Secara teknis saat gas detector menunjukkan kandungan LEL 35% maka kondisinya tetap aman. Juga bila menunjukkan angka 20% ataupun 50%, bahkan 80%. Time-Weighted Average (TWA) is the average concentration of contaminants over a specified time period. Permissible Exposure Limit (PEL) and Threshold Limit Value (TLV) are TWA permissible concentrations, to which workers may be exposed continuously, day after day, without adverse effects, for a normal eight-hour workday and a forty-hour work week. Short-Term Exposure Limit (STEL) is defined as a fifteen-minute TWA exposure which should not be exceeded at any time during a work day even if the eight-hour TWA is within limits. Exposures at the STEL should not be longer than fifteen minutes and should not be repeated more than four times per day. There should be at least 60 minutes between successive exposures at the STEL. Ceiling Limit: The concentration which should not be exceeded at any time. Mungkin pendekar2 yang masih dibalik meja bersedia menambahkan, ditunggu kontribusinya untuk pencerahan buat generasi penerus.
wassalam kkk "Ricky, Iswanto" <[EMAIL PROTECTED]> wrote: Dear Capt, LEL 35% dan jika kadar O2 diatas 11% artinya keadaan ini kalau tidak salah telah memasuki daerah flammable area yang mana diatas dari daerah Too lean ( miskin akan hydrocarbon - mungkin kita bisa kembali melihat Diagram Flammable yang mana kalau tidak salah tergambar 3 area yaitu 1. area too lean, 2 .flammable area dan yang ke 3 daerah Too rich. Kindly see http://www.ilpi.com/msds/ref/stel.html for your referenced. STEL = Short Term Exposure Limit (STEL) is defined by ACGIH as the concentration to which workers can be exposed continuously for a short period of time without suffering from irritation chronic or irreversible tissue damage narcosis of sufficient degree to increase the likelihood of accidental injury, impair self-rescue or materially reduce work efficiency STEL's are generally used only when toxic effects have been reported from high acute (short-term) exposures in either humans or animals. An STEL is not a separate independent exposure limit, but supplements (TWA) time-weighted average limits where there are recognized acute effects from a substance whose toxic effects generally chronic (long-term) in nature. For example, one can not be exposed to an STEL concentration if the TLV-TWA (time weighted average for an 8 hour shift; see Permissible Exposure Limit (PEL)) would be exceeded. Workers can be exposed to a maximum of four STEL periods per 8 hour shift, with at least 60 minutes between exposure periods. Regards, RI --------------------------------- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of kokok purwoko Sent: Friday, January 25, 2008 9:30 PM To: pelaut Subject: [pelaut] sharing LEL Sekedar iseng2 dan sharing informasi untuk rekan2, bukan bermaksud menggurui lho. Case : Suatu saat sebelum masuk ruangan tertutup ( confined space ) kita melakukan pengukuran kadar Lower Explosive Limit ruangan tsb dengan portable gas detektor dan saat itu LEL-nya terbaca 35%. Problem : 1. Apakah ruangan tsb secara teknis / matematis dapat terbakar atau dengan kata lain kondisi ruangan tsb sudah mencapai titik terendah yang dapat terbakar (meledak) ? 2. Ada yang mau bantu untuk menjabarkan istilah2 STEL, TWA, ceiling limit yang ada di gas detector? Note: kalau ada kalimat yg salah / tidak tepat mohon dimaafkan yaa. Ditunggu komen dari rekan2 Have a nice day. wassalam kkk Send instant messages to your online friends http://uk.messenger.yahoo.com Send instant messages to your online friends http://uk.messenger.yahoo.com
