Topic: Industrial Hazards

Responding to incidents involving oxidizers takes awareness and planning

Responders are called to an ever-increasing number of diverse types of incidents these days, which makes it difficult to stay prepared and practiced for all the possibilities we may encounter. That especially applies to responding to hazardous materials incidents. So, if you are not on a hazardous materials response team how often do you review and refresh your knowledge on the classes of hazardous materials we encounter in the course of doing the job? Sure, it’s important to keep sharp on fire operations but those calls that we don’t respond to very often can really hurt us or worse. Recent events like the devastating explosion in Beirut, Lebanon give us pause to think about those firefighters who were just doing their jobs and, boom, tragedy happens. This incident makes me think about the impact that oxidizers can have on fire and what they can do when they mix with incompatible material such as organic compounds. Guidelines for safely handling incidents involving oxidizers A good definition of oxidizers can be found in NFPA 400, Hazardous Materials Code, 2022 edition. Oxidizers are: “Any solid or liquid material that readily yields oxygen or other oxidizing gas or that readily reacts to promote or initiate combustion of combustible materials and that can, under some circumstances, undergo a vigorous self-sustained decomposition due to contamination or heat exposure.” Furthermore, oxidizers are broken down into four classes from Class 1, “…does not moderately increase the burning rate…” to Class 4, “…can undergo an explosive reaction due to contamination or exposure to thermal or physical shock…” NFPA 400 provides a wealth of information and can be a helpful resource. Annex E covers Properties and Uses of Ammonium Nitrate and Fire-Fighting Procedures and is included for informational purposes only, but can be a helpful guide when developing department standard operating procedures for handling events that include oxidizers. An additionally helpful chapter is Annex I, Emergency Response Guideline. This chapter speaks to the emergency response training requirements for handling hazardous materials emergencies found in OSHA 29 CFR 1910.120, including the levels of awareness, operations, technician, specialist and incident commander also explained in NFPA 470 Hazardous Materials/Weapons of Mass Destruction Standard for Responders, 2022 edition. Sure, the larger cities have hazmat units to handle all that, but many of our more rural departments may rely on a regional response team who is several miles away or some teams may have to assemble at the station before they respond to your incident, which takes time. Some departments don’t even have that luxury, so what do we do? Oxidizer identification and pre-planning matter One of the first things that is necessary is identification. Identifying what oxidizers look like, how they are identified, and where they exist in your response area is an important step. You can do that by reviewing what the container markings look like and by getting out into your response area on pre-planning trips to learn about what and where they are used and stored. In the case of rail transport, what is traveling through your jurisdiction? I would recommend connecting with the rail transport organizations that have stock rolling through your jurisdiction. Pre-planning is a very important part of keeping your team situationally aware and prepared for an incident at a specific location. When arriving on-scene, the Emergency Responder Guide (ERG) can help Another very useful quick guide is the Emergency Response Guide (ERG). This guidebook created by the US Department of Transportation, Pipeline and Hazardous Materials Safety Administration, is a guide designed to provide important information to responders in the first minutes of an incident. The guide is set up with separately colored pages that provide important information about material identification, classification, attributable hazards, and response and evacuation guidelines. For example, information on general oxidizers can be found in Guide #140. In this yellow page portion of the document, you will find information on potential hazards such as fire or health, what considerations to make on protective clothing, evacuation measures to consider, emergency response actions in the case of spill or fire, and first aid measures to take if exposed. The information found on this guide page and others can be reviewed with your team in a quick drill format and be a useful refresher on dealing with oxidizers. Another example of what can happen when oxidizers are exposed to heat is an incident that occurred May 28, 2013 in Rosedale, Maryland when a three-axle roll-off straight truck entered a grade level train crossing and was struck by an oncoming freight train. Fifteen of the train cars derailed with three of the cars carrying hazardous materials. Two of the cars spilled their contents, including an oxidizer and an organic acid, resulting in fire. The heat from the fire caused the oxidizer to explode early into the fire. Fortunately, the responding units had not arrived, or the results might have been tragic. Additional information about this accident may be found in the investigation report, which can be accessed at the NTSB website under report number NTSB/HAR-14/02. Slow down and be cautious So especially when responding to bulk storage units or large capacity transportation rail cars, use the utmost caution until you can verify the identity of the contents contained within. Based on the reports of the first due units trained to identify railcars carrying chemicals such as oxidizers, they can alert other incoming units and help initiate the appropriate action plan. Remember when responding into a potential hazardous materials incident: slow down and take some time to look for signs that indicate what you may be dealing with before getting into a potentially career ending event. Take the time to refresh on the basic types of hazardous materials and what their characteristics are. Especially with oxidizers, remember that when exposed to other types of organic compound they can react explosively and when exposed to heat they can explode. It’s all part of situational awareness. Be aware and be safe.

Hazardous Materials and the Applicability of NFPA 400

As I discussed in a previous blog, organizations, and even different documents produced by the same organization, define hazardous material differently. NFPA 400, Hazardous Materials Code, defines hazardous material as: A chemical or substance that is classified as a physical hazard material or a health hazard material, whether the chemical or substance is in usable or waste condition. One quality that makes a chemical or substance a physical hazard material is if it is flammable. If that material is a liquid, how would you know if NFPA 400, NFPA 30, Flammable and Combustible Liquids Code, or both apply? The answer to this question and many like it can often be found in Chapter 1 of most NFPA documents. Chapter 1 is typically the administration chapter. I believe it is often overlooked but contains some extremely important information regarding the scope and application of a particular document. Let’s focus on the scope and applicability of NFPA 400. There are two different components that must be considered when determining if NFPA 400 is applicable to a particular situation: 1) what is the material; and 2) what is being done with that material. NFPA 400 covers the use, storage, and handling (including on-site transportation) of certain hazardous materials. Any other use, such as off-site transportation, of these materials would be outside the scope. NFPA 400 covers the following materials: Ammonium nitrate solids and liquids Corrosive solids and liquids Flammable solids Organic peroxide formulations Oxidizer—solids and liquids Pyrophoric solids and liquids Toxic and highly toxic solids and liquids Unstable (reactive) solids and liquids Water-reactive solids and liquids Compressed gases and cryogenic fluids as included within the context of NFPA 55 There are chemicals or substances that meet the hazardous materials definition in NFPA 400 that fall outside the scope of the document. One example is a flammable or combustible liquid. Ignitibility is one characteristic that results in a liquid being considered a physical hazard material; however, you will not see ignitible liquid (or flammable or combustible liquid) in the above list. This is because a flammable or combustible liquid, which has no other physical or health hazard properties covered by NFPA 400, is outside the scope of NFPA 400. Instead, NFPA 30 would provide the requirements. If, however, the flammable or combustible liquid has an additional health or physical hazard property covered by NFPA 400, then both NFPA 30 and NFPA 400 would be applicable. It is important to remember that multiple codes and standards may apply. So, when designing or determining how much of a material can be stored or used it is imperative that all relevant documents be consulted. For example, if quantities of hazardous materials exceed certain thresholds set by Occupational Safety and Health Administration (OSHA) or Environmental Protection Agency (EPA) then federal requirements under the Process Safety Management and Risk Management Program may apply in addition to NFPA 400. Chapter 1 of NFPA 400 not only identifies what is covered, it also includes a list of items that are not covered. Many of the situations that NFPA 400 does not apply to, are covered by other codes and standards, like the ignitible liquid example above. The complete list of what NFPA 400 does not apply to is: Storage or use of hazardous materials for individual use on the premises of one- and two-family dwellings Explosives or blasting agents, which are regulated by NFPA 495, and fireworks Refrigerants and refrigerant oil contained within closed-cycle refrigeration systems complying with the fire code and the mechanical code adopted by the jurisdiction High-hazard contents stored or used in farm building or similar occupancies and in remote locations for on-premises agricultural use Corrosive materials in stationary batteries utilized for facility emergency power or uninterrupted power supply, or similar purposes, in accordance with NFPA 1 Aerosols complying with NFPA 30B Corrosive materials displayed in original packaging in mercantile occupancies and intended for personal or household use or as building materials Ignitible (flammable or combustible) liquids having no other physical or health hazard properties covered by NFPA 400 Organic peroxide formulations that are capable of detonation as manufactured or when unpackaged or in authorized shipping containers under conditions of fire exposure, when stored, manufactured, or used in accordance with NFPA 495 Combustible metals, as defined in NFPA 484 LP-Gas complying with NFPA 58 or NFPA 59 Where approved, materials that have been satisfactorily demonstrated not to present a potential danger to public health, safety, or welfare based upon the quantity or condition of storage The off-site transportation of hazardous materials when in accordance with Department of Transportation (DOT) regulations Cellulose nitrate film complying with NFPA 40. As you can see, there are a number of documents that regulate hazardous materials. Therefore, before even digging into the actual requirements you need to: 1) make sure you are defining a hazardous material correctly; 2) confirm that the material you have, in the specific situation you have, is covered by that particular document. Remember, Chapter 1 of NFPA documents will help you through this process. Be on the lookout for my future blogs which will take a deeper dive into NFPA 400, covering topics like, maximum allowable quantities (MAQs), control areas, and more. If you missed the first blog in the series on how to define hazardous materials, you can find it here. 

What is Hazardous Material?

Which code or standard applies to hazardous materials? How much of a particular hazardous material can be stored or used? What floor of the building can that hazardous material be stored or used on? These are all questions some are faced with daily. There is an assumption that people, such as facility managers, building owners, engineers, and first responders, just inherently know when a material is a hazardous material. And, that once they know it is a hazardous material, they know how to deal with that material properly and safely. We have seen the potential impacts of materials that are improperly stored or used such as in the 2013 fire and explosion at West Fertilizer Company in Texas. How can we prevent incidents like this from happening? The first step is knowing how to identify a hazardous material. Part of the challenge when it comes to determining and classifying hazardous materials is that there is not one consistent definition of “hazardous material” nor is there one consistent approach to the classification of hazardous materials. Therefore, when looking at Safety Data Sheets (SDS) or literature provided by the manufacturer, it is imperative to know and understand which hazardous material classification system is being used. NFPA 400, Hazardous Materials Code, has its own definition and classification method that consists of 14 different categories. The U.S. DOT uses a 9-category classification system. OSHA has its own definitions established in 29 CFR, which has been revised to align with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).  While there has been an effort to coordinate between the groups, differences do still exist. Information on SDS is often based on the GHS system and not the system in NFPA 400. Defining Hazardous Material The approach I like to take is to assume materials are hazardous, until I have proven that a particular material is not. As we will discuss there are a number of different definitions and triggers that could lead to a material being considered hazardous. Therefore, I would not want to rely on an initial assumption that a material is not hazardous. When determining if a material is to be considered hazardous, the first step is to identify for what purpose you are evaluating the material for. If you are transporting the material in the United States then the DOT’s definition is what you would need to use, whereas if you are storing or using the material, then you would need to use the definition found in the applicable building code or fire code. GHS does not define the term “hazardous material”, but the DOT defines a hazardous material as “means a substance or material that the Secretary of Transportation has determined is capable of posing an unreasonable risk to health, safety, and property when transported in commerce, and has designated as hazardous under section 5103 of Federal hazardous materials transportation law (49 U.S.C. 5103). The term includes hazardous substances, hazardous wastes, marine pollutants, elevated temperature materials, materials designated as hazardous in the Hazardous Materials Table (see 49 CFR 172.101), and materials that meet the defining criteria for hazard classes and divisions in part 173 of this subchapter.” NFPA 1, Fire Code, NFPA 101, Life Safety Code, and NFPA 5000, Building Construction and Safety Code, all use the definition from NFPA 400 for hazardous material. NFPA 400 defines a hazardous material as: A chemical or substance that is classified as a physical hazard material or a health hazard material, whether the chemical or substance is in usable or waste condition.  The definitions of physical hazard material and health hazard material are integral in understanding and properly applying this definition. A physical hazard material per NFPA 400 is a substance that is classified as any one of the following: Explosive Flammable cryogen Flammable gas Flammable solid Ignitible (flammable or combustible) liquid Organic peroxide Oxidizer Oxidizing cryogen Pyrophoric Unstable (reactive) Water-reactive material A health hazard material per NFPA 400 is a chemical or substance that is classified as any one of the following: Toxic Highly toxic Corrosive material Many of these terms are defined within NFPA 400 to further help in defining what a hazardous material is. It is also worth noting that other NFPA codes and standards may use a different definition for “hazardous material”. That is why it is essential to understand for what purpose (e.g., offsite transportation, storage, use, etc.) you need to determine whether something is a hazardous material or not and then consult the appropriate document to determine if it meets the definition. There is not one universally accepted definition. One example of a document that defines hazardous material differently is NFPA 30, Flammable and Combustible Liquids Code. NFPA 30 defines hazardous material or hazardous chemical as a “material presenting dangers beyond the fire problems relating to flash point and boiling point.” The annex material goes on to explain that the other dangers could include things like toxicity, reactivity, instability, or corrosivity. However, that is not intended to be an exhaustive list.  While this may seem to conflict with NFPA 400, when you consider the scope of NFPA 400 the definition from NFPA 30 actually aligns with how NFPA 400 is applied. Although a flammable and combustible liquid that has no other physical or health hazards would be considered a hazardous material per NFPA 400, it is excluded from the scope of the document. I’ll talk more about this in a future blog where we will look in detail at the scope and applicability of NFPA 400.  Classifying Hazardous Materials As I mentioned earlier, different organizations have different ways of classifying hazardous materials. The DOT uses a 9-system classification method while NFPA 400 uses a 14-system category method. Some of the DOT classifications are further broken into divisions, while some of the NFPA 400 categories are broken into subclassifications. The 9 classes used by the DOT are: Class 1: Explosives Class 2: Gases Class 3: Flammable Liquid and Combustible Liquid Class 4: Flammable Solid, Spontaneously Combustible, and Dangerous When Wet Class 5: Oxidizer and Organic Peroxide Class 6: Poison (Toxic) and Poison Inhalation Hazard Class 7: Radioactive Class 8: Corrosive Class 9: Miscellaneous The 14 categories of hazardous materials used in NFPA 400 are: Corrosive solids, liquids, or gases Flammable solids Flammable gases Flammable cryogenic fluids Inert cryogenic fluids Inert gases Organic peroxide formulations Oxidizer solids or liquids Oxidizing gases Oxidizing cryogenic fluids Pyrophoric solids, liquids, or gases Toxic or highly toxic solids, liquids, or gases Unstable (reactive) solids, liquids, or gases Water-reactive solids or liquids Compounding the challenge associated with determining and classifying hazardous materials, is the fact that between the two systems many of the categories use similar verbiage but may have different thresholds that trigger that particular classification.  One example is flammable liquid. DOT defines flammable liquid as “a liquid having a flash point of not more than 60 °C (140 °F), or any material in a liquid phase with a flash point at or above 37.8 °C (100 °F) that is intentionally heated and offered for transportation or transported at or above its flash point in a bulk packaging”. NFPA 400 states that a flammable liquid is an ignitible liquid that is classified as a Class I liquid. There are three subclassifications of a Class I liquid. The table below summarizes the specific thresholds for the subclassifications. Subclassification Flash point Boiling point Class IA Liquid Below 73 OF (22.8O C) Below 100 OF (37.8O C) Class IB Liquid Below 73 OF (22.8O C) At or above 100 OF (37.8OC) Class IC Liquid At or above 73O F (22.8O C) but below 100O F (37.8O C N/A These discrepancies mean that when determining the category of hazardous material you have, you need to know what system was used to provide a classification, such as the one found on a Safety Data Sheet, or you need the actual test data so the classification can be determined based on the definitions. In summary, although there is agreement that hazardous materials are physical or health hazard materials, there is not one standard definition or approach to determining if a material should be considered hazardous or not. NFPA 400 defines hazardous material as any chemical or substance that is a physical hazard material or a health hazard material. Hazardous materials are then categorized based on the physical or health hazard they present. There are 14 different categories in NFPA 400 and a material may fall into one or more of those categories. Be on the lookout for my future blogs which will take a deeper dive into NFPA 400, covering topics like applicability of NFPA 400, maximum allowable quantities (MAQs), and more.
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NFPA LiNK Empowers Users to Quickly and Easily Navigate Digital Codes and Standards

Did you catch the first free one-hour webinar educating users on our revolutionary digital platform, NFPA LiNK®? If not, don’t worry, it won’t be the last. At the March session, hosted by me, prospective and current NFPA LiNK subscribers from all over the world gathered virtually for an interactive discussion. I presented a complete demonstration of all features and content within NFPA LiNK followed by a Q&A session. Below are some key features that were demonstrated for our webinar attendees: Complete access to all NFPA codes and standards: NFPA LiNK houses the latest edition of every NFPA® code and standard, as well as a growing library of legacy editions for the organization’s most referenced publications. Subscribers also receive early access to newly released editions and can favorite their most cited publications for easy reference.  Enhanced publication navigation: Once a publication is open, users can view all enhanced content and collaborative notes. The bookmark feature enables users to save content (both sections and tables), leave notes, add bookmarks to larger collections, and color-code bookmarks. For easy side-by-side viewing of different sections of code, users can utilize the reference panel feature. NFPA LiNK also makes it easy to share sections of code with others (nonsubscribers included) via email from directly within a publication. Comprehensive search capabilities: The search feature within NFPA LiNK allows users to quickly search all NFPA publications by keyword or phrase. Users can also utilize filters to further refine a search and narrow down code content results. Custom MyLink page: MyLink is where subscribers can easily access and search all bookmarked content and collections. Within MyLink, users can create and reference individual collections of bookmarks as well as team collections for sharing and collaboration with others. Additional NFPA DiRECT™ content: NFPA DiRECT allows subscribers to find interactive, industry-specific content through situational navigation. With new content added on a weekly basis, the NFPA DiRECT hub within NFPA LiNK highlights situations and solutions created by NFPA experts to help users better understand requirements in varying situations. Offline Capabilities: The offline feature allows users to store publications, notes, and enhanced content for uninterrupted access anywhere at any time. Team Management Feature: NFPA LiNK’s team management capabilities mean team admins don’t need to contact NFPA or IT whenever they want to reassign licenses among team members. This feature allows users to conveniently invite, add, and remove team members.  Want to see it all in action? You can catch a recording of the session, “How to Quickly and Easily Navigate Digital Codes and Standards,” on our webinar page here.  As game-changing as these features are, NFPA LiNK continues to grow with you. We are constantly listening to and interacting with our users to learn more about the best updates that will help you excel in your daily roles. NFPA LiNK users can expect to see new content and features on a continuous basis—all of which will be shared with users within the “Announcements” section of NFPA LiNK. Stay tuned for more information on the next free NFPA LiNK educational webinar, coming in June 2022. Check here for more details soon. To find out more about NFPA LiNK, including how to sign up for a free trial, visit 
plant fire

Recent NC Fire Shines Light on Gaps in Ammonium Nitrate Regulation That No Longer Can be Ignored

With the flames of a North Carolina January 31 fertilizer plant fire now safely extinguished, it’s now time for local, state, and federal officials to focus on fixing the holes that govern ammonium nitrate (AN) storage and handling. On April 17, 2013, a fire in Texas led to the detonation of about 30 tons of AN and the deaths of 15 people, along with the injury of hundreds more, and major destruction to the town of West. Nine years later, the city of Winston-Salem, North Carolina came dangerously close to experiencing the same fate. The fact that fate was avoided should not mean we avoid addressing this issue. In its final report on the West, Texas tragedy, the U.S. Chemical Safety Board (CSB) observed, “This is not to say that West is an anomaly. Many communities in Texas and nationwide are located too close to facilities resembling the [West Fertilizer Company] plant.”[1] The Winston Weaver Fertilizer plant is exactly the situation the CSB was referring to. Like the facility in West, the North Carolina plant began operating mid-century, surrounded by farmers’ fields and few neighbors. Over time, homes, businesses, and other buildings sprung up around it as the town grew. The pattern, both in West and in Winston-Salem is not unique. The American Farmland Trust reports that over 11 million acres of U.S. farmland have been developed over the last 20 years, putting homes and suburban infrastructure next to facilities that manufacture, store, and sell fertilizers and other chemicals. Local planners in places like Winston-Salem, which grew by around 8 percent over the last 10 years, must recognize this hazard and limit development around these locations to compatible uses, like warehouses, not homes and school.  When the fire broke out at the Winston Weaver Fertilizer plant, the fire department promptly called for an evacuation of the surrounding neighborhoods, fearing the detonation of the plant’s 600 tons of AN. Over 6,500 people left their homes in the middle of the night. In addition to a well-prepared fire department though, towns and cities have another tool to save lives and property from hazardous materials like AN—the fire code. When handled and stored properly, AN can be stable. But, when exposed to fire, there is a significant danger of a powerful explosion (see for instance, the recent blast that leveled a portion of Beirut, Lebanon). Recognizing, as the CSB did, that the hazard present in West, Texas was not unique, the technical committee that develops NFPA 400, the National Fire Protection Association’s Hazardous Materials Code, determined fire sprinkler systems in these facilities is a must. They voted in 2015 to make the installation of sprinkler and fire detection systems in new and existing facilities a requirement of the accepted minimum level of safety for any building with over 1000 pounds of AN. The NFPA fire code, NFPA 1, refers users to NFPA 400 for facilities storing AN, and expressly enables the relevant authority to enforce construction requirements—like sprinklers systems—retroactively when warranted by dangerous conditions. Unfortunately, in many places, the laws in place are not this proactive. In the case of Winston-Salem, the North Carolina state fire code does not require facilities like Winston Weaver to meet NFPA 400’s requirements. However, the fire that occurred on January 31st should prompt the North Carolina legislature to require NFPA 400’s retroactive fire protection requirements, especially where an explosion poses a risk to surrounding homes, businesses, schools, hospitals and other community facilities. It should also prompt the North Carolina Building Code Council to amend the state fire code to include the NFPA 400 requirements. Even if the state does not act though, local governments in North Carolina are not powerless. State law permits local jurisdictions to adopt their own fire code provisions so long as those provisions are stricter than those promulgated by the state. In addition to ensuring fire code protection, the CSB made a number of other recommendations to reduce the risk of another West-type catastrophe. For one, state legislatures could enact laws that would require facilities like the Winston Weaver Fertilizer plant to hold general liability insurance policies commensurate with the risk they pose to their surroundings. The CSB investigation revealed that four years before the explosion, West Fertilizer Company (WFC) was dropped by its insurance carrier for failure to address a number of safety concerns identified by the insurer’s inspection process. The $1 million general liability policy WFC turned to instead came with minimal safety inspections. After the explosion, the policy was woefully inadequate to redress the $230 million-plus damage to the town and its residents. More stringent insurance requirements would motivate greater due diligence in identifying and controlling hazards. At the federal level, CSB made recommendations to several agencies. Among those was a call to the Environmental Protection Agency (EPA) to add AN to the list of chemicals covered in its Risk Management Program (RMP). Developed in the 1990s, the RMP regulations require facilities handling listed chemicals to assess the potential worst-case scenarios for communities beyond the fence line, implement hazard controls, and report on these to the agency. As the CSB pointed out, AN’s reactivity, its potential to cause high loss of life, and its presence in high volumes at sites across the country all favor its inclusion on the RMP list. Unfortunately, nearly a decade after the West incident, many of these recommendations remain open. Texas did not adopt stricter insurance requirements and the EPA still hasn’t added AN to the list of chemicals covered by the RMP. However, the EPA’s announced plans to improve health and safety conditions for people living in fence line communities presents an ideal opportunity to revisit how we handle and store AN, and other hazardous materials, and reduce the risk of catastrophic accidents for all communities. North Carolina too must not wait to identify other AN hazards in the state and enact the policies discussed here to prevent another close call—or worse.   [1] U.S. Chemical Safety Board, Investigation Report: West Fertilizer Company Fire & Explosion, January 2016, p 223. [1] § 143-138(e)

Commodity Classifications in NFPA 13

Commodity classifications are used to categorize the contents of storage occupancies so that the appropriate sprinkler system design can be identified. Commodity classifications are determined by not only the product but also the packaging of that product, the container those packaged products are in, and even the pallet type. This can get a little complicated, so I’ll run through a quick example. We have glass jars stored in a double layered carboard box with cardboard dividers and it is sitting on a reinforced plastic pallet. Even though the glass jars are only a Class I commodity, the cardboard box and plastic pallet increases the fuel load so that it should be considered a Class IV. Commodity Classifications are broken down into Classes I through IV and Group A though C plastics with Class I being the lowest hazard level and Group A expanded plastics being the highest hazard level. Class I: A Class I commodity is defined as a noncombustible product that meets one of the following criteria: Placed directly on wood pallets Placed in single-layer corrugated cardboard boxes, with or without single-thickness cardboard dividers Shrink-wrapped or paper-wrapped as a unit load Class II: A Class II commodity is defined as a noncombustible product that is in slatted wooden crates, solid wood boxes, multiple-layered corrugated cardboard box, or equivalent combustible packaging material. Class III: A Class III commodity is defined as a product fashioned from wood, paper, natural fibers, or Group C plastics with or without cartons, boxes, or crates. A Class III commodity shall be permitted to contain a limited amount (5 percent or less by weight of nonexpanded plastic or 5 percent or less by volume of expanded plastic) of Group A or Group B plastics. Class IV: A Class IV commodity is defined as a product that meets one of the following criteria: Constructed partially or totally of Group B plastics Consists of free-flowing Group A plastic materials Cartoned, or within a wooden container, that contains greater than 5 percent and up to 15 percent by weight of Group A nonexpanded plastic Cartoned, or within a wooden container, that contains greater than 5 percent and up to 25 percent by volume of expanded Group A plastics Cartoned, or within a wooden container, that contains a mix of Group A expanded and nonexpanded plastics and complies with the graph section at the end of the blog Exposed, that contains greater than 5 percent and up to 15 percent by weight of Group A nonexpanded plastic Exposed, that contains a mix of Group A expanded and nonexpanded plastics and complies with the graph section at the end of the blog PLASTICS Plastics are a little more straightforward since there is a specific list of what each group contains. Classifying plastics gets complicated when the commodity being stored is a combination of different groups of plastics, but the graphs at the end of this blog should be able to help alleviate some of that work. Group C Plastics: Group C plastics are treated as Class III Commodities and consist of the following: Fluoroplastics (PCTFE — polychlorotrifluoroethylene; PTFE — polytetrafluoroethylene) Melamine (melamine formaldehyde) Phenolic PVC (polyvinyl chloride — flexible — PVCs with plasticizer content up to 20 percent) PVDC (polyvinylidene chloride) PVDF (polyvinylidene fluoride) Urea (urea formaldehyde) Group B Plastics: Group B plastics are treated as Class IV Commodities and consist of the following: Chloroprene rubber Fluoroplastics (ECTFE — ethylene-chlorotrifluoro-ethylene copolymer; ETFE — ethylene-tetrafluoroethylene-copolymer; FEP — fluorinated ethylene-propylene copolymer) Silicone rubber Group A Plastic: Group A plastics are further subdivided into expanded and nonexpanded Group A plastics and consist of all of the plastics listed in the table below. ABS (acrylonitrile-butadiene-styrene copolymer) FRP (fiberglass-reinforced polyester) Polycarbonate PVC (polyvinyl chloride — highly plasticized, with plasticizer content greater than 20 percent) (rarely found) Acetal (polyformaldehyde) Natural rubber Polyester elastomer Acrylic (polymethyl methacrylate) Nitrile-rubber (acrylonitrile-butadiene-rubber) Polyethylene Butyl rubber Nylon (nylon 6, nylon 6/6) Polypropylene PVF (polyvinyl fluoride) Cellulosics (cellulose acetate, cellulose acetate butyrate, ethyl cellulose) PET (thermoplastic polyester) Polystyrene SAN (styrene acrylonitrile) EPDM (ethylene-propylene rubber) Polybutadiene Polyurethane SBR (styrene-butadiene rubber) HELPFUL DEFINITIONS One of the biggest issues I see when people are starting to learn about sprinkler design for storage occupancies is that they don’t know the terminology. It is important to fully understand the definitions for the terms used in the storage chapters of NFPA 13, Standard for the Installation of Sprinkler Systems. I recommend looking at the definition chapter of NFPA 13 to make sure you understand exactly what a term means because oftentimes it means something different than what you would expect. Here are a couple of definitions that are important to understanding this blog. Expanded Group A Plastics: Those plastics, the density of which is reduced by the presence of air pockets dispersed throughout their mass. Some examples include packing peanuts or acoustic foam. Nonexpanded is everything else that is not covered under the definition of expanded. Free Flowing Group A Plastics (protect as Class IV): Those plastics that fall out of their containers during a fire, fill flue spaces, and create a smothering effect on the fire. Examples include powder, pellets, flakes or random-packed small objects. Free flowing plastics are those small objects that fill a box or a subdivision within the box without restraint. The theory is that during a fire. The objects will freely fall out of the box and either smother the fire or fall away from it, removing themselves as fuel. Since the burning rate is reduced and fuel load has been lessened, free-flowing plastics are permitted to be treated as a Class IV commodity. Exposed: Commodities not in packaging or coverings that absorb water. For example, a cardboard box or wooden container can both absorb water so they would not be considered exposed. However, something that is wrapped in plastic sheeting could be considered exposed since plastic sheeting doesn’t absorb water. Cartoned - A method of storage consisting of corrugated cardboard or paperboard containers fully enclosing the commodity. GRAPHS The following tables come from NFPA 13 to help with navigating how a commodity should be classified when it contains Group A plastics. Note that the X axis is percentage by volume while the Y axis is percentage be weight.  The first graph addresses exposed commodities while the second graph addresses commodities that are cartoned or within a wooden container (non-exposed). PALLETS When commodities are tested, they are tested on wooden pallets. This means that wooden pallets are assumed to be used in commodity classifications, however if plastic pallets are used, they increase the commodity classification by two classes. Although, if the plastic pallet is made of polypropylene or high-density polyethylene and marked as “nonreinforced” then the commodity classification only needs to be increased by one classification. Plastic Pallet Increase (+2) Class I --> Class III Class II --> Class IV Class III --> Group A Plastics Class IV --> Cartoned nonexpanded Group A plastic Group A Plastics --> Group A Plastics (No increase)  Unreinforced Polypropylene or High-Density Polyethylene Plastic Pallet Increase (+1) Class I --> Class II Class II --> Class III Class III --> Class IV Class IV --> Cartoned nonexpanded Group A plastic Group A Plastics --> Group A Plastics (No increase) Determining the classification for commodities in storage occupancies can get complicated at times but I can not stress how important of a step this is during the sprinkler design process. It is also imperative that the owner understands what the building is designed to handle as well as what can and can not be stored in the facility once it is built. I hope you enjoyed the blog. Comment below if you have questions and be sure to share this with friends and colleagues who might find it helpful.
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