I am sorry for the delay in this edition, but I took leave for the month of July to spend time with my 94 year old mother at the shore. She gave me many opportunities in life and I really wanted to spend time with her while I could this summer. Of course one of the benefits was going to the beach, swimming and watching the parade of bathing suits (protective clothing) worn to swim in and for limited protection from the sun and UV light responsible for skin cancer. The risk of skin cancer was one of the big protective clothing news items this summer besides the heat waves and drought. As we all know radiation is a physical hazard and items of protective clothing coated with UV absorbing chemicals can provide skin protection factors (SPF’s), reduce exposure and potentially prevent skin cancer. While this is a beneficial aspect of protective clothing, my column and expertise reside in chemical protection, so I will report on the latest standard chemical test method developments and technical protective equipment committee activities and projects.
As I reported in my last 2nd Quarterly column, ASTM Committee F23 On Protective Clothing and Equipment was scheduled to meet in San Diego, California the last week in June and finalize plans for ASTM’s Chemical Permeation Test Method F739 Inter-laboratory Test Method Round Robin. The latest update is that they are going ahead with the round robin tests using both neoprene and Mylar as reference materials. Several laboratories have committed to participate and should be receiving samples of the reference materials and directions for completing the round robin tests. I also reported that the AIHA Protective Clothing and Equipment committee was meeting June 16-21 in Indianapolis. One of the accomplishments of this committee has been support for publication of Chapter 36 On Protective Clothing in the 3 rd edition of the Industrial Hygiene White Book and continued development of professional development courses on protective clothing. They are also supportive of plans to publish the 6 th edition of the Quick Selection Guide for Chemical Protective Clothing that I have agreed to be a co- author with Krister Forsberg and others. Another publication that I would like to you know about is an interesting feature article in the ACS May/June issue of Chemical Health and Safety (CHAS) on dissolvable protective clothing in the LANL research laboratory (1). This is a good example of a protective clothing program that uses radiological chemicals and used re-usable launderable protective clothing in a their research environment, but has now discovered that replacing launderable clothing with single-use dissolvable protective clothing offers nuclear facilities the opportunity for improved performance by reducing radiological and heat stress risks.
Next I would like to continue to share my experience on the portable permeation test methods. This test method is one that I used to screen potential protective clothing materials to hydrogen cyanide, acetone, benzene and carbon tetrachloride using Drager tubes and the 1 inch permeation test cell in the open loop configuration. A picture of the test set up is shown below:
One inch F-23 Permeation Test Cell with Drager Tube Connected to a low flow air sample pump.
This open loop sampling set up with Drager tubes is simple, inexpensive and reliable for determining breakthrough time and permeation rates. Breakthrough time is easy to determine with the indicator change in color of the tube and quantitation can be measured by length of stain or color of the reaction indicated by numerical concentrations in ppm on the tube. An industrial hygiene sample pump (low flow) such as the one shown above with a sample flow rate of between 30 -50 mL/min can be used to convert air concentrations to mg of permeate to give permeation rates in mg/min. A published reference to this method is listed below.(2) While this method is useful and inexpensive it is limited to the current Drager tube analytical methods and technology . Another advantage is that that testing can be done on site with specific chemicals by an experienced industrial hygienist or technician.
Finally, both Rich and I would like to wish you an enjoyable and safe summer whether you stay at home or travel about. If you have any questions about permeation testing, test cells and standard protective clothing test methods just give us a call and we will try to help.
(1) Technical Aspects of Dissolvable Protective Clothing, Michael E. Cournoyer et al. Journal of Chemical Health & Safety, May/June 2012, Volume 19, Number 3, pages 3-11. (2) The Use of Detector Tubes for Measuring Permeation Resistance of Clothing Following ASTM Method 739-85, Stanley Sarner and Norman W. Henry III, AIHA Journal 50 (6): 298- 302, June 1989.