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The importance of Respiratory Protective Equipment (RPE) cannot be over emphasised. It sits amongst the typical PPE used in protecting individual wearers against inhalation of hazardous substances in the workplace. The RPE can be suitable for use when adequate control of exposure cannot be achieved by any other means.
RPE is worn to protect against inhalation of air contaminants and to help employers prevent workplace injuries. Control of harmful air contaminants is achieved through engineering and administrative controls as well as PPE, a last resort of hierarchy of control measures. It is required by employers to firstly attempt to eliminate the hazard at source. The RPE would be used only after all other reasonably practicable control measures have been considered and additional measures required are taken. PPE is considered as a last resort because it only protects individual workers. Any failure, misuse or wearing of the wrong RPE for a job, and employees wearing it may get a false sense of safety when RPE is not properly used. Respiratory Protective Equipment (RPE) that is not worn or selected appropriately would be totally ineffective and may give the user a false sense of protection.
Injuries sustained without RPE
The number of deaths that have been recorded over time has indicated compatibility problems with major factors involving inappropriate supply of non-respirable gas to the respirators worn by workers as the basic causes of casualties in workplaces.
In 2014, OSHA reported deaths involving unintentional connection of airline respirators. A worker was involved in abrasive blasting, painting gratings and railing activities. The airline from the abrasive blasting respirator was hooked onto the plant air supply, but that supply wasn’t a grade D type and was meant to be used only for pneumatic tools and valve gauges. During this activity, the air compressor had been shut down for maintenance, so nitrogen was back fed into plant airlines.
No one from the company had informed the contract employee that the lines now contained nitrogen. This meant that when he donned the abrasive-blasting respirator, he inhaled nitrogen and was asphyxiated.
The basic safety protection practice is that all airline respirators, in spite of configuration with a hood, helmet, coverall, or facepiece, must have a hose with terminal detachable couplings. When a respirator’s airline is connected to a source of inert gas rather than to breathable air, the wearer must be able to determine whether he/she is connected to breathing air and have a warning before losing consciousness. Ordinarily the buildup of carbon dioxide causes the sensation of breathlessness that could alert the individual wearing the respirator. The victim is deceived, however, because there is no clear indication that anything is amiss. This means that suppression may occur quickly and without warning. Victims wearing respirators connected to inert gas lines are in a zero percent oxygen atmosphere; unconsciousness can occur within seconds and death follows in a matter of minutes. Many times the situation continues to be critical because victims may still be wearing respirators and continue to breathe inert gas even after they have collapsed.
Types of RPE
In the oil and gas industry, two common types of RPE are used to protect employees from contaminations: respirators and breathing apparatus. Respirators use filters to remove contaminants in the workplace air to purify it. Breathing apparatus (BA), on the other hand, would need a supply of air from a clean source to the wearer (e.g. an air cylinder or air compressor). Figure 1 shows the different types and various specifications.
Respirators – air purifying
The respirator devices are designed to protect the wearer from inhalation of harmful dusts, fumes, vapours, or gases as the case may be. In most cases, respirators are required until controls are implemented, either where engineering controls are not feasible or in an emergency situation. Respirators come in a wide range of types and sizes used by both the private industry and the public. Every worker using an airline respirator is urged to review the equipment to ensure that couplings of the respirator airlines are incompatible with any other fittings used at the worksite and that airline respirators are tested and approved by NIOSH as part of the unit. Certain incidents have occurred due to non-compliance with this directive and there have been several fatalities and case histories that have occurred as a result of failures in the use of RPE.
According to Occupational Safety and Health Administration (OSHA) investigation reports, most work related fatalities involve violations of both procedures and regulations that could have been prevented by training and strict compliance with existing regulations. Air Purifying Respirators (APRs) do not supply air, but purify the ambient air by a mechanical process using filters or sorbent-filled cartridges or canisters. These respirators do not provide oxygen, and must not be used in oxygen-deficient or Immediately Dangerous to life or Health (IDLH) atmospheres, or where the airborne contaminants have inadequate warning properties (carbon monoxide and high hydrogen sulphide concentrations).
Air Purifying Respirators (APR) are approved only when potential air contaminants and concentrations are known and it has been determined that the APR with appropriate cartridge/canister will provided adequate protection. Certified respirators and components, such as canisters, cartridges and filters shall be labelled and colour coded in line with NIOSH standard requirements. Cartridges/filters used with air purifying respirators have a limited service life and must be replaced before the chemical starts to break through.
Supplied Air Respirators (SARs) provide fresh air from an outside source. They include Self Contained Breathing Apparatus (SCBAs), Supplied Air Breathing Apparatus (SABA) which use a hose-line that is connected to either a breathing air compressor, bottle, or cascade system, Supplied air escape-only respirator, i.e. hood type. SARs provide protection for most dusts, mists, fumes, gases, and vapours. Non-escape SARs use a tight fitting full face mask with either demand or pressure demand type regulators. Most times, the demand regulators could be destructive when compared to the ambient air pressure during inhalation. Pressure demand regulators always maintain a positive pressure compared to ambient air pressure. All SCBA must provide full face protection, have positive pressure and have at least a 30min rating. All SABAs must be used with a self-contained escape pack that has at least a five-minute rating, have an air supply between 414 to 862 kPa (60 to 125 psi), provide full face protection and be worn with positive pressure inside the mask. Supply hoses for airline respirators must be no longer than 60m (200 feet), have neoprene double reinforced hoses with a pressure rating suited to the hose’s use, and be protected, for example with armoured wire mesh with a neoprene core when there is danger of the hose being cut or damaged. It must be equipped with factory fitted couplings such as Schrader or Hansen-type couplings that cannot be connected to anything but breathing air supply fittings. This shall be electrically non-conductive, joined by metal couplings that would be secured to the outside of the hose to avoid erosion and weakening of the couplings. It must also be capped and protected when not in use.
Self-Contained Breathing Apparatus (SCBA)
SCBA is worn by workers, firefighters and others to provide breathable air in an immediately dangerous to life or health atmosphere. They are sometimes called industrial breathing sets. When not used underwater, the term self-contained could also mean that the breathing set is not dependent on a remote supply (e.g. through a long hose).
If for use under water this equipment is called SCUBA (self-contained underwater breathing apparatus). There are three main components of SCBA; the high-pressure tank (2,216 to 4,500 psi (15,280 to 31,030 kPa), about 150 to 300 atmospheres), a pressure regulator, and an inhalation connection (mouthpiece, mouth mask or face mask), connected together and mounted to a carrying frame. This self-contained breathing apparatus has two categories. SCBA is an integrated protective environment that will always feature gas tight suits for whole body protection and ease of decontamination.
Selection of RPE
Employers should ensure that respirators provided to employees are adequate to protect users’ health under routine conditions and reasonably foreseeable emergency situations. The need for respirators is driven by tasks and areas where air contaminant concentrations may exceed regulated Occupational Exposure Limits (OELs) or internal company OELs. Where gas test results are above regulated Occupational Exposure Limits (OELs) and emergency response involving entry into and escape from unknown atmospheres. The adequacy of protection may be further defined through the use of Assigned Protection Factors (APF) and Maximum Use Concentration for each respirator. Assigned Protection Factors are assigned based on mask type and are used in conjunction with occupational Exposure Limits (OEL) to calculate Maximum Use Concentrations per containment for each respirator type. Figures 2 and 3 show the respirator selection process/guidelines and maximum use concentrations.
What the law says
OSHA regulation (29 CFR 1910.134(i)(8)) and the American National Standards Institute (ANSI) standard Z88.2, “Practices for Respiratory Protection,” specifies that respirator airline couplings must be incompatible with outlets for other gas systems to prevent inadvertent servicing of airline respirators with non-respirable gases or oxygen. Inert gases such as helium, argon, and nitrogen are widely used in industrial settings as fire suppression blankets for flammable work in confined spaces, to operate pneumatic equipment, and to prevent oxidation in industrial processes.
Safe use of respirators
Just as employers have the responsibility of providing a fit for purpose RPE, so too are workers held accountable. Workers also must leave an area requiring respiratory protection if they encounter any of the following conditions:
- Need to wash their face or flush their eyes
- Breakthrough is detected
- High resistance to breathing
- Leak is detected
- Respirator components need to be replaced or if the respirator becomes damaged
- Low pressure alarm sounds while under supplied air
Workers should not remove their respirators until they are in a clean atmosphere, and should not re-enter an area requiring respiratory protection until wearing a properly functioning respirator appropriate for that area. Cartridges/filters used with air purifying respirators have a limited service life and must be replaced before the chemical starts to break through.
The purpose of field fit checks is to identify errors in the mark assembly, identify faulty or missing parts and to ensure the masks are worn correctly. All workers must perform the following checks each time the respirator is donned before entering a hazardous atmosphere:
a) Negative pressure test – This test consists of closing off the inlets of the cartridges or filters by covering with the palms so that air cannot pass. The worker then inhales lightly and holds his or her breadth for 10 seconds. If the facepiece remains slightly collapsed and no inward leakage is detected, the test is successful.
b) Positive Pressure Test – This test is conducted by closing off the exhalation valve with the palm and exhaling gently into the facepiece. The fit is considered satisfactory if slight positive pressure can be built up inside the facepiece without evidence of outward leakage for 15 seconds.
Workers who are required or expected to wear a tight-fitting respirator must not have facial hair that interferes with the face seal of the respirator or the function of the valves. Facial hair must be kept properly trimmed at all times to meet this requirement. Only trained personnel should perform respirator maintenance and repairs. All maintenance and repairs must be made in accordance with the manufacturer’s recommendations and specifications. Only NIOSH approved parts for a respirator can be used for repairs. Defective respirators must be returned by employees to authorised personnel for adjustment, repairs or to be discarded.
Employers must ensure training is conducted for all employees involved in using respirators and this should be repeated every three years or as prescribed by local regulations. The following will be the content of the training package. As a minimum the training must address the following:
- Use of respirators in emergencies
- Respirator inspection and maintenance
- Cleaning and storage methods
- The importance of proper fit and use
- Respirators’ capabilities and limitations
- Performing respirator self-checks
- Site required uses of respirators
- Donning the respirators
- Maximum use concentrations
Respiratory protection programme elements
According to programme details in OSHA’s respiratory protection standard (29 CFR 1910.134), the seven key elements that every respiratory protection programme should contain are as follows:
- A written plan detailing how the programme is managed
- A complete assessment and knowledge of respiratory hazards that will be encountered in the workplace
- Procedure and equipment to control respiratory hazards, including the use of engineering controls and work practices designed to limit or reduce employee exposure to such hazards
- Guidelines for the proper selection of appropriate RPE
- An employee training programme covering hazard recognition, the dangers associated with respiratory hazards, and proper care and use of respiratory equipment
- Inspection maintenance, and repair of RPE
- Medical surveillance of employees
Importance of RPE
What constitutes a hazardous substance could be a range of solids, liquids, gases or vapours: from solid particles including asbestos, stone and wood dust, engine exhaust particles, smoke and fungal spores; to liquid particles and mists including paints, pesticides, liquid jetting and cutting fluids; gases including carbon monoxide, chlorine and engine exhaust gases; and vapours such as solvent and mercury vapour. RPE is critical for those working with hazardous substances because it protects health and can even save lives. A significant number of the gases, vapours and dusts that cause serious damage to the respiratory system and other parts of the body are invisible to the naked eye, and RPE is an effective way to block them.
Employers should start by looking out for the ‘CE’ mark which confirms health and safety equipment has been designed and tested to meet the minimum legal requirements. Ensuring RPE fits properly when put on will improve the level of protection provided and drastically reduce the chances of ill health or even death.
While RPE is important to have at hand, you should avoid using it as a first port of call. It is far better to carry out a risk assessment and control exposure by using a safer form of the substance in question, eliminating the hazardous substance altogether, extracting emissions such as dust, vapour and gases from substances, hemming in the task to prevent the substance escaping into the workplace air and minimising the length of time workers are exposed. Investing in RPE not only helps you fulfil legal workplace requirements but also keeps your workers safe, happy and motivated – why not add it to your PPE supplies today?
Storage and procurement guide
As well as ensuring that the right type of RPE is used correctly, you need to ensure that it is maintained and stored properly. If it is stored incorrectly or not properly maintained its protective qualities can be adversely affected, which could negatively impact on workers’ safety. RPE left in unhygienic areas may increase the risk of being exposed to contaminations on the inside of the facepiece. In addition, some parts could weaken from exposure to UV light, sunlight, oil and vapours. Maintenance may include cleaning, examination, repair, testing or replacement.
Conclusion
Employers have a legal responsibility to control all substances hazardous to health of their workers and to prevent and control the exposure to the harmful substances by providing appropriate RPE that may be necessary as part of their control regime. COSHH risk assessment must be conducted to identify exposure hazards in the area of work. Products for use at work that are hazardous substances must come with a safety datasheet provided by the supplier and must contain information on the health hazards, form of the substances contained and type of RPE necessary for its use.
