Combustible liquid defined

Combustible Eiquid A term used to classify certain liquids that will burn on the basis of flash points. The National Fire Protection Association (NFPA) defines a combustible liquid as having a flash point of 100°F (37.8°C) or higher. See also, Flammable Liquid. Class II liquids have flash points at or above 100°F, but below 140°F. Class III liquids are subdivided into two subclasses. 

Class IIIB Those having flash points at or above 200°F (93.4°C). The Department of Transportation (DOT) defines combustible liquids as those having flash points of not more than 141°F (60.5°C) and below 200°F (93.4°C). 

In a general sense any material than can bum. This implies a lower degree of flammability, although there is no precise distinction between a material that is flammable and one that is combustible (NFPA 30, Combustible and Flammable Liquids Code, defines differences between the classification of combustible liquids and flammable liquids based on flash point and vapor pressure). 

Local containment is a passive mitigation system intended to retain liquid spills or releases from process systems within the immediate area of the release. Local containment may be appropriate where the quantity of potential flammable or combustible liquid spills is well defined and small to moderate. Where larger quantities of liquids are involved, e.g. continuous process operations, local containment alone is usually not an appropriate design. Containment systems are commonly used for the following purposes ... 

As shown in Section 1.2, the vapour of a combustible liquid in thermal equilibrium with air can be ignited only at temperatures exceeding the flash point (FP). Table 1.5 summarizes the flash points (FP) for some combustible liquids. The propagation of flames in gas-air or vapour-air mixtures can be avoided by using joints with a defined ratio gap, w, w to flame path length,... 

Vaporization is the major problem in the ignition and spread of fires. Vapors from flammable and combustible liquids and soHds form a flammable mixture with air. They are characterized by their flash point, where the flash point is defined as the lowest temperature at which a solvent gives off flammable vapors in the close vicinity of its surface. The mixture at its flash point ignites when exposed to a source of ignition. At temperatures below the flash point, the vapor given off is considered too lean for ignition. 

Fire Point The minimum temperature at which a flammable or combustible liquid, as herein defined, and some volatile combustible solids will evolve sufficient vapor to produce a mixture with air that will support sustained combustion when exposed to a source of ignition, such as a spark or flame. 

It should be noted that the U.S. OSHA and U.S. DOT have differing definitions for the terms flammable and combustible. DOT defines a flammable liquid as one that, under specified procedures, has a flash point of not more than 141°F/60.5°C. A combustible liquid is defined as one having a flash point above 141 °F/60.5°C and below 200°F/93°C. This definition is used in this book. Many experts use 100°F/37.8°C as the point to differentiate these... 

For the purposes of the regulation a combustible liquid is defined as any liquid that does not meet the definition of any other classification specified in the regulation and has a flash point at or above 100°F (37.8°C) and below 200°F (93.3°C) except any mixture having one component or more with a flash point at 200°F (93.3°C) or higher, that makes up at least 99 percent of the total volume of the mixture. 

Liquids meeting the definition in 2.3.1.1 with a flash point of more than 35 C which do not sustain combustion need not be considered as flammable liquids for the purposes of these Regulations. Liquids are considered to be unable to sustain combustion for the purposes of these Regulations (i.e. they do not sustain combustion under defined test conditions) if (a) They have passed a suitable combustibility test [text continues] (b) Their fire point according to ISO 2592 1973 is greater than 100°C or (c) They are water miscible solutions with a water content of more than 90% by mass. UN 2.3.1.2... 

The OSHA regulations regarding container sizes are based on sections of the 1969 version of the NFPA Standard 30. Before returning to the topic of flammable material storage cabinets. Table 3.5 defines the various classes of flammable and combustible liquids and the maximum container sizes permitted by OSHA for each class. Table 3.5 is equivalent to Table H-12 from the OSHA General Industry Standards. Table 3.5 A provides similar data from NFPA 30-1996. Recall, however, that unless adopted by a local jurisdiction, the NFPA standards are only recommendations, not regulations. 

As generally defined by National Fire Protection Association (NFPA), 30, Flammable and Combustible Liquids Code, it is any liquid that has a closed-cup flash point defined as at or above 37.8°C (100°F). Combustible liquids are classified as Class II or Class III and flammable liquids are classed as lA, IB, or IC. Class II liquid Any liquid tested with a flash point defined as at or above 37.8°C (100°F) and below 60°C (140°F). Class IIIA Any liquid tested with a flash point defined as at or above 60°C (140°F), but below 93°C (200°F). Class IIIB Any liquid tested with a flash point defined as at or above 93°C (200°F). See also Flammable Liquid. 

As defined by the National Fire Protection Association (NFPA), 30, Flammable and Combustible Liquids Code, any liquid having a flash point below 37.8°C (100°F), except any mixture having components with flash points of 37.8°C (100°F) or higher, the total of which make up 99 percent or more of the total volume of the mixture. Flammable liquids are known as Class I liquids. Class I liquids are divided into three classes lA, IB, and IC. Class LA includes liquids having flash points below 22.8°C (73°F) and a boiling point below 37.8°C (100°F). Class IB includes liquids having flash points below 22.8°C (73°F) and a boiling point at or above 37.8°C (100°F). 

According to NEPA 30, Class I flammable liquids possess a flash point of less than 100°F (38 C) while combustible liquids possess a flash point of 100°F (38°C) or more. Please note that the Globally Harmonized System (GHS) may define flammable liquids using different criteria. Vapor is simply the gaseous state of a material. We can smell some vapors, and some possess no odor. 

The Department of Transportation (DOT) defines the term hazardous materials (or hazmat) as materials capable of posing an unreasonable risk to health, safety, and property, when transported in commerce. Each person who offers a material for transport must determine whether the material is hazardous. That is, the person must determine whether it is identified as an explosive, gas, flammable or combustible liquid, flammable solid, oxidizer or organic peroxide, poison, radioactive material, corrosive, or miscellaneous hazardous material. 

TABLE 5.1.2.1 Properties of Flammable and Combustible Liquids as Defined by the Globally Harmonized System for Classification and Labelling of Chemicals ... 

The Transportation Safety Act defines several classes of hazardous materials. Classes include explosives, radioactive material, flammable liquids or solids, combustible liquids or solids, oxidizing or corrosive materials, compressed gases, poisons, etiologic agents (hazardous biological materials), irritating materials, and other regulated materials (ORM). The act excludes firearms and ammunition. Other chapters in this book discuss hazards associated with some of these materials. 

Define or characterize each of the following for a flammable or combustible liquid ... 

Electrical installations in Class I hazardous locations as defined in Article 500 of the National Electrical Code, should be installed according to Article 501 of the code and electrical equipment should be suitable for use in atmospheres containing MC vapors. See Flammable and Combustible Liquids Code (NFPA No. 325M), Chemical Safety Data Sheet SD-86 (Manufacturing Chemists Association, Inc.). 

Note The Code requirements relative to flammable and combustible liquids appear in only two provisions in 1910.106 1910.106(b) and (i). By its terms, 1910.106(b) applies to tank storage. Because the pressure vessels in question are process vessels and not storage vessels, it does not appear that 1910.106(b) wordd apply to the vessels in question. Similarly, by its terms, 1910.106(i) apphes to refineries, chemical plants, and distilleries. The pressure vessels in question are not used in refineries, chemical plants, or distilleries as those terms are specifically defined in 1910.106(a). Consequently, it wordd seem that 1910.106 does not impose any requirements regarding the Code on the vessels in question. 

The NFPA and GHS define combustible liquids differently. The NFPA defines combustibles as compounds with flash points >38 °C (100 °F) but <93 °C (200 °F). The GHS defines combustibles... 

Flammable Liquids. Cleanrooms will use many flammable and combustible liquids. A flammable liquid is defined in NFPA 30 as a liquid having a flash point below 100°F (37.8°C) and having a vapor pressure not exceeding 40 PSIA (2068 mm Hq) at 100"F. Combustible liquids are defined as liquids with a flash point above 100"F (37.8"C). They share many of the same hazards and could really be treated alike. A headed combustible liquid is equally as dangerous as a flammable liquid at room temperature. 

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