OSHA regulations seem to be ever-changing. One of the more significant changes that recently occurred was the inclusion of the Global Harmonization System (GHS) into the Hazard Communication Standard (HAZ- COM). Although many significant changes to OSHA regulations make it to the headlines of safety magazines and websites, there are some changes that do not receive the same attention. One such change, which was part of the revisions to the HAZCOM standard, was how OSHA defines flammable and combustible liquids.
The regulations that cover the definition and management of flammable and combustible liquids were dramatically changed due to OSHA revising how they define “flammable liquids.” The change was required so that the regulation of 29 CFR 1910.106 would be consistent with the Global Harmonization System.
Flammable Liquids
The most important change is that OSHA has eliminated the definition of a “combustible” liquid and now uses the term “flammable” for all liquids that are capable of catching on fire and sustaining combustion. This change departs from the National Fire Protection Association’s (NFPA) definition, which was used as the basis for the original regulations.
Under the “old regulations” OSHA had two categories used to describe liquids: “flammable” and “combustible.” The difference between the two was based on the flashpoint. Any liquid with a flashpoint below 100oF was designated as flammable and those with a flashpoint at or above 100°F were defined as combustible. Combustible liquids were further divided into two classes, Class II and Class III, based on their flashpoint. Flammable liquids were divided into three categories of Class IA, Class IB, and Class IC, based on the flashpoint and boiling point of the liquid.
Under the revised regulation, OSHA now defines a flammable liquid as any liquid having a flashpoint at or below 199.4°F. Flammable liquids are subdivided into four categories, which are based on flashpoint and boiling point. The categories are as follows:
- Category 1. Liquids with a flashpoint below 73.4°F (23°C) and boiling point at or below 95°F (35°C).
- Category 2. Liquids with a flashpoint below 73.4°F (23°C) and boiling point at or above 95°F (35°C).
- Category 3. Liquids with a flashpoint between 73.4°F (23°C) and 140°F (60°C). When a Category 3 liquid with a flashpoint at or above 100°F (37.8°C) is heated for use to within 30°F (16.7°C) of its flash- point, it must be handled as a Category 3 liquid with a flashpoint below 100°F (37.8 °C).
- Category 4. Liquids having a flashpoint between 140°F (60°C) and 199.4°F (93°C). When a Category 4 flammable liquid is heated for use to within 30°F (16.7°C) of its flashpoint, it must be handled as a Category 3 liquid with a flashpoint at or above 100°F (37.8°C).
Knowing the category plays a role in how to store chemicals. This information may be on the safety data sheet (SDS). With the new standardized SDSs, the flashpoint information can be found in Section 9: Physical and chemical properties.
Storage Requirements—Containers
OSHA has established very specific requirements for the safe storage of flammable substances. Table H-12 in 29 CFR 1910.106 specifies maxi- mum allowable sizes for various types of containers.
Safety cans are defined as an approved container of not more than 5 gallons capacity, having a spring-closing lid and spout cover which is designed so that it will safely relieve internal pressure when subjected to fire exposure. Only use storage cans that have been approved by the U.S. Department of Transportation (DOT) or a nationally recognized testing laboratory. They may be either metal or plastic and have a capacity of five gallons or less.
Flammable containers must be closed. OSHA requires that Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100ºF (37.8ºC), to be kept in covered containers when not in use.
Storage Requirements—Inside Solvent Storage
To best illustrate grounding and bonding, this diagram indicates the proper way to ground and bond containers. | Credit: Flammable Liquids Fact Sheet, OR-OSHA (10/13) FS-12 by Oregon OSHA
OSHA has very specific requirements for the storage of flammable liquids in areas where the use of the solvent is incidental to the operation. The maximum amount of flammable liquid that can be stored outside of a solvent storage cabinet or solvent storage room is as follows:
- 25 gallons of Category 1 flammable liquids in containers
- 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
The limits are for each “fire area” which is not defined by OSHA. A fire area is defined by NFPA Code 30 (1.6.15) as, “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.” The construction can be barriers, walls, doors, or other means in order to contain fire within the area.
The requirements for storage cabinets can be found in 29 CFR 1910.106 (d)(3) of the standard. Most commercially available cabinets will meet the standard. The cabinets must be labeled “Flammable, Keep Fire Away.” No more than 60 gallons of Category 1, 2, or 3 liquids or more than 120 gallons of Category 4 liquids can be stored in a storage cabinet; this includes aerosol cans.
The NFPA also provides a special provision for the grouping of flammable cabinets in an industrial facility. Most industrial settings do not have walls or barriers within a facility, “In an industrial occupancy, additional cabinets may be located in the same fire area if the additional cabinets, or the group of not more than three (3) cabinets, is separated from the other cabinets or group of cabinets by at least 100 feet (30 m)” (4.3.2 Exception 1).
An inside storage room permits the storage of larger quantities of flammable liquids than other methods. 29 CFR 1910.106 (d)(4) has specific requirements for the design and construction of inside storage rooms. It references NFPA standards that be must followed and addresses wiring, ventilation, and the ways to configure stored containers.
Transferring Liquids
Special safety practices, such as grounding and bonding, must be utilized when transferring or dispensing flammable liquids. Moving liquid from one container to another can cause static electricity, increasing the chance of ignition or explosion caused by a spark.
OSHA’s regulations at 29 CFR 1910.106(e)(6)(ii) states, “Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100°F (37.8°C), shall not be run/dispensed into containers unless the nozzle and container are electrically interconnected.
The process of bonding and grounding allows for an electrically conductive pathway between a dispensing container, a receiving container, and an earth ground. This pathway eliminates the buildup of static electricity and allows it to safely dissipate into the ground. The purpose of bonding is to eliminate a difference in the static electrical charge potential between two or more objects.
Grounding eliminates the potential difference between an object and the ground. If the containers are not properly bonded and grounded, the resulting static spark could be capable of raising the vapor temperature above the flash point, causing an explosion.
| MAXIMUM ALLOWABLE SIZES FOR CONTAINERS |
| Container Type |
Category 1 |
Category 2 |
Category 3 |
Category 4 |
| Glass or approved plastic |
1 pint |
1 quart |
1 gallon |
1 gallon |
| Metal (other than DOT drums) |
1 gallon |
5 gallon |
5 gallon |
5 gallon |
| Safety cans |
2 gallon |
5 gallon |
5 gallon |
5 gallon |
| Metal drums (DOT specifications) |
60 gallon |
60 gallon |
60 gallon |
60 gallon |
| Approved portable tanks |
660 gallon |
660 gallon |
660 gallon |
660 gallon |
For bonding and grounding to be effective, a metal-to-metal connection must be maintained between the bonding and grounding cables and the containers.
To accomplish this, all paint, dirt, rust, etc., must be removed from the area of connection. In most instances simple alligator clamps are not sufficient, as they don’t break the surface of the paint. There are clamps that have points that are better suited for this application, and they can break the surface of the paint.
OSHA’s change in the definition of flammable and combustible materials has significantly altered the regulation which was originally established in he early 1970’s. One of the impacts is that the new classification scheme has caused some chemicals to change categories.
The definition change has also created some confusion as to the safe management and handling of flammable liquids. In order to ensure that flammable liquids are being properly managed, and compliance is met with the regulations, these are several steps that should be completed. The first step would be to develop a complete inventory of all flammable substance that are used, including their volume and location. The second step would be to classify them, and the last step would be to ensure that the above requirements regarding storage and handling are being met.
Impact of OSHA's Flammable Liquid Definition Change
The regulations that cover the definition and management of flammable and combustible liquids were dramatically changed due to OSHA revising how they define “flammable liquids.” The change was required so that the regulation of 29 CFR 1910.106 would be consistent with the Global Harmonization System.
Flammable Liquids
The most important change is that OSHA has eliminated the definition of a “combustible” liquid and now uses the term “flammable” for all liquids that are capable of catching on fire and sustaining combustion. This change departs from the National Fire Protection Association’s (NFPA) definition, which was used as the basis for the original regulations.
Under the “old regulations” OSHA had two categories used to describe liquids: “flammable” and “combustible.” The difference between the two was based on the flashpoint. Any liquid with a flashpoint below 100oF was designated as flammable and those with a flashpoint at or above 100°F were defined as combustible. Combustible liquids were further divided into two classes, Class II and Class III, based on their flashpoint. Flammable liquids were divided into three categories of Class IA, Class IB, and Class IC, based on the flashpoint and boiling point of the liquid.
Under the revised regulation, OSHA now defines a flammable liquid as any liquid having a flashpoint at or below 199.4°F. Flammable liquids are subdivided into four categories, which are based on flashpoint and boiling point. The categories are as follows:
Knowing the category plays a role in how to store chemicals. This information may be on the safety data sheet (SDS). With the new standardized SDSs, the flashpoint information can be found in Section 9: Physical and chemical properties.
Storage Requirements—Containers
OSHA has established very specific requirements for the safe storage of flammable substances. Table H-12 in 29 CFR 1910.106 specifies maxi- mum allowable sizes for various types of containers.
Safety cans are defined as an approved container of not more than 5 gallons capacity, having a spring-closing lid and spout cover which is designed so that it will safely relieve internal pressure when subjected to fire exposure. Only use storage cans that have been approved by the U.S. Department of Transportation (DOT) or a nationally recognized testing laboratory. They may be either metal or plastic and have a capacity of five gallons or less.
Flammable containers must be closed. OSHA requires that Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100ºF (37.8ºC), to be kept in covered containers when not in use.
Storage Requirements—Inside Solvent Storage
To best illustrate grounding and bonding, this diagram indicates the proper way to ground and bond containers. | Credit: Flammable Liquids Fact Sheet, OR-OSHA (10/13) FS-12 by Oregon OSHA
OSHA has very specific requirements for the storage of flammable liquids in areas where the use of the solvent is incidental to the operation. The maximum amount of flammable liquid that can be stored outside of a solvent storage cabinet or solvent storage room is as follows:
The limits are for each “fire area” which is not defined by OSHA. A fire area is defined by NFPA Code 30 (1.6.15) as, “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.” The construction can be barriers, walls, doors, or other means in order to contain fire within the area.
The requirements for storage cabinets can be found in 29 CFR 1910.106 (d)(3) of the standard. Most commercially available cabinets will meet the standard. The cabinets must be labeled “Flammable, Keep Fire Away.” No more than 60 gallons of Category 1, 2, or 3 liquids or more than 120 gallons of Category 4 liquids can be stored in a storage cabinet; this includes aerosol cans.
The NFPA also provides a special provision for the grouping of flammable cabinets in an industrial facility. Most industrial settings do not have walls or barriers within a facility, “In an industrial occupancy, additional cabinets may be located in the same fire area if the additional cabinets, or the group of not more than three (3) cabinets, is separated from the other cabinets or group of cabinets by at least 100 feet (30 m)” (4.3.2 Exception 1).
An inside storage room permits the storage of larger quantities of flammable liquids than other methods. 29 CFR 1910.106 (d)(4) has specific requirements for the design and construction of inside storage rooms. It references NFPA standards that be must followed and addresses wiring, ventilation, and the ways to configure stored containers.
Transferring Liquids
Special safety practices, such as grounding and bonding, must be utilized when transferring or dispensing flammable liquids. Moving liquid from one container to another can cause static electricity, increasing the chance of ignition or explosion caused by a spark.
OSHA’s regulations at 29 CFR 1910.106(e)(6)(ii) states, “Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100°F (37.8°C), shall not be run/dispensed into containers unless the nozzle and container are electrically interconnected.
The process of bonding and grounding allows for an electrically conductive pathway between a dispensing container, a receiving container, and an earth ground. This pathway eliminates the buildup of static electricity and allows it to safely dissipate into the ground. The purpose of bonding is to eliminate a difference in the static electrical charge potential between two or more objects.
Grounding eliminates the potential difference between an object and the ground. If the containers are not properly bonded and grounded, the resulting static spark could be capable of raising the vapor temperature above the flash point, causing an explosion.
For bonding and grounding to be effective, a metal-to-metal connection must be maintained between the bonding and grounding cables and the containers.
To accomplish this, all paint, dirt, rust, etc., must be removed from the area of connection. In most instances simple alligator clamps are not sufficient, as they don’t break the surface of the paint. There are clamps that have points that are better suited for this application, and they can break the surface of the paint.
OSHA’s change in the definition of flammable and combustible materials has significantly altered the regulation which was originally established in he early 1970’s. One of the impacts is that the new classification scheme has caused some chemicals to change categories.
The definition change has also created some confusion as to the safe management and handling of flammable liquids. In order to ensure that flammable liquids are being properly managed, and compliance is met with the regulations, these are several steps that should be completed. The first step would be to develop a complete inventory of all flammable substance that are used, including their volume and location. The second step would be to classify them, and the last step would be to ensure that the above requirements regarding storage and handling are being met.
Gary A. Jones is the director of environmental, health and safety (EHS) affairs at PRINTING United Alliance in Fairfax, VA. His primary responsibility is to monitor and analyze EHS regulatory activities at all domestic and some international government levels. He provides representation on behalf of the printing and specialty graphic imaging industry. In doing so, Mr. Jones works closely with the federal and state-level Environmental Protection Agencies (EPA), Occupational Safety and Health Agency (OSHA), Department of Transportation (DOT), and other agencies. He also provides membership assistance on EHS compliance and sustainability programs through a variety of approaches including responding to inquiries, presentations, writing, and consulting services.
Mr. Jones is also supporting PRINTING United Alliance’s efforts for the Sustainable Green Printing Partnership (SGP). SGP is dedicated to assisting printing operations respond to the customer demand for sustainable printing.
He holds a BS in biology from LaRoche College and an MS in chemistry from the University of Pittsburgh.