July 05

Front 1

(a) In relation to automatic fire detection and alarm systems, outline the basic principles of operation of: (i) heat detectors (ii) smoke detectors

Back 1

Heat Detectors = Fixed temperature – activated when the temperature in the area reaches a predetermined level by means of thermocouple. Rate of temperature rise – activated when there is abnormally rapid rise in the temperature means of electronic resistors; usually incorporate fixed temp element as well.
Smoke Detectors = Ionisation type - has two plates set apart, one charged negatively and the other positively; 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 – primarily responds to the obstruction of a focused light ray or the scattering of light from an optical ray by smoke.

Front 2

(b) Identify the circumstances in which EACH type of detector would be inappropriate.

Back 2

Heat Detectors = Unsuitable for - Rapid heat rise workplace e.g. laundrettes, steel manufactures. Smoke Detectors = Unsuitable for - Dusty workplace due to false alarms e.g. flour mills; Workplace which generate smoke e.g. kitchen, welding workshops

Front 3

Identify the safety features needed to protect against ignition by static electricity of the vapour of an extremely flammable liquid while it is being transferred from a bulk storage tank to a road tanker.

Back 3

Complete containment of flammable liquid – no leaks (seal joints); control pump rate – not to spread static build up; avoid splash filling; earthing all conductive surface – tankers, pipe work; worker(s) involved trained and competent; overfill protection system – high level indicator; provision of anti static clothing including footwear; use of inert gas blanketing above the liquid; implementation of vapour return system;

Front 4

Section 34 of the Environmental Protection Act 1990 places a duty of care on persons concerned with controlled waste. (i) Outline the meaning of ‘controlled waste’.

Back 4

'Controlled waste' means household, industrial and commercial waste. Industrial – factories, premises related to any public transport services; commercial - waste from premises used wholly or mainly for the purposes of a trade or business or the purposes of sport, recreation or entertainment; household - domestic property or residential home etc

Front 5

Maintenance work on electrical distribution panels and control circuitry commonly involves diagnostic testing and fault finding on live systems. With reference to the relevant requirements of the Electricity at Work Regulations 1989, outline the conditions that must be met, and the safety measures that should be in place, before this type of work is undertaken

Back 5

Reg 14 of EAWR 3 condition of working on a live system (i) that it is unreasonable for it to be made dead and (ii) that it is reasonable to work on it while it is live (iii) that suitable precautions are taken
Competent staff; Adequate information; Suitable tools: insulated tools, mats and/or gloves, protective clothing may be required; Area should be cordoned off by the use of barriers to prevent unauthorised access; Instruments and insulated test probe checked prior use to identify what is live and what is dead; Accompaniment; Designated test areas; PTW All live working should be subject to a permit-to-work system. Reg 16 Engineer to be technically competent (or to be closely supervised, having regard to the nature of the work, by someone who is competent); possess recognised qualifications; have experience in the type of work being undertaken. Reg 7 All incoming and outgoing supplies should be suitably insulated and shrouded. Reg 8 The cabinet should be connected to the main earth, and the cabinet door earth-bonded to the cabinet. Reg 15 Ensure sufficient working space, suitable access and adequate lighting

Front 6

An independent tied scaffold is to be erected against the façade of a multi-storey building. (i) Provide simple sketches to show THREE methods of ‘tying’ the scaffold to the building.

Back 6

the presence and availability of windows or other openings (for through and/or reveal ties), the presence and suitability of columns (for box ties), the presence and width of pilasters and other reveals (for reveal ties again) and the possible presence of, or ability to install, ring-bolts. General factors that would need to be considered are the condition of the fabric of the building and the anticipated loading on the scaffold. In practice, a variety of different types of tie may be needed and better informed candidates indicated that their relative proportions can be important – eg. no more than 50 per cent of the ties should be reveal ties.

Front 7

With reference to the mechanical hazards associated with the operation of a hydraulic robotic arm on a production line, outline a range of measures aimed at minimising the risk of injury

Back 7

opportunities to eliminate the hazards entirely, the elimination of a crushing hazard between the robot and another object by increasing the distance between them was one that was worthy of mention. In terms of safeguarding in this situation, distance guarding (of adequate height, interlocked and allowing authorised access only), presence sensing devices (eg. photoelectric systems, pressure mats, etc) and guarding of nip points were all relevant. Procedural measures might include software checks to avoid aberrant behaviour (mainly related to impact hazards) and adequate safety maintenance (eg. to check the integrity of hydraulics). In this situation, maintenance personnel would be at particular risk and so procedures such as permit systems would be imperative. In addition, technical measures should be introduced to allow maintenance work to be performed remotely as far as possible. This would also apply to ‘teaching’, which should be done either remotely or with the robot in ‘slow mode’. For anyone needing access to the robot, then measures should be in place to release any stored energy and to protect against hydraulic failure. Finally, in terms of behavioural controls, all staff should be informed of the dangers, instructed in the procedures to be followed and trained in safe working practices

Front 8

It is proposed to inspect, clean and repair the inside of a tank that is 6 metres in diameter and 10 metres high and which has previously been used for storing leaded petrol.
Outline the arrangements that should be considered in order to comply with the Confined Spaces Regulations 1997

Back 8

Regulation 4(1) of CSR requires that no person shall enter a confined space unless it is not reasonably practicable to achieve the intended purpose without such entry. Carry out the work by using remotely controlled cameras, robotic inspection systems or a cleaning lance operated from outside the tank without going into the tank. If unavoidable, regulation 4(2) requires a safe system of work in relation to any relevant specified risks (as defined in regulation 1). To develop the systems of work, a full risk assessment would be required.
This would need to look at the likelihood of flammable atmospheres from the previous contents of the tank, the possibility of air contamination from the cleaning or repair methods used and the build-up of heat within the tank. The risk assessment would also need to look at other (non-CSR) issues from the work to be carried out, including work from height and the toxic effects of lead. The arrangements that the risk assessment might find to be necessary relate to the possible need to purge the tank with an inert gas, the use of forced ventilation, atmospheric testing before and during entry, and the provision of PPE, possibly including air-fed breathing apparatus. Attention would also need to be paid to the requirements for electrical equipment (eg. intrinsically safe, flameproof) and earthing arrangements. If heat were to be a foreseeable problem, then consideration should be given to issues such as job rotation and fluid intake. The physical arrangements for working at height would need to be considered in terms of both prevention of falls and, in relation to CSR, access and egress in the event of escape or rescue. Procedural arrangements would centre on the establishment of well-defined systems of work, the implementation of an entry permit system, limiting the number of people working in the tank, communication with standby personnel and drawing up the emergency arrangements required by CSR regulation 5.
The emergency arrangements to be considered would include issues such as the provision and maintenance of cutting equipment, hoists, fire-fighting equipment, PPE (eg. breathing apparatus) and first-aid facilities, and liaison with emergency services. Arrangements should also be in place to ensure that all personnel involved in the operation have received sufficient training in the work methods, the precautions needed and emergency procedures

Front 9

A new design of hydraulic press is intended for use within the European Economic Area. Outline the ‘essential health and safety requirements’ that you would expect to have been addressed in the technical file for the machine in order to demonstrate that it is in fact safe.

Back 9

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. 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. Required Characteristics of guards = Fixed; Movable guards; Adjustable guards; Special requirements for protective devices. 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
Indicators = Information devices; Warning devices e.g.. alarms/lights; Warning of residual risks; Markings; Instructions

Front 10

The jib of a large mobile crane has failed during a lifting operation. Describe, with sketches where appropriate, the range of issues and evidence that an investigation team will need to examine in order to determine the reasons for the failure

Back 10

Crane= identify the type of mobile crane being used, its safe working load and other operational criteria, its design characteristics (eg. use of counterbalance, outriggers, etc) and its configuration for the task. Maintenance and certification records, and lifting history, would provide some relevant information.
Lift operation= details of the load (weight, centre of gravity, slinging method, etc), the type of lift (eg. static, slewing, lift and travel, drag and lift) and the site conditions (eg. wet, windy, sloping, presence of obstructions/excavations, etc). The lifting plan, witness statements and visual inspection should provide useful information on these factors. The training records of the driver, slinger, rigger and banksman may also need to be inspected.
forensic evidence=determine the type of failure (eg. buckling, brittle, ductile), the integrity of the jib (looking for evidence of alterations, repairs, corrosion, cracks, missing bolts, etc) and the settings and functionality of controls, switches and alarms.

Front 11

(a) Describe the effects of a fire in a workplace on the following structural materials: (i) steel (ii) concrete (iii) wood.

Back 11

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; Thin sections will burn and promote fire
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

Front 12

(b) Outline the precautions that could be taken to prevent failure of these materials (steel, concrete & wood) in the event of fire.

Back 12

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

Front 13

Describe the legal and practical requirements relating to the provision of welfare and first-aid facilities on a civil engineering site where the work involves excavation of contaminated land and on which a large number of persons will be working.

Back 13

Health and Safety (First Aid) Regulations 1981 Reg 3 – employers to provide equipment and facilities adequate and appropriate in the circumstances for enabling first-aid to be rendered to his employees if they are injured or become ill at work. Schedule 2 The Construction (Design and Management) Regulations 2007 = Sanitary conveniences (toilets) = Separate men/women; lockable (inside) if not possible; adequately lit; kept clean; adequate supplies of toilet rolls; sanitary disposal for female employees. Washing facilities = Hot, cold or warm water supply; soap or other means of cleaning; towel or other means of drying; adequately lit; kept clean; large sink for face, hand or forearm; unisex shower (separate lockable room with one person present at a time); decontamination facilities with showers. Drinking water = Clearly marked supply of drinking water with cups. Changing rooms & lockers = Separate change area men/women; means for drying wet clothing and for separate storage of contaminated clothing; means for drying wet clothing and for separate storage of contaminated clothing. Rest facilities -sufficient tables & seats, arrangements for preparing and heating food and for boiling water, facilities for nursing mothers and means or procedures for preventing contamination of the area where food and drink are taken and ensure it’s warm

Front 14

An independent tied scaffold is to be erected against the façade of a multi-storey building. (ii) Identify the factors that may determine the most appropriate method in any particular situation.

Back 14

Presence/availability of windows or other openings (for through and/or reveal ties); presence/suitability of columns (for box ties); presence/width of pilasters and other reveals (for reveal ties again); possible presence of, or ability to install, ring-bolts.Consider the condition of the fabric of the building; the anticipated loading on the scaffold.

Front 15

Section 34 of the Environmental Protection Act 1990 places a duty of care on persons concerned with controlled waste. (ii) Identify the categories of persons on whom the duty is placed, and those who are exempt.

Back 15

Persons who imports, produces, carries, keeps, treats or disposes of controlled waste or, as a broker, that has control of such waste. It does not apply to household waste produced on the property.