January 2006
Examiners’ Report
NEBOSH National
Diploma in
Occupational Health
and Safety
Examiners’ Report
NEBOSH National Diploma in
Occupational Health and Safety
January 2006 examinations
CONTENTS
Unit A – Managing health and safety
2
Unit B – Hazardous agents in the workplace
11
Unit C – Workplace and work equipment
20
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The National Examination Board in Occupational Safety and Health is a registered charity, number 1010444
T(s):exrpts/D/D-0106
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UNIT A – Managing health and safety
General comments
This was the third Unit A examination paper of the re-formed NEBOSH Diploma and the questions set were
taken from the syllabus material published in the Diploma Guide. 358 papers were submitted for
examination.
To be successful in this part of the examination process, candidates need to be prepared to deliver and
apply a level of knowledge commensurate with the Diploma award. As always, there were some excellent
answers with maximum or near maximum marks being achieved on most questions by a small number of
candidates, but not necessarily the same candidates on each occasion. Where candidates achieved low
marks overall, this was generally for at least one of the following three reasons. Firstly, candidates were not
always armed with the degree of understanding and detail required at this level. This was particularly
evident in many of the answers provided to Questions 5 and 8 for example. Candidates setting out on a
course of study for the level 6 Diploma need to ask themselves whether they have provided for the
necessary preparation, revision and examination question practice that is important for maximising their
chances of success in the examination; this is a very different level of examination from the NEBOSH
National General Certificate. Secondly, many candidates achieved less than their possible potential through
focusing on only a limited range of issues on a question that had scope for a broader range to be tackled.
Questions 1 (a) provided numerous examples of this. Examination question practice, with feedback provided
by training providers, together with the use of answer plans (on Section B questions in particular) are
important elements in trying to maximise marks. Thirdly, candidates wasted much time and lost many
opportunities for marks by failing to read the question carefully, not relating their answers to the question
asked or the scenario set, and providing information that was not asked for or required. This was a particular
issue for scenario questions such as Questions 7(c) and 11.
Section A – all questions compulsory
Question 1
The Management of Health and Safety at Work Regulations 1999 requires that
employers appoint a Health and Safety Assistant.
(a)
(b)
List the key legal requirements that must be satisfied by the employer
when making such an appointment.
(5)
Outline the key elements of the strategic role of the health and safety
professional with respect to the employer’s current health and safety
management system.
(5)
Examiners expected candidates to find this question simple to answer, as it is assumed that
candidates are aspiring to become practising health and safety professionals. A number of
candidates made reference to HASAWA even though the question clearly referred to The
Management of Health and Safety at Work Regulations 1999. The key to answering the
question well was knowledge of Regulation 7 of MHSWR. Most candidates identified
competence as a key requirement but then failed to go any further by identifying
appointment of one or more persons, arrangements for cooperation if 2 or more; numbers
and time available sufficient for size, risk and risk distribution; information on health and
safety issues provided to external appointees; preference for internal appointment;
information on temporary workers; or exemptions for partnerships where one partner is
sufficiently competent.
2
The second part of the question was reasonably well answered, although candidates who
reproduced HSG(65) without relating it to the role of the health and safety professional did
not gain high marks. Candidates who read the question carefully and focused on the
strategic role gave good answers which included elements such as: formulating and
developing elements of the health and safety management system; developing and agreeing
plans for improvement including short and long-term targets; involvement in reactive
monitoring such as reporting and accident investigation; involvement in proactive monitoring
such as inspections and audits; developing/agreeing plans to improve safety culture;
organising and participating in review arrangements; developing/agreeing a suitable safety
policy statement; managing relationships with enforcing bodies; advising senior
managers/Board on strategic safety issues; and co-ordination and support issues of a health
and safety department.
Question 2
A risk management programme encompasses the following concepts:
(i)
risk avoidance;
(2)
(ii)
risk reduction;
(3)
(iii)
risk transfer;
(3)
(iv)
risk retention.
(2)
Identify the key features of each of these concepts and give an appropriate
example in each case.
Most candidates provided good answers to this question, although a number confused the
principles of risk avoidance and risk transfer. A number of candidates missed opportunities
for marks by failing to give examples.
Risk avoidance involves taking active steps to avoid or eliminate risk for example
discontinuing the process, avoiding the activity, eliminating a hazardous substance.
Risk reduction involves evaluating the risks and developing risk reduction strategies,
requires the organisation to define an acceptable level of risk control to be achieved; this
could be by the use of safety/risk management systems or use of a hierarchy of control.
Risk Transfer involves transferring risk to other parties but paying a premium for this; for
example by the use of insurance; transfer of risk by use of contractors to undertake certain
works; use of third parties for business interruption recovery planning or outsourcing the
process.
Risk retention involves accepting a level of risk within the organisation along with a decision
to fund losses internally; it could involve risk retention with knowledge where the risk has
been recognised and evaluated; or risk retention without knowledge where the risk has not
been identified (obviously an unfavourable position for the organisation to be in).
Question 3
(a)
(b)
Outline the main defences available to a defendant in a civil case who is
being sued in an action for the tort of negligence.
(6)
Outline factors which will be considered in determining the level of
damages paid to a successful claimant.
(4)
Most candidates answered this question well, although it should be noted that answers
which comprise of simple lists are not acceptable at this level. The main defences that could
have been covered are: that no duty was owed by the defendant to the claimant; that
although there was a duty there, it was not breached (to gain marks her, candidates are
expected to make reference to foreseeability and reasonableness); the damages may not be
as a result of the breach; the damage may be too remote; volenti non fit injuria; the type of
damage may not have been foreseeable; contributory negligence.
3
Many factors are taken into consideration in determining the level of damages, the most
obvious being the degree of disability; the loss of earnings and/or opportunities; and the pain
and suffering. Other factors that could be considered are: medical costs and expenses; the
cost of special adaptations; the cost of care; loss of amenity; and contributory negligence
might result in a reduction of damages awarded.
Question 4
An advertising campaign was used to promote improvement in safety standards
within a particular organisation. During the period of the campaign the rate of
reported accidents significantly increased, and the campaign was deemed to be
a failure.
(a)
(b)
Suggest, with reasons, why the rate of reported accidents may have been
a poor measure of the campaign’s effectiveness.
(2)
Describe four proactive (active) measures which might have been used to
measure the organisation’s health and safety performance.
(8)
The first part of the question was reasonably well answered with candidates correctly
identifying that a reason why the number of reported accidents had increased was because
they may have previously been under-reported. Unfortunately, some candidates stopped at
that point, which did not fulfil the requirement for an explanation. Marks were available for
explaining that raised awareness may have led to previously unreported accidents now
being reported, but that, in the absence of other data, it is almost impossible to tell whether
or not the increase is ‘real’. Better answers suggested why accidents may have been
previously under-reported.
Although some very good answers were given to part (b), candidates failing to achieve good
marks in this part of the question did not describe the methods of measuring in sufficient
detail. Many answers identified good methods of improving safety within an organisation
such as increased consultation, toolbox talks, risk assessment, training etc without
identifying the need to count the number done to use them as a year-on-year indicator.
These were means of improving safety, not measuring it. Proactive measures that could
have been considered include: safety audits; safety tours, workplace inspections; safety
sampling; safety surveys; environmental monitoring and health surveillance safety climate
measures; various types of behavioural safety measurements; benchmarking; or, as
discussed measuring of any health and safety performance against set targets.
Question 5
Human failure was identified as a significant factor in an accident involving a
crane. A contractor’s employee was seriously injured when struck by material
being transported by the crane.
Outline the types of human error which may have contributed to the accident.
Refer to relevant examples based on the scenario to illustrate your answer.
(10)
Examiners expected candidates to outline skill based errors, mistakes, and violations.
These could have occurred in the given scenario.
Skill based errors could be: slips of action where a familiar task or action was carried out as
planned such as operating the wrong switch/controls; or lapse of memory where a step was
missed in the action sequence due to memory, for instance commencing the lifting operation
out of sequence when other workers were not prepared
Mistakes are errors of judgement which could be: rule based ie application of the wrong
rule, such as lifting instead of lowering, or crossing the path of the lifting operation; or
knowledge based such as: an unfamiliar situation, no rules, wrong conclusion formed for
instance the first time the crane driver had undertaken that particular lifting operation, wrong
height of lift, or it could involve the injured person being unaware that the lifting operation
was taking place.
4
Although HSG 48 defines violations as human failings rather than human error, the
Examiners decided to accept violations in answer to this question. Violations involve rule
breaking, ie a deliberate failure to follow rules (eg not sounding siren when lifting operation
taking place, or intentionally walking close to lifting operation). Better responses went on to
cover the subdivisions of routine, situational, and exceptional violations with suitable
examples. Reference to model systems such as HSG 48 or Rassmussen gained marks.
Some candidates provided examples from well known situations such as flying a plane
rather than applying their understanding to the scenario as required by the question; others
described factors that may affect the likelihood of the error occurring – again not required by
the question. This demonstrates that even at this level some candidates do not read the
questions carefully, wasting time on answers that cannot gain marks.
Question 6
Explain with reference to case law, the meaning of the terms ‘practicable’ and
‘reasonably practicable’ as they apply to health and safety legislation.
(10)
The ability to distinguish between the terms ‘practicable’ and ‘reasonably practicable’ is
fundamental to an understanding of health and safety law. Good answers were those that
were backed up with appropriate reference to case law and regulations that illustrated the
use of the terms. Candidates should bear in mind that the actual circumstances of a case
are normally less important than the basis of the decision (the ratio decidendi).
Most candidates were able to explain that though ‘practicable’ was not an absolute duty, it
was of a higher standard than that of ‘reasonably practicable’ This means that there must be
compliance with the duty as far as technical and practical feasibility allows, with no reference
to cost. ‘Reasonably practicable’ requirements as those where a balance is made between
risk and cost (in terms of money, time and trouble) and which are met when the cost of
further control is grossly disproportionate to any reduction in risk. Reference was made to
cases such as Adsett v. K&L Steelfounders and Engineers Ltd (1953), Marshall v Gotham
[1954] and Edwards v National Coal Board [1949] in order to demonstrate the principles
involved.
Section B – three from five questions to be attempted
Question 7
A forklift truck is used to move palletised goods in a large distribution
warehouse. On one particular occasion the truck skidded on a patch of oil. As a
consequence the truck collided with an unaccompanied visitor and crushed the
visitor’s leg.
(a)
State, with reasons, why the accident should be investigated.
(4)
(b)
Outline the actions which should be followed in order to collect evidence
for an investigation of the accident. Assume that the initial responses of
reporting and securing the scene of the accident have been carried out.
(8)
Describe factors which should be considered in analysis of the
information gathered in the evidence collection.
(8)
(c)
This question was a popular choice with candidates, not unexpectedly considering most
Health and Safety Practitioners are involved in accident investigation at some time in their
careers.
5
Although some candidates wanted to use the exercise as an opportunity to apportion blame
they should note that the apportionment of blame for the sake of it can damage the
organisation’s safety culture. They should also note that there are many other reasons for
investigating accidents and most candidates were able to identify reasons such as to identify
its causes (immediate and underlying), to prevent a recurrence, to assess compliance with
legal requirements, to demonstrate management’s commitment to health and safety and to
obtain information and evidence for use in the event of any subsequent civil claim. Few,
however, mentioned that the investigation could provide useful information for the costing of
accidents and in identifying trends.
Part (b) was generally well answered with responses set out in a realistic chronological
order: starting with taking photographs, sketches and measuring relevant parts of the
accident scene before anything is disturbed, obtaining any CCTV footage available; then
moving on to examining the condition of the fork lift truck; determining its speed at the time
of the accident; the loads carried, the safe working load of the truck and any forward visibility
issues with the load in place; the reasons for the oil spillage; emergency spillage procedures
in place and the reasons why they were not followed on this occasion; the failure to follow
laid down operating procedures; the competence of the fork lift truck driver and examining
the workplace to determine any contributing environmental factors such as the condition of
the floor and the standard of lighting; interviewing relevant persons such as the visitor
(where this is possible), the reception personnel (to identify working practices against any
written visitor procedures).
Part (c) was not so well answered. It is not sufficient to merely collect data and put it into a
report, it must be analysed and examined objectively before inclusion in an official accident
report (which may be used in a subsequent legal action). Good answers considered: job
factors such as the attention needed for task, any distractions that may have contributed to
the accident, whether any procedures were inadequate and the time available to carry out
the job; human factors such as competence of the driver and whether there was any
evidence of fatigue and/or stress; organisation factors such as work pressure, availability of
sufficient resources, quality of supervision and the general health and safety culture within
the warehouse; and finally whether plant and equipment factors such as the forklift truck
controls or layout of workplace or signage (too much, too little) could have contributed to the
accident. Credit was also given for describing factors which related to the reliability and
quality of evidence.
A number of candidates assumed that the visitor was unauthorised, which was not stated in
the question and spent time focusing on duties to trespassers.
Question 8
A fast-growing manufacturing company now employs 150 people. Health and
safety standards at the company are not good, as arrangements have
developed without professional advice in an unplanned way during the time of
rapid growth. The company has, though, managed to avoid any serious
accidents and, in the main, staff at all levels do not seem particularly concerned.
Two employees, however, have recently experienced two separate near-miss
incidents and have complained jointly to the Health and Safety Executive. A
subsequent visit by an HSE inspector has resulted in the issue of three
improvement notices. The Managing Director wishes to dismiss the employees
(whom he has described as ‘troublemakers’) even though he accepts that their
concerns were probably justified.
(a)
(b)
State the advice you would give the Managing Director with respect to the
proposed disciplinary action to the employees who have complained and
give supporting reasons.
Outline the steps that should be taken to gain the support of the
workforce to improve the health and safety culture within the company.
(5)
(15)
This was a popular question that required application of employment law knowledge and a
strategy for changing the perception, involvement and ownership of employees on matters of
health and safety in their workplace.
6
The first part of the question produced a few good answers but many answers were unclear
and incorrect. About half of the candidates recognised that this was a protected disclosure
under the Public Interest Disclosure Act 1998 (see Element A7 of the Diploma Guide)
though unfortunately, many of them could not name the Act or explain the real nature of the
protection, despite many recognising that an action at an Employment Tribunal may result.
Some candidates had the mistaken belief that employees were protected from dismissal
simply by complying with Section 7 of the HSW Act 1974. A number recognised the
negative cultural implications of disciplining the two employees and the need to recognise
the root causes of employee concerns.
Part (b) required candidates to identify the components of a strategy to improve employee
support for and perception of health and safety issues within the workplace. Many
candidates performed reasonably well on this part although as is often the case, a significant
minority felt that reciting the key elements of HSG 65 was the solution to all problems.
Better answers began by recognising the value of using tools to help them understand
current employee perceptions such as informal discussions and safety climate
questionnaires. Methods of demonstrating the commitment of the business to good safety
management such as the development of a new policy and arrangements for health and
safety; the introduction of new consultative arrangements and training programmes and the
behaviour and communication techniques, targets, reporting, resourcing and priorities
relating to health and safety issues adopted by senior and line managers were all
reasonable issues to explore. Steps to increase employee participation were also important
and could have included involvement in risk assessments, the development of safe systems
of work, inspections, incident investigation and team briefing sessions.
Question 9
(a)
Outline the use and limitations of fault tree analysis.
(b)
A machine operator is required to reach between the tools of a vertical
hydraulic press between each cycle of the press. Under fault conditions,
the operator is at risk from a crushing injury due either (a) to the press
tool falling by gravity or (b) to an unplanned (powered) stroke of the
press. The expected frequencies of the failures that would lead to either
of these effects are given in the table below:
Failure type
Frequency (per year)
Flexible hose failure
Detachment of press
tool
Electrical fault
Hydraulic valve failure
(i)
(ii)
(iii)
(4)
Effect
0.2
a
0.1
a
0.1
0.05
b
a or b
Given that the operator is at risk for 20 per cent of the time that the
machine is operating, construct and quantify a simple fault tree to
show the expected frequency of the top event (a crushing injury to
the operator’s hand).
(10)
If the press is one of ten such presses in a machine shop, state,
with reasons, whether or not the level of risk calculated should be
tolerated.
(4)
Assuming that the nature of the task cannot be changed, explain
how the fault tree might be used to prioritise remedial actions.
(2)
This question was designed to test candidates’ understanding and application of fault tree
analysis. It was not a popular question but was generally well answered by those who did
attempt it. Candidates recognised that fault tree analysis is useful in analysing accidents
where there are multiple causes to an accident to calculate the probability of the top event; it
can be used to identify the most effective points of intervention in order to reduce the
probability of the top event occurring. On the negative side it is limited by the requirement of
skilled analysts to work the calculations out in complex situations and its reliance on the
accuracy and availability of failure data.
7
(b) (i)
Fault tree
CRUSHING
INJURY
f = 0.2 x 0.5 = 0.1/yr
or 1 in 10 years
&
Tool comes down as
result of failure
P = 0.2
Operator
exposed
f = 0.15 + 0.35
= 0.5/yr
Powered
stroke
Gravity
fall
f = 0.05 + 0.1
= 0.15/yr
f = 0.05 + 0.2 + 0.1
= 0.35/yr
Valve
failure
Electrical
fault
Valve
failure
Hose
failure
Detachment of
tool
f = 0.05 /yr
f = 0.1 /yr
f = 0.05 /yr
f = 0.2 /yr
f = 0.1 /yr
Part (b) (i) required the construction of a fault tree and its quantification using the data
presented. A significant number of candidates constructed an event tree rather than a fault
tree and so gained no marks. Many of the remainder who attempted the construction made
a reasonable attempt at a fault tree consisting of four levels: crushing injury at the top;
operator exposure and tool descent at the second level; type of tool descent (powered
stroke or gravity fall) at the third; and component failures at the bottom. Those who
achieved a reasonable construction also tended to achieve good marks for quantification.
Part (ii) was seeking not just an opinion but some commentary on, or justification for, the
opinion in terms of the frequency of unexpected tool descent or operator injury. Those
candidates who did not give reasons for their opinions could not expect to gain high marks.
Some reference was therefore needed to the likely disabling nature of the injury and to such
an event occurring once in about ten years (which was the estimated frequency). Better
candidates offered a risk level that might be considered to be more acceptable, with some
suggesting that if several of these presses were operating (perhaps within the same factory),
then a serious injury could be a regular occurrence.
Part (iii) needed candidates to explain the general principles of using the probability data in
the fault tree so that priority is given to those actions that would give the greatest reduction
in the probability of the undesired events. For instance, gravity fall was highlighted as the
most likely event, therefore priority should be given to actions that would prevent this.
8
Question 10
Atom Chemicals Ltd engaged the services of an industrial cleaning company,
Becom Cleaners Ltd, to clean their chemical processing vessel using Atom
Chemicals’ own electrical cleaning equipment. The production supervisor of
Atom Chemicals issued a permit-to-work for Becom Cleaners to undertake the
work. The vessel cleaning operation involved the use of flammable solvents
and the Becom Cleaners’ employee was badly burned whilst using the electrical
equipment.
Identify and explain the possible breaches of the Health and Safety at Work etc
Act 1974 and the Management of Health and Safety at Work Regulations 1999
by:
(a)
Atom Chemicals.
(8)
(b)
Becom Cleaners.
(6)
(c)
Individuals.
(2)
Make reference to relevant case law and explain the relevance in this case.
(4)
This was not a popular question even though it concerned two significant pieces of health
and safety legislation. Candidates who did well on this question identified the following
possible breaches of HSWA by Atom Chemicals: s3(1) regarding ‘undertaking’ and so far as
is reasonably practicable; s4 as occupier and controller of non-domestic premises, regarding
provision of plant — s2 in relation to the risk to its own employees, s2(1), s2(2)(c); Under
MHSWR Reg 3 risk assessment; Reg 5 effective safety management arrangements; Reg 11
cooperation and coordination; Reg 12 instructions / information for workers in host
employers undertakings.
Possible breaches by Becom Cleaners were under HSWA s2(1) and s2(2) (a)-(e) – duties to
employees; HSWA s3(1) putting Atom Chemical’s employees at risk; Under MHSWR Reg 3
risk assessment; Reg 5 effective safety management arrangements; Reg 11 cooperation
and coordination; Reg 10 Information to employees on hazards/controls; Reg 13
competence and training of employees.
Possible breaches by individuals in consideration of the duties of employees under HSWA
s7 and MHSW Reg 14; with consideration of the permit issuer: HSWA s7, MHSW Reg 14
and HSWA s36.
Relevant case law correctly included by candidates was: R v Associated Octel Co Ltd (1996)
4 All ER 846; R v Swan Hunter Shipbuilders Ltd and Another (1982) 1 All ER 264.
Answers which included breaches under COSHH, DSEAR and PUWER did not attract
marks as the question specifically asked for possible breaches under the Health and Safety
at Work etc Act 1974 and the Management of Health and Safety at Work Regulations 1999.
Question 11
A new chemical plant which falls within the scope of the Control of Major
Accidents and Hazards (COMAH) Regulations 1999 is being planned. The
manufacturing process will involve toxic and flammable substances. The plant
is near to a residential area.
Identify the issues to be considered in the development of an emergency plan to
minimize the consequences of any major incident.
(20)
This was a reasonably popular question with many candidates giving answers which
identified a sufficient number of relevant points related to the emergency plan. Some poor
answers discussed producing a MAPP and describing measures to control and manage the
risk rather than the emergency measures to mitigate the consequences of an emergency.
9
Good answers recognised the role of key individuals in the planning stage with effective
communication and practising of the plan. Issues that candidates successfully identified
were: to consider the quantities involved; to provide information to local authority as part of
the planning requirements; possible causes of a major incident; estimating the likely extent
of damage; staff and equipment call-out arrangements; resources needed to deal with
incident; how the alarm will be raised both on-site and in the neighbourhood; evacuation or
shelter arrangements on and off-site; training of staff in emergency plan; action to minimize
extent such as shutting off services; search and rescue arrangements; notification of
emergency services; co-ordination with emergency services; control and management on
site including clear allocation of responsibilities for emergencies during all shifts and out of
working hours; communication with community; emergency plan testing arrangements;
control of spillage/pollution; toxicity/flammability and any possible additive effects; clean
up/decontamination; dealing with the media; consultation with emergency services / third
parties / stakeholders; establishing control centres; and ensuring the availability of
information / site plans / inventory etc.
10
UNIT B – Hazardous agents in the workplace
General comments
This was the second time that a Unit B paper had been set for the Diploma in its present form and 498
candidates presented themselves for the examination. All questions were based clearly on the content of
the published syllabus and a balance was achieved between questions that required specific technical
knowledge relating to occupational health risks, their measurement and control and those that addressed
workplace health issues in a more general way. In the event, performance on the two types of question was
mixed– for instance, Questions 7 relating to specific technical knowledge and Question 11 which looked at
broader workplace issue both performed well. It became apparent to the Examiners that a significant
number of candidates lacked much of the specific knowledge that was required to achieve high marks on the
paper overall. Of particular concern was an inability to carry out simple calculations involving WELs, Q 2.
However, the fact that all six questions in Section A attracted answers that gained full marks demonstrates
that high marks are not only achievable but were actually achieved. There were some similarly excellent
answers in Section B. This should provide some reassurance to those who were unsuccessful on this
occasion. But a prerequisite for success is the accumulation of knowledge in order to gain a high level of
understanding that can be demonstrated in the examination. This requires a significant amount of study on
the part of candidates, together with structured revision and practice in writing examination answers. It was
apparent on this occasion that a large number of candidates were unprepared for the examination, which
hopefully they will be able to address for the future.
Section A – all questions compulsory
Question 1
(a)
(b)
Compare and contrast the following epidemiological methods:
(i)
Retrospective Cohort Study and
(3)
(ii)
Prospective Cohort Study.
(3)
Outline factors that may affect the reliability of these epidemiological
methods.
(4)
In answering this question many candidates showed confusion in their understanding of the
meaning of retrospective and prospective studies. Compare and contrast was not reflected
in most answers. Both methods involve looking for a link between cause (exposure) and
effect (disease); using two cohorts in order to compare those that have been ‘exposed’
against those that were ‘unexposed’ and looking for a dose/response link. In contrast a
retrospective cohort study starts at a point in the past and follows cohort forward in order to
determine past exposure histories and health outcomes from records; a prospective cohort
study starts at the present time and follows cohort forward and enables monitoring of
exposure and health outcomes.
Many candidates were able to provide reasonable answers to the second part of the
question, recognising that reliability may be affected by factors such as: the cohort size; the
accuracy of historical data on exposure and health effects; the accuracy of diagnosis; there
may be non-occupational exposure; long latency periods for the effect; the frequency of
disease in unexposed cohort; lifestyle factors such as alcohol consumption, diet, smoking
etc; there may be selection bias (cohort may not be representative of exposed population);
the ‘healthy worker effect’ (sick people leave); and the difficulty in following all of cohort for
instance a geographic move, non co-operation etc.
11
Question 2
(a)
(b)
The term Workplace Exposure Limit (WEL) is defined in the Control of
Substances Hazardous to Health (COSHH) Amendment Regulations
2004.
Explain what this term means in practice.
(3)
Use the data below to calculate the 8 hour TWA exposure to flour dust for
a bakery operative. Your answer should include detailed working to show
your understanding of how the exposure is determined.
(7)
Working Period
(Total shift time = 8hours)
Tasks undertaken by
bakery operative
Exposure to Flour dust
3
(mg/m )
8.00 – 10.30
10.45 – 12.45
12.45 - 13.45
13.45 – 15.45
15.45 - 16.15
Weighing ingredients
Charging the mixers
Lunch
Cleaning equipment
Assisting maintenance staff
20
30
25
0 (assumed)
Assume that exposure is zero during break times.
These Amendment Regulations brought some significant changes to the COSHH
Regulations: introducing a single new workplace exposure limit for substances hazardous to
health which replaces occupational exposure standards and maximum exposure limits; and
introducing requirements to observe principles of good practice for the control of exposure to
substances hazardous to health set out in Schedule 2A, to ensure that workplace exposure
limits are not exceeded, and to ensure in respect of carcinogens and asthmagens that
exposure is reduced to as low a level as is reasonably practicable. Keeping abreast of new
legislation is a requirement for any health and safety practitioner and this question provided
an opportunity for candidates to demonstrate this. A number of candidates correctly
identified that the term Workplace Exposure Limit (WEL) as the maximum concentration of
an airborne substance, averaged over a reference period, to which employees may be
exposed by inhalation. A surprising number of candidates thought that it referred to the time
exposed, rather than the concentration of hazardous substance in the air. Better responses
went on to explain that concentrations are usually expressed in mg/m3 or ppm; that the WEL
is set at a level below which there is evidence of no adverse effect.
There were many reasonable responses to the second part of the question which stated that
each time period and exposure need to be multiplied together, then added, then divided by 8
and included the time of zero exposure in the workings of the calculation producing the
correct 8 hour TWA of 20 mg/m3.
Or numerically:
(20 x 2.5) + (30 x 2) + (25 x 2) + (0 x 0.5) + (0 x 1) )/8
( (20 x 2.5) + (30 x 2) + 25 x 2) + (0 x 1.5) )/8
= (50 + 60 + 50 + 0 + 0) /8
= 160/8
= 20 mg/m3
Question 3
Hand-Arm Vibration Syndrome (HAVS) can be caused by frequent and
prolonged use of hand-held power tools.
(a)
Identify the symptoms of Hand-Arm vibration syndrome.
(2)
(b)
Outline a hierarchy of control measures that could be used to minimise
the risks to employees of developing HAVS when using such power tools.
(8)
Although knowledge of the Control of Vibration at Work Regulations 2005 was not required
in answering this question, Examiners were pleased that many candidates demonstrated
their familiarity with these recently introduced regulations. Symptoms of Hand-Arm vibration
syndrome identified by candidates were: loss of feeling, numbness, tingling and dexterity in
the finger tips; blanching (white finger); that the symptoms are generally worse during cold
weather; and that the condition can be progressive, affecting more fingers or parts of fingers,
leading possibly to gangrene.
12
Candidates tended to focus on either organisational or technical control measures when
answering this question. The best responses considered both types of control measure,
relevant to the use of small hand tools and presented them in an appropriate hierarchy.
Starting with : consideration of alternative work methods to eliminate the task; automating, or
mechanising, the work; avoiding tools that are too small and not powerful enough as these
prolong the task; replacing the equipment with a lower vibration model along with regular
maintenance to reduce vibration in tools and use of tools with heated handle grips to
improve circulation. Organisation control measures would be to ensure the organisation’s
purchasing policy takes account of vibration emissions (as well as other requirements);
change work station design to minimise loads on hand, wrists and arms for instance by use
of jigs/ or suspension systems to grip heavy tools; planning work schedules to limit time of
exposure to vibration; provide warm clothing and a warm environment to encourage good
blood circulation; refer those experiencing early symptoms to Occupational Health as well as
having a surveillance programme in place and a final control measure is to ensure that
employees receive adequate information and training on risk, control and recognising
symptoms.
Question 4
The risk of contracting Weil’s Disease (Leptospirosis) is a concern to
windsurfers at a local water sports centre. Provide advice to these windsurfers
which outlines:(a)
the ill-health effects associated with this disease
(2)
(b)
why windsurfers might be at risk
(2)
(c)
practical steps that instructors can take to minimise the risks to
themselves.
(6)
In most cases the infection causes a flu-like illness with severe headaches and myalgia
(lower back, and legs). The severe form of the disease (called ‘Weil’s Disease’ after the
doctor who first identified it) causes jaundice and liver damage and carries a reported death
rate anywhere between 4 and 40 per cent. Only about 10 to 15 per cent of affected people
suffer this more dangerous form.
Other symptoms include fever, vomiting, abdominal pain, skin rashes, conjunctival
haemorrhage, uveitis, and Leptospirosis may present as aseptic meningitis.
The most common carriers are rats, but other rodents can do this (but less frequently). It is
generally assumed that across the developed world, 1 in 5 wild rats are carriers of
pathogenic leptospires. Rats are such efficient hosts because they live in close proximity to
water and they are incontinent. Carrier-state rats emit bacteria in their urine, and this is
distributed everywhere they go. Normally this is inactivated once it dries out, but if it enters
water the bacteria can remain viable for longer periods. The bacteria can then enter the
windsurfers’ bodies via cuts to the skin, nose, mouth or other mucous membranes.
A killed vaccine is only available for humans in Asia (China, Japan and Viet Nam), immunity
is restricted to the serovars in the particular vaccine, is of short duration and there are a
number of side effects. In the scenario set out in the question , practical steps that can be
taken are to prevent the bacteria getting into the body. Many candidates correctly outlined
measures such as maximising dry training ( to limit the potential contact time); showering
after being in water and washing hands thoroughly before eating; avoid swallowing water;
wearing protective footwear and minimising skin contact by wearing full-body wet suit;
protecting all existing cuts and abrasions with waterproof dressings; seeking medical advice
and treatment for any cuts or bites received whilst in the water (advising their GP of their
occupation to aid in early diagnosis); washing down equipment and wet suits and reporting
any sighting of rats to ensure effective rodent control in and around the water.
Although infection is virtually zero in salt water, responses advising this course of action did
not attract marks as it was not a practical solution in this scenario.
13
Leptospirosis is rare in the UK, and Weil‘s disease extremely rare. Weil‘s disease is however
a very serious illness, and must be swiftly diagnosed and treated.
For anyone with a particular interest in this topic, in-depth information can be found at:
http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=230
http://www.patient.co.uk/showdoc/40000444/
http://www.leptospirosis.org/medical/precautions.php
http://www.who.int/csr/don/en/WHO_CDS_CSR_EPH_2002.23.pdf
Question 5
Low Power lasers are widely used to read bar-code labelled products at
checkouts in retail premises. There is no specific regulatory legislation relating
to the use of laser products.
(i)
(ii)
Identify statutory legislation that should be considered by retailers in
relation to the use of these laser products.
(2)
Outline the design features and the procedural controls that should be in
place to ensure the safe operation and the maintenance of this
equipment.
(8)
Most candidates were able to identify sufficient relevant statutory legislation to gain full
marks for this part of the question. A number of candidates did make some strange
references to The Consumer Protection Act; COSHH, DSE and CDM Regulations and some
even invented legislation (such as the Non-Ionising Regulations). The legislation correctly
identified included: HASAWA S2 - to provide safe equipment, S3 - protecting others
(customers); MHSWR Regulation 3 - requirement to undertake a risk assessment for the
operation and maintenance of this equipment; Examiners also accepted PUWER Regulation
5 - maintenance and The Electricity at Work Regulations where relevant reference was
made. The best responses made reference to EN60825-1 and its requirements.
Candidates who answered the second part of the question in two parts (design features and
procedural controls) achieved better marks. Design features could include reference to
features such as : in retailers lasers should be no greater power than Class 1; use of
embedded systems; protective housing; incorporating a key control with interlock to power
source; signage and appropriate positioning of the laser to avoid eye-level exposure,
including any hand-held equipment.
Procedural controls included ensuring that: manufacturers’ guidance is available and
followed; employees trained in safe use: having arrangements and safe systems of work in
place for maintenance: where maintenance requires removal of casing, the risk of exposure
to the beam is properly controlled; control of the key used to gain access to housing; only
using competent person; and a robust system for the reporting of defects.
14
Question 6
Here is an audiogram for an adult worker
(a)
Explain what is meant by threshold shift.
(2)
(b)
What does the shape of the audiogram show?
(2)
(c)
Identify the benefits and limitations of audiometry as part of a hearing
conservation programme.
(3 + 3)
Threshold shift is the difference between the hearing threshold of the subject and the
hearing threshold of an average young adult with healthy, disease-free ears.
A number of candidates described the shape of the audiogram, rather than what the shape
shows. Good responses identified that the shape, with the 4kHz notch is typical of noise
induced hearing loss (NIHL); that the threshold is reduced at all frequencies; the high
frequency loss shows age related hearing loss (presbyacusis); and the dip beyond 12kHz is
expected as it is outside the normal hearing range.
Part (c) provided the best responses, with most candidates able to identify some benefits
and limitations. Against benefits candidates correctly identified that audiometry: provides
evidence of effectiveness of hearing conservation programme; pre-employment screening
identifies those with existing problem; enables identification of susceptible individuals and/or
early signs of hearing loss; provides opportunities to educate workers about NIHL and
prevention; may lead to reduced insurance premiums and provides information that may be
used to defend civil claims.
Limitations identified were that audiometry: is not preventive since some damage has to
occur before problem identified; may actually encourage claims; diverts resources away
from noise control; is subject to inaccuracy and abuse; and that it detects hearing loss but
not the source of NIHL.
15
Section B – three from five questions to be attempted
Question 7
A slightly corrosive solution is used as a treatment in part of a manufacturing
process. The solution is applied by hand brushing. Alternative methods of
application have been found to be impracticable.
(i)
(ii)
(iii)
Outline the factors that should be considered in the selection of personal
protective equipment. The equipment should ensure that the skin and
the eyes of those involved in the process are adequately protected.
(10)
Identify the content of a training programme that will assist employees to
use the PPE correctly.
(5)
List a range of practical measures (other than training) that can be taken
to encourage the use of the protective equipment and maintain its
effectiveness.
(5)
This was a popular question which was well answered by many candidates, especially those
who took a logical ‘head-to-toe’ approach.
For the selection of protective gloves candidates considered factors such as: the appropriate
chemical resistance for the solution and the chemical breakthrough time; the length of time
the gloves can be worn for before they require replacing; the level of dexterity required for
the task; the length of glove for adequate protection; durability of gloves; ensuring a suitable
range of sizes for the various users is available; any allergies to the glove material or other
skin problems. In the selection of eye protection candidates considered: the risk of
splashing the face as well as eyes; advised to consider the use of goggles or a face shield
with the appropriate level of chemical resistance; and its compatibility with other PPE (if
required). Against selection of body protection candidates considered appropriate chemical
resistant apron and overalls and appropriate footwear. The best answers then concluded by
considering factors such as consultation and user trials; comfort factors; that all PPE meets
appropriate standards (eg Gloves - BS EN 374 chemical 420 / 388; eye protection - BS EN
166 and that everything purchased is CE marked.
Good responses to the second part of the question identified that employees should receive
training prior to issue in topics such as: the health risks of chemical; the PPE to be used and
why; the method of putting on and removing PPE without contamination, including
decontaminating or discarding of gloves after use; not to contaminate other parts of the body
whilst wearing gloves; how to examine PPE for damage or degradation (particularly gloves)
and how to report any defects and obtain replacements; how to store the PPE correctly; and
training in self examination of the skin and action to take if any problems occur.
For the third part of the question, candidates correctly identified other practical measures to
encourage the use of PPE such as: Management leading by example; staff being involved in
the selection; ensuring a range of sizes of gloves available and that shields are fully
adjustable; employees signing for PPE and maintaining records of issue; providing adequate
storage facilities; personal issue of PPE with an adequate supply; use of propaganda, signs
and posters; supervision and monitoring of use; measures taken for non-use (eg
disciplinary); and monitoring the effectiveness of PPE.
16
Question 8
In a manufacturing process workers use a range of solvents.
(a)
(b)
(c)
Outline the issues that should be considered and the information which
should be consulted when preparing a Control of Substances Hazardous
to Health (COSHH) risk assessment for this situation.
(6)
Describe an overall monitoring strategy that could be used to assess the
actual exposure of the process workers to solvent vapours.
(6)
Explain how the range of data obtained might be interpreted in order to
determine the acceptability of such exposures and the adequacy of
current controls.
(8)
This was not a popular question, although those candidates who attempted it generally
provided reasonable answers. Relevant factors candidates included were: reference to
COSHH Regulations and ACOP, HSG173 (Monitoring strategies for toxic substances),
material safety data sheets; background information on solvents (types, health effects, target
organs, synergistic/additive effects, etc); working practices, exposure patterns, efficiency of
existing controls; need for monitoring (eg deterioration of controls) and health surveillance;
current exposure limits (EH40); route/s of entry (inhalation / skin absorption) relevant to how
the substance is used and who is exposed (including any vulnerable groups).
The better responses considered atmospheric and biological monitoring within their answers
and referred to the three-stage approach in HSG 173. Suitable monitoring strategies
included consideration of: personal versus static monitoring; biological monitoring (total body
burden v inhalation); who to monitor, for how long and when; how to monitor: grab sampling
— stain tubes versus integrated sampling (pump, passive, adsorption tubes etc); examples
of analytical methods; and reference to appropriate MDHS’s.
Many answers were limited to comparison of data against WEL’s, whereas better responses
included the following points in explaining how data might be interpreted: measurements
obtained versus work practices (representative, cyclical, etc); comparisons with exposure
standards: calculations for mixtures, taking into account synergistic/additive effects, etc;
comparisons with biological standards; comparisons with previous results; measurements
reviewed against LEV performance tests, or PPE selection and usage, or results of health
surveillance.
Question 9
A parcel sorting depot is experiencing a high number of manual handling related
injuries. The employees handle a large number of different parcels and
packages each day.
(a)
(b)
(c)
Identify the different types of hazard that may be inherent in the loads
being handled.
In order to reduce the manual handling the employer has decided to
invest in a range of non-powered handling devices, (eg trolleys, trucks,
etc). Explain what steps should be taken when selecting such devices
and introducing their use.
Outline a range of other control measures that could be introduced to
further minimise the risks associated with manual handling.
(6)
(10)
(4)
This was a very popular question which produced some excellent answers. The different
types of hazard that candidates identified included: weight of load and the fact that the
weights would be unknown; parcels may be difficult to grasp, as they are likely to be smooth
with no hand holds with unstable contents which are likely to move or with the centre of
gravity not in the centre of the parcel; awkward shapes would be common or parcels that are
too large for the handler to see over; sharp edges or corners and their contents may spill out
(and may have hazardous contents).
17
Better answers spilt this into two sections, dealing with selection and introduction separately.
Selection of such devices requires: consulting employees and safety representatives in
selection and trials; seeking advice on suitability from suppliers; request equipment on trial
basis, if possible to check it solves the problem without creating new problems; seeing it in
use at other organisations; consideration of maintenance requirements; ensuring the
proposed use will be within the safe working load of the device; ensuring there is sufficient
room to manoeuvre; suitability regarding the terrain in terms of stability and ground surface
(eg type of wheels); appropriate braking controls; adjustable handle height between waist
and shoulder; correct design to prevent parcels falling off. Introduction requires
consideration of operator training; storage; maintenance arrangements and ensuring there
are a sufficient number available.
Other control measures candidates could have considered were: changing the workplace
layout to reduce carrying distances, twisting and stooping and avoiding lifting from floor level
or above shoulder height; varying the work, duration and pace; marking up loads with
information (weights/heavy end, etc); introduction of mechanical assistance (conveyers, fork
lifts, etc); using team lifting where appropriate and manual handling training.
Question 10
Drug and alcohol misuse can adversely influence performance at work, even
when the misuse takes place outside of the workplace.
(a)
(b)
(c)
Outline specific signs that an employer can look for when attempting to
identify if an employee has a drug or alcohol misuse problem.
(7)
As a health and safety advisor you have been asked to prepare a
company policy on drug and alcohol misuse. Outline the key points that
such a policy should include.
(10)
Identify the types of circumstances in which an employer may consider
using drug screening and testing as part of their approach to managing
drug and alcohol misuse.
(3)
This was another popular question which produced good answers from many candidates.
Signs that an employer could look for include: sudden mood change, unusual irritability,
aggression or erratic behaviour; a tendency to become confused; abnormal fluctuations in
concentration and energy; impaired job performance and increased accidents; poor timekeeping; increased short term sickness absence; deterioration in relationships with
colleagues, customers or managers; dishonesty or theft; smell of alcohol; slurred speech
and poor coordination; change in appearance (becoming scruffy, where previously the
employee had been well groomed); appearance of needlestick marks (or covering of limbs to
hide them).
Candidates who concentrated their answer on alcohol limits of a policy produced narrowly
focused answers in the second part of the question. However, many candidates produced
reasonable answers that considered points such as: a general statement of aims, for
instance – the employer expects all employees to ensure that drug misuse does not have a
detrimental effect on their work; responsibilities for carrying out the policy (managers,
employees, occupational health counsellors etc and who is covered by the policy
(employees, contractors, visitors etc); a definition of drug misuse that includes misuse of
prescription drugs as well as prohibited drugs; statement of rules such as: no lunch time
drinking, with any exceptions such as Christmas or other celebrations included; any support,
or help, that will be available to employees who have a drug or alcohol problem; recognition
that treatment may result in absence which will be treated as normal sick leave; statement
assuring confidentiality; clear statement when disciplinary action may result (for instance if
help is refused, if impaired performance continues, or in cases of gross misconduct; the
Company’s response to possession or dealing illegal drugs in the workplace; and the
Company’s approach to drug screening.
18
The third part of the question was generally well answered with relevant circumstances
identified including: where drug misuse has been identified as a problem, which could be via
signs identified in (a) or whistleblowing; as part of the job selection process; in a safety
critical role; after an accident which shows drugs or alcohol might be a factor; or as art of a
rehabilitation or return work programme.
Question 11
A soft drinks manufacturer employs 400 people undertaking a range of different
jobs including production, warehousing, delivery and administration. It has
been noted that there are significant risks to staff from noise, manual handling /
ergonomic issues and pressure of work and also high levels of sickness
absence.
(a)
(b)
Outline the benefits, composition, role and possible functions of an
Occupational Health Service within this organisation.
What contribution could an Occupational Health specialist make in
addressing the risks to staff from stress, manual handling / ergonomic
issues and noise?
(12)
(8)
Candidates who produced specific, structured answers were able to gain high marks for this
question. Benefits of an Occupational Health Service include: legal compliance where health
surveillance is required; sick absence management leading to a reduction and therefore
saving money; contributing to risk assessment process; providing advice on occupational
health controls and competent advice in specialised areas; and it is often seen as
independent from the employer. The composition will depend on the actual activity of the
organisation but might include: an occupation health physician and nurse; a screening
nurse; physiotherapist; occupational hygienist; counsellor or psychologist; manual handling
trainer; and an ergonomist. The role and function includes: training on occupational health
controls; pre-employment screening; health surveillance and record keeping; fitness to work
assessments; sick absence reviews; counselling; rehabilitation; testing and monitoring (eg
audiometry); immunisation; liaison with GP, or enforcing agency; and health promotion.
The contribution the specialist could make in relation to:
ƒ
ƒ
ƒ
stress include: rehabilitation; counselling; and in carrying out risk assessment and
ensuring control measures are reasonable
manual handling / ergonomic issues include: assessment and control; physical
competency of workers; eye sight screening and rehabilitation
noise includes: noise assessment, control and audiometry.
In all cases the specialist could contribute to training, monitoring and managing sickness
absence.
19
UNIT C – Workplace and work equipment
General comments
Unit C of the Diploma addresses the technical aspects of safety and this paper is therefore designed to test
candidates’ knowledge and understanding of some of these technical issues. While some candidates met
the challenge admirably (nearly all questions attracted answers that gained full marks), there were many that
showed confusion and a lack of technical knowledge. Overall, there was much reliance placed on general
and generic statements that neither demonstrated the level of technical understanding required nor, very
often, addressed the specific question being asked. As a result, the question that produced the highest
average mark (Question 9, on Forklift Trucks), was one that centred largely on procedural rather than
technical matters. In questions where a greater amount of technical content was required (eg. Question 4 on
electrical risks and Question 8 on properties of LPG and their links to precautions for safe storage), then
candidates fared less well. Question 1, where a significant number of candidates discussed design features
of the building rather than a fire evacuation procedure, and Question 2 where some candidates discussed
BLEVEs and flash points provided examples of candidates not answering the question asked
Also evident from many candidates’ scripts was a lack of knowledge of specific legal requirements and the
terms used in legislation. This problem came to the fore in answers to Question 5 on designer’s duties under
CDM.
Section A – all questions compulsory
Question 1
Outline the issues that need to be addressed when planning a fire evacuation
procedure for an office building occupied by a number of different companies.
Your answer should include examples where appropriate.
(10)
An initial issue to be addressed would be the means of raising of the alarm when a fire or
other emergency is discovered and the summoning of the emergency services. In order to
achieve the safe evacuation of both employees and members of the public (some of whom
may have sensory or physical disabilities), consideration would have to be given to physical
measures such as travel distances and alternative routes, emergency lighting, clear signage
of exit routes, refuges and evacuation equipment – as well as procedural measures such as
clarifying staff responsibilities, training fire wardens, accounting for personnel and providing
door marshals to prevent entry or re-entry to the office building. Security considerations
such as minimising the opportunity for theft would also be an issue here.
Liaison with the emergency services should form part of the planning process. They can
help with advice on issues such as response times, their access requirements and
appropriate locations of assembly areas. There should also be liaison with neighbouring
businesses that could be affected by an emergency within the store. The procedures, once
drawn up, would need to be summarised on prominently displayed fire notices and tested
with regular fire drills.
This question was generally well answered with most candidates demonstrating an
understanding of the key issues that need to be addressed when planning an evacuation
procedure in a fairly complex situation.
20
Question 2
The investigation of an accident at a food processor handling corn starch
products concluded that the explosion had taken place in two stages, a
preliminary explosion followed by a more severe secondary explosion.
(a)
(b)
Identify the principles underlying the control measures that may be
needed to prevent or minimise the effects of such an accident.
(3)
For each of principles identified, suggest control measures which are
based upon the principle.
(7)
Examiners were not sure whether candidates who discussed BLEVEs and flash points did
not read the question properly or simply had no understanding of dust explosions. Principles
that were successfully identified were: elimination of sources of ignition; limitation of dust
cloud generation and minimising harm by controlling explosion. For the second part of the
question control measures that could have been suggested to eliminate ignition sources
were: to ensure electrically conducting safety footwear is worn; the use of non sparking tools
and correctly rated Ex electrical equipment; no smoking; prevention of equipment hot spots;
magnetic extraction of rogue ferrous metals; electrical bonding and earthing; and carrying
out an assessment to meet the requirements of DSEAR and correct zoning of areas.
Dust cloud suppression could be achieved by damping down combined with the use of a
pressure monitoring device; having LEV at point of transfer; use of an interlock to prevent
overfilling of silo; good housekeeping to prevent dust build up and ensuring all ducting is
dust tight.
Controlling explosion could be by use of: equipment that is able to withstand explosion;
explosion relief venting and explosion panels; ensuring building integrity.
Question 3
Outline the main design features of a workplace designed to reduce the risk of
injury associated with internal transport.
(10)
A number candidates wasted time discussing behavioural and vehicle issues, training and
maintenance when this was a straightforward question about design of a workplace.
Features that could have been included are: those that segregate vehicles and pedestrians,
including separate pedestrian access and egress; inclusion of passing places; protection of
racking to reduce the likelihood of items falling; lighting; barriers and raised walkway; convex
mirrors on blind corners; suitable road surfaces; edge protection on loading bays; design of
layout to avoid sharp bends and blind corners and to avoid the need to reverse; designated
crossing places for pedestrians; lighting of transition areas between inside and outside to
avoid glare and to ensure the workplace is wide enough for foreseeable types of vehicle that
will use the area.
Question 4
(a)
(b)
Identify the particular aspects of a working environment that may
increase electrical risks.
(5)
Outline the means by which protection is afforded by, and the limitations
of, the following:
(i)
intrinsically safe equipment
(ii)
flame proof electrical equipment.
(5)
Part (a) was generally well answered but there were many poor responses to part (b) where
candidates were unable to apply the principles of intrinsically safe or flame-proof.
21
Aspects of the working area that successful candidates identified in (a) were: where the
environment exposes equipment to mechanical damage such as impact, stress, abrasion,
wear, or vibration; working outdoors where equipment is exposed to changes in the weather;
high/low temperatures; contaminants (water or corrosive atmosphere); flammable
atmosphere (vapour, gas or dust).
The protection afforded by intrinsically safe equipment: is based on the restriction of
electrical energy within the equipment such that it is insufficient to cause a spark or heating
effect. However, faults may raise energy levels above the safe limit.
Flame proof equipment is of substantial construction and enclosed so that, although a
flammable atmosphere may enter, it is able to withstand the pressure of an internal
explosion and prevent the ignition of any flammable atmosphere that surrounds the
equipment. Flame proof equipment may not be suitable for use with combustible powders or
dusts, and may require special measures to prevent the ingress of water.
Question 5
(a)
(b)
Outline the duties of designers under the Construction (Design and
Management) Regulations 1994.
(6)
Explain the importance of the designer’s role to health and safety.
(4)
Designers duties are: to inform client of client’s duties under CDM Regulations and the
requirements of the accompanying ACOP; to ensure that the design considers the need to:
avoid foreseeable risks to construction workers and cleaners, and others affected by the
work of such persons; to combat at source risks to the health and safety of construction
workers and cleaners, and others affected by the work of such persons; to give priority to
measures that protect all, not just individuals; to ensure that the design includes adequate
information about hazards; to co-operate with the planning supervisor and with other
designers. Good responses also made reference to the fact that the designer’s duty applies
at all times.
Good responses explained the importance of the designer’s role in terms of: the ability to
design out hazards from start (elimination); specifying safer materials and construction
methods; designing the building to be safer to use and maintain; providing key information
for the health and safety plan and file.
Many poor responses to this question were noted by Examiners, this was very disappointing
considering candidates should have knowledge of this topic as part of their prior learning at
level 3 (shown as blue in the Diploma Guide).
Question 6
Outline the factors that should be considered to ensure the safe operation of a
bench-mounted circular saw.
(10)
This question sought the application of machinery safety principles to a specific item of work
equipment. Unfortunately, many candidates gave very general answers and hence obtained
poor marks. Good answers included reference to the need for the correct operation and/or
adjustment of the top guard, the effective guarding of the blade beneath the bench, the use
of a push-stick to feed through the material being sawn, the riving knife correctly positioned,
and the correct selection, maintenance and adjustment of the blade. More general issues
related to a suitable risk assessment, training and competence of operators, the provision of
a local exhaust ventilation system, use of personal protective equipment (eg goggles and
hearing protection), sufficient space around the machine that is kept free of obstruction, the
provision of emergency stops and means of isolation, adequate lighting, stability of the
machine and the need for maintenance.
22
Section B – three from five questions to be attempted
Question 7
(a)
With reference to the Pressure Systems and Safety Regulations 2000
explain what is meant by a ‘pressure system’.
(4)
(b)
Describe common causes of structural failure in pressure systems.
(8)
(c)
Outline the technical and procedural measures to minimize the likelihood
of failures in pressure systems.
(8)
A "pressure system" is a system comprising one or more pressure vessels of rigid
construction, any associated pipework and protective devices; the pipework with its
protective devices to which a transportable pressure receptacle is, or is intended to be,
connected; or a pipeline and its protective devices, which contains or is liable to contain a
relevant fluid, but does not include a transportable pressure receptacle. Better responses
included examples of a ‘relevant fluid’, such as: steam; a liquid which has pressure. 0.5 bar
above atmospheric at temp of liquid or 17.5 C; a fluid or mixture of fluids which is at a
pressure greater than 0.5 bar above atmospheric pressure, the fluid being either a gas, or a
liquid which would have a vapour pressure greater than 0.5 bar above atmospheric pressure
when in equilibrium with its vapour at either the actual temperature of the liquid or at 17.5
degrees Celsius; or a gas dissolved under pressure in solvent contained in a porous
substance at ambient temp and which could be released from the solvent without the
application of heat.
The second part of the question required candidates to identify possible modes of failure
such as excessive stress, abnormal external loading, overpressure, mechanical damage or
ductile failure; overheating; mechanical fatigue; thermal fatigue; brittle fracture; creep;
hydrogen embrittlement at welding re[pairs; corrosion; water/steam hammer and caustic
embrittlement. In some cases candidates dealt with only one or two possible failure modes
and thus restricted the number of marks that could be awarded.
The second part of the question required candidates to look at the design, operation,
inspection, test and maintenance requirements that would be needed to minimise the risk of
structural failure. This was generally well answered. Reference was needed to: the design
specification being correct (fit for purpose, CE marking etc); specific safety features
(pressure relief valves, level sensors, etc), quality control during the manufacture, inspection
and maintenance arrangements (including statutory examination and the scheme of
examination being prepared by a competent person); the role of non destructive testing;
ensuring that the vessel operates within its performance envelope and, in the case of
boilers, the filtering and treatment of water; and the training of personnel.
Question 8
The physical and chemical properties of liquified petroleum gas (LPG) dictate a
number of precautions which should be taken in the storage of LPG in cylinders.
(a)
(b)
Select four of these properties and explain how one of the precautions is
related to each property.
(8)
Give, with reasons, additional precautions for the safe storage of LPG in
cylinders.
(12)
The properties that candidates selected include: LPG is a flammable gas at standard temp
and pressure; it is denser than air; escape clouds cool and therefore are not buoyant on
thermal diffusion; liquid releases float on water; the lower explosive limit (LEL) is reached
with small concentrations of LPG; it is slightly anaesthetic and suffocating in high
concentrations.
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Precautions for the safe storage of LPG in cylinders include: preferably stored in the open
air; minimize quantity; elimination of ignition sources (no smoking, intrinsically safe /flame
proof electrical equipment); only electrical apparatus for use in Zone 2 area should be
allowed in storage area or within separation distance; provision of signage with ‘extremely
flammable’ warnings; dry powder extinguishers at storage location; control of combustibles;
removal of vegetation around storage area (not sodium chlorate weed killers / other oxidising
agents); floors should be concreted; any slope away from stored materials; empty cylinders
stored separately from full with valves shut; cylinders stored upright; protective caps kept in
place on valves; segregated from oxygen cylinders (3m); storage compound should be
protected from vehicle impact; storage situation greater than 3m from cellars, drains or
excavations and protected from the elements; if more than 400kg stored must have 2m high
mesh fence, 2 exits, with cylinders at least 1.5m from fence; any store room must be: non
combustible or fire resistant and ventilated with an explosimeter installed.
This was not a popular question, answers given to part (a) were generally poor, answers to
part (b) were better, although a number of responses discussed bulk storage, whereas the
question refers to cylinders.
Question 9
(a)
Outline the causes of instability in fork lift trucks (FLT).
(b)
Describe the different stages of training which FLT operators should
undergo if they are to be able to use a variety of fork lift trucks.
(7)
Give three situations in which refresher training for fork-lift truck drivers
would be appropriate.
(3)
(c)
(10)
Good responses discussed the causes of stability in fork lift trucks under the headings of
lateral and longitudinal instability. Causes of lateral instability could be due to: having an
insecure load; driving laterally on slope (factors; angle of slope, elevation of load); hitting low
obstruction (eg kerb); driving on uneven ground; cornering (eg fast, sharp); or the poor
condition of tyres or incorrect tyre pressure. Causes of longitudinal instability included:
overloaded vehicle; incorrect positioning of load on forks; load slipping forward (often as a
result of the mast not being tilted back); driving with load elevated or changing tilt; travelling
with loads forward down slope, or reversing with load up slope; sudden braking or striking an
overhead obstruction
Training should include the following stages:•
•
•
Basic training
Specific job training, relating to the FLT to be used
Familiarisation training at the workplace, under supervision.
Basic training covers the skills and knowledge relevant to the type of fork lift truck; the risks
arising from FLT operation; maintenance and checks. This is undertaken off site or in a
dedicated area.
Specific training should also be undertaken off site or in a dedicated area. This training
covers knowledge and operating principles of truck to be used; use of truck in conditions met
in the workplace; on-site rules; work to be undertaken and safe systems of work.
Familiarisation training is undertaken on site and covers: the application of skills already
learned; familiarisation with the site layout and local emergency procedures.
Refresher training would be appropriate where operators: have not used trucks for some
time; have been involved in an accident or near miss; have developed unsafe working
practices; where there has been change in working practices or environment; subject to
company policy have regular refresher training. Operators who are only occasional users
would probably require refresher training more frequently than those who operate fork lift
trucks on a daily basis.
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This was a very popular question, with good responses to parts (a) and (c). Many candidates
had difficulty identifying the three stages of training. All parts of this question are identified as
prior learning at level 3 (identified in blue in element C7 in the Diploma Guide).
Question 10
(a)
(b)
(c)
Outline the dangers against which protection is provided by a fuse in an
electric circuit and explain how such protection is achieved.
(3)
With respect to UK mains voltage electricity, describe the methods and
devices other than fuses designed to improve electrical safety.
(11)
Describe the precautions which should be taken when maintaining or
repairing electrical systems.
(6)
This question was generally well answered with candidates outlining that a fuse: prevents
overload of electrical systems and overheating of electrical wiring; limits shock under severe
fault conditions; limits over-current and chives this by the heating effect of electric current
which melts the metal link if the current exceeds the design value, breaks the circuit and this
remains broken until the fuse is replaced.
Other than fuses other methods and devices described were miniature circuit breakers,
residual current devices and reduced low voltage systems.
Descriptions of miniature circuit breakers included that they involved close tolerances for
design current flow and speed of operation; provide visual detection following operation;
need to be reset after fault detection; are reliable and are a system protection system.
Residual current devices (RCDs) or earth leakage circuit breakers (ELCBs) are designed as
shock limiting device, not for system protection; a shock is still received but time current
flows through body is limited; monitors balance of current flow in line and neutral; operates
on earth leakage fault; live and neutral disconnect from local power supply.
Reduced low voltage systems such as 110v/50v/25v with transformer supply centre tap to
earth consist of: earthed systems and class 1 equipment, or double insulated class 2
equipment and require procedural measures to be followed.
Precautions for maintaining or repairing electrical systems candidates included were:
identifying the apparatus to be worked on; obtaining system drawings and information;
considering whether working can be done dead and if so; following a safe system of work
for working dead including isolation and lock off; testing for dead; testing test equipment. If
however it is unrealistic to work dead then a safe system for live work includes: screening
any conductors near to work if it is reasonable for them to be live; testing live conductors
through holes for test probes; using suitable test equipment; having testing arrangements in
place for testing equipment - before and after; consideration of accompaniment;
consideration of insulating PPE and insulated tools; adequate working space and lighting.
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Question 11
As part of its water treatment system, a manufacturer is to install a plant
suitable for the reception and storage of sulphuric acid and caustic soda, both of
which will be delivered in bulk tankers. Both of these substances are highly
corrosive and can react together violently.
Outline the safety provisions required for:
(i)
the design,
(10)
(ii)
the operation and
(6)
(iii)
the maintenance
(4)
of the proposed storage facility.
This was a very popular question concerning the design, operation and maintenance of bulk
acid and alkali storage facilities. It was reasonably well answered by the majority of
candidates but those who divided the question into its component parts (ie design, operation
and maintenance) and tackled the detail of each of those issues in turn, achieved more
success.
Under design issues it was expected that candidates would deal with the material to be used
for the construction of storage tanks and pipe work; the layout of the storage facility; the
design and positioning of delivery inlets to prevent connection being made to the wrong tank;
bunding of the tanks; the fitting of level indicators and high-level alarms to prevent overfilling;
vehicle access; lighting and labelling and arrangements for spill containment.
Operational issues should have included the introduction of a safe system of work including
emergency procedures to deal with spillages, training the personnel involved including
tanker drivers, and providing personal protective equipment such as chemical suits,
chemical resistant gloves and full face protection.
In outlining the provisions for maintenance, candidates should have referred to
arrangements for the examination and testing of safety-critical plant, permit to work systems,
cleaning and isolation before maintenance work is started, regular bund cleaning and the
provision of training to maintenance staff in emergency procedures.
Many candidates missed marks because they resorted to generalisations such as ‘suitable
bunding’ instead of indicating the relationship between bund size and tank volume. In
answering an “outline” question, candidates must provide additional detail to obtain the
marks available. A number of candidates spent some time dealing with precautions for
flammable liquids which were not relevant to this scenario.
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The National Examination
Board in Occupational
Safety and Health
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Meridian Business Park
Leicester LE19 1QW
telephone +44 (0)116 2634700
fax +44 (0)116 2824000
email info@nebosh.org.uk
www.nebosh.org.uk