Respiratory Protection – Everything You Must Know.
Respiratory protection is not well practiced in the construction industry that’s why respiratory hazards are very common at the construction worksites. The World Health Organization (WHO) ranked respiratory diseases as the leading causes of death and disability in the world. The Center for Construction, Research, and Training (CPWR) reported that construction trade workers had a higher percentage of deaths from diseases of the respiratory system than their white-collar counterparts (13.4% against 8.9%). In addition to physical suffering, the annual costs of chronic obstructive pulmonary disease (COPD) to the nation from medical bills and absenteeism alone were $36 billion in 2010, and are expected to experience a 136.1% rise by 2020. Reducing occupational exposures and respiratory diseases among construction workers would benefit the workers, employers, society, and the nation.
There are many types of air contaminants and there is no single method of controlling them in all workplaces. What makes a substance harmful depends on its toxicity, chemical state, physical form, concentration, and the period one is exposed. The effect might take place immediately or after a long time.
Respiratory protection is vital for construction activities not limited to blasting, sweeping, vacuuming concrete cutting, and concrete mixing. It can be achieved through the supplementation of engineering controls with the use of respirators.
What is a respirator?
A respirator is a device that protects construction workers against insufficient oxygen environments, harmful dust, fogs, smokes, mist, gases, vapors, and sprays among other chemicals and infectious particles. However, respirators should not be used as the only means of preventing or minimizing exposures e.g. lead exposure; it should serve as support to engineering controls e.g. use of ventilators at the worksites. Compliance with the OSHA respiratory protection standard could avert hundreds of deaths and thousands of illnesses annually.
When would you use a respirator?
Respirators should be used whenever and wherever there is a potential of being exposed to particulates, gases, vapors, and biological organisms in your work environment. For example, when a fuel-powered tool is used inside a closed area, effective ventilation and proper respirators such as atmosphere-supplying respirators must be utilized to avoid breathing carbon monoxide and to reduce exposure to the lowest possible levels
Selecting the appropriate respirator for a job
Employers must provide appropriate respirators based on the respiratory hazard(s) to which the worker is exposed to and the user factors that affect respirator performance and reliability in the workplace. For instance:
1. For protection against particulates, the employer must provide:
- An atmosphere-supplying respirator
- An air-purifying respirator equipped with a filter certified by NIOSH
- An air-purifying respirator equipped with any filter certified for particulates by NIOSH
2. For atmospheres that are immediately dangerous to life or health (IDLH), the employer must provide:
- A full facepiece pressure-demand Self-Contained Breathing Apparatus (SCBA) certified by NIOSH for a minimum of 30 mins or;
- A combination full facepiece pressure-demand supplied-air respirator with auxiliary self-contained air supply
What are the Respirators Made From?
Filtering facepiece (dust masks) are generally made directly from a cloth-like filter material. Chemical cartridge/gas mask respirators can be made from a variety of materials. The most popular facepiece materials are silicone, neoprene, and rubber. In general, rubber and neoprene are rigid, durable materials. Silicone is usually preferred for its comfort, flexibility, and ease of cleaning. Full-face respirators are available with strap harnesses or ratchet suspensions. The harness type can be worn under a hard hat, but ratchet suspensions are generally easier to adjust, making donning and doffing easier.
What optional features are available for respirators?
Various features are available to help you customize respirators to suit your employees and the specific hazards they encounter. For example, nose cups reduce lens fogging with full facepiece respirators and lens covers protect the lens from paint, minor chemical splash, and scratches.
Spectacle kits are needed when using prescription corrective lenses. The frame mounts into full-face masks, and the prescription lenses are made by the users’ optometrist. This allows the wearer to maintain a proper fit and still wear prescription lenses.
How do respirators work?
Respirators work by either filtering particles from the air, chemically cleaning (purifying) the air, or supplying clean air from an outside source.
The materials that safety respirators are made up of usually consist of a tangled mat of fine fibers that creates convoluted pathways to the inhaling air. The inhaling air has to pass through these convoluted pathways with any particles and droplets being carried by it.
For particles big enough to be seen by the naked eyes, these fiber mats behave like a sieve by physically blocking the particle from passing through.
For the superfine particles, it is their inability to follow the convoluted pathway through the filter material that leads to them being captured.
The smallest lightest particles can easily dance through the fine fibers because they have little mass, nonetheless, very fine fibers are used in collecting these particles.
The middle-sized articles (they are too small to be capture because of their inertia but too large to be capture by diffusion) usually 0.3 micrometers (um) in size, they are the hardest to remove. The respirator manufacturers use 0.3 um sized particles to test the effectiveness of their respirator.
Selecting the appropriate respirator depends on the contaminant(s) to which you are exposed and the protection factor (PF) of the respirator. Required respirators must be NIOSH-approved and medical evaluation and training must be provided before use.
1. Non-NIOSH-Approved Single-strap Dust Masks – are useful in providing comfort from pollen or other allergens. Not fit for working in hazardous atmospheres.
2. NIOSH-Approved Single-strap Dust Masks – can be used for dust, mists, welding fumes, etc. They do not protect from gases or vapors. Do not use for protection from ASBESTOS or LEAD
3. Approved Filtering Face Pieces – Half-face respirators can be used for protection against most vapors, acid gases, dust, or welding fumes. Cartridges/filters must match contaminant(s) and be changed periodically
4. Half-Face Respirators – are suitable for protection against most vapors, acid gases, dust, or welding fumes. The face shield protects the face and eyes from irritants and contaminants. However, they are not as protective as the full-face respirators. Cartridges/filters must match contaminant(s) and be changed periodically
5. Full-Face Respirators – Loose-fitting powered-air-purifying respirators (PAPR) offer breathing comfort from a battery-powered fan which pulls air through filters and circulates air throughout helmet or hood. They can be worn by workers with beards. Cartridges/filters must match contaminant(s) and be changed periodically
6. Loose-Fitting Powered-Air-Purifying Respirators – A Self-Contained Breathing Apparatus (SCBA) is used for entry and escape from atmospheres that are considered immediately dangerous to life and health (IDLH) or oxygen-deficient. They use their air tank.
Differences between a Mask and a Respirator
For protection, both surgical masks and respirators need to be worn correctly and consistently. If used properly, surgical masks and respirators both have a role in preventing different types of exposures.
Respirators are designed to reduce a worker’s exposure to airborne contaminants. It comes in various sizes and must be individually selected to fit the wearer’s face and to provide a tight seal. A proper seal between the user’s face and the respirator forces inhaled air to be pulled through the respirator’s filter material and not through gaps between the face and respirator. Respirators offer the best protection for workers who work in occupations classified as very high exposure risk or high exposure risk to pandemic influenza or coronavirus.
2. Surgical Masks
Surgical masks are used as a physical barrier to protect the user from hazards, such as splashes of large droplets of blood or body fluids. Surgical masks also protect other people against infection from the person wearing the surgical mask. Their ability to filter small particles varies significantly based upon the type of material used to make the surgical mask, so they cannot be relied upon to protect workers against airborne infectious agents.
It is important to note that:
– Surgical masks are not designed or certified to prevent the inhalation of small airborne contaminants. These particles are not visible to the naked eye but may still be capable of causing infection.
– Surgical masks are not designed to seal tightly against the user’s face. During inhalation, much of the potentially contaminated air can pass through gaps between the face and the surgical mask and not be pulled through the filter material of the mask.
Differences between a Particulate Respirator and Gas Masks Respirator
1. Particulate Respirators:
Particulate respirators are the simplest, least expensive, and least protective of the respirator types available. These respirators only protect against particles (e.g., dust). They do not protect against chemicals, gases, or vapors, and are intended only for low hazard levels. The commonly known “N-95” filtering facepiece respirator or “dust mask” is one type of particulate respirator, often used in hospitals to protect against infectious agents. Particulate respirators are “air-purifying respirators” because they clean particles out of the air as you breathe.
Furthermore, particulate respirators:
- Filter out dust, fumes, and mists.
- Are usually disposable dust masks or respirators with disposable filters.
- Must be replaced when they become discolored, damaged, or clogged.
- Examples: filtering facepiece or elastomeric respirator.
How are particulate filters classified?
There are nine classes of particulate filters which are broken down into three series: N, R, and P. Each series (N = Not resistant to oil, R = Somewhat Resistant to oil, and P = Strongly resistant to oil (oil-Proof)) is available at three efficiency levels: 95%, 99%, and 99.97%. The N series filter is used in environments free of oil mists. The R series filters can be exposed to oil mists, but should only be worn for one work shift. The P filter can be exposed to oil mists for longer than one work shift.
2. Chemical Cartridge/Gas Mask Respirator:
Gas mask respirators are also known as “air-purifying respirators” because they filter or clean chemical gases out of the air as you breathe. This respirator includes a facepiece or mask, and a cartridge or canister. Straps secure the facepiece to the head. The cartridge may also have a filter to remove particles.
Gas masks are effective only if used with the correct cartridge or filter for a particular biological or chemical substance. Selecting the proper filter can be a complicated process. There are cartridges available that protect against more than one hazard, but there is no “all-in-one” cartridge that protects against all substances. To be certain you are choosing the right filters/cartridges, it is important to know what hazards you will be facing.
Furthermore, Chemical Cartridge/Gas Mask respirator:
- Uses replaceable chemical cartridges or canisters to remove the contaminant.
- Are color-coded to help you select the right one.
- May require more than one cartridge to protect against multiple hazards.
Types of Gas Mask Respirator
1. Powered Air-Purifying Respirator (PAPR): Powered air-purifying respirators use a fan to draw air through the filter to the user. They are easier to breathe through; however, they need a fully charged battery to work properly. They use the same type of filters/cartridges as other air-purifying respirators. It is important to know what the hazard is, and how much of it is in the air, to select the proper filters/cartridges.
2. Self-Contained Breathing Apparatus (SCBA): SCBA is the respirator commonly used by firefighters. They use their air tank to supply clean air, so you don’t need to worry about filters. They also protect against higher concentrations of dangerous chemicals. However, they are very heavy (30 pounds or more) and require very special training on how to use and to maintain them. Also, the air tanks typically last an hour or less depending upon their rating and your breathing rate (how hard you are breathing).
Moreover, Self-Contained Breathing Apparatus:
- Provide clean air from a portable air tank when the air around you is simply too dangerous to breathe.
- All of these respirators (except for the “dust masks” or filtering facepieces) are available in either half-mask or full-face pieces.
Maintenance of Respirators.
- Respirators must be properly cleaned and disinfected after each use
- It must be stored in a convenient, clean and sanitary location
- Replacement of respirators must be done only by experienced persons with parts designed for the respirator
- No attempt must be made to replace components or to make adjustment or repairs beyond the manufacturer’s recommendations
- Reducing or admission valves must be returned to the manufacturer or a trained technician for adjustment or repair
- Respirators must be stored to protect it against dust, sunlight heat, extreme cold, excessive moisture or damaging chemicals
Precautions for Use of Respirators
- A respirator cannot be worn if prohibited by the respirator requirements for substance-specific standards (i.e. methylene chloride)
- All oxygen-deficient atmospheres must be considered Immediately Dangerous to Life or Health (IDLH)
- Air-purifying respirators must not be worn in unknown and/or IDLH atmospheres, in oxygen-deficient atmospheres, or in situations where the employer cannot prevent the canister or cartridge from becoming saturated.
- Do not wear respirators when conditions prevent a good face seal e.g a growth of beard, sideburns, etc.
- A respirator may be unacceptable if it causes irritation or pain to an employee, if the employee is unable because of discomfort to wear the respirator for the time required, or if the employee is unable to maintain a proper seal
The use of respirators should supplement the continued use of engineering controls and good work practices.
A NIOSH-certified respirator must be selected and it must be used in compliance with the condition of its certification