By Andrew Taggart, PE – Senior Fire Protection Engineer | Denver Office
When evaluating the hazardous materials stored or used at a facility, whether evaluating an existing hazardous materials operation or developing a new operation, a watchful eye is needed to observe less apparent hazards. This article describes three frequently overlooked hazards that may be present in facilities handling hazardous materials.
Heated combustible liquids
The International Fire Code (IFC) defines combustible liquids as having flash points at or above 100°F. Typical examples include liquids such as diesel fuel, mineral oil, olive oil, ethylene glycol, lubricating oils, and hydraulic fluids. These materials generally support combustion but are less readily ignitable than flammable liquids. The IFC treats combustible liquids as a minimal hazard compared to flammable and combustible liquids of other classes. As such, the IFC permitted maximum allowable quantities for combustible liquids are larger than those for flammable liquids. A maximum allowable quantity is not established for Class IIIB combustible liquids in buildings equipped throughout with an automatic fire sprinkler system.
The key word in the description of combustible liquids given above is generally. When heated to temperatures near or above their flash point, combustible liquids may release enough vapors to form ignitable mixtures with air and pose hazards similar to flammable liquids. Common industrial processes that may heat combustible liquids above their flash point include distillation processes, heated chemical processing, and heat transfer fluid operations. When combustible liquids are heated above their flash points, the IFC requires that the appropriate provisions for flammable liquids be applied (IFC Section 5701.5, 2021 edition). *
Hazardous material business managers and owners have many concerns beyond the hazards posed by their operations. As a result, non-revenue generating waste materials are frequently at risk of becoming an ancillary concern. Considerations for how waste products from a new hazardous material operation will be handled, stored, and disposed of may be overlooked entirely during the early planning stages of a new project.
In addition to understating the hazards these materials pose, a realistic expectation must be established for the quantity of material expected to be on site. The use and production of new hazardous materials are unlikely to be stopped if the typically scheduled pickup of waste materials does not occur on a given week.
It is imperative that any waste products and any other hazardous materials considered secondary to the primary operation are accounted for when applying building and fire code requirements.
Empty storage containers
Empty containers previously used to store hazardous materials are frequently found in hazardous material facilities. Whether the container is a drum, intermediate bulk container, or other type, it is easy to incorrectly assume that an empty container does not pose a hazardous materials hazard. In some cases, empty containers may pose more significant hazards than full containers. Even minimal liquid residue may generate a flammable mixture within empty storage vessels.
Unless the empty containers are free from residual material and vapor as defined by the Resource Conservation and Recovery Act (RCRA) standard or another regulating authority, empty containers must be maintained and stored as required for filled containers. In other words, unless a container can meet stringent requirements to ensure it is purged of residual hazardous materials, it is treated by the IFC as if it was full of material.
Review by a licensed fire protection engineer
These often overlooked hazards illustrate the importance of fully understanding the process to be employed at a facility handling hazardous materials and correctly applying the fire and building code requirements. A licensed fire protection engineering consultant can assist operators and owners in understanding the code surrounding the handling and storage of hazardous materials as each facility is unique.
*Note that OSHA rules for flammable and combustible liquids pose additional requirements when combustible liquids are heated to within 30°F of their flash point.