What is the difference between single-use, limited-use and reusable chemical protective garments?
Single-use garments are intended for a one-time wear. Limited-use garments can be worn until they are damaged, altered or contaminated. Reusable garments can be worn multiple times as long as the suits have not become damaged during use (or if so, repaired), the suits have been completely decontaminated after use and the barrier performance of the fabric has not been compromised. Determining whether or not a reusable garment has been fully decontaminated and that the contaminates have not altered the strength or protection capabilities of the garment can be a difficult decision. DuPont chemical protective garments are limited-use garments. As long as they have not been damaged, altered or contaminated, they have sufficient durability to be worn multiple times.
What is the difference between penetration and permeation? How do I know which test method to use?
In terms of chemical protective clothing, penetration is the passage of a chemical through a pore or opening in the barrier material. Permeation is the absorption, diffusion and desorption of a chemical through the barrier material at the molecular level.
To help you understand the difference between these two mechanisms, consider this example. Have you ever opened an old bottle of soda to find out that it was flat? There aren't any holes in the bottle. The liquid is still inside. Why is the soda flat? It's flat because the carbon dioxide that gives soda its fizz has permeated through the walls of the bottle over time. If you opened a fresh bottle of soda and did not replace the cap, the carbon dioxide would just escape out of the top of the bottle. That would be penetration.
Penetration tests are well suited for determining particle barrier in fabrics like Tyvek® and ProShield®. Some factors that influence particle penetration include the size of the particle and the size of the pores/openings in the fabric structure. The more open a fabric structure is, the more likely a particle will be able to penetrate the fabric.
Permeation tests, by comparison, are better suited for testing hazardous liquids and vapors. It is the test method of choice for Tychem® fabrics. There are many critical factors that influence permeation: the challenge chemical (i.e. concentration, temperature, surface tension, the size of the molecules, functional groups, etc.), the make-up of the barrier material, the exposure time and several physical factors like ambient temperature and pressure, just to name a few. Because there are so many variables, DuPont has performed permeation tests on hundreds of chemicals against our Tychem® fabrics. Our Chemical Resistance Database will help you make more informed decisions about protective clothing.
Regarding permeation, what is the breakthrough time? What is a normalized breakthrough time?
In permeation testing, the breakthrough time is the length of time it takes for a challenge chemical to permeate the barrier fabric being tested. It is measured from the point of initial contact of the challenge chemical with the outside surface of the test fabric to the time that the challenge chemical is detected on the inside of the fabric. Sensitive analytical equipment is often used to measure the amount of chemical permeating the fabric.
Normalized, or sometimes called "standardized" breakthrough time, is a measure of the elapsed time from initial contact with the challenge chemical until the chemical permeates the fabric at a rate of 0.1 ug/cm2/min. This is defined in ASTM F739 test method. Normalized breakthrough times eliminate biased results due to differences in the sensitivity of the detection equipment and are thus the industry standard measure of breakthrough times. DuPont reports normalized breakthrough times for permeation data.
Does DuPont offer any garments that would be compliant with the OSHA Bloodborne Pathogens Regulation, (29 CFR 1910.1030)? What are ASTM F1670 and ASTM F1671? Does DuPont offer any garments that pass these tests?
Tyvek® and all Tychem® garments could be considered for use as protection against blood and bloodborne pathogens per OSHA 29 CFR 1910.1030.
ASTM F1670 is a synthetic blood penetration test and ASTM F1671 is a viral penetration test. Tychem® 2000, Tychem® 4000, Tychem® 5000, Tychem® 6000 and Tychem® 6000 FR fabrics and taped seams have been tested and pass ASTM F1670 and F1671.
Read about these test methods as well as OSHA's Bloodborne Pathogens Rule in our technical paper -- Protective Clothing and Bloodborne Pathogens: What you need to Know.
To find a garment that will provide protection against blood and/or bodily fluids, please try the SafeSPEC™ Selector Tools.
I worked through a hazard scenario in "Selector Tools" and my scenario resulted in multiple garment results. How do I know which one is the best?
All of the results that are showing are suitable for your scenario based on the information you provided. If you want to further refine your results, you can select different products to compare and refine. Click in the empty boxes of the products of interest and select either compare all or compare selected. Once on this screen, you can refine your selection based on your preferences for specific garment attributes. Use the drop down filters on the left of the screen to down-select your choices.
TIP: Click on the "+" next to "Permeation Data" header toward the bottom of the screen. Notice that the chemicals/hazards that you selected are at the top of the list highlighted in green.
Whose responsibility is it to select the appropriate chemical protective clothing?
In the USA, OSHA 29CFR1910.132 states that it is the responsibility of the employer to: Perform a hazard assessment Select PPE and inform employees Fit and train employees on use, care and service life of PPE Verify training and audit compliance Retrain employees as necessary "Responsibility in selecting appropriate protective clothing should be vested in a specific individual who is trained in both chemical hazards and protective clothing use such as a safety officer or industrial hygienist." Reference: OSHA Technical Manual, Section VIII, Chapter 1, Chemical Protective Clothing, V.
How do I know which garment will provide protection for my unique set of conditions?
Try the SafeSPEC™ Selector Tools. You can search by Hazard or Industry and Task. If you have a specific product in mind, you can use the Double Check feature (found on the top right corner) on that product's detail page. If you know your product's part number, you can use the quick garment search ("Search Model No.") located in the header.
The concentration of my hazard is LOWER than what is listed in the "Search Hazards" box. What should I do?
If the concentration of your hazard is LOWER than the hazard concentration listed in the hazard search box, select the higher concentration hazard as long as the solvent is the same. In the case of inorganic acids (i.e. sulfuric acid, nitric acid, hydrochloric acid, etc.) and inorganic bases (i.e. sodium hydroxide, potassium hydroxide, etc.) the solvent is assumed to be water.
The concentration of my hazard is HIGHER than what is listed in the "Search Hazards" box. What should I do?
If the concentration of your hazard is HIGHER than the hazard concentration listed in the hazard search box, you can NOT use the data for the lower concentration hazard. This data will not give you an accurate assessment of suitable garments. Please Contact Us for assistance.
The temperature of my hazard is LOWER than what is listed in the "Search hazards" box. What should I do?
If the temperature of your hazard is LOWER than the hazard listed in the hazard search box, go ahead and select the higher temperature hazard as long as the physical phase (solid, liquid or gas/vapor) is the same. Because chemical hazards become more aggressive with increasing temperatures, selecting a higher temperature chemical hazard will lead to a more conservative result. <br> PLEASE NOTE: DuPont garments do not provide adequate insulation to protect the wearer's skin against prolonged exposures to cold temperature hazards. Depending on the temperature of the chemical and the duration of exposure, the wearer could be subjected to frostbite. In addition, at temperatures below -13°F (-25°C), some DuPont fabrics could lose flexibility.<br>Unless otherwise stated, DuPont tests chemical hazards per ASTM F739 at ambient temperatures (approximately 72-81°F ; 22-27°C).
The temperature of my hazard is HIGHER than what is listed in the "Search Hazards" box. What should I do?
If the temperature of your hazard is HIGHER than the hazard listed in the hazard search box, you can NOT use the data for the lower temperature hazard. Chemical hazards become more aggressive with increasing temperatures. Selecting a lower temperature chemical hazard will not give you an accurate assessment of suitable garments.<br>PLEASE NOTE: DuPont garments do not provide adequate insulation to protect the wearer's skin against prolonged exposures to high temperature chemical hazards. Depending on the temperature of the chemical hazard and the duration of exposure, the wearer could be subjected to a thermal burn.<br>Unless otherwise stated, DuPont tests chemical hazards per ASTM F739 at ambient temperatures (approximately 72-81°F ; 22-27°C).
I have a chemical mixture, what guidance can you give me?
Try our newest Product Selector Tool - Guide. It was built using the guidance provided by OSHA.<br>OSHA's Guidance on Chemical Mixtures:<br><ul><li>Mixtures of chemicals can be significantly more aggressive towards protective clothing materials than any single chemical alone.</li><li>One permeating chemical may pull another with it through the material.</li><li>Very little data is available for chemical mixtures.</li><li>Serious consideration must be given to deciding which protective clothing is selected.</li><li>If clothing must be used without test data, garments with materials having the broadest chemical resistance should be worn, i.e. materials which demonstrate the best chemical resistance against the widest range of chemicals.</li></ul><br>Ultimately, it is the end users' responsibility for selecting the appropriate personal protective equipment.<br>Reference: OSHA Technical Manual, Section VIII, Chapter 1, Chemical Protective Clothing, III(B)(5). U.S. Department of Labor. http://www.dol.gov.
Why aren't Tyvek® 400, ProShield®, ProShield® 60, ProShield® 3, Tyvek® FC or ProShield® 6 SFR fabrics listed in the Chemical Resistance Database?
The Chemical Resistance Database is a permeation database. Tychem®, Tyvek® 500, Tyvek® 600 and Tyvek® 800J fabrics are subjected to permeation testing. If you are looking for applications in which Tyvek® 400, ProShield®, ProShield® 60, ProShield® 3, Tyvek® FC or ProShield® 6 SFR may be suitable, use SafeSPEC™ Selector Tools.
What are the test conditions used for the permeation testing - what are the chemical concentrations and test temperatures? What method is used?
Permeation data is obtained per ASTM F739. Normalized breakthrough times (the time at which the permeation rate is equal to 0.1 µg/cm2/min) are reported in minutes. All liquid chemicals have been tested between approximately 20°C and 27°C unless otherwise stated. All chemicals have been tested at a concentration of greater than 95% unless otherwise stated. Chemical warfare agents (Lewisite, Sarin, Soman, Sulfur Mustard, Tabun and VX Nerve Agent) have been tested at 22°C and 50% relative humidity per military standard MIL-STD-282.
My question was not answered here. Now what?
If you have a question that is specific to a particular product, try looking at the Question and Answer section on that product's webpage. You can navigate to a product page by using the Product Browser or by using the "Search Model No." box at the top of every page. There is also help text throughout the website. This help text is designated with a "?" icon. If you still have questions, please Contact Us.