Spring is here. We have set our clocks ahead, the daffodils are blooming, and soon we will be cutting our lawns after the unusually warm weather. It’s also time for my quarterly column and update on what is going on in protective clothing test methods, technical committee activities and standards development.
First, I’ll report on ASTM F23 committee standards development. Currently, the F23.30 technical committee on chemicals is in the process of conducting a round robin inter-laboratory test with a new reference test material, Mylar, using the F739 permeation test method and cell. Several laboratories have agreed to participate including me, in order provide a precision and bias section in the method so that other users can compare their results using their permeation test systems and validate their testing capability. Samples of Mylar will be sent out to the participating laboratories and they will follow the F739 test procedure to test permeation of acetone through three replicate samples for breakthrough time and permeation rate. The results will be summarized and reported in an inter-laboratory round robin report to be included in an updated section of the F739 permeation test method. Hopefully, the samples will be sent out soon, testing completed and the results available for the next F23 committee meeting scheduled in June. I also want to report on a feature review article in the ASTM International News publication, March/April 2012 issue on worker protection that includes a section on Committee F23 contributions to worker protection with protective clothing standards. Committee F23 now has 60 protective clothing standard test methods, practices, specifications and guidance documents for evaluating the performance of protective clothing that help protect workers in their workplace environment. I always remember the saying that “Many of the accomplishments of man would not be possible without protective clothing. ”
The AIHA protective clothing and equipment committee is scheduled to meet at the AIHce conference June 16-21 in Indianapolis. They will be sponsoring professional development courses, technical presentations, panel discussions and poster sessions on protective clothing issues. One of the latest contributions of AIHA is the publication of the 3rd edition of the “White Book” The Industrial Environment, It’s Evaluation, Management and Control, AIHA Press, 2011. Chapter 36 on protective clothing has been updated and is an excellent reference on the status of controlling exposure with protective clothing. Also under consideration by the committee is the possible publication of the 6 th edition of the Quick Selection Guide for Chemical Protective Clothing, by Krister Forsberg and Zack Mansdorf. Both Krister and Zack have retired and are unsure about continuing to review and update the data for this next edition.
Next, I thought I would share with you some history about permeation test methods and a portable permeation test kit that was introduced by Author D. Little Inc , in the early 1980’s. I recently acquired a test kit from a retired ASTM member and thought you may be interested. This test kit was designed to test permeation resistance of potential protective clothing materials on site and or in emergency situations where the chemical was not known or was a mixture of chemicals and responders needed to select appropriate clothing to clean up a spill or a hazardous waste site. The test kit could be taken to the site where there was a sample of the chemical and swatches of protective clothing materials could be tested to help select a material that would be resistant to permeation. The method was based on gravimetric analysis using a single pan Ohaus balance that was powered by batteries and used a permeation test cup (see picture). A sample of the protective clothing was placed in the test cup with approximately 10 mL of test chemical covering the outside surface of the material. Next the test cup was inverted and placed on the balance to measure weight loss at timed intervals as the chemical permeated through the material. By visually observing the material in the test cup and recording the weight change with time you could determine the breakthrough time and permeation rate. This quantitative method eliminated the cost of costly analytical equipment and also provided quick turn- around time for results on the best protective clothing material to use. This test kit was popular for the Coast Guard and other emergency response groups in need of selecting clothing materials in emergency situations.
I hope you find this historical information on the portable test kit interesting and maybe even practical to use if you would like to do permeation testing on site, particularly if you only have a balance and a permeation test cup. I do not believe Arthur D. Little is still in the business of selling this kit now. In my next quarterly column I will describe how you can use the 1 inch F739 glass permeation test cell with Drager tubes to do on site permeation tests.
Finally, I want to remind you that if you have any questions regarding the permeation test method, cells and procedures give Rich Pesce and me a call and we will try to help set up a permeation test system, select a test cell or analytical method compatible with your test needs.
Norm Henry