hrmm, it looks as if thte reuse period is more ciritical than anything else; ie. if it goes beyond a few days of non-use then migration starts to happen. BTW, did OSHA have any suggestions for alternatives?
James Slayden On Thu, 9 Jan 2003, girl mark wrote: > My friend Jeff Biosmell just took a long look at OSHA (US industrial > safety > regulator) and other safety regulations regarding handling of methanol. > Some scary stuff turned up that a lot of us didn't know, and that many > are > basing our biodiesel-making practice on. I feel especially responsible > due > to all of the people in the classes I've taught, since we focused > strongly > on organic vapor cartridge respirator safety and it turned out to be > dangerously inaccurate information: > > It turns out that organic vapor cartridge respirators are useless against > methanol vapors. > > I imagine that this also means that such a respirator will not protect > you > from any vapors arising from the agitation and settling portion of the > biodiesel making process, as methanol will vaporize during this process > to > some extent in an open processor (obviously many people use a completely > enclosed processor to protect themselves from poisonous vapors). > > Methanol handling/methoxide mixing can be done in a completely enclosed > environment as well, rather easily and inexpensively, so don't panic, but > it's time to get rid of all our open-tank methoxide mixers (a la > Tickell). I devised a decent carboy-based non-mechanically-agitated > system > to minimise methoxide handling here (look at journeytoforever.org for the > 'methoxide the easy way' description, it's the start of that carboy > system > I've got) which can then be plumbed into a closed processor easily. there > are many other ways that others have accomplished this as well. > > > I have copied some info below (I believe it might be from the 3M site, > but > what I saw from more 'neutral' sources was very similar to 3M's > recommendation not to use organic vapor cartridges for longer than a few > hours max) > > OSHA and the other safety regulators all had the same answer when we > called > them: no organic vapor cartridge respirator will protect against methanol > vapors, only a supplied-air system will do so. > > > Here's some more info, I don't remember which source it's from: > > > Q. Can chemical cartridges be used for more than one shift? > Organic vapors are removed by the process of adsorption. Weak physical > forces > hold the organic vapor on the activated carbon. Since these forces are > weak, > the process can be reversed and the organic vapor can be desorbed. > Desorption > during storage or nonuse periods can result in the migration of the > chemical > through the cartridge. Migration is mainly a concern only for organic > vapor > cartridges. Organic vapors adsorbed on an organic vapor cartridge can > migrate > through the carbon bed without airflow. Desorption of very volatile > contaminants can occur after a short period (hours) without use (e.g., > overnight). Partial use of the chemical cartridge and subsequent reuse > could > potentially expose the user to the contaminant. This is most significant > for > the most volatile and poorly retained organic vapors (e.g., boiling point > < > 65∞ C). For organic vapors with a boiling point less than 65∞ C, it > is > recommended that the organic vapor cartridge never be used longer than > one > shift even if the estimated service life is greater than 8 hours and the > cartridge is used for only a short time during the shift. > However, a boiling point of 65 oC is not a fine line between chemicals > that > migrate and those that do not. Chemicals with boiling points greater than > 65 > oC can still migrate, but the nonuse period of concern may be longer than > above. For chemicals with boiling points greater than 65 oC, nonuse or > storage periods of a few days, like over a weekend, may be the concern. > For > these chemicals, (e.g., ethyl acetate, boiling point 77oC), reuse should > not > be allowed after two days of nonuse even if the service life estimate > would > suggest it. As the volatility decreases migration will become less of a > concern. Your reuse pattern should still be carefully evaluated even for > these less volatile chemicals. Chemicals with low volatility will give > long > service lives, but even in these situations use should probably not > extend > beyond a week or two even if the service life estimate is longer. > For workers that use their respirators intermittently and perhaps in > different environments, such as a maintenance worker or inspector, the > organic vapor cartridges should never be reused. > The user can conduct desorption studies, mimicking the work conditions of > use > and nonuse, to determine acceptable patterns of reuse. The ANSI > Z88.2-1992 > American National Standard for Respiratory Protection recommends that > organic > vapor cartridges be changed daily unless desorption studies support > longer > use. > For more detail on chemical bed migration see: > Reuse of Organic Vapor Chemical Cartridges (pdf - 50Kb) > Chemical Sampling Information > Methyl Alcohol >  Chemical Sampling Information - Table of Contents  Field Definitions >  Analytical Methods > General Description > ------------------------------------------------------------------------ > NAME: Methyl Alcohol > SYNONYM(s): Methanol; Wood alcohol; Columbian spirits; Carbinol > IMIS: 1660 > CAS: 67-56-1 > NIOSH: RTECS PC1400000; 48518 > DOT: UN1230 Flammable Liquid; Poison > DESCRIPTION: > Colorless liquid with a characteristic, pungent odor. > MW: 32.04 > BP: 148 F > VP: 97 mm > MP: -144 F > > INCOM: Strong oxidizers > Exposure Limits > ------------------------------------------------------------------------ > OSHA GENERAL INDUSTRY PEL: 200 ppm, 260 mg/m3 > OSHA CONSTRUCTION INDUSTRY PEL: 200 ppm, 260 mg/m3 TWA > ACGIH TLV: 200 ppm TWA; 250 ppm STEL (Skin); (TLV listed under Methanol) > NIOSH REL: 200 ppm TWA (Skin); 250 ppm STEL (Skin) > Health Factors > ------------------------------------------------------------------------ > SYMPTOM(s): Eye irritation; headaches, drowsiness, lightheadedness; > nausea, > vomiting; visual disturbance, blindness > HEALTH EFFECTS: Cumulative CNS effects (HE7); Narcosis (HE8) > Irritation-Eye, > Nose, Throat, Skin---Mild (HE16) > ORGAN: Eyes, skin, CNS, GI tract > Monitoring > ------------------------------------------------------------------------ > PRIMARY SAMPLING/ANALYTICAL METHOD (SLC1): > > MEDIA: Two Anasorb 747 Tubes in series(First tube 400mg, second tube 200 > mg > section) See note > ANL SOLVENT: 50:50 Carbon Disulfide:Dimethylformamide > MAX V: 3 Liters (RH<50% @ 25 C)   MAX F: 0.05 L/min (TWA) > MAX V: 5 Liters (RH>50% @ 25 C)   MAX F: 0.05 L/min (TWA) > MAX V: 0.75 Liters   MAX F: 0.05 L/min (STEL) > ANL 1: Gas Chromatography; GC/FID > REF: 2 (OSHA 91) > SAE: 0.09 > CLASS: Fully Validated . > NOTE: Separate tubes and seal each after sampling. > MEDIA: Silica Gel Tube (520/260 mg sections, 20/40 mesh) > ANL SOLVENT: 0.02 N H2SO4 > MAX V: 6 Liters   MAX F: 0.1 L/min (TWA) > MAX V: 1.5 Liters   MAX F: 0.1 L/min (STEL) > ANL 1: Gas Chromatography; GC/FID > REF: 1,2 (OSHA Modified NIOSH 2000) > SAE: 0.16 > CLASS: Fully Validated > NOTE: The larger size tube is recommended due to low capacity of the > 150/75 > mg tubes at high humidities. > SECONDARY SAMPLING/ANALYTICAL METHOD (SAM2): > DEVICE: Detector Tube COMPANY: Gastec > PART #: 111L RANGE: 25-1000 ppm > CLASS: Mfg > DEVICE: Detector Tube COMPANY: Draeger > PART #: CH 29701 RANGE: 100-3,000 ppm > CLASS: Mfg > DEVICE: Detector Tube COMPANY: Draeger > PART #: 67 28941 RANGE: 50-3,000 ppm > CLASS: Mfg > DEVICE: Detector Tube COMPANY: MSA > PART #: 95097 RANGE: 100-10,000 ppm > CLASS: Mfg > DEVICE: Detector Tube COMPANY: Kitagawa > PART #: 119U RANGE: 20-1000 ppm > CLASS: Mfg > DEVICE: Instrumentation COMPANY: Infrared Spectrophotometer > PART #: MIRAN 1A & 1B RANGE: 0.3 ppm @ 9.7 um > CLASS: Mfg > DEVICE: Instrumentation COMPANY: Infrared Spectrophotometer > PART #: MIRAN 103 RANGE: 0-300 ppm @ 9.9 um > CLASS: Mfg > DEVICE: Instrumentation COMPANY: Organic Vapor Analyzer > PART #: Organic Vapor Analyzer > CLASS: Mfg > DEVICE: Instrumentation COMPANY: PID > PART #: Photoionization Detector > CLASS: Mfg >  Chemical Sampling Information - Table of Contents > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuels list archives: > http://archive.nnytech.net/ > > Please do NOT send Unsubscribe messages to the list address. > To unsubscribe, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! 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