B3-CONTROLS AND PPE

Question 1

What are the 8 Principles of Good Practice

Answer 1

Design and operate processes and activities to minimise emission, release and spread of substances hazardous to health.

Take into account all relevant routes of exposure – inhalation, skin and ingestion – when developing control measures.

Control exposure by measures that are proportional to the health risk.

Choose the most effective and reliable control options that minimise the escape and spread of substances hazardous to health.

Where adequate control of exposure cannot be achieved by other means, provide, in combination with other control measures, suitable personal protective equipment.

Check and review regularly all elements of control measures for their continuing effectiveness.

Inform and train all employees on the hazards and risks from substances with which they work, and the use of control measures developed to minimise the risks.

Ensure that the introduction of measures to control exposure does not increase the overall risk to health and safety.

Question 2

Additional controls for Carcinogens, Mutagens and Asthmagens

Answer 2

COSHH Reg 7(5): Where not RP to prevent exposure:

(a) Totally enclose process and handling systems (unless not RP).
(b) Prohibit eating, drinking and smoking in areas that may be contaminated by carcinogens or mutagens.
(c) Clean floors, walls, etc. regularly.
(d) Designating potentially contaminated areas and using warning signs.
(e) Safe storage, handling and disposal, including using closed and clearly labelled containers.

Question 3

“Adequate Control” for carcinogens, mutagens and asthmagens

Answer 3

COSHH (Reg 7) states that control of exposure to most hazardous substances will only be treated as adequate if the:

appropriate Workplace Exposure Limit (WEL) is not exceeded; and

eight “principles of good practice” have been applied.

Stricter Control for Carcinogens, Mutagens and Asthmagens

Regulation 7 requires a stricter level of control where:

the substance is either carcinogenic /mutagenic (R45, R46, R49 or is listed in Schedule 1 of COSHH);

or can cause occupational asthma (R42, R42/43 or is listed in Section C of “Asthmagen? Critical Assessments of the Evidence for Agents Implicated in Occupational Asthma”).

Then control of exposure to the hazardous substances will only be treated as adequate if:

the appropriate WEL is not exceeded;

the eight “principles of good practice” have been applied;

and

exposure is reduced to as low a level as is reasonably practicable.

Question 4

The hierarchy of controls of COSHH regulation 7

Answer 4

Eliminate exposure

Substitute the substance

Modify work

Total enclosure

Engineering controls

Minimise numbers exposed

PPE

Question 5

Three main types of asbestos commonly used were:

Answer 5

Crocidolite (blue).
Amosite (brown).
Chrysotile (white).

Question 6

Common Illnesses from Asbestos

Answer 6

Asbestosis
Lung Cancer
Mesothelioma
Diffused plural thickening

Question 7

managing asbestos in non-domestic premises reg 4 of car

Answer 7

The duty holder must:
Carry out an assessment - to identify ACMs, their location and condition.

Assume that materials are ACMs - unless evidence that they are not.

Keep an up-to-date register of ACMs, their location and condition.

Assess the risks - of exposure to fibres from these ACMs.

Establish a plan - to manage these materials.

Provide information - to anyone likely to work on or disturb the ACMs (e.g. contractors).

Monitor and review - the assessment and plan

Question 8

Outline Asbestos Surveys

Answer 8

Management survey:
should be carried out to identify the asbestos risk for normal day-to-day occupation and maintenance of the building,
normal non-invasive (i.e. materials are not removed or damaged during the survey
samples may be taken for analysis.

Refurbishment and demolition survey:
should carried out if there is planned upgrade, refurbishment or demolition work on premises where ACMs potentially exist.
is normally invasive and destructive premises must be vacant before it can take place; and cannot be re-occupied until certified as fit for re-occupation.

Question 9

MANAGEMENT PLAN

Determined by the condition of the ACM?

Answer 9

Good condition - label but leave undisturbed.

Damaged but acceptable – cover, encapsulate or otherwise make safe, label and leave in place.

Poor condition or likely to be disturbed – remove.

Question 10

State the criteria when work with asbestos can be considered to be ‘unlicensed’.

Answer 10

Sporadic exposure and low intensity, risk assessment shows the control limit is not exceeded,

short maintenance activities,

asbestos fibres are firmly linked,

sealing ACM’s that are in good condition, air monitoring, collection and analysis of samples

Question 11

CONTROL MEASURES FOR ASBESTOS

Answer 11

Carry out a risk assessment.

Prepare a written plan of work.

Only carry out licensed asbestos work if he holds a licence – note exceptions.

Notify the enforcing authority at least 14 days before licensed work starts (some non-licensable work also notifiable).

Provide information, instruction and training.

Prevent or reduce exposure to asbestos.

Ensure that control measures are used.

Maintain control measures.

Provide protective clothing.

Prepare and practise procedures to deal with accidents, incidents and emergencies.

Prevent or reduce the spread of asbestos.

Ensure premises and plant are kept suitably clean.

Ensure work areas are designated and marked as asbestos areas or respirator zones as appropriate.

Carry out air monitoring.

Ensure that any air monitoring carried out is done by suitably accredited persons using the approved standard method.

Carry out health surveillance for all workers who undertake licensed work.

Provide adequate washing and changing facilities.

Ensure that ACMs are appropriately stored and disposed of.

Question 12

CONTROL LIMITS FOR ASBESTOS

Answer 12

In the UK limits are established by the Control of Asbestos Regulations 2012:

The control limit is 0.1 fibres cm3 of air averaged over a continuous period of 4 hours.

Sporadic and of low intensity means that the concentration of asbestos in the air does not exceed 0.6 f/cm3 measured over 10 minute period

Question 13

How does a LEV (Local exhaust ventilation) System operation?

Answer 13

Operate by removing contaminated air at the point of generation and ducting it away from work areas. The contaminated air might then be cleaned and is then exhausted to atmosphere.

Question 14

LEV System Types – by Hood Design

Answer 14

Enclosing Hood

Receiving (Receptor) Hood

Capturing (Captor) Hood

Question 15

LEV General Principles of Hood Design

Answer 15

Enclose the source as much as possible.

Position the hood as close as possible to the source.

Take advantage of speed and direction of contaminant.

Match the hood size to the process and cloud size.

Keep contaminant away from worker’s breathing zone.

Minimise eddies within the hood.

Make sure the hood is practical and comfortable to use.

Trial and test before putting into full use.

Question 16

LEV DUCTING

Answer 16

As straight as possible (to maintain laminar flow).
Gentle bends and acute angle joins.

Well supported.
Sufficient airflow to prevent deposition of solids.
Access ports for regular cleaning.

Question 17

LEV FILTER OR PURIFYING SYSTEM:

Answer 17

Must be appropriate.

Toxic gases may need to be neutralised.

Particulates often removed by cyclone or bag filter.

Explosion risk may exist with dusts or vapours/gases.

VARIOUS AIR CLEANING DEVICES CAN BE USED:

PARTICLE COLLECTORS:
Fabric filters.
Cyclones.
Electrostatic precipitators.

GAS/VAPOUR COLLECTORS:
Thermal oxidisers (destroy solvents).
Scrubbers (remove contaminants).
Recovery units (collect and reclaim).

Question 18

LEV FANS AND MOTORS:

Answer 18

Correct type for the system.

Correct capacity:
Sufficient power.
Margin for overloads.

Centrifugal fans are typical.

Question 19

LEV DISCHARGE TO ATMOSPHERE:

Answer 19

Discharged air must not re-enter buildings until diluted down to negligible concentrations.

Discharge is normally via a ‘stack’.

Emissions to Atmosphere:

Extracted air must not re-enter building.

Question 20

SOURCE STRENGTH, CAPTURE ZONES AND CAPTURE VELOCITY

Answer 20

SOURCE STRENGTH: Combination of the volume rate of release of the contaminant cloud, the cloud volume, shape and speed and the contaminant concentration.

Worker exposure depends on many things including: source strength and distance from source

CAPTURE ZONE - the area around the inlet to the LEV system that the system is extracting contaminated air from.

CAPTURE VELOCITY – the air velocity required at a contaminant source to overcome the movement of the contaminant cloud and draw it into the hood.

Question 21

LEV Testing statutory

Answer 21

Engineering controls such as LEV are subject to statutory examination and test:
COSHH - 14 months
CLAW -14 months
CAR - 6 months
By a competent person.

Question 22

Proof of competence for LEV testing

Answer 22

Proof of competence might mean qualified through:

British Occupational Hygiene Society (BOHS),

Chartered Institution of Building Service Engineers (CIBSE) or

Institute of Local Exhaust Ventilation Engineers (ILEVE).

There is a UKAS accreditation scheme for LEV Thorough Examination and Test (TExT

Question 23

Sources of Information available to the examiner:

Answer 23

LEV system commissioning report.
LEV user manual.
System logbook.
Previous LEV system statutory report. 
Confirmation that there have been no changes to the LEV, layout or process since the last test.

Question 24

Stages of LEV testing (Big question, might take a while to get head round it)

Answer 24

Stage 1 – Thorough Visual and Structural Inspection of LEV

Examination of:

All external parts of the system for damage, wear and tear.

Internal duct and hatch seals.

Filter material and any built-in filter pressure gauges.

Filter cleaning devices to ensure they work properly.

Water flow and sump in a wet scrubber.

Monitors and alarms fitted to the system.

The fan and associated drive mechanism, e.g. fan belt.

Three Stages to Carrying Out TestingStage 2 – Measuring Technical Performance

Quantitative methods are used to measure the technical characteristics of the LEV system for comparison against its design specification:

Transport velocity and duct velocity.

Static pressure.

Face velocity.

Transport Velocity
The air velocity required to convey particles and prevent deposition in ducts.
Duct velocity can be directly measured using pitot tube.

Static Pressure
Difference between inside and outside air.
Measured using pressure gauge:
Manometer.
Diaphragm gauge.

Face Velocity
The average velocity of air at the open front face of a hood or booth.
Measured using an anemometer.

The face of the inlet is divided up into an imaginary grid.
The air velocity is measured at the centre of each imaginary rectangle.
Readings can be averaged and each reading compared to the average to note the degree of variation.
Variations over 20% of average indicate that the airflow distribution is uneven and requires adjustment.

Three Stages to Carrying Out TestingStage 3 – Assessing Control Effectiveness

Qualitative techniques are used to assess the effectiveness of the LEV system. These often involve the visualisation of air movement using different techniques:

Dust lamp (Tyndall beam).
Smoke.

Dust Lamp (Tyndall Illumination)
A powerful light illuminates the dust cloud.
The cloud is viewed obliquely to the light beam and a screen is used to shield the lamp.
Cloud is observed directly or photographed.

Smoke
Smoke produced as a single cloud.

Used to visualise air movement.

Can be formed by:
Smoke tubes.
Smoke generators.
Smoke pellets.

Question 25

Report on LEV Test

Answer 25

Pass and fail labels may be used on the LEV.

LEV engineer will complete a report of their findings for the LEV owner.

Record of thorough examination and test contains:

Name and address of employer
Identification of the LEV, process, and substance

Date of last examination and test

Information about the LEV system:

• Intended operating specification
• Actual level of performance
• Any repairs required

Methods used in assessment

Question 26

What is PPE?

Answer 26

“…all equipment (including clothing affording protection against the weather) which is intended to be worn or held by a person at work and which protects him against one or more risks to his health or safety, and any addition or accessory designed to meet that objective”

Question 27

Statutory requirements of PPE

Answer 27

General requirements:
Personal Protective Equipment at Work Regulations 1992

Specific requirements for hazardous substances:
COSHH; (Control of substances hazardous to health)
CLAW; (Control of lead at work regulations)or
CAR (Control of asbestos regulations)

These regulations often establish the specific legal standard.

Question 28

Personal Protective Equipment at Work Regulations 1992

It is the employer’s duty to:

Answer 28

Supply suitable PPE to his employees where risks cannot be controlled by other more effective methods.

Ensure that when two or more items of PPE have to be worn together they are compatible.

Undertake an assessment of the suitability of PPE.

Ensure that PPE is maintained in proper working state (this includes cleaning or replacement).

Provide suitable storage accommodation for PPE when not in use.

Provide information, instruction and training.

Enforce the use of PPE.

Suitable= Appropriate for the risks involved, the conditions where it will be used and the duration of time over which it will be worn.

Takes account of ergonomic factors and the health of the user.

Fits the user.

Controls specific risk without increasing overall risk.

CE-marked and complies with any relevant standards (in accordance with the Personal Protective Equipment Regulations 2002).

Question 29

What Personal Protective Equipment (PPE) Should be Used When Working With Lead?

Answer 29

The worker must be properly trained in the use maintenance and storage of PPE.

If tight fitting respirators are used, the employer must arrange for face-fit testing to ensure it correctly fits the worker.

If disposable masks are used, the worker must be clean shaven and the employee must wear the mask properly otherwise the level of protection given will not be as good as expected.

Question 30

Different types of Respiratory Protective Equipment (RPE)

Answer 30

Respirators - use filters to remove contaminants from the air being breathed in, and can be either:

Non-powered respirators, relying on the wearer’s breathing to draw air through the filter.
Powered respirators, using a motor.

Breathing Apparatus (BA) - which supplies pure respirable air from an uncontaminated source.

Question 31

Factors to consider on the selection of RPE

Answer 31

Many factors have to be taken into account when choosing RPE:

Atmosphere-/substance-related factors.
Level of protection required and the Assigned Protection Factor (APF).

Task and work-related factors.
Wearer-related factors.
Quality-related factors.

Task and Work-Related Factors
Factors such as:
• 	Work rate.
• 	Duration of use.
• 	Temperature/humidity.
• 	Vision.
• 	Communications.
• 	Mobility and space constraints.
• 	Tools.
• 	Explosive atmospheres.

Wearer-Related Factors
• 	Fit and comfort.
• 	Beards.
• 	Spectacles.
• 	Facial markings.
• 	Compatibility with other PPE 
• 	Medical conditions

• Face fit testing
• Quality related (CE marking)

Question 32

The Need for RPE “Face-Fit” Tests

Answer 32

Many types of RPE rely heavily on a tight seal between the face and the face piece, e.g. filtering face piece, half-mask, full-face mask.

Not applicable to other types of RPE (e.g. powered hood/blouse).

Qualitative Fit-testing (for half-masks, filtering face pieces):
e.g. use of odour compounds (pass/fail).

Quantitative Fit-testing (recommended for full-face masks):Numerical estimate of “fit-factor”.Specialised equipment needed, e.g. negative pressure device.

Question 33

Glove Characteristics

Answer 33

Breakthrough time - the time a chemical takes to permeate through the glove material and reach the inside.

Permeation rate - the amount that then permeates through.

Degradation rating - indicating the deterioration of the glove material on contact with a specific chemical.

Question 34

Problems Associated with Use of Gloves

Answer 34

Loss of dexterity and tactile sensation.

Local heating of the hands/sweating.

Pin-holes.

Removal of glove during a hazardous operation.

Spilling chemicals down the sleeve of the glove/gauntlet.

Question 35

Other Methods of Hand/Lower Arm Protection

Answer 35

Use of Pre- and Post-Exposure Skin Cream

Barrier creams – where low risk but high dexterity needed.

Post exposure antiseptic hand creams - used as part of a good hygiene regime.

Question 36

Protection of Other Areas of Skin

Answer 36

Aprons (PVC).
Full suits (including hood) – PVC, “Tyvek” coveralls.
Lab coats.
Boots/wellingtons.
Etc.

Question 37

Eye Protection

Answer 37

BS EN 166 - Personal eye protection - specification

Spectacles
Mainly impact protection. Very limited protection for chemical liquid splashes (low risk areas only). Prescription type and “cover specs” available.

Goggles
Almost complete protection for eyes from liquids, mists, dusts (depending on the type). Some ventilated (anti-mist) types.

Full-face Visors
Eye AND face protection. Chin guards and use with goggles where high risk.

Question 38

Selection of Skin and Eye Protection Substance-related factors:

Answer 38

Type of protection required.
Level of protection required.

Task-related factors:
Duration of work.
Dexterity and durability.
Gloves and gauntlets.

Wearer-related factors:
Fit.
Compatibility.
Personal issues.
Wearer acceptability.

Quality-related factors:
Compliance with relevant standards.

Question 39

Storage and Maintenance of PPE

Answer 39

Protect from contamination
(locker/container).
Cleaned.
Check/inspect.
Maintain/repair (if maintainable rather than disposable).

Question 40

User Training for PPE

Answer 40

Risks the PPE is intended to protect against (including limitations).

How and when the PPE should be used.

How and when to clean, inspect, maintain or replace the PPE.

Requirements for storage of the PPE.

Question 41

When respiratory protective equipment is in use it may not provide the level of
protection stated by the manufacturer. Outline the possible reasons for this.

Answer 41

a poor air flow or a reduction in battery power;

the fitting of incorrect cartridges or a failure to replace them before saturation;

equipment incorrectly fitted or incompatible with other personal protective equipment being worn;

the presence of other contaminants resulting in a decrease in saturation time;

inadequate training in its use and particularly in the care that should be taken in its removal;

poor maintenance and inadequate storage resulting in the face piece being left exposed;

damage occurring during use and inadequate monitoring and supervision to ensure the equipment was always used when required and the fact that the equipment might not have been manufactured to the appropriate standards.

Question 42

A large manufacturer uses hydrochloric acid in a large open tank to remove rust from sheet steel. This creates acid mist in the immediate
work area and the company has decided to install a local exhaust ventilation (LEV) system.

This system consists of an inlet, ducting, air
cleaner, air mover and exhaust.

For EACH of the components listed above outline the design features required for the LEV system to be effective.

Answer 42

The hood would need to be of a suitable size to cover the tank and have a face velocity adequate to capture the acid mist.

Because of the acidic nature of
the contaminant, the ducting would have to be corrosion resistant, be smooth with
rounded bends, of size appropriate for the required transport velocity and provided
with access for testing and maintenance.

The air cleaner would probably be by means
of a wet scrubber, possibly in combination with an alkali neutraliser, with appropriate
means for disposing of effluent.

The fan, either axial or centrifugal, would need to be corrosion resistant, of sufficient power to provide the necessary extraction velocity and
be designed to minimise noise generation.

The exhaust outlet should be located following consideration of all environmental
implications including noise, should be corrosion resistant and should be fitted with a weather cowl and deflector baffles to prevent the entry of vermin.

Question 43

Explain the requirements of the Control of Substances Hazardous to Health (COSHH) Regulations 2002 for inspection and testing of the LEV system.

Answer 43

A periodic visual inspection of a local exhaust ventilation system together with a thorough examination and test must be carried out by a competent person at least once in every period of fourteen months.

A record of the examinations must be kept available for at least five years from the date on which they were carried out.

Question 44

The LEV system breaks down and will take a number of weeks to repair. In the meantime the employees will need to use respiratory protective equipment (RPE) to control their exposure to the acid mist.

Outline factors to be considered when selecting the RPE to protect the employees whilst engineers are repairing the LEV
system. (7)

Answer 44

its type either full face or half mask, the protection factor required, the selection of the
correct cartridges with respect to the acid mist and the battery life of the chosen
equipment.

Task related factors would also be important such as the degree of movement required by the wearer, their work rate, the compatibility of the respirators with other personal protective equipment such as eye protection and the comfort factor.

Cost factors would also have to be considered such as those involved in the maintenance and storage of the equipment and that which would be necessary to provide training for the user in fit testing for close fitting respirators.

Question 45

A grounds maintenance contractor is selecting eye protection to wear during grass strimming.

Describe the specific features of the eye protection required for
this task.

Answer 45

In carrying out the task described, the probability would be that impact might come
from a variety of directions and as a consequence goggles or a face shield should be selected as eye protection.

They would need to have good mechanical and impact strength, be shatterproof with medium energy impact (B), be adjustable to allow appropriate fit and comfort and be compatible with other personal protective
equipment such as hearing, head or respiratory protection.

Other possible features to be considered would be the optical class of the lenses and their resistance to misting and surface damage, and the resistance of the frames to dusts.

Finally the protection should be CE marked and comply with a recognised standard.

Question 46

Outline the arrangements the grounds maintenance contractor should put in place when the selected eye protection is in use.

Answer 46

once the selected protection is in use, arrangements should be made for
the provision of training in its use and its correct fitting with other equipment;

for the cleaning and storage of the equipment and for reporting defects and providing
replacements when these are seen to be necessary.

Additionally, measures should be taken to ensure that the protection is used at all times when grass strimming is being carried out with disciplinary action being taken for non-use.

Question 47

A welder undertakes work in an open plan workshop.

Outline the factors to be considered when selecting suitable Respiratory
Protective Equipment for this work.

Answer 47

Factors that should be considered when selecting respiratory protective equipment for
the welding work described include:

the type, duration and frequency of the work and its position in the workplace;

the fume control measures currently in place such as general or local exhaust ventilation;

the health hazard category of the welding fume for example whether toxic or irritant;

the level of protection (protection factor) required for each substance based on considerations such as the amount of the substance, the volatility of the welding consumables, the concentration and particle size and the relevant workplace exposure limits (WELs);

the choice of the equipment in relation to
the protection factor whether half face, full face or forced air breathing apparatus;

the choice of the correct filter type based on the determined protection factor;

task related factors such as the work rate and wear time, the presence of humidity, the need for mobility and communication and the amount of physical effort and degree of
movement required to carry out the task;

the fit and comfort of the equipment taking
into account facial hair and the need to wear spectacles;

the compatibility of the equipment with other personal protective equipment such as eye, head or hearing protection;

the heat resistant properties of the equipment; the battery life of specified types of equipment;

the cost of the equipment and the amount of training and maintenance required for its use;

the manufacture of the equipment to recognised standards and finally any relevant medical conditions of the potential user such as heart disease, asthma or claustrophobia.

Question 48

In relation to respiratory protection equipment (RPE):

Explain the meaning of `assigned protection factor’ (apf).

Answer 48

The assigned protection factor (apf) is a numerical value that indicates the “efficiency” of the RPE in terms of the effectiveness with which it reduces the concentration of the airborne contaminant that passes through the filter;

it is calculated as the ratio between the concentration of the contaminant in the air and the concentration within the face-piece when the RPE is worn.

The apf is derived experimentally from a survey of 10 subjects wearing RPE under laboratory conditions

Question 49

Explain why exposure levels to an airborne contaminant may be higher in practice than those theoretically obtained by the application of an “apf”.

Answer 49

Exposure tends to be higher than that predicted in theory from the apf data because of:

the lack of an effective seal between the RPE and the face of the wearer eg. due to perspiration;

facial hair;

face movements during work;

‘unusual’ face contours;

incompatibility with other PPE;

inadequate user training;

contamination of the RPE during storage, fitting and removal;

poor maintenance / failure to replace damaged or worn parts;

removal of the RPE for even short periods
(lack of supervision);

misuse of the equipment;

the laboratory tests of apf are “artificial” ideal conditions and are very different from the way the RPE may be worn / used in the workplace

Question 50

A slightly corrosive solution is used as part of a manufacturing process. The solution is applied by hand brushing.

Alternative methods of application have been found to be impracticable.

Outline the factors that should be considered in the selection of PPE (the PPE should ensure
that the skin and the eyes of those involved in the process are adequately protected).

Answer 50

Factors to consider in the selection of PPE include:

• requirements of PPE regs - in particular:
• the nature of the task - spray / droplets - skin & eyes
• the nature of the hazard - slightly corrosive
• the types of PPE required for the task(s) - eye protection; face / visor; gloves / gauntlets; aprons / whole body
• the need for PPE to be fit for purpose in relation to the (corrosive) hazard - CE marking / manufactured to an approved design standard eg designed for chemical resistance / breakthrough
• the need for the PPE to be compatible with other PPE / RPE / clothing
• the need to provide a range of sizes
• the comfort of the user
• duration of use
• levels of exertion
• need for dexterity and manoeuvrability
• need to ensure PPE does not introduce additional risk -

Question 51

List a range of practical measures (other than training), that can be taken to encourage the use of the PPE and maintain its effectiveness.

Answer 51

Use of PPE can be encouraged via:

• consultation / staff involvement in selection / user trials = acceptability
• making PPE readily available and accessible - ease of replacement
• providing a range of sizes
• PPE on personal issue rather than shared use
• use of posters / signs
• supervision and monitoring of useage - backed up by disciplinary action

Effectiveness can be maintained via:

• providing adequate facilities for cleaning and storing PPE
• keeping records of date of issue - hours of use etc
• ensuring regular inspection of PPE by a competent person

Question 52

An airborne contaminant has a Workplace Exposure Limit (WEL) of 40ppm, 8 hour time-weighted average (TWA).

Despite the introduction of a range of engineering controls the airborne
concentration of this contaminant in a workshop has been measured and has been found to be 160ppm, 8 hour TWA.

The local manager has chosen a piece of respiratory protective equipment
(RPE) with an assigned protection factor (APF) of 40 to be worn by all employees in the
contaminated area.

(a) Using the data above explain how you determine if the manager has made an appropriate choice
of RPE. (4)

The APF is a measure of the degree of protection provided by RPE. An APF of 40 indicates that the RPE gives a 40-fold reduction in the concentration of a contaminant.

Answer 52

The required APF is calculated by dividing the airborne concentration of the contaminant by the maximum concentration
to which the person may be exposed.

Concentration of contaminant in workplace air = 160ppm APF for RPE = 40 (ie RPE reduces airborne concentration by a factor of 40)

Therefore employee exposure when wearing the RPE will be 160/40 = 4ppm

This is 10% of the WEL so the level of protection is 10 x that required

So the manager has made an appropriate choice - but cost implication

Question 53

When respiratory protective equipment is in use it may not provide the level of protection stated by the manufacturer.

Outline possible reasons for this.

Answer 53

RPE may not provide stated level of protection because:

incorrect type for hazard - dust masks used
for vapours, wrong cartridge etc;

not used correctly - poor fit / inadequate seal - facial hair, jewellery
etc;

damaged / inefficient; contaminated - inadequate care / storage / maintenance;

cartridge saturated;

incompatible with or effectiveness reduced by other PPE;

low air flow in powered equipment - battery low etc;

effectiveness compromised by mixed exposures;

manufacturer figures are obtained in “ideal conditions”

Question 54

Assuming that suitable PPE has been selected, outline a range of practical measures that can be taken to ensure the correct use of the PPE and to maintain its effectiveness.

Answer 54

Practical measures to ensure that the PPE provided is regularly and correctly used:

give employees information on the hazards / risks associated with the work and how the PPE will give protection against these risks;

training on the correct method for putting on and fitting the equipment, how to remove it without contaminating themselves, how to recognise defects and damage, how to obtain replacements when needed and where and how to store the equipment when it is not in use;

management and supervisors setting an example by wearing it themselves and by enforcing use and when necessary using disciplinary measures (persistent offenders);

carrying out inspections of the equipment for damage, issuing replacements when needed and keeping records of the items that have been withdrawn and replaced;

periodic review of the selected items of equipment to check their compatibility and whether different models might be used to obtain combined protection such as for example for eye and respiratory protection;

gathering feedback, views of and
complaints from users.

Comment: PPE already selected so NOT consultation with the workforce, user trials etc

Question 55

An LEV system is used to reduce workers’ exposure to dust.

Identify three visual inspection methods that provide a qualitative assessment of the
effectiveness of the LEV system

Answer 55

Smoke bomb - smoke being drawn into system;

Tyndall light beam;

leak test - smoke escape;

build up of dust on surfaces;

signs of damage, corrosion

Question 56

Outline why transport (duct) velocity is an important parameter to measure when assessing the efficiency of a local exhaust ventilation (LEV) system.

Answer 56

Transport velocity is one quantitative measure of the effectiveness of an LEV system.

Transport (duct) velocity is an important parameter to measure when assessing the efficiency of an LEV system because the TV must be sufficient to keep particles / fumes / vapours moving through the system;

if this is not the case, then particles may settle out in the ductwork (sedimentation) and affect the overall efficiency of the system. Also increases fire risk.

TV is an indicator of how the pressure gradient within the system and therefore of how effectively the system
(fan etc) is working.

The actual TV required can be determined by considering the nature of the particles that the system is handling (eg size and density).

Question 57

A facilities manager of a multi-occupancy office block built in the 1970s is concerned about the risks associated with asbestos in the building.

Outline the steps the facilities manager should take to minimise risks associated with any asbestos that may be present in the
building.

Answer 57

The facilities manager should initially accept that his/her company is the duty holder
who has the responsibility to manage asbestos in the multi-occupancy building and
should assume that because of the age of the building that asbestos will be present.

He/she should therefore identify all materials in the building that might contain asbestos and arrange for a competent person to undertake a survey using intrusive
and destructive sampling to determine the presence or absence of the material.

A record would have to be kept of where asbestos containing materials (ACMs) are
located and updated following regular reviews of their condition.

The information should be made available to all tenants in the block.

Finally consideration would need to be given to what action was necessary to deal with the various ACMs whether to remove, repair, enclose or leave in place and an action plan drawn up once the decisions had been made

Question 58

An occupant of one of the offices engages a contractor to fit a hand dryer in a toilet which involves drilling through some asbestos insulating board.

Outline the required steps to be taken by the contractor to carry out this work, in accordance with the Control of Asbestos
Regulations 2006.

Answer 58

the work to be carried out was of short duration and therefore classed as non-licensed.

However, precautions would be necessary and whilst the work was being carried out, access to the toilet should be restricted, the door closed and a warning sign displayed.

The fixtures and surfaces in the toilet would have to be covered with a polythene sheet fixed with tape, paste or foam used to coat the drill entry point and a hand drill used to make the required hole which should then be lined or sleeved to prevent fibre release.

The paste would have to be cleaned off with damp cloths and all waste double bagged and disposed of as asbestos waste.

The complete area where the work was carried out and the equipment used would need to be cleaned down with a type H vacuum.

Reference should also have been made to the requirement for the person carrying out
the work to have been fully informed of its related hazards and the precautions to be
observed including the wearing of personal protective equipment such as disposable
overalls and the appropriate respirator.

Question 59

Explain the meaning of the term “carcinogen”

Answer 59

A carcinogen is an agent that has the ability to produce malignant tumours (cancer) by attacking the human cell reproduction mechanism, causing changes in the cells, such as abnormal cell formation and/or uncontrollable growth

Question 60

Outline the measurements 
that you would expect to 
have been taken as part of 
the examination and test of 
the LEV system.

Answer 60

Measurements that should have been taken in examining and testing the LEV system should have included:

 the face velocity across the hood or opening

 the capture velocity; the duct velocity

 the pressure drop across the filter or fan

 the static pressure in the hood or duct and the fan/motor speed

 the power consumption

Question 61

A26 Asbestos removal steps

Answer 61

1. Restrict access to work area. A two-stage airlock not required.
2. PPE: Type 5 disposable overalls with hood, boots without laces, and an FFP3, FMP3, or P3 respirator.
3. Remove furniture and fittings or cover with 500 gauge polythene sheet.
4. Cover drill entry and exit points with paste (such as wallpaper paste), foam (such as shaving foam), or a cowl attached to a Class H vacuum cleaner.
5. Drill slowly by hand-drill, or electric drill on slowest setting.
6. Clean off with damp rags before drill-hole edges are sealed with sealant.
7. Clean area with Class H vacuum cleaner and damp rags.
8. Decontaminate clothing before removal PPE (RPE last).
9. All waste double bagged and labelled as asbestos waste.