and society at
large.is given vide Sl.No VIII for information of the readers.
7.
Scenario Examples:
7.1. Bulk
Storage of Propane: Consequences in case of accidental release of gas
A Chemical factory has bulk storage
of Propane in a 150 KL Bullet installed within a dyke A village is situated at a distance of 1KM
With a population density is about 20
persons / ha. The minimum distance of the village from the storage is 100 m.
The village extends beyond the distance of 100 m from the storage. The village
occupies 20% of the area within 100 m from the storage.The bullet is filled in
by a road tanker depending on the necessity.
Various Loss of Containment (LOC)
probabilities can be thought of as under:
Ø Vehicular Impact against pumps and
pipes causing heavy leakage of Propane.
Ø Static Spark
Ø Tanker moves off with filling hose still connected
to tank
Ø Transfer hose not secured correctly during filling
operation
Ø External impact to tank wall or bund
Ø Containment Failure & Consequences
Ø Flange leakage
Ø Lightening
Ø Overfilling of Tank
Risk and severity consequences due to
all probable incidences causing environmental, individual and societal risks
are be assessed without which; the HARA/PHA
Report does not serve its purpose.
Assuming of an incident causing a
release of continuous Flow of liquid propane, the following
Example with
certain dispersioneffects causing individual and societal threats is given for the general understanding of the readers
7.2. THERMAL RADIATION AT THE THREAT ZONE
Total mass of propane gas leaked out: 66 TONNES
Threat Modeled: Thermal radiation from jet
fire
10 meters --- (10.0 kW/(sq m) =
potentially lethal within 60 sec)
Orange: 13 meters --- (5.0 kW/(sq m) = 2nd degree burns within 60 sec)
Yellow: 20 meters ---
(2.0 kW/(sq m) = pain within 60 sec)
2
Figure: 2
Model Dispersion Effects
ATMOSPHERIC
DATA: (MANUAL INPUT OF DATA)
SITE DATA:
Building Air Exchanges Per Hour: 0.51
(unsheltered single storied)
CHEMICAL DATA:
Chemical Name: PROPANE Molecular Weight: 44.10 g/mol
AEGL-1 (60 min): 5500 ppm AEGL-2 (60 min): 17000 ppm AEGL-3 (60 min): 33000 ppm
IDLH: 2100 ppm LEL: 21000 ppm UEL: 95000 ppm
Ambient Boiling Point: -43.5° C
Vapor Pressure at Ambient Temperature:
greater than 1 atm
Ambient Saturation Concentration: 1,000,000
ppm or 100.0%
Wind: 5 miles/hour from ESE at 3 meters
Ground Roughness: open country Cloud Cover: 5 tenths
Air Temperature: 60° F Stability Class: B
No Inversion Height Relative Humidity: 50%
SOURCE STRENGTH:
Leak from hole in horizontal cylindrical
tank
Flammable chemical is burning as it escapes
from tank
Tank Diameter: 8 meters Tank Length: 10 meters
Tank Volume: 503 cubic meters
Tank contains gas only Internal Temperature: 60° F
Chemical Mass in Tank: 2.13 tons
7.3. Individual & Societal Risks
i.
Estimation of the number of fatalities:: 12 fatalities as per established calculation guidelines
ii.
Societal Risk Estimation of frequency of occurrence: 10-4 accidents/year
8.
On-Site Emergency Plan
The Third
document for submission to the RA is On-Site Emergency Plan
The overall objectives of an
emergency plan are:
·
To
localize the emergency and, if possible, eliminate it; and
·
To
minimize the effects of the accident on people and property.
This Plan
consists of management’s existing measures, onsite resources, to combat the
emergency with trained manpower in first aid , firefighting and availability of
fire protection systems.
9.
Conclusion
There is no industry in the world
without any hazard. Much depends on the organization‘s design features, its safety management system,
employees’ operational practices , and their prompt actions to mitigate site
emergencies and finally the management’s
compliance to such regulatory controls
play a larger role in preventing serious accidents and creating a
sustained zero risk atmosphere.
Further Suggested Reading
Major Hazard Control-Practical Manual
ILO publication
Hazardous Industry Planning Advisory
Paper No 3-Risk Assessment
REFERENCES
.
[1]
Major Hazard Control-Practical Manual ILO publication
[2] # Hazard Identification, Risk Assessment and Control
Measures for Major Hazard Facilities published by Comcare . Gov. Au.
https://www.comcare.gov.au/__.../Hazard_identification_risk_as...
ANNEXURE-1
Seveso
Directive I, II and III
|
Author Profile
VENUGOPALA RAO VAKADA
Venugopala Rao is a Mechanical
Engineer by Qualification, but a full-fledged ENVIRONMENT, HEALTH SAFETY &
SOCIAL RESPONSIBILITY PROFESSIONAL having extensive experience over 40 years in
varied industries covering
Petrochemicals, Refineries ,Viscose Rayon, Pesticide factories and
Tobacco factories. Prior to present occupation, he worked as Group Manager(Risk
Mgmt. & CSR) for a UK Based multinational Tobacco Company, He is an EHS Auditor trained by BAT & Rhone Poulenc
industries, France and a certified Safety Auditor from Govt. of India, besides
being an accredited ISO 14001, OSHAS
18001 AND SA 8001 Auditor and a a Certified Safety Specialist from World
Safety Organization, USA He is A
COMPETENT PERSON approved by Govt. of India under Petroleum Regulations. He is currently
an Associate Member of International Institute of Risk &
Safety Management, UK and Affiliate
Member of World Safety Organization, USA
. Presently He is Principal
Consultant of his Consultancy Firm NAGA
CONSULTANTS & ENGINEERS, INDIA( URL: www.nagace.com)
Readers may contact him via his
email venu@nagace.com Mobile: +919676612929
for any clarifications, consulting assignments or assistance.
