Importance Of Filter Change - Respirator Filters Don't Last Forever!

The use of personal respiratory protection against airborne contaminants is essential. The most broadly used respirators are disposable and reusable air-purifying respirators that are powered by the wearers own breathing. These respirators use filters to remove contaminants from the inhaled air. 
Disposable respirators are throw away and therefore are maintenance free. If using a reusable respirator, these do require some maintenance. Reusable respirators both half and full face should be cleaned with an a - in particular the filters. Filters do not last forever and the most commonly asked questions are:

• How long will my filters last?
• Why do i need to replace my filters?
• When do i replace the filters?

The following information can be used as a guideline to answer these questions. 

What Types Of Filters Are There?

There are a variety of different filters available for use with both full and half face respirators. These filters help protect against the multitude of airborne hazards including particles, gases, fumes and vapours. When selecting the correct filter to use you must first consider the hazards present and the level of protection required.  

Particulate Filters Protects ONLY against particles e.g. dust, mist, smoke, mould etc.
Gas & Vapour Cartridge Filters Protects ONLY against gases and vapours
Combination Filters Protects against particles, gases and vapours

How Long Will Filters Last?
When filters are stored unopened in their original packaging they are usable up until the expiry date printed on the packaging OR filter. If filters are removed from their packaging gas and vapour cartridges can potentially be used for up to 6 months and then must be replaced (regardless of the amount of use). 
Once a filter is opened the life span is dependent on a few different variables including; the quality and capacity of the filter, the contaminant it is filtering, type of filter in use and the frequency of use. Filters DO NOT have a fixed life span as every work-environment is different and the filters life span will vary dependent to the conditions of its exposure. 

User knowledge is also a key aspect in determining the life span of respirator filters. Users should determine the specific exposure to first allow selection of the most suitable product and secondly the creation of a relevant filter change schedule to ensure workers are changing their filters accordingly. 
User knowledge, good training and correct use of the product will help ensure that workers achieve the prescribed levels of respiratory protection. 

Why Do I Need To Replace My Filters Regularly?

Particulate filters get clogged and blocked up which then make them harder to breathe though. This in turn means the worker needs to work harder when breathing therefore becoming more fatigued over extended periods of use. 
Gas and vapour filters can begin to let contaminants through once their sorbents become saturated. (This is known as breakthrough)

When Do I Replace My Filters?

Particulate Filters

It is best to replace BOTH the 3M Particulate Filters when it becomes difficult to breath or the filter becomes dirty or physically damaged. Each individual wearer will need to change their filters to suit their own personal usage.

3M particulate filters rely on electrostatically charged fibres to trap particulates within the filters. As these particulate filters fill up with the contaminant, they actually become a better filter BUT they do become harder to breathe through. 
AS/NZS1716 uses a classification system to identify the different particulates the filter will protect against. 

P1	Particles generated by mechanical processes e.g. sanding, grinding
P2	Particles generated by mechanical and thermal processes e.g. welding
P3	Particles including highly toxic material

Gas & Vapour Cartridge Filters

Many factors affect the service life of any 3M gas and vapour cartridge filters. These including type of contaminants, ventilation, temperature, breathing rates etc. 
It is best to replace BOTH the 3M gas and vapour cartridge filters when the expiry date on the sealed packet has passed, once opened maximum use time is 6 months and/or when the user can smell or taste the contaminants.

These gas and vapour filters rely on sorbent material to absorb the gas and vapour molecules. Typically the sorbent is carbon grain which has been specifically treated to help absorb different types of gases and vapours.
AS/NZS1716  uses a classification system to identify the different contaminants the carbon grain in the cartridges will protect against. 

A	Organic Vapours (boiling point >65ºC)
B	Inorganic Gases
E	Acid Gases
K	Ammonia
Hg	Mercury
G	Organic Compounds with Low Vapour Pressures

Combination Filters

Combination filters life span are dependent on the exposures occurring during the operation and should be treated the same as the above mentioned particulate, gas and vapour cartridge filters. 

The information provided above is intended as a guide to assist you with 3M Cartridges and Filters used with your 3M Half or Full Facepiece Reusable Respirators.
For additional information or specific advice to assist you with Respiratory Products, contact us here!