Which Occupancy Classification is a machine shop considered?

According to NFPA 13, Standard for the Installation of Sprinkler Systems, an Ordinary Hazard (Group 1) occupancy is one where the combustibility is low, the quantity of combustibles is moderate, and stockpiles of combustibles do not exceed 8 ft (2.4 m). The standard explicitly lists "Machine shops" as a representative example of this classification. This is due to the presence of machinery, moderate amounts of processing materials, and potential for lubricants or hydraulic fluids, which present a moderate fire load and rate of heat release that aligns with the Group 1 definition.

A. Light Hazard: Incorrect. This classification has a low quantity and combustibility of materials, which is not representative of a typical machine shop's fire load.

C. Ordinary Hazard Group 2: Incorrect. This group involves higher quantities or combustibility of materials than typically found in a standard machine shop.

D. Extra Hazard Group 1: Incorrect. This classification is for occupancies with very high quantities of combustibles and a high probability of rapidly developing fires, which exceeds the hazard level of a machine shop.

1. NFPA 13, Standard for the Installation of Sprinkler Systems (2022 Edition).

Section 4.3.3.2, Examples. This section provides a list of occupancies considered to be Ordinary Hazard (Group 1). Item (17) in this list is "Machine shops."

Section 4.3.3.1, Ordinary Hazard (Group 1). This section defines the criteria for this classification, which a machine shop meets.

2. SFPE Handbook of Fire Protection Engineering (5th Edition).

Chapter 54, "Automatic Sprinkler System Calculations," Section 54.3.1.2, "Occupancy Hazard Fire Control." This section discusses the hazard classifications from NFPA 13, confirming that machine shops are categorized as Ordinary Hazard (Group 1) for determining sprinkler design criteria. (DOI: https://doi.org/10.1007/978-1-4939-2562-454)