Standard Operating Procedure: Flammable Liquids

Transcription

1 Standard Operating Procedure: Flammable Liquids Standard operating procedures (SOP) are intended to provide you with general guidance on how to safely work with a specific class of chemical or hazard. This SOP is generic in nature. It addresses the use and handling of substances by hazard class only. In some instances multiple SOPs may be applicable for a specific chemical (i.e., both the SOPs for flammable liquids and carcinogens would apply to benzene). If you have questions concerning the applicability of any item listed in this procedure contact the EHRS or the Principal Investigator of your laboratory. Specific written procedures are the responsibility of the Principal Investigator. If compliance with all the requirements of this standard operating procedure is not possible, the Principal Investigator must develop a written procedure that will be used in its place. This alternate procedure must provide the same level of protection as the SOP it replaces. The Office of Environmental Health and Radiation Safety is available to provide guidance during the development of alternate procedures. JUMP TO SECTION IN THIS S.O.P. Before you begin Setting-up Carrying out your work Cleaning-up Emergencies FLAMMABLE & COMBUSTIBLE LIQUIDS IN THE LABORATORY The flashpoint of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air and produce a flame when a source of ignition is present. Flammable liquids are chemicals that have a flash point below 100 o F (38.7 o C) and a vapor pressure that does not exceed 40 psig at 100 o F. Flammable liquids are commonly divided into three classes Class Flash Point Boiling Point Example IA Below 73 F Below 100 F Ethyl Ether IB Below 73 F At or above 100 F Acetone, Benzene, Toluene IC At or above 73 F and Hydrazine and Styrene

2 below 100 F Combustible liquids are divided into three classes Class Flash Point Example II F Acetic acid, naptha and stoddard solvent IIIA F Cyclohexanol, formic acid and nitrobenzene IIIB 200 F or above Formalin and picric acid Before you begin Approvals and Notifications o Most flammable liquids can be used by properly-trained individuals in the laboratory environment without the need for specific EHRS approval. Special circumstances, such as abnormally large-scale use may require evaluation. Contact EHRS at x84453 for assistance. Training required o Training requirements based on job duties and responsibilities are determined for each employee by completing the Penn Profiler. o Any flammable liquids users should have taken an Introduction to Laboratory Safety course as well as any required annual updates. o Most introductory programs are offered monthly. Dates are published in the Almanac and on the EHRS website. Annual updates of these programs can be completed online. For more information on these programs or to request a training program on safety or health topics for your department, please contact Valerie Perez at or send to: traininghelp@ehrs.upenn.edu Purchasing materials o Purchase of any container of flammable liquids with a volume of greater than 5 gallons requires EHRS approval. Hazard Assessment o A hazard assessment for work involving flammable liquids must thoroughly address the issues of proper use and handling, fire safety, chemical toxicity, storage, and spill response. o A hazard assessment must be conducted when a process/reaction/work-up/or purification is changed or when scaling-up any flammable liquids use to more than 10 times the original volume. o The first time a highly flammable solvent such as diethyl ether or hexane is used for a process, a hazard assessment should be conducted.

3 Setting-up Storage: FLAMMABLE LIQUID STORAGE CABINETS o One or more Flammable Liquid Storage Cabinets (FLSC) are required for laboratories which store, use or handle more than 5 gallons of flammable or combustible liquids. o Containers one gallon and larger of flammable liquids must be stored in a flammable-liquids storage cabinet. o The storage of flammable and combustible liquids in a laboratory, shop, or building area must be kept to the minimum needed for research and/or operations. FLSC are not intended for the storage of highly toxic materials, acids, bases, compressed gases or pyrophoric chemicals. o In most university laboratories flammable liquids storage is provided under the chemical fume hood. These cabinets are clearly marked Flammable Storage. Flammable liquids storage cabinets are constructed to limit the internal temperature when exposed to fire. When additional storage is needed, NFPA approved flammable liquids storage cabinet (FLSC) may be purchased. All containers of flammable liquids must be stored in a FLSC when not in use. The following requirements apply: General Requirements Cabinets shall be no larger than 45 gallon capacity Cabinets should be located near fume hood alcoves Cabinets shall be marked Flammable-Keep Fire Away Cabinets should be kept in good condition. Doors that do not close and latch must be repaired or the cabinet must be replaced. o Flammable liquids storage cabinets are equipped with a grounding system that can be connected to a building ground. If you are pouring from a container in the storage cabinet and if the container being poured into is conductive then a bonding strap must be attached between them as explained in PROCEDURES TO AVOID STATIC ELECTRICITY found in the Transferring section of this SOP. Engineering Controls (ventilation, shielding, vacuum protection) o Biomedical Laboratories Free standing cabinets in biomedical labs shall not be vented. Bungs shall be used to seal vent openings. o Physical Science Laboratories Free standing cabinets may be vented into the fume hood exhaust system or a dedicated system for hazardous materials exhaust if present. Replacement air

4 shall be ducted into the cabinet in such a way as not to compromise the specified performance of the cabinet. Venting details shall be submitted to EHRS and University Engineer for approval. o Safety Shielding: Shielding is required any time there is a risk of explosion, splash hazard or a highly exothermic reaction. All manipulations of flammable liquids which pose this risk should occur in a fume hood with the sash in the lowest feasible position. Portable shields, which provide protection to all laboratory occupants, are acceptable. o Special Ventilation: Manipulation of flammable liquids outside of a fume hood may require special ventilation controls in order to minimize exposure to the material. Fume hoods provide the best protection against exposure to flammable liquids in the laboratory and are the preferred ventilation control device. Always attempt to handle quantities of flammable liquids greater than 500 ml in a fume hood. If your research does not permit the handing of large quantities of flammable liquids in your fume hood, contact the EHRS to review the adequacy of all special ventilation. o Vacuum Protection: Evacuated glassware can implode and eject flying glass, and chemicals. Vacuum work involving flammable liquids must be conducted in a fume hood, glove box or isolated in an acceptable manner. Mechanical vacuum pumps must be protected using cold traps and, where appropriate, filtered to prevent particulate release. The exhaust for the pumps must be vented into an exhaust hood. Vacuum pumps should be rated for use with flammable liquids. Personal Protective Equipment o Splash proof goggles in addition to standard laboratory personal protective equipment (PPE) consisting of a 100% cotton lab coat, closed toe shoes and nitrile gloves must be worn when there is a significant risk of splash. Pouring very large volumes may require additional PPE consisting of thicker gloves and an apron. o Eye protection in the form of safety glasses must be worn at all times when handling flammable liquids. Ordinary (street) prescription glasses do not provide adequate protection. (Contrary to popular opinion these glasses cannot pass the rigorous test for industrial safety glasses.) Adequate safety glasses must meet the requirements of the Practice for Occupational and Educational Eye and Face Protection (ANSI Z ) and must be equipped with side shields. Safety glasses with side shields do not provide adequate protection from splashes; therefore, when the potential for a splash hazard exists other eye protection and/or face protection must be worn. o Gloves should be worn when handling flammable liquids. Disposable nitrile gloves provide adequate protection against accidental hand contact with small quantities of most laboratory chemicals. Lab workers should contact EHRS for

5 advice on chemical resistant glove selection when direct or prolonged contact with hazardous chemicals is anticipated. o 100% cotton lab coats, closed toed shoes and long-sleeved clothing should be worn when handling flammable liquids. Additional protective clothing should be worn if the possibility of skin contact is likely. Nomex (fire resistant) lab coats and nomex/leather gloves are available for extra protection during higher hazard flammable liquids handling procedures. (More information is available in the Pyrophoric Chemicals SOP) Emergency Irrigation (Eyewash and safety shower) o A safety or drench shower should be available within 10 seconds of travel from where the flammable liquids are used. o Safety showers are tested annually by facility s personnel. o Where the eyes or body of any person may be exposed to flammable liquids, suitable facilities for quick drenching or flushing of the eyes and body shall be provided within the work area for immediate emergency use. Bottle type eyewash stations are not acceptable. o Eyewashes must be activated weekly by laboratory workers to ensure proper function of equipment and to flush the plumbing. Carrying out your work Transferring/Dispensing STATIC ELECTRICITY HAZARDS IN THE LABORATORY The flow of flammable and combustible liquids can cause the buildup of static electricity. When enough of a charge is built up a spark can result and potentially cause a fire or explosion. The likelihood of this happening is dependent upon how well the liquid conducts electricity, the flash point and the capacity to generate static electricity. Static electricity can be generated when liquid is transferred from one metal container to another. Liquids have the ability to generate static electricity when they move in contact with other materials during pouring, pumping or agitating. The build up of this static electricity can cause a spark to form where the solvent exits the container. This could result in a fire or explosion. PROCEDURES TO AVOID STATIC ELECTRICITY To avoid the buildup of static electricity that may cause a spark, it is important to bond and ground metal or special conductive plastic containers. Bonding eliminates the electrical potential between two containers therefore eliminating the likelihood of sparks. A bonding

6 wire is connected to two conductive objects as seen in the drums pictured below. Bonding wires between drums Grounding eliminates the difference in static potential charge between the conductive object and ground. Grounding is accomplished by connecting the conductive object directly to the earth, usually using cold water copper pipes, building steel or grounding bus/bar. Bonding and grounding require good electrical connections. Remove any dirt, paint or rust ensuring metal to metal contact. Building Static Grounding Bus (Mounted on Wall) Cable of Sufficient Length Small Grounding Clamp Attached to Portable Solvent Container Portable Container

7 Bonding and Grounding wires come in a variety of styles and lengths. They can be purchased through Fisher Scientific:, Justrite Manufacturing: and through Lab Safety Supply: Hand Clamp C Clamp and Alligator Clip Static hazards may also exist in non-metallic plastic or glass containers that cannot be grounded. Static may be generated by the free fall and turbulence of the liquid being poured. To minimize this hazard, pour as slowly as possible and use a grounded nozzle extension that allows filling the container from the bottom. DISPENSING FLAMMABLE LIQUIDS FROM 5 GALLON PAILS Manual dispensing pumps for 5-gallon pails/cans are available. These pumps are specifically designed to dispense liquids into small laboratory-size bottles without spilling. If you are pouring into a conductive container, a bonding wire should be attached from the 5-gallon pail to the container being filled. The 5-gallon pail should be grounded.

8 The dispenser shown in the picture below can be purchased through Fisher Scientific The metal strap in the picture hooks over the bottom of the pail and secures the dispenser while pumping. Metal Strap Two adapters are provided with the dispensing pump from Fisher (grey and black). Use the appropriate adapter to achieve the correct seal with the solvent container you have. Some solvent containers have a grey fitting at the opening, and others have the black one. DISPENSING FLAMMABLES FROM SAFETY CANS Safety cans have self-closing air tight lids and a flame arrester that protects the contents from an external ignition source. Bonding and grounding is still required on safety cans since static electricity generation is possible. The nozzle provides a bonding path to a receiving metallic vessel.

9 If either of the containers are non-metallic (conductive) it is still important to follow the limited velocity and grounded nozzle extension information given previously. Safety can with extended nozzle Safety cans do not offer protection from heat when exposed to fire and should be stored in a flammable liquids storage cabinet when not in use. Labeling o All flammable liquids must be clearly labeled with the correct chemical name. Handwritten labels are acceptable; chemical formulas and structural formulas are not acceptable. o The label on any containers of flammable liquids should say Flammable and include any other hazard information, such as Corrosive or Toxic, as applicable. Heating/Open flame o Do not store flammable liquids in chemical fume hoods or allow containers of flammable liquids in proximity to heating mantles, hot plates, or torches. o With the exception of vacuum drying ovens, laboratory ovens rarely have any means of preventing the discharge of material volatilized within them. Thus it should be assumed that these substances will escape into the laboratory atmosphere, but may also be present in sufficient concentration to form explosive mixtures within the oven itself. Venting the oven to an exhausted system will reduce this hazard. o Drying ovens should not be used to dry glassware that has been rinsed with organic solvents until the majority of the solvent has had the opportunity to drain or evaporate at room temperature.

10 o Do not use mercury thermometers to monitor oven temperatures. Accidental breakage of the thermometer will cause a serious hazard since uncontained mercury will volatilize very rapidly. Cleaning-up Small spills o Anticipate spills by having the appropriate clean up equipment on hand. The appropriate clean up supplies can be determined by consulting the material safety data sheet. This should occur prior to the use of any flammable liquids. Spill supplies for flammable liquids are designed to control the liquid portion of the spill and minimize the production of flammable vapors. Never use paper towels on large spills of flammable liquids because it exacerbates vapor production. o In the event of a spill all personnel in the area should be alerted. Turn off all sources of ignition. Waste disposal o Flammable liquids are hazardous wastes. Questions regarding waste disposal should be directed to the EHRS. Emergencies Decontamination o Wash with soap and water immediately following any skin contact with flammable liquids. Large spills o Do not attempt to handle a large spill of flammable liquids. Vacate the laboratory immediately and call for assistance. Office of Environmental Health & Radiation Safety, University Police 511 or This is a 24 hour service. o Remain on the scene, but at a safe distance, to receive and direct safety personnel when they arrive. Fire o Pull the fire alarm o Turn out the lights and close your laboratory door when everyone is out o Evacuate the building o Call 511 from a university phone or from a safe location to give Penn Police more information about the fire situation o Make yourself available to give emergency responders information as needed