A respirator is a safety device that helps protect your lungs from harmful dust, fumes, mists, vapors, and gases in a workshop. It matters because many hazards are too small to see, yet they can damage the respiratory system after short or repeated exposure. A half-face respirator with dual cartridges seals around the nose and mouth and filters air before you breathe it in.
Choosing and using the correct respirator is as important as wearing eye protection or hearing protection around machines.
Key Facts
- Assigned protection factor for many half-face respirators is APF = 10 when properly fitted.
- Fit factor = concentration outside mask / concentration inside mask.
- Filter efficiency = 1 - penetration fraction.
- If a filter has 95 percent efficiency, penetration fraction = 0.05.
- Airflow resistance increases as filters load with dust, so breathing effort rises over time.
- Respirators do not supply oxygen unless they are supplied-air or self-contained breathing apparatus systems.
Vocabulary
- Respirator
- A respirator is a device worn over the face to reduce inhalation of hazardous particles, vapors, or gases.
- Cartridge
- A cartridge is a replaceable filter unit designed to capture specific hazards such as organic vapors, acid gases, or particulates.
- Fit test
- A fit test is a procedure that checks whether a respirator seals properly to a specific person's face.
- Particulate filter
- A particulate filter traps solid or liquid particles such as dust, smoke, or mist as air passes through it.
- Breakthrough
- Breakthrough is the point when a cartridge no longer captures a vapor or gas effectively and the contaminant begins to pass through.
Common Mistakes to Avoid
- Using the wrong cartridge for the hazard, which is wrong because a dust filter may not stop organic vapors and a vapor cartridge may not stop fine particles.
- Wearing a respirator over facial hair, which is wrong because hair can break the face seal and let contaminated air leak around the mask.
- Skipping the seal check before each use, which is wrong because straps can shift and a small leak can greatly reduce protection.
- Keeping old cartridges in service too long, which is wrong because saturated cartridges can allow contaminants through even if the mask still looks clean.
Practice Questions
- 1 A workshop air sample has 80 mg/m3 of wood dust outside a respirator and 8 mg/m3 inside the mask. Calculate the fit factor.
- 2 A particulate filter removes 99 percent of incoming dust. If 5000 particles enter the filter each second, how many particles pass through each second?
- 3 A student is spray painting with an organic solvent while wearing only a basic dust mask. Explain why this is unsafe and identify the type of respirator protection that would be more appropriate.