04-04-2002, 05:45 PM | #1 (permalink) |
Join Date: Feb 25 2000 Location: Tucson, AZ
Posts: 1,643
Rep Power: 26 | MJ: This will be the "short version" of the MED vs SED situation. For those of you who are interested in the long version (not for the faint of heart!), go to http://www.naatso.org and "click" on the "Regulatory" tab at the top of the home page. Then, go to "FDA Meeeting Report ( Part 8 ): Calculating The UVI" and "FDA Meeting Report ( Part 9 ): Units of Measure." FDA began discussing the possibility of adopting SED (Standard Erythemal Dose) to replace MED (Minimal Erythemal Dose) several months ago and proposed this course of action at the 2/7/02 and 2/8/02 meeting. The "logic" behind this change is sound and should be supported because MED is a very poorly defined term and SED is a more "neutral" term. The "primary" reason FDA wanted to make this change is to "harmonize" with IEC (something like the EEU version of FDA). Also, FDA wanted to "quantitate" the definition of one (1) SED and one (MED). So far, so good. FDA (and IEC) also proposed that one SED be defined as a 100 J/m2 (joules per meter squared) "dose" of UVR and one (1) MED be defined as 200 J/m2 (which means that 1 MED is equal to 2 SED). Currently, one MED is defined by FDA as 156 J/m2 (78 J/m2 per SED); by IEC as 200 J/m2 (100 J/m2 per SED); and by NWS (National Weather Service) as 210 J/m2 (105 J/m2 per SED) so you can see that, today, confusion reigns supreme! The problem is that IEC and FDA also stated that they wanted one (1) SED to equal one (1) UVI (Ultraviolet Index) unit (which is used to measure the "sunburning power" of sunlight. That's where the problem started! Unfortunately, if you use 100 J/m2 per SED (200 J/m2 per MED)AND want one (1) SED to equal one (1) UVI, you end up with 0.9 MED per SED/UVI. If you use 105 J/m2 per SED (210 J/m2 per MED) as is the case in outdoor measurement of sunlight AND want one (1) SED to equal one (1) UVI, you end up with 0.86 MED per SED/UVI. Only when you use 90 J/m2 per SED (180 J/m2 per MED) do you end up with 1.0 MED being equal to 2.0 SED/UVI! That's why I have sent a formal proposal (following up on my presentation at the FDA meeting) to (1) FDA, (2) IEC, (3) NWS, and (4) the American Society for Photobiology recommending that 90 J/m2 (180 J/m2 per MED) be adopted as the " dose definition" of one (1) SED. Will this recommendation be adopted by FDA, IEC and NWS? It will if they want 1.0 MED to equal 2.0 SED/UVI! The "bottom line" for tanning salon owners who aren't interested in all of these calculations is that, hopefully (if logic prevails!), one MED will equal 2 SED/UVI units and one SED/UVI will be defined as 90 J/m2 (and one MED will be defined as 180 J/m2). FDA also "announced" that they would "allow" 8.0 SED to replace the current 4.0 MED as the MAD (Maximum Allowable Dose). If you do the math, you will find that 8 SED times 90 J/m2 = 720 J/m2 MAD and 4 MED times 180 J/m2 = 720 J/m2 MAD, so we are talking the same "cumulative" maximum allowable dose. I know that this stuff is complicated and so if it is "clear as mud", please let me know and I'll try again. If we are all "In Sync" (N/Sync?) so far, I'll cover some other MAJOR "changes" that FDA proposed at the meeting. Don [ This Message was edited by: Don Smith on 2002-04-04 17:48 ] |
04-04-2002, 05:49 PM | #3 (permalink) |
Join Date: Jan 21 2002
Posts: 2,709
Rep Power: 23 | Ummm you had me until about the 8th or ninth paragraph...I will reread when I am not trying to sneak inbetween customers.. I will get it.. ..and Don please edit Bruces.. comments not pertaining to this thread. Mj _________________ TanTalk Moderator TanTalk Rocks!!! "And now back to tanning"--ChippMeet "Little Chunn Chunn!!"[ This Message was edited by: MJ on 2002-04-04 17:51 ] |
04-04-2002, 06:44 PM | #4 (permalink) |
Join Date: Feb 25 2000 Location: Tucson, AZ
Posts: 1,643
Rep Power: 26 | MJ: I KNOW you (and everyone else) will "get it" but I'm going to try to restate the SED vs MED discussion so "you-know-who" can understand it. LOL 1. FDA/IEC want to replace MED (Minimal Erythemal Dose) with SED (Standard Erythemal Dose). 2. FDA/IEC will "allow" a MAD (Maximum Allowable Dose) of 8 SED whereas today we have a MAD of 4.0 MED. 3. FDA/IEC also want one (1) MED to equal two (2) SED. 4. Moreover, FDA/IEC also want one (1) SED to equal one (1) UVI (Ultraviolet Index) unit. Thus, two (2) SED or UVI would equal one (1) MED. 5. The only way to make all of the above happen is to adopt a "dose definition" of 180 J/m2 per MED (90 J/m2 per SED/UVI). This will make 1.0 MED equal to 2.0 SED/UVI. 6. FDA/IEC want to adopt a "dose definition" of 200 J/m2 per MED (100 J/m2 per SED/UVI) but that will end up making 0.9 MED equal two (2) SED/UVI. Something has to give! As mentioned above, I have "formally" recommended the adoption of the "dose definition" of 180 J/m2 per MED (90 J/m2 Per SED/UVI). Let's hope Bruce "gets it" now and goes away! Don |
04-04-2002, 07:48 PM | #5 (permalink) |
Join Date: Jan 21 2002
Posts: 2,709
Rep Power: 23 | Okk.. let me see if I Gots this since you didn't draw a picture or nuttin'...LOL if (1) SED is equal to (1) UVI unit. Then, two (2) SED /UVI would ==(1) MED. Which will be the standard in the industry ..as well as the NWS and so on.. By golly I think I can..I think I can.. Mj _________________ TanTalk Moderator TanTalk Rocks!!! "And now back to tanning"--ChippMeet "Little Chunn Chunn!!"[ This Message was edited by: MJ on 2002-04-04 19:49 ] |
04-05-2002, 08:14 AM | #7 (permalink) |
Join Date: Feb 25 2000 Location: Tucson, AZ
Posts: 1,643
Rep Power: 26 | MJ: Bruce doesn't still doesn't "get it" regarding MED vs SED! He posted the first answer to the MED vs SED issue that I gave you with this "lead" statement. "yesterday some gal asked Don about sunburns, to which Don answered..." (and then he posted my answer). Is it possible he has ADD? You CLEARLY asked about MED vs SED and said nothing about "sunburns" in your post. The boy has REALLY lost it! Do you think that he has the "guts" to post my second "explanation" that was done SPECIFICALLY in the hope that he would understand the issue? (Don't bet any money on it or hold your breath waiting!) My advice to Little Brucie: Take two Ritalin, take a "time out" to collect your senses and then re-read the second explanation of the MED vs SED issue(I'm sorry the first one was too far above your level of competence) and feel perfectly free to "Ask Don" any questions you still have. LOL Don |
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