When responding to hazardous materials (hazmats) incidents, responders must be familiar with the fire code requirements for hazmat use and storage. A hazardous material is generally defined as a product or substance that poses a significant risk to health, safety, or property either by itself or with interaction with other factors. These products or substances are present on every fire call and most emergency medical services (EMS) calls. Responders must recognize that hazmats may be present even when the call for service is not specifically for hazmats.
NFPA 704 Marking System
Most responders are familiar with National Fire Protection Association (NFPA) 704, Standard System for the Identification of the Hazards of Materials for Emergency Response, marking system and the associated ratings (Figure 1). Any responder will tell you “0 = not a significant hazard” and “4 = significant hazard.” I will focus on the NFPA 704 ratings and provide an overview of the code required storage and use provisions for hazmat.
RELATED FIREFIGHTER TRAINING
Most jurisdictions use some form of the International Fire Code (IFC) published by the International Code Council (ICC). It is impractical for any code to list the code requirements for every single chemical or substance available. For example, if you were to look at the code requirements for the storage and use of “acetone,” you will come up short in most model codes. To enable quantifying the hazards present at each facility, the IFC classifies chemicals according to their physical, health, and instability hazards. Acetone is classified as a “Flammable Liquid, Class IB” based on its flash point and boiling point. This would be assigned a flammability hazard ranking of 3 according to NFPA 704. Acetone’s health and instability hazards are minimal and are not assigned a classification in accordance with the IFC but are referenced in NFPA 704. Acetone’s health hazard is 2 and instability hazard is 0.
Figure 1. Acetone NFPA 704 Placard
Figures by author.
The IFC requires placing the NFPA 704 marking on stationary containers, on aboveground tanks, and at entrances to locations where hazmats are present in quantities requiring a permit. Responders can quickly look at the placard and identify the “3” in the red diamond and determine that a significant flammable material is present at the location. However, remember that the NFPA 704 marking system provides only information on the hazards present; it does not specifically identify the material that is stored or handled at the location.
Classifying the hazmat present at each facility is the responsibility of the engineering design professional and the authority having jurisdiction (AHJ) to ensure that the chemicals are correctly classified and that the proper signage is provided. The safety data sheet (SDS) provides the information regarding the hazards present for each chemical. Based on the hazards identified in the SDS, the chemical is assigned a hazard classification. Several mobile applications are available to assist in the classification of chemicals such as TheHazMatApp, WISER, and the Emergency Response Guidebook (ERG).
The IFC limits the amount of hazmat that can be present at each facility; these limits are known as the maximum allowable quantity (MAQ). When this amount is exceeded, the building must follow the building and fire code provisions for Group H “High-Hazard” occupancies. The building and fire codes have certain building design requirements to mitigate the hazards associated with Group H occupancies. Depending on the hazard classifications and use/storage configuration, spill control, secondary containment, mechanical exhaust, emergency power, and other design upgrades may be necessary to store the desired amount of hazmat within a facility.
Note that the IFC allows the building to be separated into a maximum of four control areas constructed of one-hour fire-resistive construction (in some cases two hours) to increase the overall allowable hazmat quantity in the building. Each control area is permitted to store the MAQ. The number of control areas and the MAQ permitted in each control area are reduced on floors above and below grade.
Unless responders have been involved with the detailed preplanning of a facility, it is almost impossible to know if a facility has exceeded the code-allowed MAQ on arrival. It is up to emergency responders to identify building features and interpret the NFPA 704 placards to determine the hazards present. Features such as spill control and secondary containment indicate that if a chemical is leaked from a tank or vessel, it poses a significant hazard and must be contained. The concrete berm in Figure 2 indicates that a specific hazard is intended to be contained if the container is breached.
The containment berm is designed to contain the capacity of the vessel plus a calculated rainfall amount if outdoors. If the vessel is indoors, the berm is designed to contain the capacity of the vessel and the fire sprinkler discharge.
When significant combustible or flammable vapors are present, the facility must provide a mechanical exhaust system to mitigate the fire and explosion hazard. Typically, the mechanical exhaust provided must exhaust the room or area at the rate of 1 cubic foot per minute per square feet of area. The exhaust systems must run continually when the vapors are present and must be equipped with emergency power to run continually if power is lost. If the anticipated flammable vapors are heavier than air, you will see low-level exhaust fans or ductwork near the floor.
When these building features are present, responders should be aware that they indicate the presence of a significant hazard. To determine the hazard’s significance, responders must be able to accurately interpret the NFPA 704 placard.
Figure 2. Concrete Containment Berm
Health (blue background). The health hazard ranking considers only the material’s physical and toxic properties. A hazard ranking of up to 2 indicates that the chemical is primarily irritating to the skin and/or respiratory tract. A hazard ranking of 3 or 4 indicates that the material may be extremely corrosive to the skin or respiratory tract and would also be toxic if ingested.
Flammability (red background). Flammability ratings are based on the material’s flash point or its ability to burn rapidly. Liquids that have a flash point at or above 100°F are classified as combustible and assigned a hazard ranking between 0 and 2. Liquids with flash points below 100°F or solids that burn rapidly and support combustion are classified as flammable and assigned a ranking of 3 or above.
Instability (yellow background). Instability hazards of 0-1 indicate that the material is normally stable but can become unstable at elevated temperatures and pressures. A rating of 2 indicates the material undergoes violent chemical changes at elevated temperatures or pressures. A degree hazard of 3 or above indicates that the material can be readily capable of detonation or an explosive reaction if heated or at normal temperatures and pressures.
Special hazards (white background). The special hazards currently recognized by NFPA 704 are “OX” (oxidizer), “W” (water reactive), and “SA” (simple asphyxiant). Although some facilities will provide other hazards in the special hazard category such as “COR” (corrosive), these are not considered to be part of the NFPA 704 hazard rating system since the hazards are already represented in the health, flammability, or instability rating categories.
When responding to any service calls, particularly hazmat-specific calls, responders should be able to recognize potential hazards at each facility. The ability to identify hazards based on building features and signage is imperative to ensuring crew safety through proper tactics and personal protective equipment (PPE).
Importance of Preplanning
The most important information to gather during preplanning facilities is the emergency contact for the facility. This individual is an excellent resource for identifying the specific materials being stored and handled, chemical quantities, containment devices, and piping shutoff locations.
The IFC requires facilities to maintain SDS for the hazardous materials on site. The SDS will identify chemical hazards and recommend firefighting, accidental release, and PPE measures. For facilities that store certain quantities of chemicals, the IFC also requires the facility to maintain a hazardous materials management plan. This document will give responders the chemical names, storage/use amounts, emergency containment systems, and storage plans at the facility. This information is vital when developing tactical objectives to successfully control the incident.
The IFC requires numerous safeguards and engineering controls based on chemical hazards and associated occupancy classification. Emergency shutoff valves, leak detection, fill control valves, emergency alarms, and control areas can all be identified during preplanning to assist in developing a successful incident action plan.
JOSEPH CHACON has more than 18 years of experience of providing building/fire code consulting and designing/testing fire protection systems as a fire protection engineer. He has a bachelor of science degree in mechanical engineering from the University of Nevada—Las Vegas and a master of fire protection engineering degree from the University of Maryland. He is a licensed professional engineer in seven states and is a firefighter and hazardous materials technician with the Henderson (NV) Fire Department.