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Environmental Impact Assessment for the Proposed Expansion of Pharmaceutical Industry at SIPCOT Industrial Complex (Phase-I), Hosur Taluk, Krishnagiri District, Tamil Nadu

Chapter - 6

Risk Assessment and Disaster Management Plan \

Vimta Labs Limited, Coimbatore 143

6.0 RISK ASSESSMENT AND DISASTER MANAGEMENT PLAN

6.1 Introduction

Hazard analysis involves the identification and quantification of various hazards

(unsafe conditions) that exist in the plant. On the other hand, risk analysis deals

with the identification and quantification of risks, the plant equipment and personnel

are exposed to, due to accidents resulting from the hazards present in the plant.

In the sections below, the identification of various hazards, probable risks in the

plant, maximum credible accident analysis, and consequence analysis are addressed

which gives a broad identification of risks involved in the plant operations. Based on

the risk estimation disaster management plan has also been presented

6.2 Approach to the Study

Risk involves the occurrence or potential occurrence of some accident consisting of

an event or sequence of events. The risk analysis assessment study covers the

following:

Identification of potential hazard areas;

Identification of representative failure cases;

Visualization of the resulting scenarios in terms of fire (thermal radiation) and

explosion;

Assess the overall damage potential of the identified hazardous events and the

impact zones from the accidental scenarios;

Assess the overall suitability of the site from hazard minimization and disaster

mitigation points of view;

Furnish specific recommendations on the minimization of the worst accident

possibilities; and

Preparation of broad Disaster Management Plan (DMP), On-site and Off-site

Emergency Plan, which includes Occupational and Health safety plan.

6.3 Hazardous Chemical Storage at the Plant

The storage capacities of various fuels in the plant are given in Table-6.1. In the

proposed expansion few more storage tanks will add to the existing inventory.

TABLE-6.1

STORAGE CAPACITIES OF FUELS AND CHEMICALS IN PLANT

Sr. No.

Name of the Chemical Storage Capacity

(KL)

Type of Storage Classification of Storage

Tank

1 Toluene 45 KL Under Ground B

2 Acetone 46 KL Under Ground B

3 DNS 221 KL Under Ground B

4 Methanol 120 KL Under Ground B

5 Ethyl acetate 21 KL Under Ground B

6 DMF 6 KL Barrel B

7 Hexane 12 KL Barrel B


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Sr. No.

Name of the Chemical Storage Capacity

(KL)

Type of Storage Classification of Storage

Tank

8 THF 12 KL Barrel B

9 Pyridine 8 KL Barrel B

10 MTBE 16 KL Barrel B

11 MDC 34 KL Barrel B

12 Isopropanol 16 KL Barrel B

13 EDC 31 KL Under Ground B

A: Dangerous Petroleum B: Non- Dangerous Petroleum C: Heavy Petroleum

6.4 Hazard Identification

6.4.1 Introduction

Identification of hazards in plant is of primary significance in the analysis,

quantification and cost effective control of accidents involving chemicals and

process. A classical definition of hazard states that hazard is in fact the

characteristic of system/plant/process that presents potential for an accident.

Hence, all the components of a system/plant/process need to be thoroughly

examined to assess their potential for initiating or propagating an unplanned

event/sequence of events, which can be termed as an accident. The following two

methods for hazard identification have been employed in the study:

Identification of major hazardous units based on Manufacture, Storage and

Import of Hazardous Chemicals Rules, 1989 of Government of India (GOI Rules,

1989); as amended in 2000 and;

Identification of hazardous units and segments of plants and storage units based

on relative ranking technique, viz. Fire-Explosion and Toxicity Index (FE&TI).

6.4.2 Identification of Major Hazardous Units

6.4.2.1 Classification of Major Hazardous Substance

Hazardous substances may be classified into three main classes: Flammable

substances, Unstable substances and Toxic substances. The ratings for a large

number of chemicals based on flammability, reactivity and toxicity have been given

in NFPA Codes 49 and 345 M. Hazardous characteristics of the major flammable

materials and chemicals that are employed in different processes are listed in

Table-6.2.

TABLE-6.2

PROPERTIES OF FUELS/CHEMICALS USED

Chemical Type TLV

(mg/m3) FBP MP FP UEL LEL

°C % Toluene Flammable Liquid 50 ppm

(TWA) 110.4 -95 4 7.1 1.1

Acetone Flammable Liquid 1780 56.5 - 20 12.8 2.6 DNS Flammable Liquid Methanol Flammable Liquid 260 64.5 - 11.1 36.5 6.0 Ethyl acetate Flammable Liquid 1400 - -83 37.8 - -


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Chemical Type TLV (mg/m3)

FBP MP FP UEL LEL

°C % DMF Flammable Liquid 30 - 153 136 - - Hexane Flammable Liquid 176 - -95 -22.5 - - THF Flammable Liquid 599 - -108.3 -14.5 - - Pyridine Flammable Liquid - - - - - - MTBE Flammable Liquid - -109 -28 - - MDC Flammable Liquid 50 ppm

(TWA) -95 - - -

Isopropanol Flammable Liquid 1230 82 -88.5 11.66 12.0 2.0 EDC Flammable Liquid 40 83.5 -35 13.0 15.9 6.2

TLV : Threshold Limit Value FBP : Final Boiling Point MP : Melting Point FP : Flash Point UEL : Upper Explosive Limit LEL : Lower Explosive Limit

6.4.3 Identification of Major Hazard Installations Based on GOI Rules, 1989 (amended in

2000)

Following accidents in the chemical industry in India over a few decades, a specific

legislation covering major hazard activities has been enforced by Govt. of India in

1989 in conjunction with Environment Protection Act, 1986. This is referred here as

GOI rules 1989 (amended in 2000). For the purpose of identifying major hazard

installations the rules employ certain criteria based on toxic, flammable and

explosive properties of chemicals.

A systematic analysis of the fuels and their quantities of storage has been carried

out, to determine threshold quantities as notified by GOI Rules and the applicable

rules are identified.

6.4.4 Fire Explosion and Toxicity Index (FE&TI) Approach

Fire, Explosion and Toxicity Indexing (FE & TI) is a rapid ranking method for

identifying the degree of hazard. The application of FE&TI would help to make a

quick assessment of the nature and quantification of the hazard in these areas.

However, this does not provide precise information. Respective Material Factor (MF),

General Hazard Factors (GHF), Special Process Hazard Factors (SPH) are computed

using standard procedure of awarding penalties based on storage handling and

reaction parameters. For each separate plant process, which contains flammable or

toxic substances, a fire and explosion index F and/or a toxicity index T may be

determined in a manner derived from the method for determining a fire and

explosion index developed by the Dow Chemical Company.

6.4.4.1 FE and TI Methodology

Dow's Fire and Explosion Index (F and E) is a product of Material Factor (MF) and

hazard factor (F3) while MF represents the flammability and reactivity of the

substances, the hazard factor (F3), is itself a product of general process hazards

(GPH) and special process hazards (SPH). An accurate plot plan of the plant, a

process flow sheet and Fire and Explosion Index and Hazard Classification Guide

published by Dow Chemical Company are required to estimate the FE & TI of any

process plant or a storage unit.


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6.4.4.2 Computations and Evaluation of Fire and Explosion Index

The Fire and Explosion Index (F&EI) is calculated from -

)()(& SPHGPHMFEIF

The degree of hazard potential is identified based on the numerical value of F&EI as

per the criteria given below:

TABLE-6.3

HAZARD POTENTIAL IDENTIFICATION

F&EI Range Degree of Hazard

0-60

61-96

97-127

128-158

159-up

Light

Moderate

Intermediate

Heavy

Severe

6.4.4.3 Toxicity Index (TI)

The toxicity index is primarily based on the index figures for health hazards

established by the NFPA in codes NFPA 704, NFPA 49 and NFPA 345 m.

6.4.4.4 Classification of Hazard Categories

By comparing the indices F&EI and TI, the unit in question is classified into one of

the following three categories established for the purpose are presented in Table-

6.4.

TABLE-6.4

FIRE EXPLOSION AND TOXICITY INDEX

Category Fire and Explosion Index

(F&EI)

Toxicity Index (TI)

I F&EI < 65 TI < 6

II 65 < or = F&EI < 95 6 < or = TI < 10

III F&EI > or = 95 TI > or = 10

Certain basic minimum preventive and protective measures are recommended for

the three hazard categories.

7.4.4.5 Results of FE and TI for Storage/Process Units

Based on the GOI Rules, the hazardous fuels/chemicals used in the existing plant

were identified. Fire and Explosion are the likely hazards, which may occur due to

the fuel storages. Hence, Fire and Explosion index has been calculated for in plant

storage. Detailed estimates of FE&TI are given in Table-6.5.


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TABLE-6.5

FIRE EXPLOSION AND TOXICITY INDEX FOR STORAGE FACILITIES

Sr.

No.

Chemical Total Quantity

(KL)

F&EI Category TI Category

1 Toluene 45 KL 11.2 Light - -

2 Acetone 46 KL 21.1 Light - -

3 DNS 221 KL - -

4 Methanol 120 KL 9.3 Light - -

5 Ethyl acetate 21 KL 36.2 Light - -

6 DMF 6 KL 3.0 Light - -

7 Hexane 12 KL - Light - -

8 THF 12 KL - Light - -

9 Pyridine 8 KL - Light - -

10 MTBE 16 KL -

11 MDC 34 KL 11.2 Light - -

12 Isopropanol 16 KL 36.2 Light - -

13 EDC 31 KL 10.5 Light - -

6.5 Hazard Assessment and Evaluation

6.5.1 Introduction

Preliminary hazards analysis is based on the philosophy "PREVENTION IS BETTER

THAN CURE". How safe are the operations? Safety is relative and implies freedom

from danger or injury. But there is always some element of danger or risk in

anything we do or build. When a chemical process facility is considered safe? This

calls for identification of hazards, quantification of risk and further suggests hazard-

mitigating measures, if necessary.

6.5.2 Methodology

An assessment of the conceptual design is conducted for the purpose of identifying

and examining hazards related to feed stock materials, major process components,

utility and support systems, environmental factors, proposed operations, facilities

and safeguards.

6.5.3 Preliminary Hazard Analysis (PHA)

A preliminary hazard analysis is carried out initially to identify the major hazards

associated with storages and the processes of the proposed plant. This is followed

by consequence analysis to quantify these hazards. Finally, the vulnerable zones are

plotted for which risk reducing measures are deduced and implemented.

6.5.3.1 Fuel/Chemical Storage

In case of tank of fuel/chemical released in the dyke area catching fire, a steady

state fire will ensue. Failures in pipeline may occur due to corrosion and mechanical

defect. Failure of pipeline due to external interference is not considered as this area

is licensed area and all the work within this area is closely supervised with trained

personnel.


Chapter - 6



TABLE-6.6

PRELIMINARY HAZARD ANALYSIS FOR PROCESS AND STORAGE AREAS

Sr.

No.

Blocks/Areas Hazards Identified

1 Boilers

Fire (mainly near oil burners), steam; Explosions, Fuel Explosions

2 Power Transformers Explosion and fire.

3 Switch-yard Control Room Fire in cable galleries and Switchgear/Control

Room.

4 Tank farms Fire

5 Incinerators Explosion and fire.

TABLE-6.7

PRELIMINARY HAZARD ANALYSIS FOR THE WHOLE PLANT IN GENERAL

PHA

Category Description of

Plausible Hazard

Recommendation Provision

Environmental

factors

If there is any

leakage and eventuality of source of

ignition.

-- All electrical fittings and

cables are provided as per the specified standards. All motor starters are

flame proof.

Highly

inflammable nature of the chemicals may cause fire hazard in the storage facility.

A well-designed fire

protection including protein foam, dry powder, CO2 extinguisher should be provided.

Fire extinguisher of small

size and big size are provided at all potential fire hazard places. In addition to the above, fire hydrant network is also provided.

6.5.4 Maximum Credible Accident Analysis (MCAA)

Hazardous substances may be released as a result of failures or catastrophes,

causing possible damage to the surrounding area. This section deals with the

question of how the consequences of the release of such substances and the

damage to the surrounding area can be determined by means of models. Major

hazards posed by flammable storage can be identified taking recourse to MCA

analysis. MCA analysis encompasses certain techniques to identify the hazards

and calculate the consequent effects in terms of damage distances of heat

radiation, toxic releases, vapor cloud explosion, etc. A host of probable or

potential accidents of the major units in the complex arising due to use, storage

and handling of the hazardous materials are examined to establish their

credibility. Depending upon the effective hazardous attributes and their impact on

the event, the maximum effect on the surrounding environment and the

respective damage caused can be assessed.

The reason and purpose of consequence analysis are many folds like:

Part of Risk Assessment;

Plant Layout/Code Requirements;


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Protection of other plants;

Protection of the public;

Emergency Planning; and

Design Criteria (e.g. loading on Control Room).

The results of consequence analysis are useful for getting information about all

known and unknown effects that are of importance when some failure scenario

occurs in the plant and also to get information as how to deal with the possible

catastrophic events. It also gives the workers in the plant and people living in the

vicinity of the area, an understanding of their personal situation.

6.5.4.1 Damage Criteria

The fuel storage and the supply pipelines may lead to fire and explosion hazards.

The damage criteria due to an accidental release of any hydrocarbon arise from fire

and explosion. Contamination of soil or water is not expected as these fuels will

vaporize slowly and would not leave any residue. The vapors of these fuels are not

toxic and hence no effects of toxicity are expected.

Fire Damage

A flammable liquid in a pool will burn with a large turbulent diffusion flame. This

releases heat based on the heat of combustion and the burning rate of the liquid. A

part of the heat is radiated while the rest is convicted away by rising hot air and

combustion products. The radiations can heat the contents of a nearby storage or

process unit to above its ignition temperature and thus result in a spread of fire. The

radiations can also cause severe burns or fatalities of workers or fire fighters located

within a certain distance. Hence, it will be important to know beforehand the

damage potential of a flammable liquid pool likely to be created due to leakage or

catastrophic failure of a storage or process vessel. This will help to decide the

location of other storage/process vessels, decide the type of protective clothing the

workers/fire fighters’ need, the duration of time for which they can be in the zone,

the fire extinguishing measures needed and the protection methods needed for the

nearby storage/process vessels. Table-6.8 presents the damage effect on

equipment and people due to thermal radiation intensity.

TABLE-6.8

DAMAGE DUE TO INCIDENT RADIATION INTENSITIES

Sr.

No.

Incident

Radiation (kW/m2)

Type of Damage Intensity

Damage to Equipment Damage to People

1 37.5 Damage to process equipment 100% lethality in 1 min. 1% lethality in 10 sec.

2 25.0 Minimum energy required to ignite wood at indefinitely long exposure without a flame

50% Lethality in 1 min. Significant injury in 10 sec.

3 19.0 Maximum thermal radiation

intensity allowed on thermally unprotected adjoining

equipment

-- --


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4 12.5 Minimum energy to ignite with a flame; melts plastic tubing

1% lethality in 1 min.

5 4.5 -- -- Causes pain if duration is longer than 20 sec, however blistering is un-likely (First

degree burns)

6 1.6 -- -- Causes no discomfort on long exposures

Source: Techniques for Assessing Industrial Hazards by World Bank

The effect of incident radiation intensity and exposure time on lethality is given in

Table-6.9.

TABLE-6.9

RADIATION EXPOSURE AND LETHALITY

Radiation Intensity

(kW/m2) Exposure Time

(seconds) Lethality (%) Degree of Burns

1.6 -- 0 No Discomfort even after long exposure

4.5 20 0 1st

4.5 50 0 1st

8.0 20 0 1st

8.0 50 <1 3rd

8.0 60 <1 3rd

12.0 20 <1 2nd

12.0 50 8 3rd

12.5 -- 1 --

25.0 -- 50 --

37.5 -- 100 --

6.5.5 Scenarios Considered for MCA Analysis

6.5.5.1 Modeling Scenarios

Based on the storage and consumption of all stored chemicals/fuels the following

failure scenarios in the plant have been identified for MCA analysis and the scenarios

are discussed in Table-6.10.

TABLE-6.10

SCENARIOS CONSIDERED FOR MCA ANALYSIS (EXISTING)

Sr. No. Failure of Fuel/Chemical Total Storage

Quantity (KL) Model Considered for

Assessment

1 Toluene 45 KL Pool Fire

2 Acetone 46 KL Pool Fire

3 DNS 221 KL Pool Fire

4 Methanol 120 KL Pool Fire

5 Ethyl acetate 21 KL Pool Fire

6 DMF 6 KL Pool Fire

7 Hexane 12 KL Pool Fire

8 THF 12 KL Pool Fire


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Sr. No. Failure of Fuel/Chemical Total Storage Quantity (KL)

Model Considered for Assessment

9 Pyridine 8 KL Pool Fire

10 MTBE 16 KL Pool Fire

11 MDC 34 KL Pool Fire

12 Isopropanol 16 KL Pool Fire

13 EDC 31 KL Pool Fire

6.5.5.2 Methodology

A perusal of Table-6.10 clearly indicates that the storage is flammable liquids. Fires

could occur due to presence of ignition source at or near the source of spill. Tank

fires may occur due to the following:

Ignition if rim seal leak leading to rim seal fire and escalating to full-fledged tank

fire. Lighting is a major source of ignition of tank fires.

Overflow from tank leading to spillage, vapor cloud formation and its subsequent

ignition, which flashes back to the tank leading to tank fire. The chance of

overflow should be less unless operator has grossly erred in receiving fuel into

the same tank. Spillage due to overflow may result in a dyke fire if ignition

occurs after sufficiently long period.

Sinking of floating roof: This may occur due to mechanical defect or due to

accumulation of rainwater in the roof, which is not drained.

For the present study, the scenarios under consideration assume that the peak level

of radiation intensity will not occur suddenly. Based on the past experience, it is

found that 20-30 minutes time will be required before a tank fire grows to full size.

For radiation calculations, pool fire has been considered. From the above

considerations, the criteria of 4.5 kW/m2 have been selected to judge acceptability

of the scenarios. The assumptions for calculations are:

It is not continuous exposure;

It is assumed that No fire detection and mitigation measures are initiated

There is not enough time available for warning the public and initiating

emergency action;

Secondary fire at public road and building is not likely to happen;

The effect of smoke on reduction of source radiation intensity has not been

considered; therefore hazard distances calculated tend to be conservative; and

Shielding effect of intervening trees or other structures has not been considered.

No lethality is expected from this level of intensity although burn injury takes

place depending on time of exposure.

Based on the above assumptions each storage facility have been assessed with

respect to Pool fires. The following assumptions are made for evaluating the risk on

the plant and personnel due to the failure scenarios.


Chapter - 6



6.5.5.3 Properties of Fuels Considered for Modeling Scenarios (Pool fire)

The chemical data for various fuels used for modeling is tabulated in Table-6.11

and are compiled from various literature.

TABLE-6.11

PROPERTIES OF FUELS CONSIDERED FOR MODELING

Sr.

No.

Fuel Molecular Weight

g/mol

Boiling Point (oC) Density

Kg/m3

1 Toluene 92.14 110.6 3.1

2 Acetone 58.05 56 2.0

3 DNS 228.12 174 MP -

4 Methanol 34.04 64.7 1.11

5 Ethyl acetate 88.11 170.6 3.04

6 DMF 73.09 307.4 2.51

7 Hexane 86.18 154.4 2.97

8 THF (Tetra Hydro Furan) 72.11 65 2.5

9 Pyridine 79.1 115 0.97

10 MTBE 88.15 55.2 3.1

11 MDC 84.94 40 2.9

12 Isopropanol 60.1 82.6 2.07

13 EDC 98.96 84 3.4

6.5.6 Model Computations

6.5.6.1 Results and Discussion - Pool Fire

The results of MCA analysis are tabulated indicating the distances for various

damages identified by the damage criteria. Calculations are done for radiation

intensities levels of 37.5, 25, 19, 12.5, 4.5 and 1.6 kW/m2, which are presented in

Table-6.12 and in Figure-6.1 for different scenarios.

TABLE-6.12

OCCURRENCE OF VARIOUS RADIATION INTENSITIES- POOL FIRE

Radiation Quantity (KL) Radiation Intensities (kW/m2)/Distances (m)

37.5 25.0 12.5 4.5 1.6 Toluene 45 KL 42.0 52.9 78.6 140.7 253.6 Acetone 46 KL 43.5 54.8 81.4 145.7 262.6 Methanol 120 KL 75.7 95.4 141.6 253.5 457 Ethyl acetate 21 KL 29.3 36.9 54.8 98.0 176.8 DMF 6 KL 11.3 14.2 21.1 37.8 68.2 Hexane 12 KL 24.7 31.2 46.3 82.8 149.4 THF 12 KL 29.0 36.5 54.2 97 174.8 MTBE 16 KL 31.3 39.5 58.6 104.9 189 MDC 34 KL 42.1 53.0 78.7 140.8 253.9 Isopropanol 16 KL 31.8 40.1 59.5 106.5 192.0 EDC 31 KL 37.8 47.6 70.7 126.5 228.1


Chapter - 6



FIGURE-6.1

RISK CONTOUR OF STORAGE AREAS


Chapter - 6



7.5.6.2 Conclusions on Pool Fire

A review of modeling results clearly indicates that the maximum damage and

fatality would occur at <85 m distance. The radiation intensities would envelop the

storage tank and will be confined in and around the storage area.

The radiation intensities of 37.5 kW/m2 represent 100% lethality on people and

complete damage to the process equipment and minimum energy required to ignite

wood (without a flame) and melting of plastic. The equipment and the personal

falling within the distance computed for 37.5 kW/m2 would be damaged and 100%

fatality is likely to occur, which in-turn depends on the number of people working

within this vulnerable distance at that particular time.

A perusal of modeling results tabulated in Table-6.12 indicates that the

radiation intensity of 37.5 kW/m2 is likely to occur within a maximum distance

(range) of 75.7 m around the Methanol tank. But, all the tanks are not located

at a place, but with some distance. Therefore, if one tank gets fire and it will

affect adjacent tank.

The radiation intensity of 12.5 kW/m2 represents 1% lethality on people and

minimum energy required to ignite wood (with a flame) and melting of plastic.

The equipment and the personal falling within the distance computed for 12.5

kW/m2 would be partially damaged and 1% lethality is likely to occur, which in-

turn depends on the number of people working within this vulnerable distance

at that particular time.

A perusal of modeling results tabulated in Table-6.12 indicates that the

radiation intensity of 12.5 kW/m2 is likely to occur within a distance of 141.6

m, considering the Methanol tank is at an outer edge tank farm area. About 1%

lethality and partial damage depending on the type of equipment is likely to

occur within these distances.

As the storage tanks are provided with dyke, the fire would be confined within the

dyke wall. The frequency of such a bund fire, taking place is very low and is of the

order of 1 in 2000 to 4000 years for one tank rupture. It may be noted that the

occurrence of pool fire is rather rare but such data/discussions are useful for

emergency planning. There will be adequate time to evoke emergency planning

and evacuate people by the time a small fire in tank area can grow into a full

fledge bund fire.

6.6 Risk mitigation and management measures

6.6.1 Hierarchy of Controls

There are a number of ways to control the risks associated with hazardous

chemicals. Some control measures are more effective than others. Control

measures are ranked from the highest level of protection and reliability to the

lowest. This ranking is known as the hierarchy of control.


Chapter - 6



The foremost effort has been to eliminate hazard as well as risk, and if not,

reasonable practicable risk is minimized by using one or more of the following

approaches

Substitution Isolation Engineering Controls

If the risk persists it is further minimized by administrative controls, and

further minimized with certain personnel protective equipments.

6.6.2 Eliminating the hazard

Elimination of hazardous work practices from the work places is the most

effective control measure before considering any control measures. Substituting a

less volatile material to control vapour hazard has been envisaged to maximum

extent, and use of any chemical in powder form is completely avoided. Wherever

feasible it is proposed to use less concentration of acid and alkalis.

6.6.2 Isolation of hazard

Isolation of hazard involves separating people from the chemicals or hazards by

distance or barriers to prevent or minimize exposure. Isolate workers from

chemicals, use of closed systems for transfer of chemical, use of glove boxes or

glove bags, installation of process units in closed enclosure fitted with

mechanical exhausts, and access restricted to properly protected personnel,

undertake operations under positive pressure to prevent air borne contaminants,

distancing workers from hazardous chemicals and any potential hazards

generated by their use. When storing chemicals on shelving or other storage

systems, hazardous chemicals will not be stored above or below other chemicals

or other things.

6.6.3 Engineering controls

Engineering controls are physical in nature involving usage of mechanical devices

or processes that eliminate, suppress or contain chemicals, or limit the area of

contamination in the event of spills and leaks. Installation of closed enclosures

and appropriate design of local exhaust ventilation system to eliminate air borne

contaminants.

Maintaining a safe atmosphere in the storage and handling area of hazardous

chemicals, and ensure no recirculation of air within the closed enclosure.

Provision of scrubber in the exhaust system to reduce airborne contaminants

which may be harmful to the environment or people prior to discharge to the

atmosphere.

Regular checks of exhaust system as in planned maintenance schedules to ensure

that vents remain unobstructed. Mechanical ventilation Inlet and outlet vents

located on opposite sides of the storage area at low levels provide airflow across

the floor.

For solvent storage areas, where heavier than air vapours may accumulate in

lower regions with a subsequent buildup of hazardous concentrations, vents


Chapter - 6



provided at a level immediately above any spill containment, on the opposite

sides of a room to provide for airflow across the storage or handling area.

6.6.4 Administrative controls

Administrative controls are considered to supplement other control measures.

Administrative controls are extremely important for emergencies when other

control measures fail, such as for managing spills and leaks and are particularly

important for those workers who are required to clean up spills, or who carry out

regular cleaning and maintenance work.

There is well written policy and work procedures for safe work method, and also

reducing the number of workers exposed to the chemical as also reducing the

duration and/or frequency of workers’ exposure through specific work procedures

through job rotation, reducing quantities of hazardous chemicals through

inventory reduction and prompt disposal of hazardous chemicals that are no

longer required .

Implementation of procedures where only staff who are involved in the use,

handling, storage or generation of hazardous chemicals are allowed access to

high risk areas where there may be a greater risk of exposure , implementing

procedures to prevent introduction of ignition sources into hazardous areas .

Reducing the period of time in which a chemical could escape into the work area,

by minimizing the time that mixers, reactors are open to the environment both

during and after use)

Using vacuum wet methods to suppress dust that may be generated during dry

sweeping, keeping containers of hazardous chemicals tightly closed when not in

use, cleaning up spills immediately, prompt cleaning of residues from empty

containers that have held hazardous chemicals.

Prohibiting eating, drinking and smoking in potentially contaminated areas,

providing washing facilities for rinsing off chemicals (e.g. hand washing, safety

showers, laundering of clothes). Provision of Training and supervision to ensure

administrative controls are effectively implemented.

6.6.5 Personal Protective Equipment (PPE)

PPE are selected to minimize risk to health and safety, suitable for the nature of

the work and any hazard associated with the work, a suitable size and fit and

reasonably comfortable for the person wearing it, maintained, repaired or

replaced so it continues to minimize the risk , used or worn by the worker, so far

as is reasonably practicable.

A worker is ensured, so far as reasonably able, wear the PPE in accordance with

information, training or reasonable instruction. In most circumstances, PPE

includes overalls, aprons, footwear, gloves, chemical resistant glasses, face

shields and respirators. PPE is used to supplement higher level control measures.

The effectiveness of PPE relies heavily on workers following instructions and

procedures correctly. It is also imperative to observe workers, if PPE, is fit, is


Chapter - 6



comfortable or is not a hindrance in the work. It will also be ensured to observe

workers after the task is complete to ensure that the PPE they have used is

stored and maintained correctly.

6.6.6 Specific control measures

This includes key control measures for managing risks from hazardous chemicals

in the workplace viz.,.

Use of water free vacuum generation using mechanical pumping system in a

closed circuit by means of dry pumping

Use of Surface heat exchangers

Us of pigging system in pipes using compressed air

Optimized equipment cleaning to prevent direct VOC release via openings

Often cleaning of equipment is finished with a final rinse of solvent. After addition

of solvent the vessel is cleaned by stirring or heating. Residual solvent is removed

by applying vacuum

Containment and Enclosure of sources

Elimination of openings

Use of vapor balancing

Use of circuits under nitrogen atmosphere for drying operation including

condenser for solvent recovery

Use of closed equipment for cleaning

Implementation of a Monitoring and Maintenance program

Us of pumps that designed to be tight

Use of double action mechanical seals and multiple sealing systems

Flanged joints will be used only where necessary with negligible leakage ratio

To ensure the airtightness of a vessel, all openings are checked and where

necessary sealed until the vessel keeps an applied pressure or vacuum and

pressure test carried out regularly

6.6.7 Keeping hazardous chemicals stable

As far as is reasonably practicable that hazardous chemicals do not become

unstable, decompose or change so as to create a hazard different to the hazard

originally created by the hazardous chemical or significantly increase the risk

associated with any hazard in relation to the hazardous chemical. Some

hazardous chemicals are inherently unstable or highly reactive, or they can

become unstable under certain conditions during use, often in a deliberate

process. This is mainly for hazardous chemicals that are dangerous goods,

however other hazardous chemicals may also present a risk if stability is not

maintained. To keep hazardous chemicals stable, manufacturer’s instructions are

followed, maintain specified proportions of ingredients, goods and other

components that constitute the hazardous chemicals.

Wherever appropriate, keep the hazardous chemicals within any control

temperature range where necessary, keep the hazardous chemical and the


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packaging dry, unless the packages themselves are impervious to moisture. This

does not apply where the hazardous chemicals are about to be used in a

manufacturing process. Some hazardous chemicals may provide an expiry date

on the label ,Where a chemical has passed its expiry date it should not be used,

but be disposed of in accordance with manufacturer’s instructions and local laws.

6.6.8 Impact Protection – Containers, Structures and Plant

To prevent damage from the movement of the structure or plant including any

attached pipe work or equipment, it would be ensured that structures or plant

used for the storage or handling of hazardous chemicals are appropriately located

and fixed to stable foundations. Impact protection measures are provided for

structures containing large quantities of hazardous chemicals, plant and

equipment including storage and process vessels, associated pipe work, pumps

and controls ,storage areas (including transit storage) for packages, and

associated shelves and racks „ exposed parts of the fire protection systems.

Containers are kept away from trafficable areas or prevent vehicle access.

Installation of crash protection measures, such as bollards and guardrails for

impact protection.

6.6.9 Containing spills

Wherever there is a risk of a spill or leak of a hazardous chemical in a solid or

liquid form, provision is made in each part of the workplace where a hazardous

chemical is used, handled, stored or generated for a spill containment system

that contains within the workplace any spill or leak of a hazardous chemical and

any resulting effluent. When a spill, leak or accidental release of hazardous

chemicals occurs, appropriate actions is taken to contain the hazardous chemicals

within the workplace. The spill containment system describes how to contain,

cleanup and dispose of the spill or leak and any resulting effluent.

Spill containment system will be large enough to ensure that all spills can be held

safely until cleaned up. A separate spill containment is provided for incompatible

goods.

The materials used to construct the containment system, as well as any materials

used for absorption, are compatible with the hazardous chemicals, other

materials in the vicinity that will prevent contamination of groundwater or soil,

the system’s integrity will be maintained in any reasonably foreseeable incident.

For large quantities of hazardous chemicals, bunding may be required. Bunding is

designed and constructed in accordance with the relevant Standard specific to the

type of hazardous chemical.

During the transfer process, avoiding spillage or overflow, including overflow

protection on equipment and receiving vessels „ providing emergency shut-offs to

limit the amount of hazardous chemicals released during a loss of containment „

providing a spill containment system „ reducing static electricity and vapour

generation. ensuring transfer fittings are compatible „ installing flow and pressure

regulators on pipe work or pumps „ installing interlocking of valves and switches „

implementing systems for detecting losses from pipe work and fittings, such as

static pressure loss detectors, measurement to determine losses in transfer or


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external sensors. Plumbed eye wash stations and safety showers will be installed

in areas where workers may be exposed in the event of a spill during transfer

operations.

Key considerations for safe storage and handling of gas cylinders include:

maintaining and regularly checking cylinders, regulators, hoses and pipes to

cylinders to ensure that there are no leaks or dents, storing cylinders in an

upright position to ensure the safety device functions correctly, securing cylinders

to prevent dislodgement, transport cylinders with appropriate equipment such as

trolleys or gas cages, keep the cylinder valve closed when the cylinder is not

being used, keep all sources of heat and ignition away from gas cylinders, even if

the cylinders do not contain flammable material, store cylinders outdoors or in

very well ventilated areas. Gas cylinders will be fitted with a bursting disc safety

device. If a small leak occurs, the cylinder valve will be closed if it is safe to do

so. Appropriate personal protective equipment will be put on before attempting to

locate the leak point.

For toxic gases, self-contained breathing apparatus will be used for emergency

use. The area will be well ventilated and air conditioning systems will turned off to

avoid spreading gas. However, if a large amount of gas escapes, the area will be

evacuated. If it is safe to do so, before evacuating, ventilate the area and remove

or isolate ignition sources. Contact the gas supplier for advice, or in an

emergency, contact the emergency services authority.

asphyxiation include: avoiding work being carried out in oxygen-depleted (under

19 per cent) atmospheres - for example this could be done by testing the

workplace atmosphere using an approved and intrinsically-safe gas monitor,

keeping the work area well-ventilated, particularly in low-lying areas and roof

spaces where gases can accumulate – this could be done by ensuring windows

are open where necessary and ventilation and extraction systems are on and are

fully functional, purging, using an air-supplied respirator, particularly in confined

spaces, checking cylinders, cylinder fittings, hoses and connections to ensure that

they are not damaged or in poor condition – this might include checking fittings

and hoses for signs of corrosion or degradation or spraying them with a small

amount of detergent solution or leak-detection spray and looking for bubble

formations which may indicate the presence of a gas leak.

6.6.10 Maintaining control measures

It must be ensure that the implemented control measures remain effective. This

includes checking that the control measures are fit for purpose; suitable for the

nature and duration of the work and are installed and used correctly. Maintenance

of control measures may involve the following: regular inspections of control

measures, supervision to ensure workers are using the control measures

properly, preventative maintenance and testing programs for chemical storage

and handling systems, periodic air monitoring to ensure that engineering and

administrative controls remain effective. Maintenance procedures will include

mechanisms for workers to report defective control measures as soon as they are

identified so that prompt remedial action can be taken.


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6.6.11 Preventative Maintenance and Integrity Testing

It must be ensured, so far as is reasonably practicable, that a system used at the

workplace for the use, handling or storage of hazardous chemicals is used only

for the purpose for which it was designed, manufactured, modified, supplied or

installed and is operated, tested, maintained, installed, repaired and

decommissioned having regard to the safety or workers and other persons at the

workplace.

Systems for the storage and handling of hazardous chemicals generally require

on-going maintenance and testing to ensure that they continue to be safe for the

intended use and that they maintain their operational integrity. Such systems

include, but are not limited to, reaction vessels, chemical transfer lines, pumps,

spill bunding and storage tanks, filters etc. To ensure that the integrity of

chemical handling systems is preserved, planned maintenance programs be

designed and carried out at regular intervals, consistent with manufacturer’s

instructions or advice provided by other competent persons. If this is not

reasonably practicable, inspections and maintenance should be carried out

annually.

Inspection of glass linings on steel or metal alloy reaction vessels to ensure there

are no cracks or holes which might allow contact of incompatible materials with

the metal vessel. Regular checking of bursting (rupture) discs and pressure-relief

systems on pressure vessels to ensure they have not “blown” and are of the

correct pressure rating for the work being performed. Bursting or rupture discs

are safety features of cylinders that prevent damage or injury from over-

pressurization. Checking spill bunding walls for cracks or other signs of wear to

ensure that, in the event of a spill, the bunding will not leak or fail. Checking for

signs of corrosion or degradation on tanks, pipework and compressed gas fittings.

If preventative maintenance checks show that the integrity of any chemical

handling system is in doubt or not performing as it is intended, repair or

replacement of the faulty system should be carried out as soon as practicable and

before its next use.

6.6.12 Providing information, training, instruction and supervision

It must be ensured that information, training and instruction provided to a

worker is suitable and adequate having regard to: „ the nature of the work

carried out by the worker „ the nature of the risks associated with the work at the

time the information, training or instruction is provided, and „ the control

measures implemented. Must also provide any supervision necessary to protect

workers from health and safety risks arising from the work at the workplace, if

the worker: „ uses, handles, generates or stores a hazardous chemical „ operates,

tests, maintains, repairs or decommissions a storage or handling system for a

hazardous chemical, or „ is likely to be exposed to a hazardous chemical.

Information, training, instruction and supervision must be provided not only to

workers but to other persons at the workplace such as visitors. Information,

training and instruction should include the following: the nature of the hazardous

chemicals involved and the risks to the worker, the control measures


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implemented, how to use and maintain them correctly, for example how and

when to clean or replace filters, the arrangements in place to deal with

emergencies, including evacuation procedures, containing and cleaning up spills

and first aid instructions, the selection, use, maintenance and storage of any

personal protective equipment (PPE) required to control risks and the limitations

of the PPE, any health monitoring which may be required and the worker’s rights

and obligations, the labelling of containers of hazardous chemicals, the

information that each part of the label provides and why the information is being

provided.

The work practices and procedures to be followed in the use, handling,

processing, storage, transportation, cleaning up and disposal of hazardous

chemicals. Information, training and instruction must be provided in such a way

that it is easily understood.

6.6.13 Health monitoring

it must be ensure health monitoring is provided to a worker carrying out work for

the business or undertaking if: the worker is carrying out ongoing work using,

handling generating or storing hazardous chemicals and there is a significant risk

to the worker’s health because of exposure to a hazardous chemical, and either

valid techniques are available to detect the effect on the worker’s health or a

valid way of determining biological exposure to the hazardous chemical is

available and it is uncertain, on reasonable grounds whether the exposure to the

hazardous chemical has resulted in the biological exposure standard being

exceeded. Health monitoring of a person means monitoring the person to identify

changes in the person’s health status because of exposure to certain substances.

It involves the collection of data in order to evaluate the effects of exposure and

to confirm that the absorbed dose is within safe levels. This allows decisions to be

made about implementing ways to eliminate or minimize the worker’s risk of

exposure, for example, reassigning to other duties that involve less exposure or

improving control measures.

If the results indicate that a worker is experiencing adverse health effects or signs

of exposure to a hazardous chemical, the control measure must be reviewed and

if necessary revised. inform workers and prospective workers about health

monitoring requirements, ensure health monitoring is carried out by or under the

supervision of a registered medical practitioner with experience in health

monitoring, consult workers in relation to the selection of the registered medical

practitioner, pay all expenses relating to health monitoring, provide certain

information about a worker to the registered medical practitioner, take all

reasonable steps to obtain a report from the registered medical practitioner as

soon as practicable after the monitoring has been carried out, provide a copy of

the report to the worker and the regulator if the report contains adverse test

result or recommendations that remedial measures should be taken. Also provide

the report to all other persons conducting a business or undertaking who have a

duty to provide health monitoring for the worker

6.0 risk assessment and disaster management...

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