IB3 Flashcards

1
Q

Workers in a chemical plant are provided with gloves to protect against the possible effects of the chemicals. In recent months, there has been an increase in the number of hand and lower arm skin complaints among the workers.

Outline the possible reasons for this increase in skin complaints.

A
  • Potentially the wrong gloves, whch dont provide protection against chemical, are being used.
  • Duration of work undertaken wasn’t consider , PPE resist chemical “ atack” for limited period of time.
  • It is possible that the new chemical and /or work process has been introduced, to which these gloves offer inadequate protection.
  • The current gloves may be the wrong size or may fit poorly.
  • The glove may have been damaged by chemical (degraded) during use.
  • The gloves may have been accidentally damaged (e.g punctured) whilst in use or intentionally damaged e.g by removing a finger to improve dexterity.
  • Workers may have developed an allergy to the materials that the gloves made from e;g latex.
  • Workers may be suffering from excessive perspiration whilst wearing the gloves for a long time, causing irritation.
  • There may be a poor maintenance system, meaning that gloves are not replaced when damaged.
  • There may be poor decontamination and storage procedures so gloves are not stored away from contaminants.

•Workers may not have received training in:
How to put on and remove the gloves.
•The importance of carrying out personal checks on the gloves and their skin condition and reporting problems.
•The significance of good hygiene procedures
• The use of barriers and aftercare creams.

  • Finally, it is possible that supervision is inadequate to ensure that workers wear gloves at all times.
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2
Q

Dilution ventilation is sometimes used to control certain types of hazardous substances generated in a workplace.

(a) Outline circumstances when dilution ventilation may be appropriate as a control measure.
(b) Explain how an effective dilution ventilation system is designed and operates to reduce exposure to a hazardous substance.

Workshop dimensions (metres): 10m x 10m x 3m 
Volume of air throughput each hour: 3000m3
Required air changes per hour: 10 to 15

Calculate the actual number of air changes per hour AND comment on the suitability of the specified dilution ventilation system.

A

(a)
•The OEL of the harmful substance is high.
•The vapour pressure of any liquid hazardous substances is low, i.e. it has a low evaporation rate.
•The rate of formation of a gaseous product is slow.
•Operators are not in close contact with the contamination generation point. In particular the point of generation must be distant from any person’s breathing zone (a notional spherical zone in front of the person’s nose and mouth from which inhaled air is drawn into the lungs).
•A hazardous substance is carried swiftly away from the operator, e.g. by hot gases.

(b)
-Dilution ventilation operates by simply diluting the contaminant concentration to an acceptable level. This is achieved by efficiently changing all of the air in a workplace over a given period of time, i.e. air changes per hour.

-Dilution ventilation is sometimes achieved using a passive system, where natural air movement in a room or building is used. With active systems, workplace air is extracted by the use of fans set in the walls or roof

that clean input air mixes with contaminants to dilute the contaminant concentration, to Reduce the concentration below OEL, below its LEL

when dilution ventilation two criteria have to be considered:
•The first is the rate of contaminant generation and hence the number of air changes per hour required.
•The other criterion is the position of the extraction fans. factor that controls the positioning of the extraction fan unit is the density of the contaminant.
1d fan positioned high
•When fire hazard such as ether, motors should be flameproofed zone 1.
•Consideration has to be given formation of dead area can be detected by smoke tracer tubes.

(c)

10x10x3 = 300m3. The air throughput is 3000m3/hr, which means that, every hour a volume equivalent to 10 times (3000m3/300m3 = 10) the volume of the workshop passes through it. In other words, there are 10 ‘air changes’ per hour. This is just within the specification (10 - 15 air changes per hour) but a recommendation would be to increase the throughput so it is closer to 15 air changes per hour.

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3
Q

Workers in carpentry workshops and sawmills may be exposed to hardwood dust.
(a) Outline the risks to health from hardwood dust.
(b) Identify types of respiratory protective equipment (RPE) that could be used by the workers.
(c) Other than providing RPE, outline control measures that should be considered in order to protect those who are exposed to
hardwood dust.

A

(a) it can cause serious non-reversible health problems
- Both the skin and respiratory system can become sensitized to wood dust. When a worker becomes sensitized to wood dust, he or she can suffer severe allergic reactions (such as asthma or dermatitis) after repeated exposure or exposure to lower concentrations of the dust.
- Hardwood dusts can cause cancer (usually of the nose). that is why is considered carcinogens
- Other common symptoms associated with wood dust exposure include skin and eye irritation; nasal dryness and obstruction;cavity and upper respiratory tract, rhinitis.

(b)
Disposable half masks could be used, reusable masks , powered hoods/masks both are used to control the risk from wood dust. RPE seleected to protect against wood dust must be CE marked.
-Respirators with an assigned protection factor below 20 should not be used for wood dust.

(c)
- The best way to do this is to is to use fixed LEV that will effectively control the dust at source as it is produced.
- Keep the extraction system properly maintained and working correctly (it is a legal requirement to have it examined by a competent person at least every 14 months).
- Dust lamp will help us see where and how dust escape and check that the extraction is working.
- Educate workers about the risks from wood dust and the control measures required
- Enclosure of the process for exmaple there’s cover guard for circular saw which acts as enclosing hood .
- personal hygiene measures.
- Never sweep up or use compressed air lines as this will disturb the dust and allow it to become inhaled. Always clean up using a suitable industrial vacuum cleaner that at least meets the Class M classification
- Because hardwood dust causes asthma any health effects must be picked up early. This can be done using health surveillance.
- monitoring airborne concentration levels.(Air sampler) To sample worker exposure
- warning signs to designate hazardous areas
- the setting aside of separate areas for eating
- Use of appropriate handling techniques to minimise dust creation when emptying sacks
- Adequate supervision to enforce the control measure mentioned above.

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4
Q

Workers in a chemical manufacturing plant need personal protective equipment (PPE) to protect their eyes and faces when handling open containers of highly corrosive liquids.

(a) Describe what should be considered when selecting the PPE for this task.
(b) Outline arrangements that the chemical manufacturer should put in place when the selected PPE is in use.(4)

A

(a)
To prevent the risk of splashing the face as well as the eyes by corrosive liquids The first thing to consider is choosing the right type of PPE for example Face shield, goggles with the appropriate level of chemical resistance gives more effective protection agiants splashes, than with glasses.

To ensure adequate resistence to the specefic chemical being used. MSDS provide general guidance on the appropriate materials that resist the penetration or damage by corrosive liquid.

The requirement to meet the relevant standards such as quality standards , such as the European EN standards.

Their compatibility with other protective equipment.

The effectiveness of an item of PPE is ultimately determined by whether or not users actually wear it, that why wear acceptability is an important factor to consider as it can be improved significantly by involving workers in the slecetion process.

(b)
Provision must be made for the safe storage of PPE away from sources of contamination, It is common
practice to provide a locker or storage area for PPE

PPE must be maintained in safe working order,The level of maintenance will be determined by the item, manufacturer’s recommendations and the conditions of use

If workers are to use PPE effectively, they have to be provided with information, instruction and training on the risk PPE provide protection against. how and when PPE should be used, how to inspect maintain or replace PPE
storage requirement, limitation.

Supervision to enforce the usuage of PPE.

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5
Q

An employer wants to use a local exhaust ventilation (LEV) system to
control workers’ exposure to a hazardous gas generated during a
manufacturing process.

(i) Outline control options that the employer should consider before deciding an LEV system is the
appropriate means of control.

(ii) Outline what the employer should consider when specifying an LEV system to control this hazardous gas.

Other than the employer, identify TWO other persons with responsibilities in relation to an LEV system.

A

(i)
• the elimination of either the hazardous chemical, or the process that requires it, completely eliminating the use of substance or the production of it in work place would include the following options:

  • Analysing the process may identify activities that produce harmful substances. Changing the work method may minimise or suppress the generation of the substance.
  • Modifying a process so that a hazardous by-product or waste material is no longer produced
  • if the hazardous gas generated can’t be eliminated n the next best option is to substitute it for a substance that is non-hazardous if not possible less hazardous. (the same chemical or an entirely new substance with a lower hazard classification )
  • Total enclosure or containment is an effective control, since no-one can then be exposed to the hazard

• Keeping people away from the process and its hazards is another effective method of controlling exposure
(II)

  • The Source strength of the hazardous gas which is the combination of the volume rate of release of contaminant cloud, the cloud volume, shape, and the speed, and concentration of the contaminant such info will help to both determine the engineering characteristics of the system, design required.
  • Determined the hazardous properties of the gas used, for example, if the gas is Toxic, what kind of filter is required, to help the design of the LEV
  • The likely sources or points of exposure. the sources and type of contaminant will help dictate the type of inlet/enclosure/hood required.
  • The complexity and nature of the process, the system be required to cope with changing materials and processes? Does it need to be flexible/adaptable?
  • Consulting with employees who know the process to help with design and selection.
  • is the area naturally ventilated through doors and windows? Natural ventilation will affect the performance of the LEV
  • The eas and the safety to check out and maintain and clean the LEV system.

(B)

• LEV supplier - this will be the party or parties who design and then install the LEV system for the owner.

  • LEV service provider - this is the test engineers (or company) responsible for examining and testing the LEV system, either for commissioning or thorough exmination and test.
  • LEV owner.
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6
Q

A survey of an industrial building has revealed extensive use of asbestos material.

(a) Identify where asbestos might have been used in the building.
(b) Outline control measures that could help protect workers in the iindustrial building from exposure to asbestos.

A

(a)
incorporated into many building parts, such as roofs (e.g. corrugated asbestos cement sheets), ceilings (e.g. ceiling tiles), walls and ceilings (e.g. in fire breaks), floors (e.g. vinyl floor tiles), pipes (e.g. rainwater downpipes), decorative plasters (e.g. artex) and insulation (e.g. pipe lagging)
(b)

• Process separation, automation or enclosure.
-segregating the asbestos operations from the rest of the process to reduce the potential for asbestos dust to accumulate.
-Direct handling of asbestos-containing materials should be avoided and, where practicable, the process should be totally enclosed and operated at negative pressure (using an internal exhaust) which will prevent the release of fibres example ““tent” with a filtered extraction system ensuring that the enclosure remains at negative pressure. Workers would enter this area via an airlock and would be decontaminated on leaving.”
-Dust emission and worker exposure should also be measured in order to demonstrate that the required standard of control has been achieved
-Separate workplaces for certain processes.
• Bonding asbestos fibres with other materials to prevent dust generation.
• General ventilation of the working areas with clean air, The exhausted air must be filtered thoroughly and not returned to the workplace unless the air quality and level of ASB conntamination is assured.
–Where total enclosure is not practicable, LEV should be provided and maintained.
• Local ventilation of processes, operations, equipment and tools to prevent dust dissemination (ventilation is covered in more detail later in this element).
• Use of wet methods where appropriate.
• Regular cleaning of work areas to remove contamination, This cleaning should be carried out by methods which prevent dust generation, e.g. vacuum cleaning (no worker should be present during cleaning)
• Proper use of PPE: RPE could be used as temporary or emegency control measures but not asn alternative
• Protective clothing should be provided when there is a potential for workers’ own clothing to be contaminated.
• Selection of competent people using appropriate work methods and precautions.
• Asbestos workers should be subject to health surveillance - initial examination- and at periodic intervals.
•All asbestos-containing materials should be labelled with recognised warning labels using an appropriate symbol.

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7
Q

A welder undertakes work in an open plan workshop.

Outline the factors to be considered when selecting suitable respiratory protective equipment for this work

A

The nature of the tasks to be undertaken is important since the type of welding taking place will affect the ability to filter
the contaminant. The duration, frequency and physical effort involved will also be relevant to the choice of RPE. The working environment should also be considered because high levels of heat and humidity may make the use of some types of RPE uncomfortable and may necessitate using others, such as airstream helmets.

The location where the welding actually takes place will determine the standard of existing ventilation and the fume control already available to use. If there is fume control equipment such as local exhaust ventilation already in place then this will affect the selection of RPE.

Welding produces toxic and irritant fumes, and the amount and type of particulate produced will determine the protection factor required and the filter type necessary to protect against the identified hazard. Legislation and international standards can be used for assistance in determining this.

Selection of RPE should involve the workforce, who will need to be made aware of the hazards and why controls and RPE are required. They should also be trained in how to fit the RPE correctly, how to choose the most appropriate type of RPE for the task (e.g. filtered half-mask, filtered full-mask or breathing apparatus), and also the significance of compatibility issues with other PPE such as welding masks or shields and eye protection.

Other factors to consider include the need for verbal communication whilst wearing RPE, the requirements for RPE with heatresisting properties and any relevant standards such as BS EN standards for the equipment.

There are also individual issues to consider such as fitness to wear RPE, the need for regular face-fit testing and the training required on wearing, cleaning, checking and maintenance of the RPE chosen. You should also consider the compatibility of RPE with
individuals with facial hair and glasses.

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8
Q

Outline the tests that could be used to assess the efficiency and effectiveness of local exhaust ventilation systems.

A

LEV depends on the flow of air into the hoods, up the ducts and through any filters; the clean air is then passed out to the atmosphere. The presence of the airborne contaminant that is supposed to be controlled by the LEV might be assessed. This might be done by conducting static sampling or personal dosimetry in the work area that the LEV extracts from. Visual assessment of the areas might also be made (e.g. by looking for excessive build-up of dust on surfaces in a workroom which would indicate the LEV is not working well).

Qualitative assessment of the LEV infeed efficiency might be made by either using a Tyndall beam to visualise particulates, or using a smoke generator to track air flow into the hoods. Pitot-static tubes and manometers can be used to measure the static pressure at the hoods and in ducts. The velocity of the flow of air can be measured to ensure that the particulates are not sticking to the sides of the ducts. This might be done using anemometers of various types (e.g. heated head or hot wire type). Flow meters can be used to measure the volume of air passing through the fans. Other tests can be carried out to test the effectiveness of the filters. This might be done using simple manometers to ensure those filters are not going blind (becoming clogged). Tests might be carried out on the purity of the cleaned air on the exhaust side of the ducts.

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9
Q

A hazardous substance has an Occupational Exposure Limit (OEL) of 40ppm, 8-hour Time-Weighted Average (TWA). Engineering controls in a workshop have been effective in reducing the airborne concentration of this substance down to 160ppm, 8-hour TWA.

The workshop manager has chosen some Respiratory Protective Equipment (RPE) with an Assigned Protection Factor (APF) of 40 to be worn by workers in the area.

(a) Demonstrate how to use the information above to determine if the workshop manager has made an appropriate APF choice for the RPE.
(b) Review other issues that should be considered when selecting RPE for workers.

A

(a)
APF is the ratio of the concentration of contaminant in the air (160ppm here) to that inside the face piece. Maximum allowable concentration inside the face-piece is the OEL (40ppm here). So, required minimum APF = 160/40 = 4

The actual APF of the selected RPE is 40 (i.e. 10 times the minimum required) and so offers a very good level of protection.

(b)
-What is the expected duration of use of the RPE? Short duration use might allow the selection of a lower quality item whereas long–term or continual use will require a much higher specification item to be used.

  • The nature of the contaminant which vapour and the OEL limit and toxicity on inhalation.
  • What is the type and nature of the work being carried out when wearing the RPE? Is it heavy or light work, what degree of movement is needed, are there space constraints that might prevent the use of larger bulky items?
  • Are there compatibility issues with other PPE needed? If so, how can these issues be
    overcome without compromising the effectiveness of all PPE items?
  • What standards exist for the RPE and does it meet those standards? i.e. certified to the relevant international standard.
  • What is the nature of the workforce? Are they capable of using the chosen items to an acceptable standard and have they been consulted and involved in the selection (user acceptability)?
  • What about ease of maintenance? Some items of RPE require a high level of maintenance
    and therefore should only be selected where this maintenance is available and adequately
    resourced.
  • The working environment should also be considered because high levels of heat and humidity may make the use of some types of RPE uncomfortable and may necessitate using others, such as airstream helmets.
  • The protection factor required and the filter type necessary to protect against the identified hazard. Legislation and international standards can be used for assistance in determining this.
  • Other factors to consider include the need for verbal communication whilst wearing RPE, the requirements for RPE with heat-resisting properties, and any relevant standards such as BS EN standards for the equipment.
  • There are also individual issues to consider such as fitness to wear RPE, the need for regular face-fit testing, and the training required on wearing, cleaning, also consider the compatibility of RPE with individuals with facial hair and glasses.
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10
Q

You have been sent a copy of a “Local Exhaust Ventilation (LEV) Examination Report” conducted by an external organisation and relating to an LEV system in one part of your company’s production area. You have been asked by the production manager to comment on the suitability of this report, before the company goes ahead and commissions further LEV examination work throughout the rest of the factory.

Outline the issues you would need to consider when assessing the adequacy and quality of the report in order to provide relevant comments to the production manager.

A

ƒIdentification of the LEV plant, process and substance(s) being controlled with some reference made to the appropriate legal standards.

ƒThe date of last examination and test (reference to at least every 14 months).

ƒThe LEV’s intended (design) performance specification.

ƒThe current LEV performance (as ascertained by a range of techniques, with results; e.g. static pressure, face velocity, dust lamps, visual inspections, etc.).

ƒA clear indication as to whether any improvements/repairs are needed (which will depend on an analysis of current performance relative to design and taking account of any standards).

ƒThe date of examination/test.

ƒThe name of person (and their employer) doing the test, along with any relevant credentials (qualifications, accreditations).

ƒReference to appropriate methodologies, standards and details of any calibrations carried out on technical equipment used.

ƒThe requirement to keep the record for five years.All of these factors would be used to assess the adequacy of the LEV report, along with general impression of the report and whether it was legible or not

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11
Q

Outline a hierarchy of control measures which would be applied to carcinogens in the workplace.

A

ƒEliminate the carcinogen where reasonably practicable.

ƒPrevent exposure, preferably by substitution for a non-hazardous substance or a considerably less hazardous substance.

ƒDesign and use work processes, systems and engineering controls so as to minimise the amount of carcinogens needed or produced as by-products.

ƒControl at source, by using totally enclosed systems or by the use of local exhaust ventilation systems.

ƒUse organisational measures to control numbers exposed and level/duration of exposure and quantities used/stored in the workplace.

ƒControl the working environment (including using general ventilation).

ƒProhibit eating/drinking/smoking in potentially contaminated areas.

ƒClean surfaces (walls, etc.).

ƒDesignate potentially contaminated areas and use warning signs.

ƒUse safe storage, handling and disposal methods (includes using closed and labelled containers).

ƒPPE (e.g. RPE) as a last resort (in addition to all the above).

ƒHealth surveillance for exposed workers.

ƒDevelop emergency and spillage procedures.

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12
Q

5.Describe the factors to consider when selecting, using and maintaining personal protective equipment to protect the hands and arms against a degreasing solvent.

A

There are many issues that must be considered in selecting (PPE) to protect workers in a workplace. One major factor is the parts of the body to be protected and the types of PPE that might afford appropriate protection. In this instance, the hands and arms are to be protected from a degreasing solvent. Gloves or gauntlets are an obvious choice for this role. Any gloves must cover the hands and the wrist to an adequate degree and the cuff of the glove might extend beyond the wrist and part way over the forearm. Gauntlets will extend protection beyond the forearm and to the elbow or even to the armpit. The degree to which protection is required will determine how much of the arm should be covered and therefore which type of PPE is needed. Selection will also have to consider the type of material for the gloves and their endurance for the work being carried out. Some materials will not withstand degreasing solvents and will degrade rapidly or over time. Similarly, some materials are not hard-wearing and would not withstand rough handling of heavy metal components or constant use. The comfort and fit of the glove is an important aspect, especially as user acceptability must be high for the PPE to be adopted effectively. Adequate grip and dexterity are other practical issues that can make a big difference in terms of user acceptance. Thought must also be given to any possible allergic reactions to the material, such as the Type 1 NRL (natural rubber latex) allergy which can prove extremely dangerous. User trials and consultations with the supplier and the users should be carried out so that the selection and choice is acceptable.

Once the specific PPE has been selected, some thought must be given to writing up rules and procedures for its use. It must be clearly stated when and where this PPE must be worn and it must also be clearly stated what the consequences of non-compliance might be. Training will have to be carried out to ensure the correct use, putting on and off, cleaning, disposal or storage and maintenance. Suitable storage facilities will have to be provided and maintained in good hygienic order. Line managers must receive training on the correct use of the gloves so that they recognise good and bad practices when they see them. Enforcement of the rules must be addressed and disciplinary action taken against persistent offenders.

With regards the maintenance of the gloves and gauntlets, gloves will have to be inspected routinely by users and perhaps by line management as well to ensure that they remain in serviceable order. Personal hygiene, checking for skin troubles and the reporting of any defects or health problems will also have to be covered. If individual items are found to be defective they will either have to be disposed of or repaired. Stocks of replacement items must be available so that workers are able to replace defective items easily and quickly. If stocks are not maintained, and are not immediately accessible to workers, then the temptation might be to carry on with the use of defective PPE. In most instances gloves and gauntlets would not be repaired, but simply disposed of. Some thought may need to be given to safe disposal, if PPE were contaminated with toxic materials for example. All of the arrangements in place for use of the PPE must be monitored and kept under management review.

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13
Q

Road workers are required to regularly cut kerb stones using a petrol-powered disc cutter, a job for which they are required to wear a range of Personal Protective Equipment (PPE).

(a) Outline the reasons why EACH foreseeable type of PPE is needed.
(b) The workers’ employer has selected suitable PPE and has verified that adequate levels of protection will be provided. However, the employer is worried that the PPE is not being used/used correctly.

Outline the various practical measures that the employer could take to encourage the correct and effective use of the PPE.

A

(a)
The hazards associated with cutting kerb stones using a petrol-powered disc cutter, are as follows. Cutting will generate significant noise which will require hearing protection. Dust will be generated during the cutting process and will require RPE for protection. Dust or metal sparks generated during cutting will require eye protection. The site where landscaping takes place is likely to be uneven and the kerbs will be heavy therefore foot protection will be required. Kerb stones are also rough to handle and manoeuvre therefore gloves will be needed. Exposure to vibration can affect blood circulation and cause hand/arm vibration syndrome therefore gloves will help to keep hands warm. Finally the dust generated from working with kerb stones will contaminate clothing and overalls will be needed for protection.

(b)
Practical measures to encourage the correct and effective use of the PPE and maintain its effectiveness could start with explaining the risks associated with the activity and how PPE will offer protection. Training in the correct use of PPE will need to include the correct method of putting on and fitting the PPE, how to remove it without contamination, how to spot defects and damage, which items are disposable, where to store the PPE when not in use and how to obtain replacements when required. Managers and foremen can encourage use by leading by example and reminding employees to use PPE. Provision of storage facilities when items are not in use and ease of replacement will all make the use of PPE easier. Use can also be encouraged by requiring employees to acknowledge and sign for receipt of PPE, introducing sanctions and disciplinary measures for non-use and rewarding correct use. Finally, ensuring compatibility, seeking the views and responding to the complaints from users will remove obstacles to effective use. To ensure that PPE is effective, face-fit testing for RPE will be a requirement and also provision of different sizes of PPE and facilities to clean re-usable PPE.

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14
Q

A worker in a furniture manufacturing workshop spends most of their time
machine-sanding hardwood with a hand-held power sander.

Outline control measures to help protect the worker and their colleagues from the risks of exposure to hardwood dust.

A
  • The best way to do this is to is to use fixed LEV that will effectively control the dust at source as it is produced.
  • Keep the extraction system properly maintained and working correctly (it is a legal requirement to have it examined by a competent person at least every 14 months).
  • Dust lamp will help us see where and how dust escape and check that the extraction is working.
  • Educate workers about the risks from wood dust and the control measures required
  • Enclosure of the process for exmaple there’s cover guard for circular saw which acts as enclosing hood .
  • personal hygiene measures.
  • Never sweep up or use compressed air lines as this will disturb the dust and allow it to become inhaled. Always clean up using a suitable industrial vacuum cleaner that at least meets the Class M classification
  • Because hardwood dust causes asthma any health effects must be picked up early. This can be done using health surveillance.
  • monitoring airborne concentration levels.(Air sampler) To sample worker exposure
  • warning signs to designate hazardous areas
  • the setting aside of separate areas for eating
  • Use of appropriate handling techniques to minimize dust creation when emptying sacks
  • Adequate supervision to enforce the control measure mentioned above.
  • Disposable half masks could be used, reusable masks, powered hoods/masks, RPE selected to protect against wood dust must be CE marked, with an assigned protection factor below 20 should not be used for wood dust.
  • Substitution of the hardwood for softwood, partial enclosure of the process, wet suppression techniques during the work, and cleaning afterward.
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15
Q

(a) Explain when it might be necessary to use respiratory protective equipment (RPE) as a control measure to help reduce exposure to a hazardous substance.

Workers carrying out a task involving the corrosive vapor of ammonia have been provided with RPE to protect them from exposure to ammonia
by inhalation.

The employer used the following information to determine the selection of the RPE:

-Concentration of ammonia vapor in the workplace
280 ppm.

  • The exposure limit for ammonia is 35 ppm (15-min STEL).
  • Assigned protection factor for selected RPE 20.
    (b) Explain how the employer can use this information to determine if the choice of RPE is appropriate.
    (c) Outline what an employer should consider when selecting RPE for this particular task.
A

(a)

  • When you might still breathe in contaminated air, despite other controls you have in place e.g. extraction systems.
  • When there is short-term or infrequent exposure and using other controls is impractical.
  • Whilst you are putting other controls in place.
  • When you need to provide RPE for safe exit in an emergency.
  • When you need to provide RPE for emergency work or when there is a temporary failure of controls.
  • When emergency rescue by trained personnel is necessary.

(b)

280/20=14
14 small er than 35

(c)
-What is the expected duration of use of the RPE? Short duration use might allow the selection of a lower quality item whereas long–term or continual use will require a much higher specification item to be used.

  • The nature of the contaminant which vapour and the OEL limit and toxicity on inhalation.
  • What is the type and nature of the work being carried out when wearing the RPE? Is it heavy or light work, what degree of movement is needed, are there space constraints that might prevent the use of larger bulky items?
  • Are there compatibility issues with other PPE needed? If so, how can these issues be
    overcome without compromising the effectiveness of all PPE items?
  • What standards exist for the RPE and does it meet those standards? i.e. certified to the relevant international standard.
  • What is the nature of the workforce? Are they capable of using the chosen items to an acceptable standard and have they been consulted and involved in the selection (user acceptability)?
  • What about ease of maintenance? Some items of RPE require a high level of maintenance
    and therefore should only be selected where this maintenance is available and adequately
    resourced.
  • The working environment should also be considered because high levels of heat and humidity may make the use of some types of RPE uncomfortable and may necessitate using others, such as airstream helmets.
  • The protection factor required and the filter type necessary to protect against the identified hazard. Legislation and international standards can be used for assistance in determining this.
  • Other factors to consider include the need for verbal communication whilst wearing RPE, the requirements for RPE with heat-resisting properties, and any relevant standards such as BS EN standards for the equipment.
  • There are also individual issues to consider such as fitness to wear RPE, the need for regular face-fit testing, and the training required on wearing, cleaning, also consider the compatibility of RPE with individuals with facial hair and glasses.
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16
Q

Construction workers regularly use cement. Several of the long-term workers and one of the new recruits have complained about red and sore skin on their hands.

(a) Explain the possible reasons for the symptoms they are experiencing.
(b) Outline control measures that could be used to minimize these symptoms in this situation.

A

(a)
The symptoms are consistent with the workers suffering from dermatitis caused by a chronic or repeated exposure to an irritant or irritants.

Cement is a known irritant but which can also cause allergic contact dermatitis due to the presence of chromium VI compound impurities in the material

Contact with a sensitizer produces an over-reaction from the body’s immune system.

Sensitization can occur on the first contact such as with the new recruit or after some time in the case of the long-term workers. The effect of contact with the irritant/sensitizer can also de-fat and degrease the skin.

Dermatitis is not the only possible contributor to the symptoms.

The symptoms could also be caused by caustic burns whilst friction and abrasion from the general floor laying and a failure to protect the hands with gloves and a good standard of personal hygiene will not help the condition

(b)
- Using a non-cement based leveling compound, for example, a polymeric compound

  • Wearing gloves to protect the skin and minimizing contact by the use of hand tools
  • Providing washing facilities so that contaminants can be washed from the skin as soon as possible with the hands dried thoroughly after washing
  • Using pre-work and after work moisturizing creams to replenish the natural oils in the skin;
  • Giving information to the workers on the hazards of using the material and the precautions that should be taken and encouraging them to report any problems with their skin
  • Arranging for supervisors to carry out regular skin inspections of the workers.
17
Q

A slightly corrosive solution is used as a treatment in part of a manufacturing process. The solution is applied by hand brushing. For this process, other methods of application are not practicable.

(a) Outline the factors that should be considered in the selection of personal protective equipment to adequately protect the skin and the eyes of those involved in the process.
(b) Outline the content of a training programme that will assist workers to use the personal protective equipment correctly.
(c) Identify a range of practical measures (other than training) that can be taken to encourage the use of the personal protective equipment and maintain its effectiveness.

A

(a)
For the selection of protective gloves, relevant factors are the chemical breakthrough time (compared to the time for which the glove would be worn); the level
of dexterity required for the task; the length of the glove required to afford adequate protection; the durability of the gloves; the need to ensure that a suitable range of sizes is available for the various users; and any worker allergies to the glove material or any other skin problems

In the selection of eye protection, relevant factors are the risk of splashing the face as well as eyes; the provision of advice on the use of goggles or a face shield (rather than glasses); and their compatibility with other protective equipment if this is required.

In the selection of body protection, findings from consultation and user trials; the comfort of the equipment; that all personal protective equipment provided met the appropriate national or international standards and that everything purchased possessed the appropriate resistance to the corrosive solution in question.

(b)
The health risks of the chemical in use;

The type of personal protection to be used and the reason for its use;

The methods to be used for putting on
and taking off the equipment without causing contamination including decontaminating
or discarding gloves after use;

The methods of examining the equipment for damage or degradation, particularly gloves, and for reporting defects and obtaining replacements;

How to store the equipment correctly and finally how to carry out self- examination of the skin and the action to be taken if problems are to occur.

(c)
Management leading by example; workers being involved in the selection of the equipment; ensuring the availability of a range of sizes in gloves and fully adjustable face shields; ensuring workers are required to sign for their equipment and maintaining
records of issue; issuing the equipment on a personal basis and providing adequate storage facilities; using propaganda, signs and posters and incentive schemes; monitoring compliance in the use of the equipment with a recognized code of discipline for non-use; and finally monitoring the effectiveness of the equipment issued and replacing it with an alternative type if problems are encountered.

18
Q

A small motor vehicle repair workshop uses paints known to contain isocyanates.

(a) Outline the health effects of exposure to isocyanates.
(b) Outline the factors to consider when assessing the risks arising from using these paints.
(c) Outline the practical measures to control exposure to the isocyanates when spray painting the vehicles in the workshop.

A

(a) Isocyanates (depending on their particular type) can cause:

 Irritation of the eyes, skin and respiratory system

 Respiratory sensitization (occupational asthma)

 Skin sensitization (dermatitis)

 Specific organ damage

 In some cases, cancer

(b) Factors to be considered when assessing risk

 Type of Isocyanates (some are more hazardous than others)

 Possible health effects

 Occupational Exposure Limits (OELS)

 Route of entry

 Quantity/concentration to be used

 Number and susceptibility of people who may be exposed

 Duration of exposure

 Other risks, e.g. due to fire or explosion

 How paints are to be used, e.g. how they will be moved, stored, handled, sprayed, etc.

 Operating conditions, such as high or low-temperature environments (eg high temperatures could increase the level of risk)

 Effectiveness of current controls

 Likelihood of failure

(c) Practical controls should be structured around the hierarchy of control and include

 Substitution of the isocyanates for a less harmful alternative, if possible

 Minimize quantities used

 Enclose in a spray booth, to protect those not spraying from exposure

 Extraction of the spray booth LEV to a safe location away from workers

 Maintaining and cleaning the booth and the L EV system, including testing LEV efficiency

 Respiratory Protective Equipment (RPE) may be required, e.g. a half-mask respirator with the correct protection factor for the concentration of contaminant present

 If RPE is to be worn the appropriate filters and cartridges must be selected and used. They should be changed on a regular basis to avoid saturation (and hence breakthrough of the chemical) and the respirator should be maintained

 Other PPE may be needed, eg overalls, gloves or goggles

 Health surveillance for signs of skin irritation/dermatitis or degradation in lung function, and biological monitoring to determine if absorption has taken place through the skin

 Workplace monitoring should be carried out to ascertain the level of contamination present in the workplace and, hence, determine whether
controls are adequate

 Training on the nature of the hazard and operational controls required should be provided to workers, together with supervision to ensure that these controls are adhered to

19
Q

(a) Explain the meaning of the term ‘toxicity’.

(b) Describe the physical characteristics of asbestos and give TWO occupational examples
where it is likely to be encountered.

A

a) Toxicity is the degree to which a substance can cause damage to an organism. toxicity can be acute (short term) chronic (after long term exposure) local (at the point of contact with the body) or systemic (acting throughout the organism)
(b) Asbestos is a natural fiber that was lined for use as an insulating material due to its thermal stability and fire resistance.it has also good absorbance properties, average tensile strength, and is chemically inert. It can be found in blue (crocidolite), brown ( amosite ), and white ( chrysotile) forms. As it was used historically in insulation, it can be encountered in operations such as pipe lugging removal, drilling into walls containing asbestos, insulating boards, etc.

20
Q

(c) Outline the diseases caused by exposure to asbestos AND their signs and symptoms.

(d) Outline the equipment and method that should be used to determine the level of asbestos
fibres in the air in the workplace.

A

(c)
• Asbestoses – a fiberoptic illness causes when asbestoses fibers can cause scarring of the lung tissue

  • Mesothelioma- cancer of the mesothelium (tissue covers major organs) caused by asbestos and affecting mainly the lung lining, but also the lining of the abdomen (peritoneum)
  • Lung cancer
  • Pleural plaques- fiberoptic area resulting in the thickness of pleural Sign and symptoms may take many years to appear and include:
  • Chest pain
  • Shortness of breath
  • Coughing
  • emphysema
  • asbestosis, which also causes loss of lung function

• lung cancer, which can also result in expectoration (coughing up) blood

(d) measuring the asbestos fibers in the air requires a controlled flow sampling pump with a sampling head fitted with a cowl and membrane filter
the procedures are as follows:

  • calibrate the pump
  • draw a known volume of air through the sampling device (determined by knowing the sampling duration and flow rate).
  • Air is drawn through the membrane filter, capturing fibers.
  • The filter is removed, mounted on a microscope slide, and wetted. The number of fibers is then counted.
  • The number of fibers is related to the volume of air drawn through the sampling device. The result is given in the fibers per ml of air.
21
Q

Outline reasons why respiratory protective equipment (RPE) may not provide the level of protection that is stated by the manufacturer when it is being used.

A

(a)

  • An inadequate initial assessment which did not take into account work rate, duration of wear
    required and the anticipated level of contamination;
  • A poor airflow or a loss of battery power;
  • The fitting of incorrect cartridges or a failure to replace them before saturation;
  • Poorly fitting equipment 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 facepiece 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,
  • The considerations to be taken when selecting respiratory protective equipment rather than
    why once selected, it might not provide the stated level of protection.
22
Q

A local exhaust ventilation (LEV) system is used to reduce the exposure of workers to dust in the workplace. The employer needs to assess the
the ongoing effectiveness of the LEV system.

(a) Identify THREE simple qualitative methods that can be used to assess the effectiveness of the LEV system AND, for EACH method, explain how the effectiveness can be visually assessed.
(b) Identify TWO quantitative methods that can be used to measure transport velocity in an LEV system AND explain how EACH method measures the transport velocity.

A

(a) qualitative
-Tyndall lamps which make fine particles easily visible This allows identification of:
• A dust emission that is taking place.
• The behavior and direction of the dust cloud, in order to determine whether it is likely to enter a worker’s breathing zone.

-Smoke can be artificially produced and released into a work area to visualize air movement and to simulate the movement of particles. Smoke can be produced in smoke tubes

-Simple observation of components that can
show build-up of dust deposits

(b) quantitative

-The heated head anemometer relies on the airflow to cool a sensitive head which consists of a hot wire,
thermocouple or thermistor. The degree of cooling is related to the air velocity

  • the pitot-static tube this is a device that measures velocity pressure inside the ventilation system, i.e. the pressure caused by the movement of air in the duct. The reading is then converted to velocity using a simple formula.
  • Swinging vane anemometers features a moving element consisting of a pointer and a vane mounted on a taut-band suspension. The vane is able to swing inside an air chamber, where its movement creates very little friction. The flow through the anemometer is created by the velocity pressure at the point being measured