NEBOSH DIPLOMA QUESTIONS 33
Question
The jib of a large mobile crane has failed during a lifting operation
Describe, with sketches where appropriate, the range of issues & evidence that an investigation team will need to examine in order to determine the reasons for the failure (20)
Possible Aswer:
This question proved to be the least popular on Section B, but only slightly less popular than the previous question
In contrast to Question 8, though, it produced far fewer very weak answers, & hence a much higher mean mark
The issues that an investigation team would need to look at relate broadly to the crane, to the lift being performed, & to the forensic evidence from the accident scene
Answers that were structured in this sort of way were more likely to identify the relevant points associated with the failure
In terms of the crane, the team would need to identify the type of mobile crane being used, its SWL & other operational criteria, its design characteristics (e.g. use of counterbalance, outriggers, etc) & its configuration for the task
Maintenance & certification records, & lifting history, would provide some relevant information
With respect to the lift, relevant factors would include details of the load (weight, centre of gravity, slinging method, etc), the type of lift (e.g. static, slewing, lift & travel, drag & lift) & the site conditions (e.g. wet, windy, sloping, presence of obstructions/excavations, etc)
The lifting plan, witness statements & visual inspection should provide useful information on these factors
The training records of the driver, slinger, rigger & banksman may also need to be inspected
The team would then need to look at the forensic evidence in order to determine the type of failure (e.g. buckling, brittle, ductile), the integrity of the jib (looking for evidence of alterations, repairs, corrosion, cracks, missing bolts, etc) & the setting & functionality of controls, switches & alarms
Candidates who provided context & reasoning to these factors were able to gain high marks
There were also some useful sketches provided, particularly in relation to failure types, that helped to demonstrate knowledge of some of the technical issues (although reference to “creep” suggested a lack of proper understanding)
Candidates who performed less well were often those who concentrated on why the accident should be investigated, producing answers that would have been more appropriate to Unit A, rather than what should form part of the investigation
NEBOSH INTERNATION DIPLOMA 32
A new design of hydraulic press is intended for use within the European Economic Area
Outline the “essential health & safety requirements” that you would expect to have been addresses in the technical file for the machine in order to demonstrate that it is in fact safe (20)
ANSWER
This was neither a particularly popular question nor a well-answered one
Few candidates showed that they understood the concept of “essential health & safety requirements” (EHSRs) for a machine & many candidates, instead of addressing these, attempted to describe the contents of a technical file (sometimes confused with an operating manual) &/or the requirements for CE marking & declarations of conformity
Anyone with a rudimentary knowledge of both schedule 3 to the Supply of Machinery (Safety) Regulations 1992 & basic machinery safety issues should have been able to make a reasonable attempt at this question since it was really asking was what needs to be considered in order to make a machine safe during installation, use, maintenance & decommissioning
Relating some of these issues to a hydraulic press would have gained even higher marks
Schedule 3 divides the EHSRs into
General requirements
- (e.g. safety integration principles
- Materials/products used or created
- Lighting requirements & effects on lighting
- Handling/installation of machine)
Controls & control systems
- (e.g. safety/reliability of controls
- Design of control devices
- Means of starting & stopping (including emergency stops)
- Mode selection
- Failure of power supply
- Software design)
Protection against mechanical hazards
- (e.g. stability
- Risk of break-up
- Falling/ejected objects
- Safety of surfaces/edges
- Choice of & characteristics of guards & protective devices in relation to hazards/risks)
Protection against other hazards
- (E.g. electricity & other energy sources
- Fitting errors
- Extremes of temperature
- Fire
- Noise & vibration
- Emissions of dusts/gases/liquids/etc)
Maintenance
- (e.g. remote adjustment/lubrication
- Means of access
- Means of isolation
- Automatic cleaning)
Indicators
- (e.g. information/warning devices
- Marking requirements
- Written instructions)
Schedule 3 provides further detail of the nature of the requirements & reference should be made to this for a definitive answer to this question
Since the question attracted by far the lowest score on Section B, this area
NEBOSH INTERNATIONAL DIPLOMA 31
It is proposed to inspect, clean & repair the inside of a tank that is 6 metres in diameter & 10 metres high & which has previously been used for storing leaded petrol
Outline the arrangements that should be considered in order to comply with the CSR 1997 (20)
ANSWER
This was the most popular of the Section B questions & answers generally attracted reasonable to good marks
Weaker answers were those that referred to key terms in a generic way without providing the detail needed to demonstrate application of the arrangements to the situation described
Conversely, better answers were those that approached the proposed work in a logical & sequential way, clearly explaining with examples what would be required at each stage in order to comply with the relevant legislative requirements, in this case regulations 4 & 5 of the CSR 1997
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
Few candidates asked the question of whether the work, or any part of it, could be done without entering the tank, for instance, by using remotely controlled cameras, robotic inspection systems or a cleaning lance operated from outside the tank
Given the size of the tank, this might not be entirely feasible but the question should nevertheless have been raised
If it were decided that entry cannot be avoided, then regulation 4(2) requires a safe system of work in relation to any relevant specified risks (as defined in regulation 1)
The relevant specified risks in this case relate to fire & explosion, & loss of consciousness due to asphyxiation or high temperatures
In order 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 & 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 & 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 & during entry
- & the provision of PPE, possibly including air-fed breathing apparatus
Attention would also need to be paid to the requirements for electrical equipment (e.g. intrinsically safe, flameproof) & earthing arrangements
If heat were to be a foreseeable problem, then consideration should be given to issues such as job rotation & fluid intake
The physical arrangement for working at height would need to be considered in terms of both prevention of falls &, in relation to CSR, access & 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
- & drawing up the emergency arrangements required by CSR regulation 5
- The emergency arrangements to be considered would include issues such as the provision & maintenance of cutting equipment, hoists, fire-fighting equipment, PPE (e.g. breathing apparatus) & first-aid facilities & 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 & emergency procedures
NEBOSH INTERNATIONAL DIPLOMA 30
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 (10)
Answer
From the outset, it was important for candidates to recognise that the question was asking for an outline of the safety measures needed to protect against the various mechanical hazards presented by robots
Candidates who focused their responses on specific mechanical hazards, then tried to attach controls to each of them, usually produced generic machine safety answers that did not demonstrate the understanding of robot safety that was being sought
The better answers came from candidates who took a hierarchical approach in referring to a range of possible technical, procedural & behavioural controls
For instance, while there may be a few opportunities to eliminate the hazards entirely, the elimination of a crushing hazard between the robot & 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 & allowing authorised access only)
- Presence sensing devices (e.g. photoelectric systems, pressure mats)
- & guarding of nip points were all relevant
- Procedural measure might include software checks to avoid aberrant behaviour (mainly relevant to impact hazards) & adequate safety maintenance (e.g. to check the integrity of hydraulics
- In this situation, maintenance personnel would be at particular risk & so procedures such as PTWs 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 & 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 & trained in safe working practices
Heat Exhaustion
What are the symptoms?
HEADACHES; DIZZINESS OR LIGHTHEADEDNESS; WEAKNESS; MOOD CHANGES SUCH AS IRRITABILITY,
CONFUSION, OR THE INABILITY TO THINK STRAIGHT; UPSET STOMACH; VOMITING; DECREASED OR DARKCOLORED
URINE; FAINTING OR PASSING OUT; AND PALE, CLAMMY SKIN
What should you do?
■ Act immediately. If not treated, heat exhaustion may advance to heat stroke or death.
■ Move the victim to a cool, shaded area to rest. Don’t leave the person alone. If symptoms include dizziness or lightheadedness, lay the victim on his or her back and raise the legs 6 to 8 inches. If symptoms include nausea or upset stomach, lay the victim on his or her side.
■ Loosen and remove any heavy clothing.
■ Have the person drink cool water (about a cup every 15 minutes) unless sick to the stomach.
■ Cool the person’s body by fanning and spraying with a cool mist of water or applying a wet cloth to the person’s skin.
■ Call 911 for emergency help if the person does not feel better in a few minutes.
FIND US
MENU
Meta
Categories
Archives
- April 2012
- March 2012
- November 2011
- September 2011
- August 2011
- May 2011
- April 2011
- February 2011
- January 2011
- December 2010
- November 2010
- October 2010
- September 2010
Recent Comments
- admin on NEBOSH INTERNATIONAL DIPLOMA EXAM QUESTIONS
- Iguh David on NEBOSH INTERNATIONAL DIPLOMA EXAM QUESTIONS
- akinbami abiodun on NEBOSH INTERNATIONAL DIPLOMA EXAM QUESTIONS NO :18
- Jemal on FINALY I DECIDE TO START STUDY
- Dust Explosion on ELECTRICAL SOURCES IN HAZARDOUS LOCATIONS
LOGO
Slideshow
