Play it Safe: Maintain and Fit Test Your Cartridge Respirators - UNL CropWatch, Sept. 29, 2011

Play it Safe: Maintain and Fit Test Your Cartridge Respirators - UNL CropWatch, Sept. 29, 2011

Sept. 30, 2011

When working with a pesticide, always check the label for the required personal protective equipment (PPE) and be sure to use it.

Some pesticides carry a risk of inhalation exposure and require the use of a respirator. One of the most common types is the half face cartridge respirator. A new half face cartridge respirator will be packaged with an instruction manual, faceplate with straps, two cartridges, and extra accessories to attach for dust or particulate protection. Check the labels on the cartridges to ensure they provide the protection you need, whether it is against organic vapors or other particulates.

As with other PPE, you should properly maintain your respirator to ensure that it offers adequate protection when you apply pesticides. This includes testing the respirator’s seal before each use, and properly cleaning and storing the respirator after each use. Refer to the instruction manual for more information about how to assemble, use, and care for your respirator.

 Adjusting respirator  Adjusting respirator  Adjusting respirator neck strap
Figure 1. Adjusting a respirator step-by-step: 1. Place on face. 2. Adjust "halo" strap. 3. Adjust neck straps.


Fit Testing

Fit testing is mandatory under Occupational Safety and Health Administration (OSHA) regulations. Fit testing will determine whether the respirator size is correct for the initial user. Additionally, a new fit test may be required if there is a change in size, make, or model of the respirator you are using, or changes in user characteristics (dental work, body weight, etc.). Always follow these guidelines.

OSHA Respirator Requirements

For more information about OSHA’s medical evaluation questionnaire, mandatory fit test procedures, and other respirator requirements, see and search for the regulation “1910.134.”

Pesticide applicators need to meet certain health requirements before conducting a fit test or doing work that requires a respirator. OSHA requires that employees who will be using a respirator have a medical evaluation prior to fit testing and be properly trained in respirator use.

The most important part of a fit test is obtaining a good seal. It is a good practice to test the seal on your respirator every time you put it on. Between removal, cleaning, and storage, the respirator may not fit the same, so you’ll have to readjust it before using it again. Prior to each use, check the face seal for cracks and abrasions, and ensure that respirator components are intact.

To perform a seal check, the faceplate has to fit tightly against your face. If facial hair prevents you from getting a tight seal, consider shaving or choose a different pesticide that does not require a respirator.

There are three common ways to test the seal on a respirator. Before testing, adjust the respirator to where you think you have a good fit. Start by placing the respirator on your face, then pull the top plastic strap (“halo” shaped in some models) and adjust it over and on top of your head. Next, connect the straps that go behind the neck, and pull the loose ends of the straps to adjust for comfort and fit. When you feel you have a tight seal, do the following tests to ensure your respirator is fitted properly.

 Respirator fit test - positive seal  Respirator fit test - negative seal  Respirator fit test - ampule seal
Figure 2. Three ways to conduct a respirator fit test (from left): Positive seal, negative seal, and ampule test


Positive Seal Check

Cover the exhalation valve in front of the respirator and gently exhale. If you can do this without feeling a rush of air around the faceplate, you have a good seal.

Negative Seal Check

Cover the intake portion of each of the two cartridges with your hands and inhale gently. You also can do this test without the cartridges by simply covering the inlet holes and testing the seal. If you have a good seal you should not be able to pull any air through the seal against your face. If you can pull air, check carefully around the seal for damages or obstructions. If you can clear obstructions and make additional adjustments to strengthen the seal, simply retest the unit. If you find breaks or damaged portions of the seal, you will need to replace the respirator seal or the entire unit.

Ampule Test

An ampule is a small sealed vial sold by many online suppliers. Ampule testing for respirator fit is one example of several procedures that may be required by OSHA. In the ampule test, you break an ampule designed for this purpose and see if you can detect the odor (often smelling like concentrated banana) through the respirator. If you detect the odor, your seal isn’t adequate and you’ll have to make additional adjustments. Make sure to test the ampule across all portions of the respirator seal. Also, consider simulating common working motions such as moving your head up and down and side to side as a test of field performance.

Maintaining Your Respirator

Video available To learn more about maintenance and fit testing of your respirator

When finished with your respirator, clean and store it properly after each use so that it’s in good condition for the next use.

After removing your respirator, remove the cartridges. They generally unthread, bend, or snap out of the faceplate. If the cartridge seating is damaged during removal, do not attempt to repair or bend it back in place—simply replace the cartridges.

Cartridges absorb pesticides and other organic vapors when exposed to air, thus you can extend their life by storing them properly. Store cartridges in either the original respirator packaging or a re-sealable zipper storage bag when not in use. These offer airtight seals that will help preserve the cartridges by keeping out organic vapors. It is also a good idea to mark the storage container with the purchase date of the cartridges and a running tally of the number of hours used.

After removing and storing the cartridges, wash the faceplate with soapy water and either air or towel dry before storing it for the next use in a clean and dry container such as a re-sealable zipper storage bag or a tight sealing plastic storage container . Store the respirator to preserve its shape and integrity, protecting it from distortion, contamination, and extreme temperatures. Also, be sure to inspect the respirator for any holes, damage, or wear and replace it if necessary.

Replacing Your Cartridges

Tracking Respirator Use

Keep a log of respirator usage in order to know how long the cartridges have been used. For more information and a sample log, see the UNL Safe Operating Procedure Respiratory Protection—Air Purifying Respirators: Cartridge Change Schedules.

A respirator cartridge has a limited life span, which is greatly affected by the condition of use, such as the temperature, humidity, work efforts of the user, and the chemical concentration and type of chemicals for which the cartridge is used. Cartridge life may be reduced if exposure to organic vapors is extensive and occurs over a short time. Many respirator manufacturers have online calculators where you can enter this information to determine cartridge life. Consult the manufacturer’s web site for such software.

Always replace cartridges immediately if you can smell pesticide odors when using the respirator. 

Your new cartridges should be the same type as those you are replacing. Cartridges are color coded depending on what particulates they filter. For example, a cartridge that filters organic vapors as well as pesticide dusts, mists, and fine particles (using a P100 filter) will be magenta and black.

Erin Bauer, Extension Associate
Clyde Ogg, Extension Educator
Pierce Hansen, Extension Assistant
Jan Hygnstrom, Project Coordinator


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