Storage, Handling and Processing of Dangerous Substances Flashcards
Industrial Chemistry
Raw materials > Primary bulk chemicals > Secondary commercial products
Rate of Reaction in Chemical Production
Quicker it is made the quicker it can be sold
Variables which effect the rate of reaction
Temperature Pressure Concentration Surface area of reactant Catalyst
What is a catalyst?
A substance that alters the rate of reaction without becoming permanently involved in the reaction
Exothermic reactions
Energy is given out by reactants as they form products, causing the temperature of the surroundings to rise
Endothermic reactions
Opposite of exothermic. Energy is taken in by the reactants to form products.
Energy comes from the surroundings which lose energy and cool down, resulting in a drop of temperature
Thermal Runaway reactions
Begins when the heat produced by an exothermic reaction exceeds the heat removed.
Surplus heat raises the temp. of the reaction mass and accelerates the rate of heat production
Risk from thermal runaway
Reaction vessel may become over-pressurised due to violent boiling or rapid gas generation
Harmful effects of thermal runaway
Boiling over of the reaction mass
Large increase in temp. and pressure resulting in explosion
Blast and missile damage
Secondary fires and explosions
Contamination of the wokrplace by hot liquid or toxic materials
Toxic clouds that can spread offsite
Causes of thermal runaway incidents
Inadequate understanding of the process chemistry and thermochemistry
Inadequate design for heat removal
Inadequate control and safety systems
Inadequate operational procedures, including training
HAZOP
Hazard Operability Study - structured method for identifying chemical process hazards
Methods of control to ensure safe operation of Chemical Processes
Inherently safer methods, which eliminate or reduce the hazard
Process control, which prevents a runaway reaction occurring
Protective measures, which limit the consequence of a runaway
Examples of inherently safer methods
Replacing hazardous materials with less hazardous
Having less unreacted material in the reactor, using a continuous process instead of a batch reactor
Using a semi-batch method
Using a heating medium which has a max temp. that is too low for the reaction mixture to decompose
Batch reactors
All reactants are added to a reactor at the start of the reaction. The process stops when chemical reactions are complete
Continuous processes
Reactants continually flow into and products continuously flow out of, the reactor system
Semi-batch methods
Reactants are added in a controlled manner throughout the process. Product is only removed at the end of the reaction
Process control
Includes the use of sensors, alarms, trips and other control systems that either take automatic action, or allow for manual intervention to prevent the conditions for a runaway to occur
Variables controlled in process control
Temperature
Reactant addition
Agitation
Others; PH, conductivity, concentration and pressure
Examples of protective measures
Designing plant to contain maximum pressure
Emergency relief vents
Crash cooling
Reaction inhibitors
Dumping the reaction into a quenching fluid
Legislation covering control of substances that can cause fire and explosions in the workplace
Dangerous Substances and Explosive Atmospheres Regulation 2002 (DESEAR)
Requirement under DESEAR
Employers to assess the risk of fire and explosions that may be caused by dangerous substances in the workplace
Forms of Dangerous Substances
Liquid, gas, vapours or dusts
Dangerous substances include….
Substances covered by CLP regulation
Any dust that when forms a cloud can explode
Any other substances not covered by CLP that could cause a fire or explosion in a workplace (like high flashpoint liquids)
5 steps in a DESEAR risk assessment
- Identify hazards
- Identify who may be harmed and how
- Evaluate risks
- Record significant findings
- Review and revise
Factors to be taken into account in a DESAER Risk assessment
Hazardous properties of the substance
Supplier safety information - SDS on flashpoints and safe method of handling
Circumstances of the work
Particular activities which may be a high level of risk (maintenance and repair tasks)
Likely presence of explosive atmospheres and need for haz. area classification
Hazardous properties of dangerous substances
Size of release
Temperature and pressure
Ventilation
Extent of zones
Other considerations
Purpose of hazardous area classification
Identifies places where controls over ignition sources are needed and determines controls of equipment used in a zone
Relationship between fires and explosions
In many cases where an explosive atmosphere can form, any ignition will cause a fire rather than an explosion. Consideration to be given as to whether the fire could lead to an explosion
Ignition source?
A release of energy often of short duration and localised, which can ignite dangerous substances present in the air
What is an IBC?
Intermediate Bulk Container - cubic container used for transport and storage of fluids and bulk materials. More efficient means of transport than barrels and drums as they can be moved by FLT and stacked
Control measures for the storage of flammable liquids - VICES
Ventilation Ignition Sources Containment Exchange Seperation
Separation Distances
Should allow sufficient time for people to be evacuated and for additional fire fighting equipment and emergency procedures to be mobilised
Min. separation distance for large tanks
At least 16m away from site boundary, any designated non-haz area, process area or any fixed source of ignition
Advantages of underground tanks
Soil provides impact and fire protection
Save space
Separation distances are reduced
Disadvantages of underground tanks
Increased risk of corrosion
Difficult to detect leaks
Soil contamination
Need for confined space access or excavation for all inspection and maintenance
Tank venting system should provide…
Normal pressure relief
Normal vacuum relief
Emergency pressure relief
Types of fire protection for storage tanks
Fire resistant cladding or coating
Fire Walls
Water Cooling Systems
Foam blankets or extinguishing systems
Bonding and earthing
To min. accumulation of electro-static charge and prevent sparks. Required for all metal parts
Flashpoint of flammable liquids which require liquid tight bunding
55 degrees C or below
Sufficient capacity for a bund
Enough to contain largest possible spillage, normally 110% capacity of the largest storage vessel in the bund
Bunding should….
Prevent flamm. liquid or vapour reaching ignition sources
Prevent liquid entering drains and sewers
Allow controlled recovery or treatment of spill
Minimise surface area of liquid
Prevent spread of burning liquids
Prevent contamination of water courses
Particular problems of storing flammable liquids in IBCs in warehouses
Prone to early failure in a fire, allowing leaked contents to feed the fire
Degrade over time so are prone to leak
Generally made of cheap non-conductive plastic so can become electrostatically charged in transit
Principle objectives when establishing a storage compound for drums of flammable/explosive materials
a) Minimise risk of a fire occurring in the storage area itself
b) Protect the store from fires occurring elsewhere
c) Mitigate the consequences of a fire, particularly with regard to people
Hazards of nitrocellulose
Easily ignited and burns fiercely
Emits large amount of heat and toxic fumes
May explode if incorrectly packaged and stored in a confined space
Safe Storage of Drums - Separation
Protects people and property from the effects of a fire in the store itself.
Distances can be reduced if additional fire protection measures such as fire walls are installed
Safe Storage of Drums - Fire resistant storage buildings or storerooms
Such have the following:
Sufficient fire resistance to allow time for the alarm to be raised and for escape
Good means of escape
Lightweight roof or relief panel so that in the event of a fire, escaping heat or fumes are directed to a safe place
Safe Storage of Drums - Control of ignition sources
Prohibit smoking PTW for maintenance involving hot work Control use of electrical equipment Separation from heat sources Protection from exposure to sunlight High standards of housekeeping
Safe Storage of Drums - Restricted access
Authorised people and vehicles only.
High security standards
Safe Storage of Drums - Safety signage
Posted at all entrances.
Type of flammable liquid stored
Smoking and other ignition sources prohibited
Procedure to follow in event of a fire
Section of SDS summarising labelling for CLP
Section 15
Energetic Substances
Capable of releasing energy through rapid exothermic decomposition or polymerisation
Spontaneous Combustion
When the temperature of a substance increases to it’s auto-ignition temperature, at the point it can ignite without an ignition source being needed
Pyrophoric Substances
Spontaneously combust in air or with moisture. Used in semiconductor industry
Types of Automatic Prevention devices for handling dangerous substances
Overflow
Pre-set meter
Fixed volume batch tank
Level detector linked to a pump or valve
Main spray methods
Compressed air - most common
Airless/hydrolic - use for big structures
Electrostatic
Usual way to control flammable vapours and mists when spraying
Ventilated spray booth
Purpose of a ventilated spray booth
Prevent escape of vapours into the workplace
Prevent contamination from overspray
Protect health of workers
Provide separation from sources of ignition and prevent spread of fire
Prevent contamination of workpiece by dust and grease in the work environment
Disposal of flammable liquids
Waste liquids generally need to be stored and handled to the same standards as the flammable liquid they originated from
Dangerous Goods
Liquid or solid substances and articles containing them that have been tested and classified against international criteria and found to be potentially dangerous when carried
ADR
Regulation covering carriage of DG by road
Regulations implementing ADR in the UK
Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regs 2009 (CDG)
Types of Road Tankers
Insulated or non-insulated
Pressurised or non-pressurised
Designed for single or multiple loads by means of internal divisions in the tank
Location of loading bays for road tankers
At least 10m away from occupied buildings, site boundary and fixed sources of ignition
Unloading approaches for road tankers
Transfer by gravity
Transfer by pump
Transfer under positive air pressure
Bottom unloading is generally applied
How to minimise risk of overfilling road tankers
Load using a flow meter with a trip, similar to a petrol pump
What is IiW?
Instructions in Writing Form, also referred to as Emergency Instruction Cards
Purpose of IiW
Must be carried in the vehicles crews cab (tanker) and be available to act as an aid in an accident or emergency
IiW must confirm (4 pages)
Actions in the event of an emergency
Additional guidance to vehicle crew on the hazardous characteristics of the DG and actions
Equipment for personal and general protection
What is included on road tank placards to indicate DG
Four digit UN number for the substance
Appropriate hazard label (diamond)
Types of placarding on road tankers
GB registered on domestic journeys must use Emergency Action (Hazchem) Code
All other vehicles must display hazard identification number (HIN)
EAC on Road Tanker Placards
Emergency Action Code
1st character on EAC
Determines the fire-fighting extinguishing medium
2nd character on EAC
Indicates appropriate personal protection
Codes for fire-fighting extinguishing medium on EAC
1 = Coarse water spray 2= Fine water spray 3 = Normal foam 4 = Dry agent
Codes for Personal Proection on EAC
S, T, Y, Z - Normal fire fighting clothing
P, R, W, X - Chemical protective clothing
P, R, W, Y on an EAC
Indicate there is a danger the substance can be violently or explosively reactive
W, X, Y or Z on an EAC
Indicates spillages and fire run off should be prevented from entering drains and surface/ground water systems
E on an EAC
Indicates public safety hazard, where people should be warned to stay indoors with doors and windows shut. Evacuation may be considered
Marking of packaging containing DG
Showing the UN number and classes on the packaging
Labelling of packaging containing DG
Displaying the Hazard diamond with the class number on the packaging
ADR driver training requirements for all vehicles except those carrying packages under the small load threshold
General training plus ADR Training certificate
The certificate may be endorsed for different classes of dangerous goods or different modes
ADR driver training requirements for any vehicle carrying packaged dangerous goods under the small load threshold
General Training
ADR driver training requirements for vehicles with a small tank (up to 1m cube)
General Training
VTC for Drivers
Vocational Training Certificate also know as ‘ADR Certificate’
How to obtain VTC
DFT approved training course and successfully complete exam
Format of ADR certificate
Credit card style with photo of driver
General Training covers….
Awareness of hazards
Basic info for minimising incidents taking place
Measures to ensure personal safety and public safety
Info for limiting effects of incident
DGSA
Dangerous Goods Safety Advisor
3 main duties of DGSA
Monitoring compliance with rules on DG
Advising business on the transport of DG
Preparing annual report to management on DG activities
DGSA is responsible for
Monitoring procedures and safety measures
Investigating and compiling reports of accidents or emergencies
Advising on potential security aspects
Under Electricity at Work Regs what exposures must electrical equipment be protected from?
Mechanical Damage
The effect of weather, natural hazards, temperature or pressure
The effect of wet, dirty, dusty or corrosive conditions
Any flammable or explosive substance, including dust and vapours
What is IP rating?
Ingress Protection ratings classify the degree of protection provided by enclosures against the ingress of solid objects and moisture
and
The protection afforded against contact with any live parts within the enclosure for all types of electrical equipment.
IP Rating numbers
a) protection from solid objects or materials
b) protection from liquids (water)
c) protection against mechanical impacts - Commonly Omitted
Techniques to design or construct electrical and non-electrical equipment in potentially explosive atmospheres
Sealing electrical equipment so the explosive atmosphere cannot come into contact with electrical components
Reducing the power of electrical equipment
De-energizing electrical equipment where a fault or an explosive atmosphere is detected
What marking should be on electrical equipment in an explosive atmosphere
Ex
What regulation must new electrical equipment to be used in explosive atmospheres comply with?
The equipment and protective systems intended for use in explosive atmosphere regulations 1996 (EPS) which implements the EU ATEX directive
Marking of products to be used in explosive atmospheres
To comply with EPS they must be marked with the CE conformity mark along with the number of the notified relevant body
Hazard groups for equipment and protective systems intended for use in potentially explosive atmospheres
Group I - Mining - NOT ON SYLLABUS
Group II - Surface industry
Sub-categories of Group II equipment
IIA - Propane
IIB - Ethylene
IIC - Hydrogen
Highest risk sub-category of Group II equipment
IIC is the highest risk as it is much easier to ignite.
Equipment suitable for IIC will also be suitable for IIA and IIB
Maximum surface temperature of electrical equipment rule
Should always be lower than the auto-ignition temperature of the gas/air or vapour/air mixture in which it is used
Hazardous area definition from DSEAR
Any place which an explosive atmosphere may occur in quantities such as to require special precautions to protect the safety of workers
Hazardous Zoning
Based on an assessment of the frequency of the occurrence and duration of an explosive gas atmosphere
Hazardous Zone 0 (Gas)
An area which explosive gas is present continuously or for long periods
Hazardous Zone 1 (Gas)
An area in which an explosive atmosphere is likely to occur in normal operation
Hazardous Zone 2 (Gas)
An area in which an explosive gas atmosphere is not likely to occur in normal operation and if it does will only exist for a short period of time
Hazardous Zone 20 (Dust)
An area which combustible dust, as a cloud is present continuously or frequently during normal operations, in sufficient quantity to be capable of producing an explosive concentration of combustible dust in a mixture with air
Hazardous Zone 21 (Dust)
An area which combustible dust, as a cloud is occasionally present during normal operations, in sufficient quantity to be capable of producing an explosive concentration of combustible dust in a mixture with air
Hazardous Zone 22 (Dust)
An area which combustible dust, as a cloud may occur infrequently and persist for only a short period, or in which accumulations of layers of combustible dust may give rise to an explosive concentration of combustible dust in a mixture with air
Intention of Purge/Pressurised Protection (Ex p)
To prevent the explosive atmosphere from contacting the ignition source
Purge Protection
Involves maintenance of a constant flow of air or inert gas to dilute and take away any potentially explosive atmosphere
Pressure Protection
Ensures that the pressure inside an enclosure is sufficient to prevent the entrance of flammable gas, vapour, dust or fiber and prevent possible ignition
Advantage of Purge/Pressure protection
It also accommodates possible internal releases of flammable gas, vapour or liquid
Protection Methods
Intrinsic Safety (Ex i)
Flameproof (Ex d)
Increased Safety (Ex e)
Non-sparking (Ex n)
Intrinsically Safe (Ex i)
Electrical energy within the equipment is restricted to a level below that which may cause ignition or restricted to limit the heating of the surface of the equipment
Flameproof (Ex d)
Equipment that could cause an explosion is contained within an enclosure within an enclosure which can withstand the force of an explosion to prevent transmission to the outside hazardous atmosphere
Also prevents the hazardous atmosphere entering the enclosure and coming into contact with equipment
Increased Safety (Ex e)
Intended to prevent potential ignition occurring by applying extra precautions to ensure increased security against excessive temperatures or sparks
Non-Sparking (Ex n)
Precautions are taken so electrical equipment that has the potential to arc is not capable of ignition surrounding atmosphere
Emergency Planning - What is an emergency
A situation or series of events that threatens or causes serious damage to human welfare, the environment or security
What is the aim of emergency planning?
Where possible prevent emergencies occurring. When they do occur, good planning should reduce, control or mitigate the effects of the emergency
3 key groupings of people emergency plans should focus on
Vulnerable people
Victims
Responder personnel
3 aspects to be covered by emergency planning
Prevention
Reducing, controlling or mitigating the effects
Other action in connection with an emergency
CoMAH Regulation 17
requires the competent authority to make information on any establishment covered by CoMAH regs to make information public on request:
Name of operator
Confirmation CoMAH applies
Simple explanation of activities undertaken
Hazard classification of dangerous substances
General info on how the public will be warned
Details of where further info can be obtained
MHSWR 8 & 9
Require employers to have in place:
Procedures for serious and imminent danger areas
Any necessary contacts with external services for first-aid, emergency medical care and rescue work
Procedures for serious and imminent danger areas
Every employer must:
Have procedures to be followed in the event
Sufficient number of competent persons to implement the procedures and evacuate
Ensure employees do not have access to danger areas
CoMAH 2015
Control of Major Accident Hazard Regulations 2015
Definition of a Major Accident
An occurance resulting in uncontrolled developments in the course of the operation of any establishment and leading to serious danger to human health or the environment, immediate delayed inside or outside the establishment and involving one or more dangerous substances
Main aim of CoMAH
Prevent and mitigate effects of major accidents involving dangerous substances which can cause serious damage to people and/or environment
Who enforces CoMAH
Competent authority, made up of HSE and the Environment Agency working together
When is an establishment subject to CoMAH
If it produces, uses, handles or stores on site any dangerous substance specified in schedule 1 above the qualifying quantity
Upper tier establishments under CoMAH
Have quantities equal to or greater than the upper threshold
Lower tier establishments under CoMAH
Establishments with lower quantities, but which are equal to or greater than the lower threshold
General duty under Reg 5 of CoMAH
Take all measures necessary to prevent major accidents and limit their consequences for human health and the environment
Internal Emergency Plan (IEP) - CoMAH
Should address operators complete response to a major accident. It should:
Concentrate on those events identified as being most likely to occur
Be proportional
Have flexibility to be extended or increased
Key personnel identified in IEP
Site incident controller
Site main controller
Site incident controller
Usually site manager at the time the incident occurs.
Role includes taking control at the scene
Activation of the pan
Sets up emergency control centre
Alerts emergency services
Site main controller
Normally senior establishment manager or director
Takes overall responsibility for directing operations
Confirms SIC has done all their role
Mobilizes key personnel
Liaises with external agencies
On-site Emergency Control Centre
Place from which the internal emergency response operations are directed and coordinated.
The Site Main Controller, other key personnel and senior officers of the emergency services will be based here
External Emergency Plan (EEP)
Based around the major accident hazards identified which could affect people and the environment outside the boundary of the establishment
Responsibilities for an EEP
Competent authority will inform local auth of duty to produce and off-site emergency plan
Operator has to provide local auth with the necessary info
The local auth can request additional info
Content of an EEP
1) Authorised persons
2) Early warning
3) Co-ordinating resources
4) On-site mitigation
5) Off-site mitigation
6) Public information
7) Trans-boundary incidents
Role of Police for CoMAH
Responsible for coordinating all responses at and around the scene
Role of Fire Service for CoMAH
Primary objective to rescue people trapped in a fire or in wreckage and debris.
Also responsible for the H&S of all personnel working within the inner cordon
Role of Ambulance Service for CoMAH
To save life and limb through effective treatment at the scene and transporting casualties to hospital
Role of Coastguard in CoMAH
Responsible for initiation and co-ordination of civil maritime search and rescue.
Marine pollution control unit is responsible for dealing with pollution at sea and coordinating shoreline cleanup
Role of Local Authorities in CoMAH
Support emergency services
Support local and wider community
Use if resources to mitigate effects
Co-ordination of response by organisations other than emergency services
Monitoring and Maintenance of emergency plans
Reviewed and revised for upper tier at minimum every 3 years.
Plans must be tested to ensure suitable
