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Environmental Health & Safety Use and Storage of Flammable and Combustible Liquids UTK Environmental Health & Safety Guide FS-020 This policy provides guidelines on use and storage of flammable liquids Effective Date: 01/01/2009 Revision Date: 11/01/2015 Purpose, Applicability, and Scope Purpose: It shall be the policy of the University of Tennessee that special precautions shall be taken in areas where flammable or combustible liquids are used, stored, or dispensed to reduce fire and explosion hazards. Applicability: This shall apply to all students, staff and faculty on the Knoxville campus of the University of Tennessee. Scope: This standard shall apply to the management of flammable and combustible liquids found on university property or under the control of university operations in leased space. This standard shall not apply to operations solely under the control of a third party (contractor) that does not impact the safety of UT employees or students, and does not apply to flammable and combustible liquids that have been deemed waste and are being handled under the University’s hazardous waste management program. Abbreviations and Definitions Abbreviations FM – Factory Mutual OSHA – Occupational Safety and Health Administration NFPA – National Fire Protection Association SDS – Safety Data Sheets UL – Underwriters Laboratories Definitions Aerosol – A material which is dispensed from its container as a mist, spray, or foam propellant under pressure. Classified as a Class I flammable liquid. Boiling Point – The temperature at which a liquid’s vapor pressure is equal to the atmospheric pressure. Liquids with low boiling points are very volatile. Bonding – The process of providing an electrically conductive pathway between dispensing container and a receiving container. Combustible Liquids – Liquids with flash points at or above 100oF. Combustible liquids are subdivided into Class II, IIIA and IIIB liquids. Fire Area – An area of a building separated from the remainder of the building by construction having a fire resistance of at least 1 hour and having all communicating openings properly protected by an assembly having a fire resistance rating of at least 1 hour. Flammable (Explosive) Limits/Flammable (Explosive) Range – The terms flammable and explosive are used interchangeably since unconfined vapors mixed in air will burn while confined vapors will produce an explosion. The minimum vapor concentration in air that, when ignited, will propagate a flame is the lower flammable limit (LFL or LEL). The maximum vapor concentration in air that when ignited will propagate a flame is the upper flammable or explosive limit (UFL or UEL). Flammable Storage Cabinet – A “flammable storage cabinet” is an Underwriters Laboratory (UL), or Factory Mutual (FM) listed storage cabinet designed in accordance with National Fire Protection Association (NFPA) 30 guidelines. Flash Point – The temperature at which a liquid gives off vapor sufficient to form an ignitable mixture with the air near the surface of the liquid or within the vessel used as determined by appropriate test procedure. Ground and Bonding Process – When flammable and combustible liquids travel through a pipe or through the air, static charges are accumulated. Grounding and bonding is necessary during the transfer of Class I flammable liquids to prevent a static spark from igniting the flammable vapors. Safety Can – A metal container of not more than 5 gallon capacity which is UL/FM Approved and is provided with a flame arrestor, a spring-closing lid and spout cover designed to relieve internal pressure when subjected to fire exposure. Vapor Density – The weight of a volume of pure vapor or gas (with no air present) compared to the weight of an equal volume of dry air at the same temperature and pressure. A vapor density figure less than one indicates the vapor is lighter than air. A figure greater than one indicates the vapor is heavier than air. Vapor Pressure – A measure of the pressure created by a liquid’s vapor at a specific temperature. Flammable or combustible liquids with a high vapor pressure at room temperature are more hazardous than liquids with lower vapor pressures because they will produce more flammable vapor without heating. Roles and Responsibilities Departments shall:
Supervisors shall:
Employees and Students shall:
EHS shall:
Procedures Hazards Description Flammable and combustible liquids are easily ignited and difficult to extinguish. Combustible liquids require heating for ignition and are easier to extinguish. Flammable and combustible liquids produce a high heat release rate once ignited (i.e., fires produce high temperatures in a short period of time), and associated fires spread rapidly. Vapors from flammable and combustible liquids can be present at room temperature and can form explosive mixtures with air. Some liquids are unstable or very reactive (e.g., burn when exposed to air without an ignition source, susceptible to spontaneous heating, react violently with other materials including water). These characteristics combine to create a significant fire and/or explosion hazard. Since the vapors generated from flammable liquids are most often heavier than air, they will seek the lowest available level in a building. This movement of vapors can produce potentially dangerous conditions far removed from the actual vapor source. Flammable vapor, if not removed by ventilation, can flow to an ignition source and flash back to the vapor source. The volatility of the liquid is increased when externally heated at or above its flash point. Overall, an increase in temperature will increase the hazard created by a flammable or combustible liquid by increasing its vapor’s flammable range. Due to this, heated Class II and Class III liquids should be subject to all applicable requirements for Class I and Class II liquids respectively. Combustible liquids vaporize and form flammable mixtures with air in open containers, when leaks occur, or when heated. To control these potential hazards, several properties of these materials, such as volatility, flashpoint, flammability range and auto ignition temperatures must be understood. Information on the properties of a specific liquid can be found in that liquid’s safety data sheet (SDS), or other reference material. NFPA 45 is the reference to determine the permissible amount of flammable liquids used in teaching and research laboratories. National Fire Protection Association (NFPA) hazard classifications for flammable and combustible liquids are listed below:
Considerations for working with and storing flammable liquids
Flammable Storage Cabinets With a flammable storage cabinet, the allowable quantities are doubled. Only certified cabinets listed by Factory Mutual, Underwriter’s Laboratory, or other qualified testing agencies should be purchased. The requirements for a flammable storage cabinet are:
Refrigerators Take precautions when storing flammable chemicals in a refrigerator. Refrigerator temperatures may be higher than the flash points of flammable liquids. Compressors and circuits are often located at the bottom of the refrigerator where vapors from small spills or leaks can accumulate. Electrical sparks from a conventional refrigerator can then ignite the flammable vapors that build up inside. Unless a cold room is ventilated and has a fire suppression sprinkler system, do not store flammable liquids there. Two kinds of refrigerators are approved for storage of flammables:
Transferring Liquids The main objective in working safely with flammable liquids is to avoid accumulation of vapors and to control sources of ignition. Besides the more obvious ignition sources, such as open flames from Bunsen burners, matches and cigarette smoking, less obvious sources, such as electrical equipment, static electricity and gas-fired heating devices should be considered. Some electrical equipment, including switches, stirrers, motors, and relays can produce sparks that can ignite vapors. Although some newer equipment has spark-free induction motors, the on-off switches and speed controls may be able to produce a spark when they are adjusted because they have exposed contacts. One solution is to remove any switches located on the device and insert a switch on the cord near the plug end. Pouring flammable liquids can generate static electricity. The development of static electricity is related to the humidity levels in the area. Cold, dry atmospheres are more likely to facilitate static electricity. Bonding or using ground straps for metallic or non-metallic containers can prevent static generation.
Bonding and Grounding
Additional Considerations Flammable and Combustible Solids Flammable solids often encountered in the laboratory include alkali metals, magnesium metal, metallic hydrides, some organometallic compounds, and sulfur. Many flammable solids react with water and cannot be extinguished with conventional dry chemical or carbon dioxide extinguishers.
Catalyst Ignition Some hydrogenated catalysts, such as palladium, platinum oxide, and Raney nickel, when recovered from hydrogenation reactions, may become saturated with hydrogen and present a fire or explosion hazard.
Purge gases, such as nitrogen or argon, may be used so that the catalyst can be filtered and handled in an inert atmosphere. Flammable Aerosols Flammable liquids in pressurized containers may rupture and aerosolize when exposed to heat, creating a highly flammable vapor cloud. As with flammable liquids, these should be stored in a flammable storage cabinet. Drums Containing Flammable and Combustible Liquids
Inspections EHS shall inspect all facilities on an annual basis. The management of flammable and combustible liquids shall be reviewed at this time. Deficiencies shall be noted on the inspection report and communicated the appropriate individual for corrections. Record Keeping EHS shall maintain records of all inspection reports and training records for a minimum of 10 years. Training EHS can provide general training on the use of flammable liquids upon request. Regulatory Drivers and References NFPA 30, 45, 101 OSHA 29 CFR 1910.106 OSHA 29 CFR 1926.152 DOT 49 CFR 172 Disclaimer The information provided in these guidelines is designed for educational use only and is not a substitute for specific training or experience. The University of Tennessee Knoxville and the authors of these guidelines assume no liability for any individual’s use of or reliance upon any material contained or referenced herein. The material contained in these guidelines may not be the most current. This material may be freely distributed for nonprofit educational use. However, if included in publications, written or electronic, attributions must be made to the author. Commercial use of this material is prohibited without express written permission from the author. Appendices FS-020 Flammable Liquids Guidelines (downloadable pdf) Appendix A: Guidelines for Calculating Limits on Flammable Liquid Storage in Campus Laboratories |