Download Handling and Storage of Flammable Liquids: OSHA Regulations and Safety Measures and more Schemes and Mind Maps Construction in PDF only on Docsity!
Flammable Liquids
29 CFR 1910.
OSHA’s Directorate of Training and Education These materials were developed by OSHA’s Directorate of Training and Education and are intended to assist employers, workers, and others as they strive to improve workplace health and safety. While we attempt to thoroughly address specific topics, it is not possible to include discussion of everything necessary to ensure a healthy and safe working environment in a presentation of this nature. Thus, this information must be understood as a tool for addressing workplace hazards, rather than an exhaustive statement of an employer’s legal obligations, which are defined by statute, regulations, and standards. Likewise, to the extent that this information references practices or procedures that may enhance health or safety, but which are not required by a statute, regulation, or standard, it cannot, and does not, create additional legal obligations. Finally, over time, OSHA may modify rules and interpretations in light of new technology, information, or circumstances; to keep apprised of such developments, or to review information on a wide range of occupational safety and health topics, you can visit OSHA’s website at www.osha.gov.
INTRODUCTION
This discussion covers only two sections of 29 CFR 1910.106: Container and portable tank storage Industrial plants The primary basis of this standard is the National Fire Protection Association's publication NFPA 30, Flammable Liquids Code. 29 CFR 1910.106 applies to the handling, storage, and use of flammable liquids with a flash point below 200ºF. There are two primary hazards associated with flammable liquids: explosion and fire. In order to prevent these hazards, this standard addresses the primary concerns of: design and construction, ventilation, ignition sources, and storage.
DEFINITIONS
There are a number of definitions included in 29 CFR1910.106. These definitions were derived from consensus standards, and were not uniquely developed for OSHA standards. Some of the more important definitions are discussed below. Aerosol: a material which is dispensed from its container as a mist, spray, or foam by a propellant under pressure. Approved: approved or listed by a nationally recognized testing laboratory. Boiling point: the boiling point of a liquid at a pressure of 14.7 pounds per square inch absolute (psia). This pressure is equivalent to 760 millimeters of mercury (760 mm Hg). At temperatures above the boiling point, the pressure of the atmosphere can no longer hold the liquid in the liquid state and bubbles begin to form. The lower the boiling point, the greater the vapor pressure at normal ambient temperatures and consequently the greater the fire risk. Container: any can, barrel, or drum. Closed container: a container so sealed by means of a lid or other device that neither liquid nor vapor will escape from it at ordinary temperatures. Fire area: 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. Flash point: the minimum temperature at which a liquid gives off vapor within a test vessel in sufficient concentration to form an ignitable mixture with air near the surface of the liquid. The flash point is normally an indication of susceptibility to ignition.
Portable tank: a closed container having a liquid capacity over 60 U.S. gallons and not intended for fixed installation. Safety can: an approved container, of not more than 5 gallons capacity, having a spring‐closing lid and spout cover and so designed that it will safely relieve internal pressure when subjected to fire exposure. Vapor pressure: the pressure, measured in pounds per square inch (absolute) exerted by a volatile liquid as determined by the Standard Method of Test for Vapor Pressure of Petroleum Products (Reid Method), American Society for Testing and Materials ASTM D323‐68. Vapor pressure is a measure of a liquid's propensity to evaporate. The higher the vapor pressure, the more volatile the liquid and, thus, the more readily the liquid gives off vapors. Ventilation as specified in this section is for the prevention of fire and explosion. It is considered adequate if it is sufficient to prevent accumulation of significant quantities of vapor‐air mixtures in concentration over one‐fourth of the lower flammable limit.
FLAMMABLE (EXPLOSIVE) LIMITS
When vapors of a flammable liquid are mixed with air in the proper proportions in the presence of a source of ignition, rapid combustion or an explosion can occur. The proper proportion is called the flammable range and is also often referred to as the explosive range. The flammable range includes all concentrations of flammable vapor or gas in air, in which a flash will occur or a flame will travel if the mixture is ignited. There is a minimum concentration of vapor or gas in air below which propagation of flame does not occur on contact with a source of ignition. There is also a maximum proportion of vapor in air above which propagation of flame does not occur. These boundary‐line mixtures of vapor with air are known as the lower and upper flammable limits (LFL or UFL) respectively, and they are usually expressed in terms of percentage by volume of vapor in air. See figure below.
In popular jargon, a vapor/air mixture below the lower flammable limit is too "lean" to burn or explode, and a mixture above the upper flammable limit is too "rich" to burn or explode. The LFL is also known as the lower explosive limit (LEL). The UFL is also referred to as the upper explosive limit (UEL). No attempt is made to differentiate between the terms flammable and explosive as applied to the lower and upper limits of flammability.
CONTAINER AND PORTABLE TANK STORAGE
Scope This section applies only to the storage of flammable liquids in drums or other containers (including flammable aerosols) not exceeding 60 gallons individual capacity and portable tanks of less than 660 gallon individual capacity. A portable tank is a closed container which has a liquid capacity of over 60 gallons and is not intended for fixed installations. This section does not apply to the following: Storage of containers in bulk plants, service stations, refineries, chemical plants, and distilleries Category 1, 2, or 3 flammable liquids in the fuel tanks of a motor vehicle, aircraft, boat, or portable or stationary engine Flammable paints, oils, varnishes, and similar mixtures used for painting or maintenance when not kept for a period in excess of 30 days Beverages when packed in individual containers not exceeding 1 gallon in size
Rating and Capacity Storage in inside storage rooms shall comply with the following: Wiring Electrical wiring and equipment located in inside storage rooms used for Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100 °F (37.8 °C), shall be approved under subpart S of this part for Class I, Division 2 Hazardous Locations; for Category 3 flammable liquids with a flashpoint at or above 100 °F (37.8 °C) and Category 4 flammable liquids, shall be approved for general use. Ventilation Every inside storage room shall be provided with either a gravity or a mechanical exhaust ventilation system. Such system shall be designed to provide for a complete change of air within the room at least six times per hour. If a mechanical exhaust system is used, it shall be controlled by a switch located outside of the door. The ventilating equipment and any lighting fixtures shall be operated by the same switch. A pilot light shall be installed adjacent to the switch if Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100 °F (37.8 °C), are dispensed within the room. Where gravity ventilation is provided, the fresh air intake, as well as the exhaust outlet from the room, shall be on the exterior of the building in which the room is located. Storage In every inside storage room, there shall be maintained an aisle at least 3 feet wide. Easy movement within the room is necessary in order to reduce the potential for spilling or damaging the containers and to provide both access for firefighting and a ready escape path for occupants of the room, should a fire occur. Containers over 30 gallons capacity shall not be stacked one upon the other. Such containers are built to DOT specifications and are not required to withstand a drop test greater than 3 feet when full.
Dispensing shall be only by approved pump or self‐closing faucet. Storage Inside Building Egress Flammable liquids, including stock for sale, shall not be stored so as to limit use of exits, stairways, or areas normally used for the safe egress of people. Office Occupancies Storage shall be prohibited except that which is required for maintenance and operation of equipment. Such storage shall be kept in closed metal containers stored in a storage cabinet or in safety cans or in an inside storage room not having a door that opens into that portion of the building used by the public. General Purpose Public Warehouses There are tables in the standard summarizing the storage requirements applicable to "General Purpose Public Warehouses." These tables refer to indoor storage of flammable liquids which are confined in containers and portable tanks. Storage of incompatible materials that create a fire exposure (e.g., oxidizers, water‐reactive chemicals, certain acids and other chemicals) is not permitted. Warehouses or Storage Buildings The last type of inside storage covered by this paragraph addresses storage in "warehouses or storage buildings." These structures are sometimes referred to as outside storage rooms. Practically any quantity of flammable can be stored in these buildings provided that they are stored in a configuration consistent with the tables in this paragraph. Containers in piles shall be separated by pallets or dunnage where necessary to provide stability and to prevent excessive stress on container walls. Stored material shall not be piled within 3 feet of beams or girders and shall be at least 3 feet below sprinkler deflectors or discharge orifices of water spray, or other fire protection equipment. Aisles of at least 3 feet in width shall be maintained to access doors, windows or standpipe connections. Storage Outside Buildings Requirements covering "storage outside buildings" are summarized in tables in paragraph (d)(6). Associated requirements are given for storage adjacent to buildings. Also included are requirements involving controls for diversion of spills away from buildings and security measures for protection against trespassing and tampering. Certain housekeeping requirements are given which relate to control of weeds, debris and accumulation of unnecessary combustibles. Fire Control
120 gallons of Category 2, 3, or 4 flammable liquids in containers 660 gallons of Category 2, 3, or 4 flammable liquids in a single portable tank Handling Liquids at Point of Final Use Flammable liquids shall be kept in covered containers when not actually in use. Where flammable liquids are used or handled, except in closed containers, means shall be provided to dispose promptly and safely of leakage or spills. Flammable liquids shall be drawn from or transferred into vessels, containers, or portable tanks within a building only in the following manner:
- Through a closed piping system, (2) From safety cans
- From safety cans
- By means of a device drawing through the top
- From containers or portable tanks by gravity through an approved self‐closing valve Transfer operations must be provided with adequate ventilation. Sources of ignition are not permitted in areas where flammable vapors may travel. Transferring liquids by means of air pressure on the container or portable tanks is prohibited. This may result in an overpressure which could exceed what the container or tank could withstand. In addition, a flammable atmosphere could be created within the container or tank. This atmosphere would be particularly sensitive to ignition because of the increased pressure. (^1) Fire protection system shall be sprinkler, water spray, carbon dioxide, or other system.
