Experience Files

Providing the right respiratory protection for your employees is important, but the array of filter types and nomenclature can be incredibly confusing. Let's break down what you need to know, focusing on the types I recommend for restoration professionals: full-face tightly fitting respirators and full-face PAPRs (Powered Air-Purifying Respirators). PAPRs are essential for individuals with facial hair, as a tight-fitting respirator cannot create an adequate seal. It's also essential that your employees undergo medical clearance to wear a respirator and have the respirator fit-tested to them.

Understanding Filter Labels: N, R, P, and Numbers

Every particulate filter will start with a letter (N, R, or P) and follow with a number (95, 99, or 100).

Oil Resistance (N, R, P)

This letter indicates how the filter material holds up when exposed to oily mists, not its ability to block vapors.

• N = Not resistant to oil: The filter material will saturate and become ineffective if exposed to an oily mist.

• R = Resistant to oil: The filter material offers some resistance to oily mists.

• P = Oil Proof: The filter material is designed to be unaffected by oily mists.

Particulate Arrestance (95, 99, 100)

This number denotes the filter's efficiency at capturing airborne particles. These ratings are based on capturing particles as small as 0.3 microns.

• 95 = 95% particulate arrestance.

• 99 = 99% particulate arrestance.

• 100 = 99.97% particulate arrestance (this is considered HEPA-level filtration).

These filters are generally rated for use in environments with up to 10 times the Permissible Exposure Levels (PELs) for half-face respirators and up to 50 times the PELs for a properly fitted full-face respirator, when dealing with aerosolized, non-immediately life-threatening particulate. Keep in mind that none of these filters are currently approved by manufacturers or NIOSH for sandblasting.

Beyond Particulates: Gas and Vapor Protection

Filters can also include additional layers to provide protection against nuisance levels of specific gases or vapors, typically acid gases or organic vapors. It's important to remember that these are for nuisance levels (i.e., below OSHA or NIOSH PELs). Anything exceeding these limits requires SCBAs (Self-Contained Breathing Apparatuses) or comparable systems, though such extreme situations are rare in restoration.

• Organic Vapor Filters: These provide relief from ozone gas and other organic odors associated with decomposition, feces, or other organic-based smells. They are useful for tasks like welding, brazing, or cutting metal where organic vapors might be present.

• Acid Gas Filters: These offer protection from nuisance levels of acids found in some cleaners, disinfectants, and sewage gases. They are also relevant for tasks involving welding or burning metals.

Filter Designs and Practical Application

For full-face fitted respirators, there are two primary filter designs:

• Pancake Filters: These are round, flat, and covered in fabric. They are the most commonly used and economical option. In clean environments, they have a maximum life expectancy of 40 hours or 30 days. However, on typical restoration projects requiring respirators, they should be replaced more frequently—ideally every 8 hours, or immediately if you can smell odors or if breathing becomes noticeably harder.

• Cartridge Filters: These are thicker plastic filters, often featuring a pleated pre-filter stage and a secondary assembly to block organic or acid gas vapors. While 2-3 times the cost of pancake filters, their increased filter surface area often results in lower breathing resistance and a slightly longer lifespan. Again, they are only recommended for conditions below OSHA and NIOSH PELs.

Given the unpredictable nature of restoration projects, it's prudent to use Pancake P100 filters with nuisance-level organic vapor filtration as a general-use filter. For more hazardous situations like sewage backups, bloodborne pathogen cleanups, asbestos removal, or handling bat guano/pigeon droppings, I highly recommend using a Cartridge filter with P100 and nuisance-level organic vapor and acid gas filtration.

Always prioritize protecting your and your employees' lungs. The right filter choice is a non-negotiable part of job site safety.