This came to me through another listserv. I wanted to share it w/DCHAS colleagues, and also point out that while there have been several fires in US academic labs in the past 6 months, other than the UCLA fire, which made headlines for the death of the researcher, we have heard very little in terms of analysis of what went wrong. I applaud the folks at UCalgary who have gone public with a very detailed analysis. I wish administrators who instruct their EH&S folks to say nothing would see the value of this posting. I have already sent it to colleagues at other institutions as well as my own chemistry department. The above is my personal opinion only, not legal or business advice, and may not reflect the opinion of my employer or any group to which I belong. Margaret A. Rakas, Ph.D. Manager, Inventory & Regulatory Affairs Clark Science Center Smith College Northampton, MA. 01063 p: 413-585-3877 f: 413-585-3786 >>> Tom Williamson
6/23/2009 5:40 PM >>> Hi everyone We've had an incident I'd like to share with you. I encourage you to pass this information along to your colleagues as applicable to prevent a similar incident in one of your facilities. A small fire started in a laboratory involving a rotary evaporator (detailed synopsis follows below). The fire was extinguished by the lab worker using a portable fire extinguisher but not before enough heat accumulated at the ceiling to activate a nearby sprinkler head. We were lucky in that the fire was small and contained to the rotary evaporator but the repercussions from the activation of the automatic fire suppression system were significant. Water from the sprinkler system percolated down through two floors of the building, soaking cardboard boxes & contents and computers resting on the floor. The water eventually ended up in the high energy electrical vault forcing a hasty power shutdown for the entire building. The rapid shutdown terminated several experiments in progress and left freezers & incubators without power for several hours. Tom Williamson Fire Prevention Officer Environment, Health & Safety University of Calgary P: 403-220-8105 A Safety Culture is Defined by what happens when nobody is watching! HAZARD ALERT - ROTARY EVAPORATOR (ROTOVAP) FIRE A fire started while a worker was conducting an experiment using a rotovap and approximately 100 mls of carbon disulfide. (CS2) ROTARY EVAPORATOR - ROTOVAP CARBON DISULFIDE ( CS2) Extremely flammable liquid and vapor. Vapor may cause flash fire. Conditions to avoid: Heat, flames, ignition sources and incompatibles. Autoignition temperature: 90C, Flashpoint: -30C, Boiling point: 46C, Density: 1.26, Vapor Density: 2.6 (Air=1) Upon start up of the rotovap the heating element was activated for the heated waterbath. The rotovap operates in a vacuum which serves two purposes. The first is designed for lowering the internal pressure of the system, enabling in such way distillation processes at lower temperatures. The second is a practical one. i.e., to guarantee the sample flask doesn't fall into the warm bath. Upon initiation of the experiment a small amount of CS2 flashed from the sample flask into the solvent receiver. (It was determined later that this was because a stronger vacuum than required was applied via the vacuum screw adjuster.) As a result the procedure needed to be restarted. In order to re-start the procedure, the solvent receiver was detached from the rotovap and the reflux valve was closed to maintain the vaccum. (It was determined later that not enough vacuum was applied in order to maintain the sample flask and the clamp failed to maintain the flask adhered to the tip of the rotating shaft.) Once the solvent receiver was detached the worker then went to the fumehood about 8 m away to recover the CS2 from the solvent receiver in order to restart distillation. The worker was under the direct supervision of a 'competent worker' as the worker involved in the incident had not yet been deemed competent in the use and handling of CS2. The worker who was supervising momentarily stepped away at the time the incident occurred. While at the fumehood the worker heard a noise that sounded like an explosion and turned to find flames coming from the vicinity of the rotovap. The worker extinguished the flames with a nearby fire extinguisher About 30 seconds later an overhead sprinkler activated the building fire system which led to further complications arising from the water generated by the sprinkler activation. There are three hypothesis about what caused the explosion and subsequent fire. The first is that as CS2 is more dense than water ,once the clamp failed and the sample flask fell, the vapor rose to the top of the water bath and then moved down to the vicinity of the heating element where it ignited the vapor and caused the explosion. The second is that the vapor flowed along the surface of the lab bench to an ignition source and flashed back burning the electrical outlet directly behind the rotovap and starting the fire. The third is that when the clamp failed and the sample flask fell, water from the bath splashed onto the electrical outlet directly behind the rotovap causing the explosion. LEARNINGS · Prior to using CS2 it should first be determined if it is required for the task or if it can be replaced with a less hazardous substance. A hazard review should be conducted of the replacement product to ensure it doesn`t create an alternate hazard. · Standard Operating Procedures (SOP`s) should be written and reviewed by workers prior to all hazardous operations. · Explicit written instructions should be incorporated into the rotary evaporator Standard Operating Procedure regarding the direct close surveillance of it`s operation until stationary solvent distillation is secured. (No pressure build up) · At the time of the incident the rotovap was located outside of the fumehood. Had it been inside the fumehood the fire may still have started but would have been contained and extinguished before the sprinkler head was activated. · Mechanical clamps on rotovaps should be inspected for defects and wear on a regular basis and replaced as required. · Workers must be aware of the properties of the chemicals they are working with. (i.e. CS2 is denser than some other solvents and a different amount of vacuum is required to hold the sample flask in place.) · Workers who are not yet deemed to be `competent`in a task must be under the direct supervision of a competent worker at all times. The work must stop, or someone must take their place, if the supervisor is going to be absent at any time during the process. · Workers must be supplied job specific training applicable to all tasks they do as well as general safety training such as WHMIS. · A training needs analysis should be set up for all lab workers to include both lab specific and general safety training. All workers must undertake the required training before work begins. · Inspections of the work area should be conducted on a pre-determined ongoing basis. · Hazard Identification and Assessment for should be conducted for every task.
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