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Tips to help with this exam

This guide provides tips for answering exam questions on electricity at work, including key keywords and workplace relevance. It covers important regulations and safety measures.

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Tips to help with this exam

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  1. Tips to help with this exam • Read the question! pick out the key words • Try to relate the question to a workplace situation • Break questions down e.g.. design, use, maintenance where appropriate • Remember HS principles e.g.. RA, Controls, People

  2. Regs 1 -3 1 Citation 2 Interpretation 3 persons with duties • Reg 4 Systems, work activities & protective equipment • Systems must be maintained to prevent danger • All work activities must be carried out in a manner not to give rise to danger • Equipment provided to protect people working on live equipment must be suitable and maintained • Reg 6 Adverse or hazardous environments • Must be suitable for the environment and conditions that are reasonable foreseeable • Mechanical dame e.g.. vehicle, people • Weather, temp, pressure, natural hazards e.g.. bird droppings • Wet, dusty, corrosive conditions, presence of flammable dusts • Flammable or explosive atmospheres • Reg 16 Persons to be competent to prevent danger and injury • An understanding of the concepts of electricity and the risks involved in work associated with it • Knowledge of electrical work and qualification in electrical principles • Experience • Knowledge of systems of work & ability to recognise risk & hazards • Physical attributes to recognise elements of the system e.g.. not colour blind • Reg 5 Strength & capability of electrical equipment • Must be able to withstand effects of its load • Must be able to withstand effects of transient or pulse currents • Reg 7 Insulation protection & placing of conductors • Prevent danger from direct contact through insulation etc • Reg 8 Earthing or other suitable precautions • Purpose to prevent harm from indirect contact e.g.. casings Electricity at work regs 1989 • Reg 15 Working space, access & lighting • Where there are dangerous live exposed conductors space should be adequate to • Allow persons to pull back from the hazard • Allow persons to pass each other • Lighting should be adequate preference e to natural then artificial • Reg 9 Integrity of referenced conductors • Ensure electrical continuity is never broken Reg 10 Connections – must have adequate mechanical strength e.g.. plugs • Reg 14 Work on or near live conductors • Competent staff • Adequate information • Suitable tools: insulated tools, protective clothing • Barriers or screens • Instruments and test probe to identify what is live and what is dead • Accompaniment • Designated test areas • PTW • Reg 13 Precautions for work on equipment made dead • Identify the circuit, don’t assume the labelling is correct • Disconnection & isolation e.g.. isolation switches (lock off) removal of fuse/plug • Notices, signage and barriers • Prove system dead test the test device • Earthing • PTW Reg 11 means of protecting from excess current e.g.. fuse, RCD Reg 12 Means of isolation

  3. Groups at risk • Operators • Maintenance engineers • Teachers • Layout (Envelope) • Planning during design • Minimise need to approach robot • Good viewing arrangements outside of enclosure • Adequate distance between robot & enclosure • Prevent trap points • Adequate access to rescue injured person • Access only throughinterlocked gates or similar • Interlocked perimeter fencing • Positioned to prevent access to dangerous parts • Normally 2 meters high • Rigid panels • Securely fastened to floor • Infill suitable to protect from other hazards e.g.. ejected materials • Gates/access points to be interlocked • Hinged/sliding interlocks • Trapped key exchange • Solenoid lock • Behavioural - People • Hazard aware • Trained in procedures e.g.. entry, emergency • Adequately supervised • Preventative maintenance and inspections • Software checks to avoid aberrant behaviours • Stop devices • Guard checks • Integrity of parts for wear damage e.g.. hydraulic rams • TEACHING • Remotely where possible • Slow mode when live Robot Safety • Electro-sensitive safety systems • Used in conjunction with fencing • Photo cell device • Trip with use of light curtains arranged vertically/horizontally/diagonally • Pressure mats around machinery • Trip wires etc robot comes into contact with a person should trip • All should require manual restart • Entry Procedures • SSOW defined/RA carried out • Analysis of hazards in all possible modes of operation • Release of stored energy before entry/work • PTW • ISOLATION required • Positive stops • Limits movement of robot • Defined limits to prevent trap points • Avoid creating additional trap points • Brakes • Prevent danger of fall under gravity • Should be applied automatically when machine stops • Emergency Stops provided at • Control stations • Teacher control pedestal • All workstations • Other positions as necessary

  4. Reference – Supply of machinery regs 1992 schedule 3 • Consider • Installation • Use • Maintenance • Decommissioning • General • Principles of safety integrations • Materials & products used/created • Lighting arrangements • Handling & Installation of machine • Controls • Safety & Reliability • Control devices • Means of starting stopping device • Normal stopping • Emergency stopping • Mode of operation selection • Failure of power supply • Software design • Failure of control circuit • Indicators • Information devices • Warning devices e.g.. alarms/lights • Warning of residual risks • Markings • Instructions • Protection against mechanical hazards • Stability/anchorage – e.g.. floor fixings • Risk of break up during operation • Falling objects/ejected parts • Surface risk e.g.. sharp/hot/cold • Variable speeds • Moving parts • Choice of protection arrangements Machinery ‘Essential health and safety requirements’ that should be addressed • Protection against other hazards • Electricity e.g.. insulation • Other stored energy e.g.. hydraulic pressure • Errors of fitting • Fire/explosion • Noise • Dust/gases e.g.. extraction • Vibration • Radiation • Maintenance • Machinery maintenance • Access to operating and servicing position • Isolation of energy sources • Operator intervention • Cleaning of internal parts • Lubrication etc • Required Characteristics of guards • Fixed • Movable guards • Adjustable guards • Special requirements for protective devices

  5. Key Factors • Crane • Lift • Forensic evidence • Lift • Load • Weight • Gravity – lifting point? • Slinging method – appropriate for load? • Type of lift • Static • Slewing • Lift & Travel • Drag • Site conditions e.g.. wet, windy, foggy, obstructions/excavations • Lifting plan, witness statements visual inspections • Training records • Crane driver, slingers, rigger, banksman • Crane • Type –suitable for lift? • SWL of crane • Alarm system working? • SWL indicator/radius indicator • Exceeded? • Operational criteria e.g.. adequate strength & stability • Design characteristics • Counter balance • Out riggers • Configuration for task e.g.. level ground, positioning to load, distance required to travel • Maintenance & certification records • Lifting history • Forensic evidence • Type of failure • Buckling • Brittle • Ductile • Integrity of Jib look for evidence of alterations, repair, corrosion, missing bolts • Settings & functionality of controls, switches & alarms Range of issues & evidence to examine during investigation of lift op failure (crane)

  6. Key Factors • Dead load • Live load • Dynamic load • Solar radiation • Vibration/sudden shocks • Weather • Atmospheric contaminants • Timber decay • Corrosion • Subsidence • Live Loads • People • Furniture • Equipment • Constantly moving and changing every day Dynamic loads Dead loads & Live loads change slowly and are called static loads Other loads can change suddenly such as wind gust, these loads are dynamic • Dead loads • Material which buildings is constructed from e.g.. columns, beams, floors • Solar Radiation • Absorbed when it strikes a material • Materials expand when warm • Contract when cooling • Solar radiation causes surfaces to heat up quickly • Rain falling onto hot surfaces can causes severe shock and result in tension cracking e.g.. roof membrane • Subsidence • Signs of defects include • Semi random cracks in walls • Sagging in arches/beams • Fractures of pipe joints • Builds over mine tunnels or large holes can cause serious deformation Factors Effecting Structural Safety • Vibration & Sudden Shocks • Traffic/machinery • Can effect foundations of buildings • Buildings can be struck by vehicles/plant • Corrosion • Metal combines with oxygen in the air to form rust • Rain/snow/hail • Moisture greatest cause of deterioration • Rising damp causes flaking and cracking • Frozen water causes stresses & cracks • Moisture promotes rust in metals • Moisture creates environment for fungal growth • Build of snow/ice on roofs increases structural loading • Timber Decay • Deterioration of timbers can severely cases lead to building collapse • Due to wet rot/dry rot/fungal attack & insect attack • Atmospheric contaminants • Combine with moisture to form acid rains which attack materials • Sulphur dioxide • Carbon dioxide • Oxygen • Ozone • Wind • Physical damage • Dampness by driving rain moisture into buildings • Can lift roof covering

  7. Effects Fire on materials • Steel • Will expand with heat • Loss of strength normally @600 Celsius • Deform & Buckle • When cooled will regain strength but properties may have changed • Acts as conductor transferring heat thus spreading fire • Concrete • Limited expansion • Cracks and spalls made worse by expanding reinforcement steel e.g.. rebar • Poor conductor of heat • Will have lost structural strength when cool • Wood • Thin sections will burn promoting fire spread • The charred surface of thick timber will act as insulation to inner timber • Dependant on species • Generates smoke & allows surface propagation of fire • Strength after burning depends on original thickness and proportion loss to fire Precautions to prevent failure of materials • Steel • Concrete cladding • Compartmentalise to reduce conduction • Automatic cooling with sprinkler system etc. • Concrete • Selection of type and mix to improve fire resistance • Increase thickness of concrete from exposed surface to steel reinforcement (rebar) • Wood • Selection of thick timbers • Selection of timber e.g.. hardwood burns slower than soft wood • Treat with fire retardant substance • General precautions • Sprinkle system • Fire resistance cladding • Early fire detection • Control of ignition sources & reduction of fuel type materials – fire risk assessment and adequate controls implemented

  8. Key Factors/Regs • Confined space regs • Reg 4(1) Avoid • Reg 4(2) If must SSOW to be defined • Reg 5 Define Emergency rescue plan • Specified occurrence • Fire or explosion • Loss of consciousness/asphyxiation from gas, fumes or lack of oxygen • Drowning • Asphyxiation arising from free flowing solid e.g.. mud slide • Loss of consciousness arising from high temperature • Reg 4(2) SSOW • Risk assessment to consider • People conducting work e.g.. age, experience, training • Likelihood of flammable/explosive atmosphere from previous contents • Access/egress • Contaminated air from previous contents • Build up of heat • Duration of activity • Lack of oxygen • Working at height within CFP • Ingress of solids/liquids • Impact of other plant • Outside environment Weather, other activities • Isolations required • Emergency situation • Reg 4(1) Avoid if possible • Consider other options • Cameras • Cleaning lances • Robotic inspection Confined space entry • Reg 4(2) SSOW cont. • Control measures • Trained and experienced workers to conduct activity • Entry procedures, use of equipment e.g.. BA • Purge of space with inert gas e.g.. nitrogen • Forced air ventilation • Atmospheric testing e.g.. gas/oxygen level monitoring • Suitable electrical equipment e.g.. intrinsically safe • Earthing arrangements • Job rotation e.g.. control of heat fatigue • Appropriate access and egress e.g.. scaffold, ladders • WAH provision, e.g.. scaffold internal of space • Barriers to prevent unauthorised access • Appropriate isolations as necessary • Appropriate PPE e.g.. anti static clothing, BA, gloves etc. • Reg 5 Emergency planning/Procedure • Communication with workers in vessel/space • Raising the alarm • Emergency rescue e.g.. tripod winch • Provision of stand by man/first aider • Means of fire fighting • Provision of emergency escape sets • Communication with emergency services Last paper

  9. Controlling pump rate • Speed slow – not to propagate static build up Complete containment of flammable liquid, not leaks, seals joints etc Avoid splash/spray filling Worker involved trained and competent in operation e.g.. aware of hazards and precautions necessary Earthing of all conductive surfaces e.g.. tankers, pipe work, containers e.g.. IBCs Keep at zero potential, Earthing should be interlocked to pump system Key factors to protect against ignition from static of a flammable vapour during transfer of containment of liquids Over fill protection system e.g.. high level indicator, interlocked shut down Provision of anti static clothing including footwear Use of inert gas blanketing above the liquid Implementation of a vapour return system Last paper

  10. Key points • Controlled waste • Duty of care ‘categories of persons’ • Duty of care • Controlled waste • Household • Commercial • Industrial • Exceptions • Agricultural • Mines/Quarries • Radioactive waste • Duty of care Categories of persons • Persons who • Produces CW • Imports CW • Carries CW • Stores CW • Treats CW • Disposes of CW • Exceptions of house holders EPA section 34 Concepts of duty of care • Duty of care • Reasonable steps to prevent;- • Deposits of CW without waste management license • Treatment, storage, disposal in manner likely to cause pollution • Treatment, storage disposal with out waste handling license • Prevent escape • Transfer to unlicensed holding • Transfer without written description

  11. Heat Detectors Fixed temperature type Thermocouple detects when a set temperature is reach Rate of rise type Detects abnormal temp rises (sudden) Electronic resistors Usually incorporate fixed temp element as well Unsuitable for Rapid heat rise workplace e.g.. laundrettes, steel manufactures Smoke Detectors Ionisation type Small radioactive source to ionise a chamber into which smoke enters during a fire. Detector reacts to change in current caused by neutralisation of ions by smoke particles Optical type Responds to the obstruction of a focused light ray or the scattering of light from an optical ray by smoke Unsuitable for Dusty workplace due to false alarms e.g.. flour mills Workplace which generate smoke e.g.. kitchen, welding workshops Automatic Fire Detection Heat (fixed or rate of rise) where there are fumes, steam or other particles may be present that would be detectable by a smoke detector and cause false alarms.Smoke (optical or ionization) everywhere else within reason Last paper

  12. Raising the alarm • Consider any disabilities and make provision for e.g.. visual alarm for deaf people • Contacting the emergency service e.g.. interlocked alarm system or manual call • Publishing and training of procedure • Regular drills • Documented • Fire log book • Numbers of people to evacuate & physical ability • Escape routes • Distance of travel required • Alternatives routes Accounting for people • Emergency light and signs • Exits • Escape routes • Liaison with emergency services • Numbers of people involved • Specific hazards in building Issues to address when planning a fire evacuation Refuges and safe havens (muster points) Prevention of re-entry • Training of fire wardens • Zoning • Areas of responsibility • Equipment and security • Equipment may need shutting down safely • Security could be an issue after evacuation • Roles and responsibilities • Managers • Staff

  13. Key principles • Dust control • Ignition source control • Mitigation of explosion effects • DSEAR regs • Zoning • Ignition control • No smoking policy • No mobile phones • Provision and use of anti static clothing and footwear • Earth bonding of equipment • Assessment in compliance with DSEAR regs • Appropriate zone identification of areas i.e.. 20, 21 or 22 • Use of spark protected equipment – intrinsically safe to appropriate zone • Abnormal activities generating sparks under hot work PTE • Mitigatingeffects of explosion • Equipment able to withstand explosion • Venting and explosion panels • Bursting disc on vessels • Suppression – inerting • Compartmentalisation – minimise effected • Dust control • Damping down • Extraction of dust at point of transfer (LEV) • Interlock device to prevent overfilling of vessels • High standard of house keeping • Ensuring that systems are sealed where possible Reducing risk of dust cloud explosion and mitigating explosion effects

  14. Segregate pedestrians from vehicles with the use of fixed barriers Consider automated system (robotic to almost eliminate pedestrians requiring access Separate access & egress points for vehicles/pedestrians Where possible re-route pedestrians away from vehicle movement area e.g.. elevated corridors Create safe passing places Design features to reduce risk of vehicle/pedestrian collision Introduce safe crossing points e.g.. zebra crossing Ensure lighting is adequate and suitable for tasks carried out Avoid creation of blind bends if unavoidable install wall mounts mirror (convex) to improve visibility Allow sufficient space for vehicles to operate Where possible design routes such to eliminate/reduce the need for reversing Direction of vehicle movement control e.g.. force one way traffic

  15. Mechanical hazards • Vehicle impact • Plant equipment nearby • Abrasion from operate equipment • Weather conditions • Rain – moisture entering • Freezing leading to crack through expansion • Heat • Humidity High/Low temperatures Aspects of a working environment which increase electrical risk Corrosive atmospheres leading to corrosion of parts Flammable/explosive atmosphere • Intrinsically safe • Restriction of electrical energy in equipment, insufficient to create heat/sparks • Faults may increase energy levels above safe limit • Flame proof • Heavy duty of substantial build and enclosed. When flammable atmosphere enters the equipment can withstand and enclose an explosion and prevent the ignition of any flammable atmospheres surrounding equipment • May not be suitable for use in areas with combustible powders of dust. May require special measure to prevent ingress of water

  16. Inform of any significant/unusual residual risks Duties apply at all times e.g.. appointing of CDM co-ordinator if notifiable Ensure that client is aware of their duties Provide info with the design to assist clients, contractors, designers e.g.. notes for drawings, rational behind design decisions Ensure that they (designers) are competent for the work they do Duties of designers under CDM2007 Take into account Workplace (HS&W) regs when designing workplace structures Co-operate with others as is necessary to manage risks e.g.. contractors Conduct risk analysis of major design e.g.. HAZOP/FMEA • Avoid foreseeable risks (construction and use) SFAIRP during design by • Eliminating hazards where poss. • Reduce remaining risk • Give collective risk reduction measures priority over individual measures Co-operate with CDM co-ordinator & other Provide information for h & S file

  17. Safe operation and adjustment of top guard Regular maintenance and safety inspection e.g.. guard check Effective guarding of blade under bench Adequate lighting and saw suitably fixed to floor Use of push stick to feed materials being cut Safe operation of bench mounted circular saw Provision of emergency stops and means of isolation Ensure that the riving knife is correctly positions through risk assessment Sufficient space around equipment kept clear of obstructions Ensure that operators are suitable trained and experience to use the saw, also ensure appropriate level of supervision Use of appropriate PPE e.g.. hearing protection/goggle, dust mask Provision of LEV to remove dust

  18. Corrosive Failure • Chemical/electro-chemical attack by atmosphere • Only affects metals • Materials lose strength can thin • Occurs when oxygen levels of carbon dioxide levels are high & when PH levels are low or high • ExcessiveStress • Ductility – amount of stretch before a material ruptures • Usually result of single stress over load • Materials can balloon due to excessive pressure • Abnormal external loading • Struck by something e.g.. vehicle • FLT/Fuel tankers • Explosion • Hydrogen attack • Hydrogen seeps into gaps in molecular frame work • Causes stresses within framework • Examples are cathode reaction, electroplating • Over pressure • Catastrophic results e.g.. vessel rupture • Failure of relief valves can cause • Normally systems tested to 3 times normal operating pressure Pressure systems causes of failure • Creep • Under constant load • Deforms over time (plastic) • Temperature is important, materials determine working temperatures that can be used • Overheating • Can occur if alarms/controls fail • Causes rise in pressure • Mechanical fatigue & Shock • Pressure causes tensile stress in all directions • If stresses are greater than material can cope with it will lead to ductile or brittle failure • Fatigue stress is usually progressive • Fatigue failure often triggered by surface interruption e.g.. grinding marks, weld defects, notches etc • Pressure focuses at root of defect • Brittle fracture • Fracture without deformation • Brittle materials are strong but not resistant to cracks • Impact loading causes e.g.. rapid temp changes, pressure differences • High tensile & residual stresses promote • Thermal fatigue & Shock • Shock is sudden change in temp of water • Causes rapid expansion/contraction of system components • Leads to fatigue and material stress ultimately failure of system e.g.. leaking pipes, fracture of vessels

  19. Key points • Design • Operation • Inspection/Maintenance • Design • Take account of current safe practise • Fit for purpose/CE marked • Material constructed from suitable for materials in process • Expected life • Maintenance/testing accesses • Operating pressures and provision of safety devices e.g.. • Safety valve (PRV) • Gauges • Level Controls • Blow down valves • Pressure gauges • Operation • Use within performance envelope • Operators trained and experience to identify errors and prevent faults through error arising • Aware of safe operating limits • Scheme of examination • Equipment marked with operating pressures/temperatures max/min • Quality control • Filtering/treating of water (boilers) Technical & procedural measures to minimise likelihood of pressure system failure • Inspection • Written scheme of examination – statutory • Pressure vessels • Pipe work and valves • Protective devices • Pumps and compressors • Prepared by competent person • NDT/examination

  20. Properties of LPG • Flammable at standard temp & pressure • Denser than air • Liquid form floats on water • LEL is reached in small concentrations • Can cause suffocation in high concentrations • Control of ignition sources • No smoking • Storage of cylinders away from potential ignition sources e.g.. fabrication shop • Control of mobile phones • Storage area regarded as zone 2 so only zone 2 IS rated electrical equipment to be used • Signage stating highly flammable • Dry powder fire extinguisher located close to storage area Concrete level floor, surrounding area kept free of vegetation (not with use of oxidising week killer e.g.. sodium chlorate Stored away from excavations, drains, pond, rivers, cellars at least 3 m Any store room must be non-combustible or fire resistant and ventilated with and explosimeter installed LPG in cylinders precautions (storage) Protected from elements were possible If more than 400Kg stored must have 2m high mesh fence and cylinders at least 1.5m away from fence with 2 exits Empty cylinders stored separately from full cylinders, caps fitted to valves. Well ventilated Stored away from any oxygen cylinders. oxidising substances Storage compound designed to prevent vehicle impact Cylinders stored in upright position

  21. Key points • Instability • Training • Refresher training circumstances • Causes of instability Lateral (side instability) • Insecure load • Drive laterally on slope (angle of slope, elevation of load • Hitting obstruction e.g.. curb • Uneven ground • Cornering (fast, sharp) • Poor tyre condition/uneven pressures • Refresher training appropriate • Operator not used truck for some time • Been involved in accident/near miss • Developed unsafe practices • Change in working practice • Best practice every 3 years or as per company policy • Causes on instability Longitudinally (Front to back instability) • Overloaded vehicle • Incorrect positioning of load on forks • Load slipping forward (inappropriate tilt of mast • Driving with load elevated • Changing tilt • Driving forwards down slops • Driving backwards up slopes • Sudden braking • Striking overhead obstruction FLT safety • Training • Basic training (CITB/RTITB) • Operating truck • Maintenance & checks • Specific job training • Specific truck type operation • Use of truck in various conditions • Work to be undertaken & SSOW • Familiarisation training under supervision • Site layout • Types of storage/load e.g.. racking • Local emergency procedures

  22. Key points • Fuses • Miniature circuit breakers • Residual current devices • Reduced low voltage systems • Precautions to be taken • Fuse • Protects systems not people normally • Prevents overloads of electrical system and overheating of electrical wiring • Limits shock under severe fault condition • Limits over currents • Does this by the heating effect of electric current which melts the metal link if current exceeds the design value • Remains broken until replace • Miniature circuit breaker • Close tolerances for design current flow and speed of operation • Provide visual detection following operation (e.g.. switch to off position • Need to be reset after fault detection • Are reliable • Design to protect system • Precaution to be taken when maintaining or repairing electrical systems • Identify equipment to be worked on • Obtain system drawings & information • Consider whether work can be done dead SSOW for dead: • Isolation/lock off • PTW • Proved dead • Test test equipment • If work required is live SSOW: • Screening of conductors near work • Testing live conductors through holes with probes • Use of suitable test equipment • Have testing arrangements in place for testing equipment • Consideration of accompaniment • Consideration of insulated tools • Adequate space • Adequate lighting Methods and devices designed to improve electrical safety + precautions to be taken when maintaining or repairing systems • Residual current devices or earth leakage circuit breakers • Shock limiting device not system protection • Shock is still received but time reduced • Monitors balance of current in line and neutral • Operates on earth leakage fault • Live and neutral disconnect from local power supply • Reduced voltage system e.g.. 110V • Transformer • Supply centre tap to earth consist of • Earthed systems • Class 1 equipment • Double insulated class 2 equipment • Required procedural measures to be followed

  23. Design • Material to be used for vessels and pipework • Suitable to withstand corrosive nature of substances • Layout of facility • Segregation between acid/alkalis e.g.. compartmentalisation • Design and position of inlets • Prevent cross connection • Bunding of tanks • Separate bunds • Capacity 110% of largest container min • Bunded sealed with appropriate material (with stand corrosive) • Safety devices • High level indicators • Isolations • PLC control • Interlocked system • Adequate lighting • Adequate access and egress • Arrangements for spill containment • Labelling of system e.g.. flow direction of pipes • Emergency arrangements e.g.. drench water safety shower • Operation • SSOW • Operation of equipment • Emergency procedures e.g.. spill response • Training • Tanker drivers • Operators • Provision of PPE e.g.. chemically resistant suits, gloves, full face visor • Maintenance • Arrangements for examination and inspections • PTW system • Isolation procedures • Cleaning prior to work e.g.. purge • Regular cleaning of bunds • Provision of training to maintenance staff both maintenance and emergency Safety provisions required for receiving and storing acids and alkalis

  24. Temperature Increase speeds up reaction – Le Chateliers principle • Chemical changes involve heat • Exothermic - Evolutes • Endothermic - Absorbs If the heat released from reaction is not controlled/removed reaction will speed up exponentially • Can result in • auto ignition explosion • Catastrophic over pressure resulting in loss of containment e.g.. vessel rupture and toxic release • Violent boiling • Secondary competing reaction • Operational features to prevent • High calibre of operator experienced and appropriate level of qualification to operate process • Ensure that maintenance activities/raw material handling don’t introduce potential catalysis into reaction Runaway reactions • Causes • Failure of temp control (reaction cooling) • Strong exothermic reaction • Presence of containment catalysis (speeds up reaction) • Design features to prevent • Conduct HAZOP study • Appropriate temperature control system e.g.. matrix cooler • High integrity temperature detection linked to cooling/reaction addition protection • Pressure rise detection linked to cooling/venting/auto shut down • Vessel protected by correctly sized bursting disc linked to safe haven e.g.. secondary vessel to dump reaction to • PRV’s, weighted lids to realise pressure • Agitation of liquids to promote even temp distribution

  25. Cylinder/container containing flammable gas under pressure e.g.. butane pressure turns gas into liquid state Valve opened reduces pressure turning liquid into gaseous state • Examples of incidents • San Carlos • Crashed over loaded road tanker • Explosion • 216 Dead • Mexico city Cylinder exposed to heat source e.g.. caught in a fire liquids absorbs heat BLEVE Liquids starts to vapour and is vented off • Sudden release of contents resulting in • Blast wave (low) • Radiation (thermal) high • Missiles travelling long distances • Substantial thermal heat sever burns e.g.. LPG cylinder BLEVE has serve burn range of 35m Liquid level falls heat continues Area of cylinder just above liquid level starts to weaken/thin with heat Area unable to hold internal over pressure and ruptures

  26. Identify recycling opportunities at all stages of process Substitute process materials for ones that give rise to non hazardous waste Explore becoming licensed to save cost e.g.. EA permit Improve production efficiency to produce less waste Reducing cost and environmental impact of hazardous waste (sludge) Explore other disposal means (incineration, liquefied waste to sewer) Treat waste on-site to reduce quantity (De-watering) Exchange waste streams to other companies which could use waste as raw material e.g.. waste solvents to paint producers Treat waste to reduce hazardous properties e.g.. ph balancing Selection of waste contractors that can process the waste Last paper

  27. Purpose Check for faults (e.g.. cracks) in components before they develop into total failure without affecting integrity of the component • Dye testing • Put dye on • Dye penetrates making cracks visible • Cheap & simple (pro) • Doesn’t detect sub surface faults (con) • Not totally reliable (con) • Can be enhanced by using fluorescent penetrate and UV source • Penetrate may be toxic (con) • Need good eyesight • Impact (tap testing) • Strike surface • Changes in pitch of reverberant sound • Cheap (pro) • No indication of where fault is located (con) • Relies on individual skill (con) • Other techniques • Pneumatic testing • Hydro testing • Ultrasonic Technique • Short pulses of high frequency ultrasound are used • Reflected waves detected and shown on digital display or oscilloscope • Surface and sub-surface defects • Only requires one side of joint • Quick to perform • Suitable for most environments • High level of expertise required • Coupling equipment onto rough surfaces can be difficult • Magnetic particle • Coat surface with magnetic power or liquid • Simple & Quick • Very sensitive to surface cracks • Interpretation of results can be difficult particularly on inside of vessel NDT • Eddy current testing • Surface and near surface crack detection • Electromagnetic method/instrumentation • Can be used to verify materials heat treat condition • Can be automated (pro) • Can suffer from spurious defect indications • Doesn’t work on non-conductive materials • Relatively expensive and requires skilled operator • Radiography • X-rays/Gamma rays penetrate item and leave an image on film • Defects are shown up by differences in the intensity of the radiation striking the film • Detects internal defects and a permanent record is created • Expensive • Bulky equipment • Present radiation hazard and tight controls are required • Skilled radiographers are needed

  28. Consideration of flammable atmospheres etc EX rating Maintenance, cleaning and testing considerations Availability of natural light Psychological effects Compliant with workplace (health, safety & welfare) regs Illumination ratio Level of luminance H & S Issues to identify during a lighting audit of a factory Requirements for pedestrians/vehicles Emergency lighting Close working tasks Lighting fort non-daytime external areas Equipment lighting to comply with PUWER requirements Task specific lighting Avoidance of stroboscopic effects with regard to rotating machinery DSE work station lighting Avoidance of glare

  29. Access & Egress • Maintenance workers • Pedestrians • Building workers • Vehicles • Emergency arrangements • Alarm • Muster points • Escape routes • Traffic management • Deliveries • Plant • MEWPS etc • Public safety • Falling objects • Screening • Segregations/barriers • Security • Fencing • Dust damping • Noise levels Safety aspects to consider before starting external maintenance/construction works on build with public facing front (footpath) workincludes roof • Storage of materials • Hazardous • Flammable • Housekeeping • Lay down areas • Building workers safety • Safe systems of work • Provision of PPE • Fall protection • Scaffolding • Edge protection • Signage • Hazardous materials present e.g. asbestos • Welfare facilities • Washing • Toilets • Rest/eating etc • Plant and equipment requirements • Suitability • Availability

  30. Benefits of regular drills • Compliance with legal requirements FFRO • Efficient evacuation in future • Highlights deficiencies in alarm, procedure and evacuation • Allow practise of scenarios such as abnormal normal route use etc • Refresh staff training and awareness of procedure • Fire Alarm Design/maintenance • Quiet • Does not extend into all parts of building • Poorly maintained sounders • Faults within infrastructure leading to partial failure in some areas • Deficiencies in procedure • Difficult to understand • Poorly communicated • Not exercised • Poorly planned escape routes • Untrained staff Factors that could contribute to a delay in evacuation + benefits of regular drills • Execution of procedure • Delayed response to alarm • Staff not reacting quickly • Finishing of phone calls • Switching off equipment • Fire Marshalls not following procedure • Blocked escape routes • Staff not trained • Poor response perhaps many false alarms have occurred in past • Human factors • Hearing disabilities • Belief that false alarm • Belief that above evacuating • Waiting for direct notification e.g.. phone call • Routine violations

  31. Risks Reduced Manual handling Pedestrian/vehicle collision Racking Collisions Falling objects less likely to contact person WAH access to racking Reduction of noise FLT collisions Incorrect order picking Risks Increased Programming dangers (teachers) Interference in signal Proximity sensors to prevent pedestrian contact AGV collision Guarding of order picking machinery Dropped loads to be dealt with in automated area Maintenance activities for equipment Software failure Introduction of Automated Guided Vehicle to Warehouse

  32. Planning & Organising • Consider work to be carried out and devise RA & MS • Nominate supervisor for task • All workers briefed on general & specific risks • Suitable equipment for task e.g.. PPE, tools, access etc • Preparation of Silo • Emptied • Locked off to prevent filling movement of parts • Residue removed before hot works • Damped down • Signage erected of work in progress etc • Working area • Excluding non essential personnel • Erecting barriers • Sighting of warning signs Precautions to be taken before & during repair work of a 15m high grain silo on farm (with welding required) • Working at height • Use of platforms • Handrails • Toe boards • Harnesses if required • Protection of fragile sections of silo top • Confined space entry • PTW control • Ventilation • Trained staff • Emergency rescue plan defined and trained • Ensure suitable access and egress • Oxygen monitoring

  33. Hazards Falls from height of persons/materials Instability of vehicle e.g.. uneven ground Being struck by other vehicles Trapping & impact hazards Mechanical failure Contact with over head power lines Exposure of workers to adverse weather conditions Requirements for safe use Selection of trained competent operators Persons may be connected to MEWP with fall restraint Toe boards installed/use of tool wrist straps Barriers installed to protect area MEWP used in Correct positioning e.g.. level firm ground, not close to over head services, use of outriggers where installed Prevent of use in adverse weather conditions Not exceeding SWL Regular inspections & maintenance Ensure trap points are guarded Ensure used in locked position Prohibit transfer of people/materials whilst in raised position MEWPS

  34. To supply machine under SMSR1992 process • Satisfy Essential health and safety requirements and be safe • Safe and reliable control devices including normal operation and emergency controls • Stable • Protection against mechanical hazards e.g.. moving parts guarded • Protection from other hazards e.g.. vibration, electricity & noise • Maintenance activities • Adequate indicators e.g.. alarms and warning light etc Satisfy requirements of EHSR Responsible person to prepare technical file • Preparation of technical file • Detailed drawings • Calculations, test reports • Description of methods used to eliminate hazards • Machinery RA • Instruction draw up in accordance with provision of information Responsible person to ensure machine meets requirements of other EC directives Issue a Declaration of conformance Fix the CE mark in a visible, legible and obvious manner Last paper

  35. Determine appropriate frequency of inspection for each item based on factors affecting level of risk e.g.. • Type of appliance • Protective systems used • Use • Frequency of movements • Earth boning • Age • Environment which appliance used in • Experience and competence of user • Historical information and manufacturers recommendations • Criteria for each type of examination defined including issues such as • Competence of the tester • Calibration and maintenance of test equipment • Format of records to be kept • Results of tests and examinations • Systems to identify and remove from use equipment that is found to be faulty Inventory of all equipment requiring examination and test to be made and unique means of identification e.g.. number system Factors to consider when devising scheme for PAT testing Electricity at work regs and HSE published guidance

  36. Sources Flames/sparks from exhaust/inlet systems Sparks from vehicle electrical system Static build up from over speeding/loading the engine Hot parts e.g.. exhaust Protection Fit spark/flame arrestors preventing flashback to atmosphere if drawn into inlet system plus prevent any sparks from escaping system Engine and exhaust system design to ensure surface temps are below ignition temp of atmosphere Use of water jacket around hot parts Electrical equipment on vehicle suitable for zones 1 or 2 where possible Speed limiters to prevent speed at which static could build up Use of electrically conductive materials for parts e.g.. tyres to reduce static build up. Sources of Ignition from diesel powered vehicles and possible protection to minimise risk of explosion in flammable atmosphere

  37. Bunding to contain spills Security features such as locks, alarms, and signage Facility to collect & dispose of spillages e.g.. spill kit Emergency lighting/appropriate EX rated electrical equipment e.g.. zone 2 rated lights Key safety features of building used to store highly flammables Building constructed of fire resistant materials Sprinkler systems/fire extinguishers Roof lightweight and/or blast panels Adequate access and egress e.g.. 2 points of entry/exit including ramp to facilitate drum handling Mean of segregation of materials e.g.. low walls/dividers, cabinets High and low level ventilation Adequate distance from other buildings Impermeable floor

  38. Capacity of water required and adequacy of existing supply Design of pump system e.g.. diesel back up if electrical pump installed Provision required for testing and maintenance Means of activating system (fragile bulbs or detector activated Provision of water run off Design factors to consider when providing a sprinkler system Provision of fire stopping water curtains to prevent fire spread, compartmentalisation Linkage of system to alarms Spray pattern required Height of any storage racking and distance from sprinkler heads, possible protection from vehicle movements e.g.. FLT tines Area to be covered Presence of substances which react violently with water

  39. Adverse weather conditions exceeding designed wind loading capacity of structure Excess weight on roof caused by rain water or snow Weakening of steel structure by corrosion through roof leaks Inoperation of rainwater drains Alterations to structural members which have invalidated original design calculations Subsidence or nearby tunnels/excavation leading to foundation instability Vibration caused by traffic etc leading to structural fatigue Inadequate design and/or construction of structure Possible mechanisms of structural failure of building during storm

  40. Notification of HSE under CDM 2007 regs Identification of competent demolition contractors Site traffic management if required If building partially collapsed already devise method for demolishing to avoid premature collapse of the remainder PPE required for workers e.g.. hard hats, ear protections safety boots, protective clothing, eye protection etc H & S issues to be considered when planning demolition of building Protection of nearby buildings/business/properties Welfare facilities provision e.g.. toilets, wash and rest facility plus maybe lay down area for contaminated clothing Protection of public e.g.. barriers, signs, security Precautions to prevent people or objects falling e.g.. scaffolds, edge protection Control of noise Identification of hazardous materials, control of dust and safe removal of waste from site – use of licensed carrier etc Identification of buried and/or overhead services e.g.. power cables, gas pipelines Selection of and Inspection, maintenance of plant and equipment to be used

  41. Causes of instability Incorrect selection of crane e.g.. SWL to low for lift Incorrect sling of load Unstable ground incapable of bearing weight of crane and load Uneven/sloping ground Obstructions being struck by crane of things striking crane e.g.. other plant of site Exceeding SWL of crane of lift tackle Inoperation of crane e.g.. incompetent, inexperienced operator, not using out riggers Poor lift control by AP/banksman. Unsuitable lifting plan Mechanical failure Adverse weather condition e.g.. wind Lack of maintenance of crane e.g.. incorrect tyre pressures, rope not inspected etc. Measure taken to avoid Conduct full assessment of lift required and surrounding areas including establishing the load bearing capacity of the ground that the crane will operate on Define and implement sufficient lifting plan use of competent appointed person Selection of appropriate crane for lift Ensure that maintenance and testing of crane is adequate Appoint competent person to supervise lift i.e.. appointed person, competent banksman Engineering controls e.g.. ensure that outriggers are used and fully extended where appropriate, ensure that capacity indicator and alarms are functional Ensure that the motion and performance limit device are in working condition Behavioural controls such as competence and training of driver, slinger and banksman Factors that cause instability of mobile cranes and measures to be taken to reduce likelihood of overturning during operation Last paper

  42. Explore possibility of re-routing cables or making dead Consult with utilities supplier before taking any protective measures Warning signs and protection for public if necessary Identification of safe working distance i.e. 9 m if wooden or steel poles 15m if pylons plus length of jib or boom if cranes/excavators are to be used Precautions to be taken when working near an overhead electrical supply Supervision and hazard awareness training for workers e.g.. toolbox talk on hazard associated with cable and what measure need to be taken to avoid Use of barriers, marking tape and bunting Safe systems of work to be defined and implemented Use of goal posts and/or tunnels Height restrictions on plant

  43. Planning and assessment for development of electrical supply by a competent person Safe positioning of transformers e.g.. protection from plant/vehicle impact, barriers to prevent workers accessing area Use of competent persons for installation work of electrical supply Precautions to ensure safe provision & use of electricity on construction site (feed taken from overhead lines) Routing, marking and protection for cables Development of safe systems of work Use of protective devices e.g.. reduced low voltage systems (110), RCD’s and double insulated equipment Arrangements for testing and maintenance of portable equipment Arrangements for inspection and maintenance of the fixed supply to include earth bonding checks

  44. Fatigue failure • Crack propagation from points of stress concentration (e.g.. groves, weak weld points), fluctuating stress final failure may be ductile or brittle • Factors contributing • Surface occlusions/damage • Choice of material • Residual stress imposed through manufacture • Corrosion, temperature • Measures to take to prevent • Design spec appropriate • Quality assurance on manufacture • Assembled according to spec • Correct use – avoid misuse e.g.. over ,loading • Maintenance/testing NDT • Buckling (Compressive force) • Buckling – yield of one side of structural member under axial compressive loading • Factors contributing • Excessive/non uniform loading • Weakening due to removal of cross members • Use of out of true members e.g.. scaffold tube at incorrect angle i.e.. not 90 under load • Excessive temperature • Measures to be taken to prevent • Design/material selection • Avoid overload work within spec • Temp control • Maintenance/testing NDT • Brittle failure • brittle fracture, no apparent plastic deformation takes place before fracture • Factors which promote brittle fracture • Low temperature • Inherently brittle material (cast iron) • Impact or snatch loading (does not give material time to react Component failure • Ductile Failure (stretch) • Ductile failure in metals occur when the yield stress of the material has been exceeded by the material being placed in tension (stretched). The metal moves from it’s elastic region into it’s plastic region and loses its shape. There is a reduction in cross sectional area at failure point. The failure will appear as a ‘cone / cup’ at 45 degrees to the load along the grain boundaries • Factors contributing • High temperature • Over loading • Design inappropriate • Measures to be taken to prevent • Temp control • Selection/design of materials • Maintenance/testing • Operate within spec limits of equipment • Creep • Gradual yielding of material under stress close to elastic limit (undergoes plastic deformation • Factors contributing • Continuous loading • High temp e.g.. hot pressurised pipes, turbine blades • Overloading • Design spec etc • Measures to be taken to prevent • Temp control • Selection/design of materials • Maintenance/testing • Operate within spec limits of equipment

  45. Gamma radiography uses the transmission of gamma rays from a sealed ionising radiation source (isotope) through a test object onto a film placed on the opposite side. The film records the intensity of the radiation received and since cracks and flaws are hollow, a greater intensity of rays pass onto the film showing up defects as darker regions • Advantages • Permanent record produced. • Can be used to test most materials • Internal defects can be identified • Coupling with the surface of the test piece is not required Gamma Radiography • Disadvantages • Poses a radiation exposure hazard to operators requiring specific SSOW to be implemented • Can be time consuming due to application to HSE each time test is required • Equipment can be bulking and difficult to move • Specialist operators are required and staff to interpret results • Results may take a long time to receive • Can be an expensive process to run

  46. Normal operations Emissions to air Carbon monoxide & oxides of nitrogen from burning of fossil fuels Sulphur dioxide/sulphur compounds when coal or oil is burned Other pollutants Soot & coal dust from incomplete combustion Solid waste from coal & oil ash Acid & alkali effluents from water treatment process Emissions from vehicles delivering fuel to site same for ships Abnormal operations Leaks Oil storage tanks Gas supply pipelines Acid/Alkali storage tanks Spillage of chemical from road tank accident Oil slicks from ships during offloading or major disaster e.g.. sinking Fire leading to fire water run off during fire fighting Sources of specific pollutants likely to be associated with a multi-fuel CHP power stations using either coal, oil or gas for burning under normal operations and foreseeable abnormal operations (located on river estuary taking deliveries by ship, road & pipeline) plant also has water treatment plant

  47. Design of basket • Constructed for task intended • Not exceed the width of FLT • Toe boards/guard rails installed • SWL indicated on basket in either weight or no. of people possible to carry, not exceeding 50% of FLT SWL • Guards fitted to protect against moving parts of FLT e.g.. chain Basket maintained and inspected at least every 6 months Trained and competent operator in basket, aware of hazards associated with use Factors to ensure safe use of FLT man basket FLT to be parked on firm, level ground, brake applied, driver in truck Competent FLT driver Anchorage point in cage and harness fitted and connected to persons in basket Cage securely fixed to forks and truck not moved during activity Barriers positioned around work area preventing collision from other vehicles and protect others against falling objects from basket

  48. Design & construction measures to prevent such an incident Adequate segregation between adjacent tanks Separate bunds for each tank Interlocked pumping system with high level alarms min double redundancy of alarms Level detection Vapour detection system fitted in bunds Remote shut down system Good earth bonding Measures to mitigate the effects Fixed foam installations capable to spray the surface of pool in the bunded areas Installation of foam monitors capable of reaching top of tanks Radiation walls between tanks/bunds to prevent other tanks from being heated Adequate supply of fire water Installation of remote pumps to empty affected tanks Easy route of access for fire fighters Provision of drainage interceptors to minimise enviro affects of fire water run off Regular draining and cleaning to remove rainwater from bunds Provision of site based emergency response team. A petrol storage tank in a bund containing three similar tanks is overfilled resulting in a large spillage of petrol into the bund. The petrol vapour exploded

  49. Design • Material of construction sufficiently robust to withstand workplace rigours and contain any ejected materials • Should allow sight of process if required • Method of fixing should require special tool to removed e.g.. torque bolts • Ensure that any necessary openings provide enough distance from hazards to prevent harm • Guards reverberation exacerbating noise problems Fixed guard Defined in BSENISO12100 as a guard fixed in such a manner (e.g.. by screws, nuts, welding) that can only be removed or opened by the use of tools or destruction of the affixing means. It provides protection against mechanical hazards when infrequent or no access is required during normal operation of the machine. Acts as a fence between people and dangerous machinery parts • Use • Monitoring and supervision to ensure guards are not removed/tampered with • SSOW fir carrying out maintenance operations with guards removed • Guard check procedure to ensure guard is kept in maintained condition • Provision of information and training for operators and maintenance staff detailing the hazards associated with guard defeats and other SSOW Fixed guards factors to consider in design and use to ensure people are adequately protected

  50. Type of faults found in fixed electrical system (including systems in area with corrosive atmosphere Poor earth bonding Damaged sockets and switchgear Covers missing from junction boxes Incompetent workmanship and inadequate excess current protection Exposed conductors due to damaged insulation from corrosive Short circuits caused by ingress of fluids Corrosion of system parts Unsuitability for use in wet & corrosive conditions Information needed by electrician before conducting a survey Type of equipment and its rating (operating voltage and current) IP classification (including measure of protect against ingress of water Circuit diagrams and/manuals for the equipment Details of any modifications made Means of isolations and location Earthing arrangements Type and size of cables Details on the operations of protective devices Copies of previous inspection reports and repairs made/maintenance carried out Fixed electrical systems faults (including corrosive atmospheres) & Information relating to system that electrician would need before conducting a survey of system

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