What is a high-hazard industrial occupancy in Canada?
A Group F, Division 1 industrial occupancy is defined in the National Building and Fire Code as follows:
High-hazard industrial occupancy (Group F, Division 1) means an industrial occupancy
containing sufficient quantities of highly combustible and flammable or explosive
materials which, because of their inherent characteristics, constitute a special fire
hazard
I’ve written about the classification of industrial occupancies in the past in the blog post here; but in this post I’d like to explore the types of occupancies that are typically classified as Group F, Division 1, high-hazard industrial occupancies. They can be difficult to pinpoint and the ramifications from a design standpoint can be quite significant.
Unlike the definitions for medium- and low-hazard industrial occupancies, which include a quantified combustible contents threshold, for high-hazard occupancies the language of the definition requires the classification to be based on experience, judgments, or risk evaluations. The terminology “sufficient quantities’ and “constitute a special fire hazard” are subject to interpretation. This interpretive element is unique to the definition for a high-hazard industrial classification, as most other occupancy classifications in Canada are fairly intuitive or self-explanatory – e.g., residential, mercantile, assembly.
For example, if we look to the Notes to Part 3 (Division B) specifically Sentence A-3.1.2.1.(1) of the 2020 National Building Code of Canada, the following list of example occupancies is provided for high-hazard industrial occupancies:
- Bulk plants for flammable liquids; bulk storage warehouses for hazardous substances
- Cereal mills; feed mills; flour mills; grain elevators
- Chemical manufacturing or processing plants; lacquer factores; paint, varnish and pyroxylin product factories; rubber processing plants
- Distilleries
- Dry cleaning plants
- Mattress factories
- Spray painting operations
- Waste paper processing plants
This list isn’t intended to provide a comprehensive summary of all possible high-hazard occupancies, but it is helpful to some extent in framing what one might look like. A spray painting operation for example – many of us can visualize a paint spray booth and recognize that spraying/aerosolizing flammable paint products would constitute an above-average fire hazard. That seems clear… Does that mean a limited workstation style of spraying activity is high-hazard (look it up in NFPA 33!)? Where does the definition terminology of “sufficient quantities” come into play here? What we can see here is that even a category as simple as a spraying operation can be subject to interpretation.
So what is the big deal? If you’re not sure of the occupancy classification, wouldn’t it be better to approach a design from a more conservative angle and say – when in doubt, high-hazard industrial? Yes, and No. The design implications of a Group F, Division 1 major occupancy or subsidiary occupancy classification are not trivial – travel distances are reduced from 45 m in sprinklered buildings to 25 m for a high-hazard occupancy. There are also significant restrictions with respect to overall building area and height and the need for fire alarm systems – all of which are quite costly and potential-project limiting factors. These are important limitations that increase the safety afforded to occupants in high-hazard environments; but can be very costly and complicated if they are not appropriate to the true occupancy.
As I stated earlier – it comes down to experience, judgments, or risk evaluations. Who performs these evaluations – and what happens if the design team and the Authority Having Jurisdiction disagree? What experiences have you had in classifying high-hazard industrial occupancies?
Okay – so, perhaps at this point you’re saying – Melinda, so what should the definition for high-hazard industrial occupancies include? How would you reduce the necessity for interpretation? I think you’ve posed some great questions, and I’ll let you know where I’ve landed on those… in my next post.
If you have any suggestions or ideas – leave them in the comments!
3 Responses
Hi Melinda:
It is nice to read this post.
I have a warehouse for paint storage, handling and distribution. It includes 13,000 liters class IB flammable liquids. Is the occupancy classification F1 or F2?
I classify it as F2, because there is not a number in the NBC to specify that it is sufficient quantities for F1. Further more, in the examples of F1, only bulk plants or factories of flammable liquids are considered as F1.
The plans examiner in the City said if the quantity is over 2300 liters, it shall be F1.
I don’t know where he got the number of 2300 liters for defining F1. How do you think the occupancy classification?
Thanks!
Bing Ting Duan
I work in a manufacturing facility in Saskatchewan that is mostly metal fabrication with a very low fire load throughout the building. We have two coating booths, but the paint storage and mixing room is a separate rated facility and not part of the manufacturing facility so there is no bulk paint stored in the facility, just the hoses running through to the paint guns.
The BC code committee made an interpretation on this a few years ago that stated that a paint booth does not make a building automatically F1 as long as that is not the main use of the facility.
https://boabc.org/wp-content/uploads/2019/04/12-0134-Paint-Spray-Booths-and-Major-Occupancy.pdf
What are your thoughts on this interpretation and if it would be seen the same in other provinces?
Thanks for sharing this Nolan – I have used that interpretation in the past and I would agree that typically, individual high-hazard paint booths in a larger manufacturing facility should not result in the entire facility being classified as a high hazard major occupancy (F1).
It has generally been my experience that limited, ancillary or secondary occupancies having a high hazard classification are commonly accepted within larger medium or low hazard industrial major occupancies. The paint booth is not considered to be the ‘major’ occupancy. When applying this approach, you must also be mindful of your obligations for means of egress and exits that serve the high hazard occupancy.