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Respiratory protective equipment (RPE)
Any type of PPE specifically designed to protect the respiratory system, e.g. self-contained breathing apparatus.
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Purpose and Application
The general principles of PPE can be applied to RPE, in that it is worn by workers to reduce the possibility of harm from exposure to a hazardous substance. This is called a safe person strategy. Ideally, the safe person strategy is a second line of defence against a potential hazard – control at source, or a safe place strategy, should be the first aim.
There will be situations where personal protection is the most appropriate method to deal with a particular hazard, e.g. when the cost of controlling the hazard at source is high and the time required for protection is short. Classic situations which typify these conditions are:
• Work involving planned maintenance, e.g. during plant shut-downs.
• One-off tasks generating airborne contaminants, e.g. demolition of a building by pulling it down.
• Failure of primary safety systems or emergency situations, e.g. a chemical leak from an on-site storage tank.
Types of RPE and their Effectiveness
There are two main categories of RPE:
• Respirators - designed to filter the air from the immediate environment around the wearer.
• Breathing apparatus - provides breathable air from a separate source.
The following is a description of the different types of equipment and their effectiveness.
Respirators
These come in a variety of types: • Filtering Face-Piece Respirator
This is the simplest type, consisting of a piece of filtering material worn over the nose and mouth and secured by elastic headbands. Fit around the chin and face depends on the tension in the headbands; a flexible metal strip enables the user to bend it over the bridge of the nose to ensure a personal fit.
A worker using a filtering face-piece respirator to prevent inhalation of wood dust
This type of respirator is useful to prevent inhalation of dust or fibres (and sometimes gas and vapours), but is not suitable for high concentrations of contaminant, for use against substances with high toxicity, or for long duration use.
Use and benefits Limitations
Cheap Low level of protection Easy to use Does not seal against the
face effectively
Disposable Uncomfortable to wear • Half-Mask or Ori-Nasal Respirator
This is a flexible rubber or plastic face-piece which covers the nose and mouth, with one or two filtering canisters (cartridges) that contain the filtering material. It gives a much higher level of protection than the filtering face-piece respirator.
A worker wears a half-mask respirator to seal asbestos lagging around a pipe
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Use and benefits Limitations Good level of filtration No built-in eye
protection
Good fit achievable Negative pressure inside face-piece
Easy to use Uncomfortable to wear When the wearer inhales, a negative pressure is created inside the face-piece; this means that any leak in the respirator or around the seal will allow contaminants in.
• Full Face Respirator
This is similar to the half-mask (also with canister filters) but has a built-in visor that seals in the eyes and face. This type gives a high level of protection against airborne contaminants and protects the eyes, which can be important where contaminants may splash or can cause irritation or be absorbed through the eyes.
A full face respirator with filtering canister (or cartridge)
Use and benefits Limitations Good level of filtration Restricts vision
Good fit achievable Negative pressure inside face-piece
Protects the eyes Uncomfortable to wear • Powered Visor Respirator
– A powered fan blows filtered air to the wearer. – Usually made up of a helmet and face visor, with
the air drawn in through a filter in the helmet, and fed down over the face inside the face-piece. – Powered by rechargeable battery.
This type of respirator does not have a tight seal around the face, and is especially suited to dusty, hot environments where the stream of air moving over the face is a benefit. Similar is the powered clean air respirator which has the filter remote from the visor, usually worn on the belt, and fed to the visor through a tube.
Use and benefits Limitations Intermediate level of
filtration
Heavy to wear Air movement cools
wearer
No tight face seal Air stream prevents
inward leaks
Limited battery life
Powered Visor Respirator
Breathing Apparatus (BA)
This can be classified under three general headings: • Fresh-Air Hose BA
This is the simplest type, where a large diameter hose is connected to the user’s face mask. Air is either drawn down the hose by breathing or blown down by a low speed/low pressure fan.
Use and benefits Limitations Air is from outside the
work room
Hose must be tethered Supply of air is not
time-restricted
Bends or kinks make breathing difficult User is restricted by limited hose length • Compressed Air BA
Similar to the fresh-air hose BA, but air is supplied through a small-bore hose at high pressure. Pressure is stepped-down by a regulator and supplied at low pressure to the user’s face mask.
Use and benefits Limitations Supply of air is not
time-restricted
Hose can be long, but not endless
Positive pressure inside face-piece
Wearer is not burdened with cylinder
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• Self-Contained Apparatus
Breathable air is supplied from a pressurised cylinder worn by the user. This type of BA gives the wearer complete freedom of movement, but it is the most heavy and bulky type. The air cylinder does have a limited capacity.
A firefighter wearing self-contained breathing apparatus and other personal protective equipment
Use and benefits Limitations Complete freedom of
movement
Supply of air is time- restricted
Positive pressure inside face-piece
Equipment is bulky and heavy
More technical training is required
Selection, Use and Maintenance
RPE must be selected carefully to ensure that it is suitable.
Topic Focus
Key factors in the selection of RPE:
• Contaminant concentration and its hazardous nature (e.g. harmful, toxic).
• Physical form of the substance (e.g. dust, gas, vapour).
• Level of protection offered by the RPE. • Presence or absence of normal oxygen
concentrations.
• Duration of time that it must be worn. • Compatibility with other PPE that must be
worn.
• Shape of the user’s face and influences on fit. • Wearer acceptability.
• Facial hair might interfere with an effective seal.
• Physical requirements of the job, e.g. the need to move freely.
• Physical fitness of the wearer.
The level of protection offered by an item of RPE is usually expressed as the Assigned Protection Factor (APF). This is a measure of how well the RPE keeps out the contaminant and is given by the formula:
APF = Concentration of contaminant in workplace Concentration of contaminant in face-piece Any RPE selected must meet the relevant standards (e.g. CE marked).
Users of RPE should receive appropriate information, instruction and training. In particular they should: • Understand how to fit the RPE.
• Have a face-fit test to ensure suitability and fit. • Know:
– How to test the item during use to ensure it is working effectively.
– The limitations of the item. – Any cleaning requirements.
– Any maintenance requirements (e.g. how to change the filter).
Maintenance and cleaning of RPE must be carried out in accordance with the manufacturers’ instructions and any national or local legal requirements (e.g. requirements for keeping a record of inspections, replacement parts, etc.). This should include the need to repair or replace
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worn or damaged items. Maintenance should be carried out by trained, competent personnel.
Other Protective Equipment and Clothing
There are other types of PPE used to protect from exposure to hazardous substances.
Gloves
Gloves (short cuffs) and gauntlets (long cuffs) can give protection against:
• Chemicals such as acids, alkalis, solvents, oils (e.g. corrosive cement).
• Biological agents such as blood viruses and body fluids.
• Physical agents such as contaminated dusts, and cuts from contaminated blades or syringes.
• Water – even uncontaminated water can soften and damage the skin of someone exposed for long periods.
For protection against chemicals it is important to ensure the gloves are of the right material impervious to the chemical.
Overalls
“Ordinary” overalls are not regarded as PPE, but “work wear” - in that they are not commonly intended to do more than keep a person (and their clothing) clean. However, even overalls can offer some level of protection against everyday construction contaminants such as soil, clay, oils and grease.
There are items of PPE intended to protect the construction worker from hazards:
• Flame-retardant overalls.
• Chemical-resistant overalls – protect from acids, alkalis, etc.
• Disposable coveralls (hooded) - worn in asbestos removal and impervious to the passage of extremely fine fibres.
• Aprons – prevent spills and splashes from soaking into normal work wear and the skin.
Eye Protection
Different types of eye protection common in construction activities include:
• Spectacles:
– Offer a degree of front and side protection but do not completely encase the eyes.
– Mainly for impact protection from flying objects and debris.
• Safety goggles:
– Completely encase the eyes with protection from impact, chemical gas, liquid splashes and molten metal.
• Face shields:
– Cover the eyes and face, but do not enclose them.
– Limited protection from impact and splashes. • Hoods and visors:
– Offer all-round enclosed protection, especially from liquid splashes to the face.
Safety Helmets
Protection from falling or moving objects on a construction site is required, regardless of exposure to hazardous substances.
Safety Footwear
This not only offers protection to the toes, but some may be chemical-resistant where exposure to spillages or contaminated ground may occur.
Personal Hygiene and Protection Regimes
Personal hygiene goes a long way to preventing absorption of hazardous substances into the body, by preventing contact in the simplest of situations. Many chemical and biological agents get into the body from the skin of the hands, into the mouth and eyes from cross-contamination. Likewise, food, drink and cigarettes all offer the same opportunity.
Good hygiene means:
• Hand washing when leaving the work area, and always before eating, drinking or smoking. • Careful removal and disposal of potentially
contaminated items of PPE to prevent cross- contamination to normal clothes and the skin. • Prohibition of eating, drinking and smoking in work
areas.
All construction sites must have adequate welfare facilities (water, soap and a means for drying). With more serious hazards, showers and nail brushes may be required. Barrier creams may also prove useful. Facilities should be provided to:
• Change and store clothing and PPE.
• Store, prepare and consume food and drinks. In some situations vaccinations may protect workers from biological agents:
• Vaccination against hepatitis B is often offered to first-aiders.
• Those working near water may gain some protection from immunisation against Weil’s disease.
Issues to consider before embarking on a vaccination programme:
• Worker consent must be obtained.
• Vaccination does not always grant immunity.
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• Vaccination can give workers a false sense of security. In most cases vaccination should only be offered when indicated by law or codes of practice.
Health Surveillance
The purpose of routine health surveillance is to identify, at as early a stage as possible, any variations in the health of employees which may be related to working conditions.
Two types of health surveillance are commonly carried out:
• Health monitoring – where workers are examined for symptoms and signs of disease that might be associated with a particular agent they are exposed to in their work, e.g. those working in the dustiest areas of a site or cement production may have lung- function tests (spirometry) to check for respiratory disorders.
• Biological monitoring – where a blood, urine or breath sample is taken and analysed for the presence of an agent or its breakdown products, e.g. those working with lead processes might have blood samples taken to check for cumulative levels of lead in the blood.
In certain circumstances, pre-employment health screening may be appropriate to establish a “baseline”, and then periodically to monitor for changes. The need for some health surveillance is subject to legislation.