#101Wednesdays: NFPA 101 and hazardous areas
You'll sometimes hear users of the Life Safety Code refer to hazardous areas, protection from hazards, special hazards, and other variations on the same theme. So what exactly is a hazardous area and what sort of protection does it need? The answer, as in the majority of cases when we're talking about codes, is: “It depends.” Remember that NFPA 101 predicates its requirements on the risk to a building's occupants, which varies depending on occupant characteristics. Workers in an office building have different characteristics with regard to life safety than, say, patients in a hospital. Because occupant risks vary from occupancy to occupancy, so do hazardous area protection requirements.
In general, any area having a degree of fire hazard greater than that normally associated with the general occupancy is considered a hazardous area, as described in Section 8.7 of the 2015 edition of NFPA 101. You don't necessarily need a room full of flammable liquids to be considered a hazardous area. In fact, in many cases, a storage room with ordinary combustibles is considered a hazardous area due to the concentrated fuel load. The occupancy chapters list specific areas that must be protected as hazardous areas. In all cases, the AHJ can also judge an area to be hazardous and mandate the requisite protection. Where an area is deemed to hazardous, it can be protected by one of three means:
- Separation from the remainder of the building by 1-hour fire barriers
- Installation of automatic sprinklers and separation by smoke partitions (some existing occupancies exempt the smoke partitions)
- A combination of fire barriers and sprinklers where the hazard is deemed to be severe
The occupancy-specific hazardous area protection requirements are usually in the X.3.2 subsection of the applicable occupancy chapter, where X is the chapter number. If we want to determine the protection requirements for a storage room in a new business occupancy, we would go to 38.3.2 and see the following:
38.3.2.1* General. Hazardous areas including, but not limited
to, areas used for general storage, boiler or furnace rooms,
and maintenance shops that include woodworking and painting
areas shall be protected in accordance with Section 8.7.
Based on the usual life safety characteristics of business occupants, a storage room can be protected by any of the means described in Section 8.7. This gives the designer the choice of providing a 1-hour separation, or providing automatic sprinklers with a smoke partition separation. Either method will provide the necessary protection.
On the other hand, if we wanted to know the protection requirements for a storage room in a new hospital, we would go to 18.3.2 and find the following:
18.3.2.1.2 The following areas shall be considered hazardous
areas and shall be protected by fire barriers having a minimum
1-hour fire resistance rating in accordance with Section 8.3:
(1) Boiler and fuel-fired heater rooms
(2) Central/bulk laundries larger than 100 ft2 (9.3 m2)
(3) Paint shops employing hazardous substances and materials
in quantities less than those that would be classified as
a severe hazard
(4) Physical plant maintenance shops
(5) Rooms with soiled linen in volume exceeding 64 gal (242 L)
(6) Rooms with collected trash in volume exceeding 64 gal
(242 L)
(7) Storage rooms larger than 100 ft2 (9.3 m2) and storing
combustible material
If the storage room is larger than 10 ft X 10 ft and contains combustibles, it needs to be separated from the remainder of the hospital by 1-hr fire barriers; and, by the way, it will also require automatic sprinklers because all new health care occupancies must be fully sprinklered. The requirement for 1-hour separation and sprinklers implies that storage of combustibles in a hospital poses a severe hazard to the occupants due to their inability to self-evacuate in the event of a fire.
High-hazard contents are those materials in a building that are subject to very rapid fire development or pose an explosion hazard. Protection of high-hazard contents usually involves reviewing the code or standard that applies to the specific hazard (e.g., NFPA 30 for the protection of flammable and combustible liquids).
It's important to note that NFPA 101 currently only considers fire hazard; other hazards, such as health and physical hazards (e.g., corrosives and radiological hazards) are not addressed by the Code. The upcoming 2018 edition of NFPA 101 will start to introduce broader hazardous material protection requirements – stay tuned.
In summary, to determine whether an area is a hazardous area requiring any special protection, the occupancy classification must be known, and the appropriate occupancy-specific requirements must be reviewed. If there's ever a question, the general provisions in Section 8.7 always apply such that if the AHJ believes an area is a hazardous area, it's a hazardous area. Where separation by fire barriers or smoke partitions are required, the doors have to meet the applicable requirements, and always need to be self-closing – no wooden wedges!
Be sure to protect those hazardous areas. If you do, you'll – stay safe!
Got an idea for a topic for a future #101Wednesdays? Post it in the comments below – I'd love to hear your suggestions!
Did you know NFPA 101 is available to review online for free? Head over to www.nfpa.org/101 and click on “Free access to the 2015 edition of NFPA 101.”
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