Fire sprinkler systems

For sprinkler designs, there are five occupancy classifications:

• Light Hazard — This classification applies to spaces where the quantity of combustibles is low and/or the combustibility of contents is low, resulting in relatively low rates of heat release if ignited. Examples of spaces with a light hazard classification might include offices, healthcare facilities, churches, schools, etc.
• Ordinary Hazard (Group 1) — This classification applies to spaces where the combustibility of materials present is low, and the quantity is moderate, with no stockpiles of combustible material exceeding 8 feet (2.4 meters). Examples of spaces with this classification might include mechanical plants, laundries, food processing facilities, or other manufacturing operations in which a fire would release moderate heat rates.
• Ordinary Hazard (Group 2) — This classification applies to spaces where the quantity and combustibility of contents are moderate to high. In this scenario, occupants may have stockpiles of materials up to 12 feet tall (3.7 meters) that could release reasonably high heat rates if ignited. Examples of this occupancy include distilleries, barns and stables, dry cleaners, libraries, machine rooms, and auto repair shops.
• Extra Hazard (Group 1) — This classification applies to spaces where the quantity and combustibility of contents are very high with dust, lint, or other airborne materials are present. These particles introduce the probability of fires that burn hot and spread fast, such as upholstery shops, sawmills, plywood manufacturers, or textile factories. This classification may include spaces with some small amounts of combustible or flammable liquids, but this classification is primarily based on the presence of highly combustible solids.
• Extra Hazard (Group 2) — This classification applies to spaces in with moderate to substantial amounts of flammable or combustible liquids are routinely present. It also applies to areas with large quantities of combustibles. These areas require extensive use of heat shields to prevent ignition. Examples of these include plastic manufacturing operations, steel manufacturing, and automobile paint spray booths.