Respirators

Respirators

Respiratory Protection Guide

What Is A Respirator?

A Respirator is a piece of equipment that is worn on the face. They are either worn over the mouth and nose or to cover the whole face. They are designed to protect workers against smoke, dust or fumes from toxic substances.

A Respirator is an important part of Personal Protective Equipment. It is widely acknowledged that PPE should be used as the last resort in the Hierarchy of Controls.

Please note that this guide is for information purposes only. You should use expert advice from people who are trained in assessing potential hazards and the suitability of respirators.

Types of Respirators:

  • Air Purifying Respirators
  • Atmosphere Supplying Respirators

Types of Air Purifying Respirator Mask:

  • Filtering Facepiece
  • Half facepiece
  • Full facepiece

Types of Atmosphere Supplying Respirators

  • Powered Air Purifying Respirators (PAPRs)
  • Supplied Air Respirators
  • Self-Contained Breathing Apparatus

What is Assigned Protection Factor of a Respirator?

The APF is the minimum protection that respirator should offer if it worn suitably and correctly in a work setting. An APF of ten would define that it has a protection that no more than a tenth of the contaminants would leak into the mask.

OSHA defines APF as:

“Assigned protection factor (APF) means the workplace level of respiratory protection that a respirator or class of respirators is expected to provide to employees when the employer implements a continuing, effective respiratory protection program as specified by this section.”

Filtering Facepiece Respirators

These type of Dust Mist and Fume respirators are disposable options that aim to reduce exposure inhalation to particulates.

They are more commonly used by woodworkers to protect against wood dust, those working with animals to protect against dander and those working outdoors to protect against pollen.

They work on a negative pressure basis. This means that air pressure inside of the facepiece is negative during inhalation compared to the air pressure outside of the mask.

These differ from other forms of respirator as the mask acts as the filter. If using this mask, ensure that it is NIOSH approved. This should have double straps and the packaging labelled clearly with a letter of N (Not resistant to oil), R (somewhat resistant to oil) or P (strongly resistant to oil or oil proof). The filter efficiency should also be identified with either 95,99 or 100.

NIOSH approved N95 respirators filter at least 95% of airborne particles but they do come with their limitations.

These disposable respirators are very lightweight and generally inexpensive.

Known limitations of filtering facepiece respirators are that they are difficult to establish a good face seal and also to check whether that the face seal is adequate. Wearers have to be continuously clean-shaven.

Half Face Piece Respirator

Half Face Respirator

These respirators cover the mouth and nose and chin. They are elastomeric respirators normally with replaceable filter cartridges. These mask respirators utilise a rubber seal. They often used to work with particulates. The cartridges that are used in half piece purify the air as the employee breathes. Different Cartridges are available for different task and different exposure to contaminants.

The half face mask respirator is lightweight. These masks offer protection up to a level but aren’t as effective as the protection that a full-face respirator offers.

 Full Face Piece Respirator

full face respirator

These work on the same basis as half piece respirators. The facepiece covers the whole face, however, including the eyes, nose chin and mouth. Due to design the offer a better seal and improve protection over half piece respirators. As they cover the eyes it also protects the user from any irritation due to vapors and mists and any accidental splashes.

Full face units are heavier than half face and therefore less comfortable. They can cause problems for eyeglass users. They cannot be used in oxygen-deficient atmosphere. They cannot be used in an environment where the atmosphere has high concentration levels of contaminants.

These respirators are more suited where a greater degree of protection is needed and where eyes and face protection is required.

Powered Air Purifying Respirators

These types of respiratory protection use a battery-operated fan which draws air through a filter -either a particulate or chemical. It then forces this into the facepiece. The unit is either worn as a backpack or on the user’s belt. These can be used in conjunction with half or full masks, hoods and helmets.

As this is a positive pressure system using the fan to force air in it is easier to breathe over the negative pressure options.

These systems can be expensive to purchase and maintain. They are restricted because of their battery life.

If the work carried out is strenuous it may affect the effectiveness of the positive pressure due to the heavier breathing by the wearer.

Supplied Airline Respirators

These respirators are supplied with a clean air from an external source such as a compressor or air cylinders. Like the PAPR it may be supplied to a half or full facepiece, helmet, or hood. The air must be of high quality. These respirators can be used for longer periods of time and provide minimal breathing resistance. They provide a high degree of protection against a wide range of contaminants compared to the other respirators.

The downside to these respirators is that it can be awkward to work with as the wearer is constantly attached to a hose.

Who needs a respirator?

Employees will need to wear a respirator if the existing control measures and work measures still aren’t enough to guarantee that the air is of good enough quality to work in.

If the environment does not contain enough oxygen or there are harmful dusts, smoke, fumes, vapors, sprays mists and fogs present then the employee will require use of a respirator. The employee should be tested and trained in the use of the respirator

Respiratory Protection Program

OSHA dictates that where an Employer has identified that employees must wear respirators as part of their working operations, they should set up and maintain a respiratory protection program. The standard for this requires that records should be kept regarding the suitability of a respirator, procedures to follow, training in their use, a program administrator appointed, face fit tests, medical testing and how to use the respirator including cleaning and maintenance.

Face Fit Testing

To provide the best protection that a respirator has to offer it is advised that workers have a face fit testing to ensure that is tightly sealed around the face areas. OSHA require that this is carried out on all respirators that are mandatory to carry out tasks, including disposables.

The test should be carried out annually as a minimum and if there are any changes. For instance, if the respirator is changed in style or if there is a weight loss or gain or change of face shape due to dental work or another injury.

The two main types of test are Qualitative and Quantitative:

Qualitative Face Fit Test (QLFT)

This relies on the wearer’s ability to taste or smell a particular substance. It is a pass or fail test. This is usually used for testing half face masks

 Often this is a bitter or sweet solution. The agents accepted by OSHA are:

  • Saccharin. This is a sweet taste. It can used to test particulate filters of any class.
  • Isoamyl Acetate. This smells quite like bananas
  • Bitrex-produces a bitter taste
  • Irritant Smoke- causes an involuntary cough.

This method of testing must include the following seven exercises to be carried out lasting a minute each:

  1. Normal Breathing
  2. Depp Breathing
  3. Moving head side to side
  4. Moving head and down
  5. Bending over or Jogging in place
  6. Talking
  7. Resume Normal Breathing again

Quantitative Face Fit Test (QNFT)

An instrument is used to detect leakage around the seals of the respirator in a Quantitative Face Fit Test. A probe is attached in the wearer’s respirator mask or face piece and this in turn links the to a pipe that is attached to the testing machine.

In addition to the seven exercises carried out in the qualitative test, there is also a 15-second grimacing section.

This test can be used for all types of mask.

There are three types of testing agent approve by OSHA in Quantitative fit testing:

  • Generated Aerosol
  • Ambient aerosol condensation nuclei counting (CNC) instruments
  • Controlled negative pressure (CNP) systems

The three tests require that the face mask is used with particle filters so no particles can ingress to affect the results.

This test will show in numerical form how efficient the respirator fit is. The testing machine should be calibrated regularly (annual is suggested)

Do you need to trained or qualified to undertake the test?

No but OSHA requires that person administrating the tests to have the knowledge of how to conduct the test accurately. The administrator should also know how to spot invalid tests and advise on maintenance and cleaning procedures. In our view it is best that person carrying out the test should be trained in this as wearing correctly fitted respiratory equipment is important.

Wearing PPE during the Fit Test

If you use other items of PPE whilst using a respirator it is important to wear these whilst undertaking the fit test. Eye Protection, Hard Hats, Overalls, Ear defenders

Fit Test Record

A fit test record of the employees that are required to wear respirators should be kept after a test is carried out.

The Test Record should show:

  • Details of the employee
  • Respirator and manufacturer being tested,
  • Size of respirator,
  • Types of filters used,
  • Any additional PPE worn,
  • Which test was used,
  • Location
  • Testers details
  • Date of test
  • Pass and Fail information
  • Whether the facepiece was employees, or a sample provided.

An employee could also carry a fit test wallet card showing that they have been fit tested for a respirator and the key dates.

Why Fit is important when choosing a Respirator

Fit is the most important aspect of wearing a respirator. The respirator is designed to filter out potential nasties entering your lungs. The respirator should when fitted correctly should be tightly sealed to the user’s skin.

Most masks are available in three sizes so selecting the correct size from the outset should help with the seal fit.

Face fit testing also ensures that the respirator that is being used is suitable in regard to the level of protection that is needed.

The seal should be Airtight. If the seal is loose this means that air can enter and that the air isn’t filtered as it should be.

Facial hair can interfere with the seal and the wearer should be clean-shaven on the day of face testing. OSHA states this and even stubble can affect the tight-fitting seal. That means no mustaches, beards or stubble.

The tester should also get the wearer to undertake various exercise to recreate working conditions to ensure that the seal remains tight. The respirator may slip, and this should be taken into account. The seal should be tight enough that when movement is carried out, the mask remains in place.

User Seal Check

Every time the tight-fitting respirator is worn the user should perform the seal check. This is required under OSHA regulations

Two types of seal check can take place:

Positive Pressure Check:

  • The facepiece should be worn as normal and adjusted to a comfortable fit. I should fit snuggly and not be too tight.
  • Begin by blocking the exhalation valve. This is usually situated on the bottom of the respirator.
  • Try breathing out
  • The facepiece mask should puff slightly away from the face and stay in that position for ten seconds whilst the breath is held.
  • If a leak is found, try adjusting the straps and trying again until a good fit is found.

Negative Pressure Seal Check:

  • The facepiece should be worn as normal and adjusted to a comfortable fit. I should fit snuggly and not be too tight.
  • Begin by blocking the inlets which let air in. These are normally positioned on the side of the mask facepiece.
  • Try to draw a breath in.
  • If the mask if leak-free the facepiece should collapse slightly
  • If a leak is found, try adjusting the straps and trying again until a good fit is found.

Regular checks should be made whilst wearing a mask to check the seal.

Respirator seal checks are shown here: https://www.youtube.com/watch?v=DzIDhYGnDIM

Respirator Maintenance

Respirator maintenance is essential in keeping the employee protected. To work effectively the mask and cartridges and other items should be in good working order.

Due to the areas where respirators are used, regular cleaning and maintenance should be carried out. Dirt, cracks, tears and damage should be inspected prior and after each use. The unit should be disassembled prior to cleaning.

Storage is also an important factor. Ideally, a storage tub should be used which should be kept away from chemicals and other substances and stored in a cool dry area. Cartridges should be removed

Storage factors that may affect respirator effectiveness are dust, cigarette smoke, engine exhausts, extreme heat and cold, humidity and sunlight.

Remember not to store anything on top of the mask.

Respirator Maintenance Checklist:

  • Elastic straps. Stretch them too ensure they aren’t loose and check for minor tears.
  • On full-face check the lens areas for damage and cracks.
  • Face seal- inspect and ensure there are no dirt, cracks and tears.
  • After a pressure seal check is carried out the wearer will be able to identify if the valves are functioning correctly.
  • Check for other areas of damage, missing or worn parts. If this is the case, get a new respirator or report it to get a repair.

Cleaning the Respirator

Wash hands thoroughly before taking the respirator apart. Check with manufacturers instruction on how to disassemble and reassemble.

Handwash the mask in warm soapy water as suggested by the manufacturer. Rinse completely.

Make sure that the inhalation and exhalation valves are cleaned.

Non-alcohol disposable wipe pads can be used during the working day.

Cartridges & Filters

As important as the face mask selection is making sure the correct filters and cartridges are selected for the work carried out. Depending on where the respirators are being used will determine how fast the cartridges will break down. These should be changed regularly. If any taste, odors or irritation are detected whilst wearing, leave the area and replace the cartridges.

Conclusion

The information in this guide to respirators is not an exhaustive list but aims to provide an overview of the basics of respiratory protection. Advice should be sought if working in hazardous areas. Respirators are an important part of the PPE solution and should be chosen carefully and maintained to a high standard

Further Reading:

OSHA Fit Testing Protocols:

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.134AppA

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.134AppB1

Assigned Protection Factors:

https://www.osha.gov/Publications/3352-APF-respirators.pdf

Respirator General Information:

https://www.cdc.gov/niosh/npptl/topics/respirators/factsheets/respfact.html

https://www.osha.gov/video/respiratory_protection/resptypes_transcript.html