Under 2018 and earlier IBC/IFC, the occupancy of a distillery is H-3. Electrical classification is almost an entirely separate issue – it is mentioned in the IFC with some parameters. Electrical classification comes from the International Code Council codes, through reference of the National Electric Code, and NFPA 497. In these documents, electrical classification near a potential source of vapor release is a Class 1, Division 2 (C1-D2) area. This classified electrical area extends in a 5′ radius from the potential source of vapor release. Locations within 3′ of the floor, that radius is extended to 25′. We call this the “Electric Sombrero of Death” as a way to bring this critical area and conditions to the attention of the distilling community.
Where electrical components are located in a pit or behind a containment wall, such that vapor can not dissipate horizontally, the classification becomes a more restrictive Class 1, Division 1 (C1-D1) space.
Sprinkler “occupancy” also is an entirely separate classification from the H-3 building code occupancy (although, in some instances, the I-codes will specify a particular NFPA 13 sprinkler occupancy for a particular situation). The sprinkler “occupancy classification” comes from NFPA 13 and NFPA 30. The use of the term “occupancy” by the NFPA documents is quite confusing since it refers to something different than I-code occupancy. NFPA 13 requires a sprinkler “occupancy classification” of Extra Hazard 2 (EH-2) where “moderate to substantial amounts” of flammable liquids are present. NFPA 13 further refers to NFPA 30 for the final sprinkler criteria. NFPA 30 includes several decision charts that result in the EH-2 classification for barrel warehouses. There is some flexibility in meeting EH-2 as described in the Density/Area curves in NFPA 13. The larger the design area, the lower the density can be. One of the Density/Area curve intersection points yields 0.35gpm/sf over a 4000sf remote area for the EH-2 Sprinkler Occupancy Classification.
Compounding the level of confusion regarding sprinkler requirements for barrel storage is an exception in Chapter 9 of NFPA 30 that makes that chapter not applicable to the storage of casks or wooden barrels. So, NFPA 13 sends us to NFPA 30 where barrels are exempt from the chapter that establishes the sprinkler requirements. The solution to this, per the codes, is to seek requirements from an industry source.
We have generally been using the DISCUS manual as that source. It requires 0.35gpm/sf over 4000sf for palletized barrel storage. This is the same conclusion reached in the NFPA documents if the exception was not applied. There is one difference between NFPA and DISCUS. NFPA requires only a 2hr duration (the time the sprinklers can continue to operate). Where DISCUS requires 4hrs. Both require an additional 500gpm hose stream allowance to be built into the system. For racked barrel storage, DISCUS provides different criteria based on the type of racking and the height of the racks. This includes (based on rack height primarily) provisions for in-rack sprinklers. The duration is not a concern when connected to sufficient municipal water service. However, where there is no water service, and storage tanks are required, the increased DISCUS duration has the result of doubling the stored water volume, adding a significant cost over the NFPA requirements.
Recently, FM Global revised its Data Sheet 7-29 following the testing of barrel arrays. The revised DS 7-29 now can also be used as an industry standard as required by code to overcome the lack of direction from NFPA due to the barrel exception. The FM Global method of determining sprinkler requirements is different from the method we use from NFPA. However, the result, in terms of Density/Area, is roughly the same. The big difference when using the FM standard is that there is a reduction in the hose stream volume and the duration. The result is a dramatic reduction in the volume of sprinkler water needing to be stored at facilities that do not have a suitable municipal water source. This translates to a significant reduction in cost for those facilities.
***Note that in the 2021 and later I codes, barrel warehouses become S-1, with most of the H-3 requirements added back in via the fire code.