HazMat Response and the Fire Codes
By Joseph E. Chacon, PE, TERPconsulting
(This article was originally published in the November 2020 edition of Fire Engineering magazine.)
Synopsis: The National Fire Protection Association 704, Standard System for the Identification of the Hazards of Materials for Emergency Response, marking system only indicates the hazards present; not the specific material stored or handled at the location. This article offers an overview of the International Fire Code and NFPA 704 requirements for storage and use of hazardous materials (hazmat).
When responding to hazardous materials (hazmat) 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 service (EMS) calls. Responders must recognize that hazmat may be present even when the call for service is not specifically for hazmat.
Most responders are familiar with National Fire Protection Association 704, Standard System for the Identification of the Hazards of Materials for Emergency Response, marking system and the associated ratings. 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.
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
The IFC requires placing the NFPA 704 marking on stationary containers, aboveground tanks, and at entrances to locations where hazmat is present in quantities requiring a permit. Responders can quickly look at the placard and identify the red 3 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 require 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 control areas constructed of one-hour fire-resistive construction to increase the aggregate hazmat quantity in the building, with each control area permitted to store the MAQ. These control areas are usually separate rooms or areas in the building that contain various levels of hazmat. The MAQ can also be increased when the building is provided with fire sprinklers and when the chemicals are stored in approved cabinets or exhausted enclosures.
Unless responders have been involved with 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 photo 1 indicates that a specific hazard is intended to be contained if the container is breached.
(1) Concrete containment berm [Photo courtesy of Belzona industrial coatings]
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 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 run 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 (photo 2).
(2) Photo courtesy of U.S. Chemical Storage.
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.
Health (Blue). 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). 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 1000F are classified as combustible and assigned a hazard ranking between 0 and 2. Liquids with flash points below 1000F or solids that burn rapidly and support combustion are classified as flammable and assigned a ranking of 3 or above.
Instability (Yellow) 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. Materials with a degree of hazard of 3 or above indicates that the material can be readily capable of detonation or 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 pre-planning facilities is the emergency contact for the facility. These individuals are an excellent resource in identifying the specific materials being stored and handled, chemical quantities, containment devices, and piping shutoff locations.
The IFC requires facilities to maintain SDS information onsite. 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 (HMMP). 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 upon chemical hazards and associated occupancy classification. Emergency shutoff valves, leak detection, fill control valves, emergency alarms, and control areas can all be identified during pre-planning to assist in developing a successful incident action plan.