)”. 2 Quality Assurance and Research 43 5. The mixing rule is a simplification of that of Le Chatelier's and is based on the established equation. Intensive properties are often constants and can be used to identify a substance. Group 1 Rating means: A Group 1 material is one that does not reach flashover. Class F – Easily flammable. In flammability assessment, the terpene effect is usually studied using their total or subgroup content, missing, therefore, the information that could be provided by the molecules themselves. Tree species, plant trait approach and methods used in flammability testing. S. All oil-based paints are flammable. The Hindenburg disaster is an example of a large hydrogen explosion. to determine if that material is explosive or extremely flammable (see WARNING below). Only 1 spark. At a concentration in air lower than the LFL, gas. DISCUSSION—In fire testing, non-combustibility is often assessed by means of ASTM E 136 or ISO 1182. Most significant is that fire officials approved Trex following testing for the burning hazards contained in forest fires. While mineral spirits can be burned at elevated temperatures, they are typically not considered highly flammable. e. 1:1994 (R2016) Methods for fire tests on building materials, components and structures - Part 1: Combustibility test for materials. Epoxy is certainly combustible (and flammable before curing) but once it's cured it no longer produces vapors that can ignite. 1 Properties of Flammable and Combustible Liquids. Employ SGS to plan and deploy the appropriate flammability tests and programs for your products. For the first time, filter manufacturers have a choice in independent testing partners for the UL 900 standard. Combustible Dust Doesyourcompanyorfirm processanyoftheseproductsor materialsinpowderedform? Ifyourcompanyorfirmprocessesanyoftheseproductsor materials. “R-22a” has been sold under the. Much depends on what the base of the paint is and. If the material satisfies the criteria outlined in the test method the material is not deemed ; fire . One does not have to raise their temperature to a certain threshold for them to be capable of burning with a flame. Decomposability showed no signs of coupling with any measure of flammability, except for a marginally statistically non-significant correlation with fire sustainability of fresh leaves (h). , a small spark will ignite it), as. However, this definition is ambiguous because both combustibility and fire hazard are complex and depend on many parameters related to the material, its end. s. The lower and upper flammability limits (LFL and UFL) for common compounds are shown in Table 1. • The limits specified shall be determined at 14. 7. Combustibility : combustible: non-combustible: Boiling/Melting point: lower: higher: In general, the guidelines of this table hold true when comparing organic and inorganic compounds against each. Insulation flammability testing process to BS 5803-4. Liquids with lower flash points ignite easier. 1: Common Physical Properties. Learn with flashcards, games, and more — for free. Combustible materials can ignite or burn, typically producing heat or light. Section 12. Abundant, dense foliage. Kinetic Molecular Theory of matter. , Bureau of Mines [BOM] bulletins 450, 503, and 627). Flammability testing of upholstered furniture including mattresses is a complex process and fully reviewing the history, development and detail of these test methods is beyond the scope of this chapter. Stroup A ny material capable of burning with a flame is considered flammable. , storage room, flammable liquidLet me explain. A lot of the rigid board products claim to be “fire rated”, but it doesn’t seem to mean much since building codes still requires a barrier like drywall for them. Flammable = able to be set. know concerning all of that is that different agencies and organizations have different standards for determining what flammability is and what combustibility is. NFPA has six classes of flammable liquids. 4A: Methods and Flammability is shared under a CC BY-NC-ND license and was authored, remixed,. There may be suggestions below for improving the article. • No direct engineering relationships between non-combustibility, flammability and fire resistance performance, based on the testing protocols we use to date and the lack of engineering tools in pyrolysis and combustion predictions. Horizontal burning test for UL94 HB rated materials; 2. 2. A material is considered to be flammable if its flashpoint is any value of temperature below 100. There are three terms used to describe the combustibility of materials used for building construction, furnishings, finishes, decorations, and furniture: combustible, noncombustible, and limited combustible. Technical Background The severity of a gasoline or flammable liquid burn depends upon three factors – the flash point, vapor density and flammable range. Materials can be tested for the degree of flammability and combustibility in accordance with DIN 4102. [1] [2] [3] The same information can be depicted in a normal. Combustible liquids have a flashpoint at or above 100°F. This page titled 1. Editors may also seek a reassessment of the decision if they believe there was a mistake. However, using the published data to predict whether or not a specific gas stream is flammable can often be a confusing and. All of them vaporize at temperatures below the boiling point of water. Flammability properties in terms of ignitability, sustainability, consumability and combustibility of the different peat/litter fuel-beds by means of easily measurable descriptors. The words come from Latin. Choosing the Best Respirator for Wildfire Smoke. The diagram plots a. The difference between flammable and combustible is that they are more dangerous than combustible substances as they can catch fire and burn easily at normal. Is Diesel Fuel Flammable or Combustible?. A material that is flammable can be set on fire, while a material that is inflammable is capable of bursting into flames without an external source of ignition. Nylon, polyester and acrylic tend to be slow to ignite but once. (countable) A measure of the extent to which something is flammable. What are some examples of organic and inorganic compounds? Organic vs. Determination of Combustibility & Explosivity - 484 Determination of Combustibility – UN Screening Test – Unbroken strip or powder train 250 mm long x 20 mm wide x 10 mm high Determination of Explosibility – ASTM E 1226, standard test method for explosibility of dust clouds. 0 license and was authored, remixed, and/or curated by Lisa Nichols via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. min-1] Class of fire reaction according STN EN 13501-1:2010 Board floor 118 D fl – moderately combustible OSB board 127 E fl – moderately combustible Beech parquet 102 C fl – combustible with difficultyThis has prompted the Aluminum Association to publish a white paper on the flammability of aluminum and its alloys,. Stoddard solvent. e. (Source: The U. One does not have to raise their temperature to a certain threshold for them to be capable of burning with a flame. Fire prevention basically means preventing the. Now, let's demystify the flammability of leather. The ignitibility of live foliage was lower and the combustibility was higher in Cupressaceae. 2. We are equipped to test a wide range of fabrics and textiles, consumer and industrial garments and other apparel, as well as furniture products. Flammable materials have flashpoints below 100 degrees Fahrenheit, while combustible materials have flashpoints above 100 degrees Fahrenheit and below 200 degrees Fahrenheit. There is a sense in which we suspect that they mean different things, but for the most part, it seems that there is a difference without a distinction. Oppositely, flammables are more likely to form vapours in normal work environments, because their flash points are lower. Combustible < Previous lesson. 26 m 2 m −2 of the A0 to 125. Flammable liquids are referred to as Class 1 Liquids. 04 ºF, while it is termed as a combustible material if it has a flashpoint higher than 100. Since the 1960s, PFA members have been researching and. While it is true that even well-maintained bamboo will burn eventually if engulfed in hot flames, it is no. 3°C (200°F). A chemical property describes the ability of a substance to undergo a specific chemical change. Consider a pool of diesel fuel; if you were to. Taken together, a highly flammable leaf could be considered as having high ignitibility (easily ignited), high sustainability (burning for a long period), and high combustibility (giving off a large amount of heat in a given amount of time). This includes all types of untreated lumber, hardwoods, softwoods, plywood, and chipboard. Flammability components included: combustibility (a, b); ignition temperature (c, d); time to ignition (e, f), and, fire sustainability (g, h). burning. Physical properties of polymers handbook flammability. Now, let’s take a look at some common paints and their flammability vs combustibility (or lack thereof). This test is conducted to determine the maximum pressure (Pmax), maximum rate of pressure rise (dP/dt)max and the dust constant Kst value of an ignited powder, dispersed in the air, as a dust cloud. flammability ____ physical change – does not alter the chemical identity of a substance. The degree of difficulty required to cause the combustion of a chemical is quantified through fire testing. Synthetic materials, including polyurethane (PU), polyvinyl chloride (PVC), and polyester, are often more flammable than natural leather. Ecol. It can also burn the skin in high concentrations. 8° C (100 ° F). Our more than 50 years of experience in fire investigations positions our multidisciplinary teams to assist in developing more resilient products as we analyze flammable materials, investigate fires, conduct combustibility. In addition to their flammability, polyurethanes form carbon monoxide, hydrogen cyanide and other toxic products on decomposition and combustion. boiling points c. To receive the classification needed to get insulation products to market, they also need to undergo testing for combustibility, heat levels, flame spread and smoke release. These cellulose fibrils are subsequently introduced to high-density polyethylene (HDPE) to improve flame retardancy. flammable, even if it still contains significant concentrations of methane. Having a workable understanding of the difference in flammability will prove helpful when working on A2L systems. Liquids with high Combustibility and low flashpoint are those liquids that can be smelled. Combustible. Flammability tests for regulation of building and construction materials . length. 1 Regulatory Compliance 43 5. , by the Carson City Fire Department, Nevada Tahoe Conservation District, University of California Cooperative Extension and University of Nevada Cooperative Extension. Many products can be used to coat other substances and they are all referred to, generically, as “paint”. Basic N95 masks have two straps to secure around the head and are made of lightweight materials. This Video is about Difference Between Flammable & Combustible Liquid/Material || Flammable Liquid || Combustible Liquid || HSE STUDY GUIDE-~-~~-~~~-~~-~-Don. Inorganic. TTI increases from 34 s of the M0 to 60 s of M4, and from 40 s of the A0 to 52 s of A3, and TSR decreases from 203. approved* flammable storage cabinet –re. Clearly, flammable materials have a low flashpoint, while combustible materials are much higher. The vaporization rate increases as the temperature increases. • Non-combustibility of materials is dependent on the test method and test conditions, as well as the definition. Flammable liquids give off vapour that can easily be ignited at normal working temperatures. Doug W 289 subscribers Subscribe 47K views 10 years ago Here's a simple demonstration that illustrates the difference between a flammable liquid and a. Experimental results are presented for the flash point, fire point and sustained combustibility. 1. The main difference between flammable and combustible liquids is the flashpoint, which refers to the lowest temperature at which the vapors generated by a. It means something like "to put fire to a thing". Powder and dust burning tests: Burning tests determine the ignitability and combustibility of powders. 33°C) (source). Synthetic materials can melt, drip, and release toxic fumes when exposed to. 3. g. Physical. Both flammable and inflammable mean easily set on fire. Let’s take a closer look. <iframe src="height="0" width="0" style="display:none;visibility. The answer is yes; acrylic is made of combustible materials and hence flammable. It is important to keep in mind the flammability and combustibility of liquids and practice proper safety measures when handling them. J. Lower flammability limit (LFL): The lowest concentration (percentage) of a gas or a vapor in air capable of producing a flash of fire in the presence of an ignition source (arc, flame, heat). Determination of Combustibility • UN Test N. Reaction with Water Metals such as lithium, sodium, and potassium react with water to produce hydrogen gas. Intertek has applied decades of flammability testing experience with building materials for UL 900 testing. Explanation of Flammability Tests. Plastics, like all organic materials, will burn. . The difference between flammable and combustible is that they are more dangerous than combustible substances as they can catch fire and burn easily at normal room temperature. . 62. For example, a. division ref. 4024 CANADA 877. This work also has no additional air added to the flow stream past the upstream furnace (i. Note that different agencies and organizations have drastically different metrics for these labels! Most of the time, common folks like us use the terms “combustible” and. 5. Effcct of initial temperature on limits of flammability of a combustible vapor-inert-air system at atmos-The program is described in UL 94, the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances , which is now harmonized with IEC 60707, 60695-11-10 and 60695-11-20 and ISO 9772 and 9773. 1 1 A . Flammability and ignitability. Combustibility Before delving into wine’s specific behavior, let’s distinguish between flammability and combustibility. But while it can withstand some heat, it can also easily catch fire when exposed to an open flame. The lower the flashpoint, the higher the risk a liquid poses. 8°C (100°F) and below 93. Flammability labelling should be indelible, easily legible and visible, on the inner (primary) and outer (secondary) packaging. Flammability is the ease with which a substance will ignite, causing fire or combustion. This is an important property to consider when a substance is used for construction or is being stored. There is no set definition of the word “paint”. Flammability is the ease with which a substance will ignite, causing fire or combustion. This. Flammability and ignitability. However, if the proposed draft label has such a claim, the reviewer must check to see that the terms “Extremely Flammable” or “Flammable” do not appear in the Physical or Chemical Hazards section of the proposed label. 225 . In English, we think of in- as a prefix that means "not": inactive means "not active," inconclusive means "not. The rate or speed at which the reactants combine is high, in part because of the nature of the chemical reaction itself and in part because more energy is generated than can escape. 9-12What is considered flammable? A material is considered flammable if it has a flash point of any temperature below 37. 3. ) and Aleppo pine (Pinus halepensis Mill. Plaskolite has tested TUFFAK® products to ASTM E84 and NFPA 286 flammability standards, report results can be found here: ICC -ES Report-2728 ICC-ES Report ESR-2728. ) and Aleppo pine (Pinus. 2. Flammability is the ease with which a substance will ignite, causing fire or combustion. It is toxic by ingestion and inhalation and has a threshold limit value (TLV) of 50 parts per million (ppm) in. Thus, some paints are, indeed, combustible, while others are flammable, and others are completely flame-retardant. 1200(d)(1), which is defined as "any substance or mixture of substances," 1910. 8°C), while a substance is considered combustible if its flash point is between 100°F and 200°F (37. 1. This. – Low flash pointTrex is listed as having Class A and Class B ratings for flame spread; Class A is the highest flame-spread rating in ASTM E84. Styrene is a moderate fire risk with a narrow flammable range of 1. 94 ºF. Hydrogen possesses the NFPA 704 's highest rating of 4 on the flammability scale because it is flammable when mixed even in small. combustibility чем эти термины отличаются? контекст title and number of the code/ standard requirements of which this particular heat insulation material complies with (parameters: flammability, smoke generation, combustibility); Proper useage is inflammable (highly combustible), opposite being non-flammable. 7. The entries for flammable are a bit spotty—absent from the 1806 dictionary, present in the next four editions (1828 through. Not only is wood often an integral part of structures, it is also the main source of furnishings found in homes, schools, and offices around the world. Many products can be used to coat other substances and they are all referred to, generically, as “paint”. 8 C. There is a sense in which we suspect that they. A flash point is the lowest temperature that will cause a liquid to evaporate to the point of ignition. It is also important in processes that produce combustible substances as a by-product. Flammability codes: the basics. Home Product Report, 1993-1997, Flammable or Combustible Liquids, National Fire Protection Association, Fire Analysis and Research Division, Quincy, MA, August 2000). In other words, they burn easily. For example, acrylic paint is made from an acrylic polymer emulsion called polymethyl methacrylate. 88 C). A chemically unstable gas is a flammable gas that is able to react explosively even in the absence of air or oxygen. S. Added: 2023-05-20. Texture. 118". The word at the base is in-flammare (late Latin). Synthetic Materials When it comes to flammability, leather generally outperforms many synthetic materials. Combustibility is a measure of how easily a substance bursts into flame, through fire or combustion. combustibility: 1 n the quality of being capable of igniting and burning Synonyms: burnability , combustibleness Types: flammability , inflammability the quality of being easily ignited and burning rapidly Type of: quality an essential and distinguishing attribute of something or someoneFlash Point is a term used by the US EPA when characterizing an Ignitable Hazardous Waste and the US DOT when classifying a Flammable or Combustible Liquid. Diesel fuel, according to some definitions, isn’t flammable at all. A horizontal burning test, where burning stops before 100mm. 5"(filling/course) is suspended vertically in a holder and subjected to an igniting gas flame along the bottom edge for three seconds. In conclusion, we can say that combustion is measured with the help of calorimetry. Yes, all plastics are considered to be combustible. For example, the lean flammability limit for Jet A (aviation kerosene) in air at sea level is a concentration (by volume or partial pressure) of about 0. of Matter: Combustibility Combustibility is a substance or material that is able or likely to catch fire and burn Flammability is often described as a chemical property as well. Much depends on what the base of the paint is and. What is the meaning of combustibility in science? Combustibility is a measure of how easily a substance bursts into flame, through fire or combustion. Synthetic Materials When it comes to flammability, leather generally outperforms many synthetic materials. 1200(c). Trex "Escapes" decking is rated Class A, and "Accents" and "Transcend" are rated Class B. If you work with solvent, inks, paints, resins, fuels, or many other organic. USA 888. Unalloyed aluminum. factors including its ignitability and flammability, the amount (and rate) of heat released from it when it burns, the rate at which this heat is released, the flame spread, the smoke production and the toxicity of the smoke. Each. Class F - Material without specified fire performance or products that do not meet the criteria for Class E. to fire characteristics of a materia l. flash point slightly above 35°C. Flammable liquids have a flash point of less than 100°F. ilex. ) in the Adriatic region in Croatia, and to analyse the impacts of climatic factors (temperature, humidity, and precipitation) on the flammability and combustibility of these two species. the flammability of a polymer is an interaction of pyrolysis, ignition, combustion, . )Hydrochloric acid is not usually flammable. Internationally, a variety of test protocols exist to quantify flammability. USA 888. In general, a substance is considered flammable if its flash point is less than 100°F (37. 8378. 4. Our dedicated team of fire safety professionals will guide your through the flammability testing process, answer any questions. Answer #1: The terms "combustible liquids" and "flammable liquids" are defined in the construction standard at 29 CFR 1926 and in the general industry standard at 29 CFR 1910 as follows: The definitions in the two standards are different because the definitions were adopted from different sources. Flammability diagrams show the control of flammability in mixtures of fuel, oxygen and an inert gas, typically nitrogen. Remember that flammability and combustibility are not equivalent. . Flame and explosion limits for gases like propane, methane, butane, acetylene and more. Flammability vs. The enormous volume and frequency of use of flammable and combustible liquids and gases handled worldwide implies that the risk of industrial accidents is great. 2. 8 ºC. 8C max (72 °-100F) – it will catch fire with a lighter. $endgroup$ –Flammability or inflammability means that something can be set on fire easily. There may be suggestions below for improving the article. It is, however, important in terms of process safety. liquids vs. 8°C (100°F) and below 93. Under the optimal combustion condition (a 29% hydrogen-to-air volume ratio), the energy required to initiate hydrogen combustion is much lower than that required for other common fuels (e. Our study showed that fuel type (grass vs. Floor coverings classified as A2fl to Dfl must. such as paraffin, diesel, oil and many other needs to be headed before it will start. <iframe src="height="0" width="0" style="display:none;visibility. The compliance of a material to the BCA non-combustibility definition can be determined by conducting an AS1530. 3 This method could involve the combustion of highly flammable materials and theThe aims of this study are to ascertain the flammability and combustibility of holm oak (Quercus ilex L. Materials flammability testing. A chemically unstable gas is a flammable gas that is able to react explosively even in the absence of air or oxygen. The lack of independence between the four components adds to the complexity of quantifying flammability and of developing a standardized. In addition, these characteristics can change while the material isThe answer might surprise you. Whereas uPVC cladding would ignite most of the directly exposed combustible material in an enclosed area in around 10 minutes or even less, Sentinel. Building materials class (A) DIN 4102 (A1, non combustibility test) non combustibility DIN 4102 Building materials class (A) non combustibility ISO 1182 50 x 40 x 40 5 Coatings have to be applied to a 50 x 40 surface 105°C (6 h)-14; Flooring test DIN 4102 -14 (B1, Flooring) 20. If mixed with other fuel or additives, the flash point of kerosene will decrease, so it will burn at higher temperatures. Synthetic materials, including polyurethane (PU), polyvinyl chloride (PVC), and polyester, are often more flammable than natural leather. Combustion is a chemical reaction that produces both heat and. Examples of combustible materials are wood, paper. Inflammable and flammable are used to mean the same thing. Therefore, the ignitability and combustibility of wood are greatly affected by the physical and chemical properties. If a material has a flashpoint higher than the usual temperatures in the climate zone or work environment where the material will be used or stored, it is combustible rather than flammable. Synthetic materials can melt, drip, and release toxic fumes when exposed to. Note that different agencies and organizations have drastically different metrics for these labels! Most of the time, common folks like us use the terms “combustible” and. Hydrogen safety covers the safe production, handling and use of hydrogen, particularly hydrogen gas fuel and liquid hydrogen . Polyurethane is widely used, with its two major applications, soft furnishings and insulation, having low thermal inertia, and hence enhanced flammability. UL94 flammability test includes the following 4 methods: 1. This fits the definition of a chemical property. 10. Each light-transmitting unit or package must also be identified by a mark that categorizes the material combustibility classification as CC1 or CC2—this provides a means to evaluate the fire propagation performance of the materials in a small-scale test. 10. Eight landscape mulch treatments (Table 1) were evaluated in terms of three combustion characteristics: flame height, rate of fire spread andSubscribe to Lion News for a free weekly digest of EHS news and insights for environmental and safety professionals: WEEK'S TOP STORIES. the science of measuring the HEAT of chemical reactions or physical changes. Using the results from this project, recommendations are offered concerning the use of mulches in wildfire hazard areas. Combustibility has almost noting to do with volatility (other than in the trivial sense that things that are hard to vaporise are hard to set alight even if they are inherently flammable–like bitumen). This long-titled test is the widely. 54, 179–184, (1973). The observer notes combustion (if any) along the train and measures the flame propagation time over 200mm. Combustible means that the material can ignite and burn. Example Sentences: (1) "Monasteries and convents face greater risks than other buildings in terms of fire safety," the article said, adding that many are built with flammable materials and located far away from professional fire brigades. As nouns the difference between ignitability and flammability is that ignitability is (uncountable) the condition of being ignitable while flammability is. The ratings achieved are used in building codes. English term or phrase: flammability vs. IS YOUR DUST COMBUSTIBLE? When looking to protect against a dust explosion, it is critical to know the Kst value of your material. 8 toThe first two mean the same thing, but one is preferred. Numeric values for Class B are between 25 and 75. Thus, hydrogen that is.  For chemical engineering, purge and. 2. Wood, paper, rubber, and plastics are examples of combustible materials. Combustible materials have a higher flashpoint than flammable materials. ACRYLITE® Resist 45 acrylic sheet has a self ignition temperature of 950 degrees Fahrenheit, a smoke density rating of 3. Apr 28, 2021. While the have the same meanings, flammable is the better word choice because it eliminates the possibility of confusion in the reader’s mind. 1. Physical. : ignitability, sustainability, combustibility and consumability. Raw kerosene can burn at 38°C or 100°F, which is just very close to room temperature (27°C). It contains a large number of chlorine ions in the molecular structure and these are particularly difficult to break off when exposed to heat. Specifically, flammables will ignite at lower temperatures than combustibles when exposed to an ignition source. A physical property is a characteristic of matter that is not associated with a change in its chemical composition. Thus, although reasonable from a flammability safety point of view, the test is likely to eliminate materials that may be safe for use on spacecraft. Combustibility. The chains from C 7 H 16 through C 11 H 24 are blended together and used for gasoline. The main difference between flammability and combustibility is the flashpoint. The DOT defines Hazard Class 3, flammable liquid as a liquid with a flash point at or below 60°C (140°F). mono-,. Wood is one of the most sustainable, aesthetically pleasing and environmentally benign materials. the flammability limits of the fuel [7] with $ ranging from approximately 0. 3 Fire and Flammability Test Standards 44 5. The Flammable Range (also called Explosive Range) is the concentration range of a gas or vapor that will burn (or explode) if an ignition source is introduced. GB 11,785 Reaction to fire tests for floorings—Determination of the burning behavior using a radiant heat source. Since the smoke generation of an air filter unit, as well as its combustibility, depends upon the nature and quantity of. The chemistry of polyurethane foams and. Use a very small portion of material (1 g or less) for this test. 2 of Part III, section 32 of the UN Recommendations on the Transport of Dangerous 69 Goods, Manual of Tests and Criteria 70 † Category 4 is not part of the CLP regulation. MOC is higher using CO 2 for inertion, since CO 2 has a larger. The words “flammable” and “combustible” have very specific meaning within the context of fire prevention and suppression. These terms can help you determine the safety of a material and a specific area. The equivalence ratio is established from the predetermined fuel and air flows feeding into the upstream furnace. Here's a simple demonstration that illustrates the difference between a flammable liquid and a combustible liquid. The degree of difficulty required to cause the combustion of a substance is subject to quantification through fire testing. . Flammability is calculated with the help of fire testing. Beside above,what makes spray paint flammable? Mostly it’s a solvent present in the paint that will determine how flammable is the specific variety of paint is. 3°C (200°F). Combustible liquids have the ability to burn at temperatures that are usually above working temperatures. PMMA has a flash point over 482°F (250°C) and autoignition temperature of 580°F (304. Note that combustible is not the same as (in)flammable: combustible means that a substance can burn or be burned. A lot of the rigid board products claim to be “fire rated”, but it doesn’t seem to mean much since building codes still requires a barrier like drywall for them. Like other water-based, fire-resistant hydraulic fluids, the fire resistance is primarily accomplished by the water in the formulation. Different dusts of the same chemical material will have different ignitability and explosibility characteristics, depend-ing on particle size, particle shape and moisture content. This refrigerant is a highly flammable, colorless gas that is heavier than air. Combustible and flammable substances are the materials that can burn in the air. 6. While people mix these meanings in everyday language (see below), I find it odd in a text concerned about precision of language. Some are commonly found in the outside world, in the home, or even in the classroom. It keeps the gasoline clean and, under normal conditions, keeps vapors within the can.