WHY IT IS IMPORTANT
Organizations and employers are obligated to protect workers from exposure to a hazardous biological or chemical agents in the air when other hazard control methods are not practical or possible to put in place.
They should only be used:
Respiratory hazards may be present as
Inhalation hazards can be divided into the following classes based on the type of effects they cause.
Materials that irritate the nose, eyes, lungs or throat. Some of these materials include solvent vapours, fibreglass dust, ozone and hydrogen chloride gas. Pulmonary edema, a pneumonia-like condition, can present after several hours from being exposed to materials like cadmium fume produced by welding or oxyacetylene cutting of metals coated with cadmium.
Substances that do not allow proper oxygenation to the body and can be divided into simple asphyxiants (displaced oxygen by gases or vapours), or chemical asphyxiants (elements that interfere with the body’s ability to transport oxygen).
3. Central nervous system depressants.
Cause symptoms such as headache, drowsiness, nausea, and fatigue. Most solvents are central nervous system depressants.
4. Fibrotic materials.
Asbestos and Silica can cause fibrosis or scarring of lung tissue in the air sacs.
Asbestos, Silica and Hexavalent Chromium can promote or cause cancer in specific body organs.
Excessive exposure to these substances can be adverse in itself or can aggravate existing conditions such as emphysema, asthma, or bronchitis.
7. Biological hazards.
Can cause asthma, throat, nose and eye irritation or pneumonitis.
8. Respiratory sensitizers.
Asthma can be caused by chemicals such as isocyanates in spray foam insulation or certain wood dusts.
Supervisors/Principal Investigator and All Others in Authority
Supervisors/Principal Investigator and all others in authority shall:
Respirator Users shall:
NIOSH AND CSA
What is NIOSH?
The National Institute for Occupational Safety and Health (NIOSH) is the U.S. federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH conducts scientific research, develops guidance and authoritative recommendations, disseminates information, and responds to requests for workplace health hazard evaluations. Where there is a danger of an airborne hazardous substance or an oxygen deficient atmosphere in a workplace, the employer shall provide a respiratory protective device that is listed in the NIOSH Certified Equipment List.
What is CSA Z94.4?
The Canadian Standards Association is the most widely accepted regulatory agency in Canada. CSA is an independent, not-for-profit membership association that encompasses standards development, training and advisory solutions, global testing and certification services, as well as consumer product evaluation services. Currently 40 per cent of all the standards issued by CSA are referenced in Canadian legislation CSA Z94.4.1:21 provides a classification for respirator types and performance criteria for respirator certification. It follows the requirements in 42 CFR 84 approved by the National Institute for Occupational Safety and Health (NIOSH) in the United States. The Canadian standard and accredited certification program provides manufacturers with an equivalent option to the U.S. NIOSH certification program for filtering respirators. Eventually, this certification program will replace the Health Canada Guidance on safety and performance specifications for filtering facepiece respirators (FFRs) issued during COVID-19 in 2020.
Comparing CSA Z94.4.1:21 with NIOSH (42 CFR 84):
A primary objective of CSA Z94.4.1:21 was to align the Canadian standard to NIOSH requirements. CSA also took the opportunity to address some of the specific needs and requirements identified during COVID-19. Some of the key additions include:
CSA Z94.4.1:21 excluded gas/vapour and CBRN filtering respirators, such as:
If any worker needs to use a respirator, then a respiratory protection program is
necessary. The program should include the following procedures for:
In addition, CSA standard Z94.4 requires that the employer ensure the individual is medically approved to wear a respirator. It is important to refer to the occupational health and safety legislation in your jurisdiction for additional requirements for respirator use.
Oxygen levels can determine if an atmosphere is oxygen-deficient or oxygen-enriched.
Oxygen-rich environments (above 23%) have flammable hazards that relate directly to firefighting, hazmat response and operations, and confined space entry.
FILTERS & CARTRIDGES
Filters and cartridges enhance the effectiveness of respiratory protection. Advanced planning and consideration must be given when choosing a filter or cartridge. Particulate filters are available in three classes known as N, R and P.
Each class can provide three levels of filter efficiency:
N-class filters are for non-oil atmospheres only. This means they will not provide protection in oily atmospheres.
R-Class (Somewhat Resistant to Oil)
R-class filters are resistant to oily atmospheres but must be time monitored with a maximum of eight hours of service.
P-Class (Oil Proof)
P-class filters are oil proof and may be used in oil-containing atmospheres like underground mines and machine shops.
How to Choose a Filter:
N95 Filtering Facepiece
The N95 filtering facepiece is one of the most popular respirators on the market. You can use N95 pre-filters with chemical cartridges, as well as R pre-filters and standalone P-class filters.
Pre-filters are N-series or R-series filter disks held to the top of a chemical cartridge by a filter holder. They are designed to filter particulates before air enters the cartridge.
N95s filter 95% of particulates > 3 microns in size.
They are typically worn to reduce exposure to bioaerosols or droplets produced by coughing and sneezing.
An N95 filtering facepiece respirator seals tightly and reduces exposure to smaller airborne particles. It forces inhaled air through a filter and must be fit tested to the user. Additional information on fit testing is found later in this guide.
N95 filtering facepiece respirators cannot be used:
NIOSH COLOUR CODING SYSTEM FOR CHEMICAL CARTIDGES
To help select the correct respirator cartridge, NIOSH created a colour coding system.
Air-Purifying Respirator Cartridges Cartridges and filters provide protection against a specific type of hazard. The P100 filter is the most common type of cartridge. It's used for low-level concentrations of certain toxic dust including asbestos, radionuclides and silica.
P100 can be a standalone cartridge or stacked with the following:
A qualified person must establish written procedures and schedules to outline how often workers should change cartridges and filters based on warnings that determine an end-of-service time.
The useful service life of a cartridge is based on how long it provides adequate protection from hazardous air contaminants. The service life of a cartridge depends on many factors including:
Employers should apply a maximum use time to the service life estimate. This ensures the change-out schedule is based on a conservative estimate.
Manufacturers have technical documents and tools to assist qualified persons when estimating maximum use time limits. These documents give instant access to contaminant and concentration data and other customized information.
Manufacturers also provide visual saturation indicators to let the user know when it's time to replace a cartridge.
The user can tell a cartridge needs changing based on warning properties and breathing resistance. For instance, if the hazard is a gas or vapour, the substance may be detected by smell or taste. This lets the user know that there has been a cartridge breakthrough. This however cannot be used as the sole method of cartridge change out.
If the hazard is a particulate, increased breathing resistance through the filter is the main way to determine that a change out is required.
RESPIRATOR FIT TESTING
The purpose of a qualitative or quantitative fit test is to verify a user’s ability to obtain an effective seal and an acceptably comfortable fit for a selected tight-fitting respirator. The fit test process also verifies that a user is able to demonstrate the required level of competency in donning and doffing the respirator, as well as inspecting it and performing a user seal check.
There are a few general points to consider when it comes to respirators and fit testing:
A fit test must be carried out:
User Seal Check
A user seal check is an action conducted by the respirator user to determine if the respirator is properly sealed to the face. The user seal check can be conducted by doing one of the following tests:
Positive pressure test:
Negative pressure test:
If a leak is detected, adjust the facepiece or straps and repeat the test until a good fit is achieved.
The users seal should be done prior to every use.
Important: A user seal check cannot be used as a substitute for a quantitative or qualitative fit test.
QUALITATIVE FIT TESTING (QLFT)
Qualitative fit testing relies on the user’s sensory response to detect a challenge agent in order to determine the fit of the respirator.
During qualitative fit testing, a challenge agent is introduced under a confined hood near the user to determine the integrity of the seal.
The user must perform a series of head and body motions typical of normal daily movement. If the aerosol is undetected to the user on completion of testing, the seal is considered adequate and the test is considered successful. A pass is given to the user with the tested respirator only.
When QLFT is performed, a variety of fit testing challenge agents may be used. The most common types found in the latest Standard are:
Successful Test Results
Users should refrain from the following activities for at least 30 minutes before testing to help ensure a successful process:
Individuals getting a fit test must be clean-shaven where the respirator seals to the skin of the face or neck.
For most, this means being clean-shaven within the previous 24 hours, but 12 hours is preferred.
This ensures hair won't infringe on the sealing surface of the respirator and won't interfere with the valve or respirator function.
It's best to put a clean-shaven policy in place by emphasizing its importance during training, regular reminders and ongoing conformance verification.
Important: If you cannot achieve a proper fit, do not enter the contaminated area and advise your manager or supervisor.
QUANTITATIVE FIT TESTING (QNFT)
Quantitative fit testing uses an instrument to assess the amount of leakage into a respirator to determine fit.
During a quantitative fit test, ambient airborne particles are used as the challenge agent. These particles are measured both inside and outside the respirator while the test subject performs a series of exercises described in the CSA Standard. The particles may be counted by an optical particle counter (OPC) or condensation nuclei counter (CNC) to determine the number of particles inside and outside the respirator.
The instrument will sample for particles inside and outside the test subject’s mask simultaneously while determining a ratio.
A fit test pass is determined if:
This method removes any subjectivity on the part of the user and is considered the most reliable method of fit testing.
Respirator selection shall be based on a systematic review of the hazards and knowledge of standards, regulatory criteria, and manufacturer information on the types of respirators and their limitations to ensure that appropriate respirators are selected for the intended conditions of use.
For the purpose of selection, respirators shall be grouped as follows:
In most cases a Fit Test is required to reassure the proper function and use of the respirators. If you want to learn more about that, visit our Fit Testing section.