Understanding High-Hazard Group Spaces
High-hazard areas, often referred to as "H-rooms," allow scientists to conduct research, and companies to manufacture, process, or store different types of hazardous substances in quantities greater than what is permitted in standard control areas. Control areas have been established in the International Building Code (IBC) and National Fire Protection Association (NFPA) to limit the number of hazardous materials that are used in a space to keep the occupants of the space and adjacent spaces safe. As you go vertically up in a building, control areas increasingly restrict the amount of these materials allowed in the space. This is because higher up in a building, it is more difficult for the local emergency teams to control the hazards, such as for a fire department to contain a large fire when their ladders cannot reach the floor where it is located.
There are different types of high-hazard spaces, classified by the IBC as H-1 through H-5. These classifications are based on the types of materials used in them and the hazards that are present. No matter the classification, high-hazard spaces can add substantial cost to a project, so their use is often limited to areas critical to a company’s business operations.
Why companies need high-hazard space
Different industries and site types utilize high-hazard spaces to perform functions critical to their business operations. For instance, medicinal chemists working in pharmaceutical laboratories often require these spaces to store larger quantities of flammable liquids for their experiments to proceed efficiently. Central chemical storage rooms, classified as high-hazard spaces, may free up more allowance for in-use chemicals across a floor or within a building or suite.
Manufacturing facilities often designate parts of their facility to high hazard working areas to ensure their process is happening safely, minimizing risk to their employees and avoiding disruptions to their production. Raw materials can be stored in high hazard areas as well.
Hazard categories
The IBC classification of high hazard space is a numerical system H-1 through H-5. This is often considered to be a five-level ranked numbering system, like the category ratings assigned to hurricanes or tornados, but that is only partially true. The first three levels, H-1, H-2, H-3, do represent similar hazards in decreasing severity, but H-4 and H-5 are for different categories of hazards altogether.
The differences among the levels include:
H-1 spaces contain materials with detonation potential.
H-2 spaces contain materials that promote accelerated burning.
H-3 spaces contain materials that are easily combustible or pose a physical hazard.
H-4 spaces contain materials that pose a health hazard, including toxic and corrosive chemicals.
H-5 spaces are specially classified to contain materials typically used in semiconductor fabrication facilities.
All these hazardous materials can cause significant damage and risk in the event of an incident, so extreme care should be used when designing for any level of high-hazard space.
Determining a spaces hazard level
Example of two H-2 processing suites and one H-3 storage room adjacent to open laboratory and support space. Image: Margulies Perruzzi
Before entering lease negotiations, a company should assess whether they require high-hazard space, since not all properties can accommodate such spaces. The company's Environmental, Health, and Safety (EH&S) department, along with the end users and design team, should work with a code consultant to confirm the types of hazardous materials used in the facility. Sometimes, a hazard analysis is necessary to better understand the materials being stored and used. This analysis can also help identify ways to make the process safer or more efficient.
A local fire department or other city official may need to be involved in the design process to address any safety concerns early and prevent delays during the permitting and construction process. If a space needs to accommodate multiple hazards, the code requirements for the most restrictive level must be followed, and appropriate segregation of hazardous materials must be managed.
Cost and schedule implications of high-hazard spaces
The construction requirements for maintaining safety in high-hazard spaces are very strict and go beyond those for a typical laboratory, manufacturing, or storage space. Architectural elements such as fire-resistant walls, ceilings, and flooring materials are required to separate hazardous spaces from adjacent areas, and special finishes are required within the space itself.
Shorter egress routes are a requirement for high-hazard spaces, which limits their placement within a building. In some cases, they may even need to be situated on an exterior wall. High-hazard spaces are limited in size, usually to no more than 500 square feet. Both new and existing buildings often require modifications to the construction of the space to comply with the requirements for a high-hazard space.
Mechanical, electrical, plumbing, and fire protection considerations are also more complex than for non-hazard spaces. Higher amounts of ventilation, as well as dedicated exhaust, may be required. Explosion-proof electrical devices are frequently required due to the possibility that chemical vapors could ignite from an electrical arc. There must be adequate containment to capture any potentially contaminated water if the sprinkler system goes off.
When creating high-hazard spaces, having an experienced design and construction team onboard is critical. To successfully design and construct the space, it is important for end users to provide as much information as possible during the programming and design phases. By doing so, any additional costs for special fixtures, finishes, equipment, etc. can be identified early on, and the construction schedule can be streamlined to accommodate long-lead items and special installations.
