Important Changes to the NBC 2020 and NFC 2020: Large Farm Buildings
Julia Dalphy, Technical Advisor, Codes Canada
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Video transcript
Introduction
Hi, my name is Julia Dalphy and I am a Technical Advisor supporting the Canadian Board for Harmonized Construction Codes – also referred to as the CBHCC.
This committee is the federal-provincial-territorial body responsible for developing and maintaining the National Model Codes in Canada.
I am a member of the Codes Canada team at the National Research Council of Canada.
Codes Canada acts as the secretariat to the CBHCC, providing administrative, technical and policy support, including publishing the National Model Codes.
To learn more about code changes and provisions in the National Model Codes, or about Canada’s national model code development system, please visit CBHCC’s website.
This presentation is part of a video series led by the CBHCC on the key technical changes incorporated in the 2020 editions of the National Model Codes.
This presentation will focus on important changes related to large farm buildings in the 2020 editions of the National Building Code of Canada and National Fire Code of Canada.
The need
The National Farm Building Code (NFBC) was not updated since its publication in 1995. Since that time, the farming industry has evolved significantly.
The typical single-storey, small area, timber post and beam-framed structures of a quarter century ago are no longer representative of farm buildings. Multi-storey, large area, modern structures are designed and built today to meet the farming industry’s demands. Farming operations have also become more complex, and the provisions of the NFBC no longer reflect these modern, often more automated, farming operations.
The NFBC was not updated with the National Building Code (NBC), National Fire Code (NFC) and National Plumbing Code (NPC) when they were reformed and published in an objective-based format in 2005. This difference makes the proposal and evaluation of an alternative solution for farm buildings difficult for designers and regulators, respectively.
Due to the difficulties related to compliance and enforcement, several jurisdictions across the country have not adopted the NFBC. This has inevitably led to the inconsistency in the level of safety of farm buildings across the country. In addition, the differences in the application of the building code provisions for farm buildings between jurisdictions has led to inequalities in costs for building owners.
Therefore, the provinces and territories have recommended the introduction of requirements for large farm buildings in Division B of the 2020 edition of the NBC and NFC.
The distinction between a small and large farm building is analogous to the distinction in the NBC between small buildings and everything else.
The changes introduce new requirements for fire protection, occupant safety, structural adequacy, as well as heating, ventilating and air-conditioning in a separate part of the NBC. The changes also include additions to the NFC and corresponding definitions in both documents.
Generally, the requirements for large farm buildings are relaxations of similar requirements for other buildings with a slight distinction: the sole objective attributed to the applicable technical requirements is limited to the safety of persons in or adjacent to the farm building.
NBC 2020: Application of technical provisions
This diagram shows the application of the technical provisions for large farm buildings as established in Division A of the NBC.
Part 2 of Division B of the NBC 2020 would apply to farm buildings greater than 600 m² in building area or more than three storeys in building height, used for an agricultural major occupancy.
Also, all agricultural occupancies that are identified in the diagram as Group G, Division 4 occupancies, regardless of the building area or height, are required to conform to the requirements in Part 2 of Division B of the NBC 2020.
New definitions and explanatory Notes related to agricultural occupancies are also provided.
NBC 2020 and NFC 2020: Objective
The new requirements set the minimum level of performance that should be achieved in farm buildings, with the following objective:
“to limit the probability that, as a result of the design, construction or demolition of the building, a person in or adjacent to the building will be exposed to an unacceptable risk of injury.”
That is, more specifically, to limit the probability that a person will be exposed to an unacceptable risk of injury due to fire, structural failure and other hazards.
The objective of the requirements in Part 2 is to provide the safety of persons in farm buildings.
NBC 2020 and NFC 2020: Relaxations
Generally, the requirements for farm buildings tend to consist of relaxations of similar requirements for other occupancies. This is rationalized based on the remote location of typical farm structures and the specific characteristics of farm building occupants.
The specific occupant characteristics are:
- Farm buildings have a Low occupant load.
- Members of the general public and vulnerable persons are typically not Expected to be in farm buildings.
- The occupants of farm buildings are typically Familiar with the building layout.
- Depending on the use of the farm building, occupants tend to be only in the building for short durations of limited Times throughout a day.
Remember: the objective of these provisions are related to life safety of the few occupants that are L-E-F-T in a farm building.
Next, we will highlight the following technical requirements for large farm buildings that are introduced in Part 2 of Division B of the NBC 2020, and Parts 2 and 4 of Division B of the NFC 2020.
NBC 2020 and NFC 2020: Defined terms
Firstly, let’s review the definitions for two key terms: “farm building” and “agricultural occupancy.”
- A “farm building” means a building or part thereof that contains an agricultural occupancy.
- An “agricultural occupancy” means the occupancy of a building or part thereof that is located on land that is associated with and devoted to the practice of farming, and is used for the purpose of producing crops, raising farm animals, or preparing, marketing, storing, or processing agricultural products.
It is further clarified in the explanatory Note that the term “processing” refers to activities carried out for the purpose of maintaining the quality of agricultural products or to the minimum amount of activity necessary to produce a saleable product.
The new requirements introduce the notion that every farm building or part of a farm building should be classified in one of the four classifications within the agricultural major occupancy.
The definition of each classification specifically recognizes the unique risks and characteristics associated with the use and occupancy of different types of farm buildings. The agricultural occupancy classification allows distinctions to be made in the technical provisions for specific farm building operations. Designers have the ability to design a farm building corresponding to the level of risk associated with a specific agricultural occupancy, rather than following provisions based on the highest-risk agricultural occupancy. This translates into a benefit carried throughout the technical requirements for farm buildings with a lower risk level. This concept is new for farm buildings because, for the most part, the existing NFBC does not differentiate between different types of farm buildings.
- Group G, Division 1 agricultural occupancies have a higher than usual risk to the occupants from fire conflagration or explosion due to the intended use of the space.
- Greenhouses (Group G, Division 3 agricultural occupancies) were differentiated from other farm buildings in the NFBC, with specific requirements applicable only to greenhouses. This distinction was retained in the new Part 2.
- Group G, Division 4 agricultural occupancies are a class of farm building that does not contain any human occupants.
- A final classification (Group G, Division 2 agricultural occupancies) is included to categorize all other farm buildings that do not fall within one of the other categories.
NBC 2020: Fire protection and occupant safety
Requirements related to fire protection and occupant safety are provided in Section 2.2. of Division B of the NBC 2020, which is sub-divided into eight Subsections:
- General: this Subsection includes provisions such as, but not limited to, classification, required fire separations and other general provisions related to fire protection, as well as referenced fire test methods and standards.
- Building Size and Construction Relative to Major Occupancy: this Subsection establishes building combustibility, floor separation and structural support rating requirements, and building area based on the specific agricultural occupancy, number of storeys (building height), and whether the building is sprinklered or not.
- Subsection 2.2.3. focuses on fire alarm and detection systems, which are required in certain circumstances.
- Subsection 2.2.4. includes provisions for firefighting requiring fire department access to farm buildings, and where voluntary sprinklers and fire pumps are installed, they should meet good design and installation practices that are consistent with other requirements for buildings in the NBC.
- Subsection 2.2.5. requires emergency lighting for the principal means of egress.
- Safety within Farm Buildings: this Subsection includes requirements related to egress, travel distance, doors, guards, signage, ramps and stairways. The scope statement for this Subsection requires that a means of egress be provided from every floor area containing a G1, G2 or G3 occupancy. G4 is excluded because this occupancy classification does not have any human occupants.
- Exits: this Subsection contains provisions for the types of exits permitted in farm buildings, the minimum number of exits required, the distance between them, their locations and characteristics, stairs for exits and fire escapes, and exit signs.
- Subsection 2.2.8. contains the requirements related to hazardous processes and equipment that may be applicable at the time of design and construction. Where appropriate, direct reference to the NFC is provided in the provisions.
NBC 2020: Structural design
Section 2.3. contains the structural design requirements for farm buildings and is divided into four Subsections:
- general Structural Design Requirements
- Loads Due to Use and Occupancy
- Loads Due to Snow
- Loads Due to Earthquakes
The structural design requirements reflect the changing nature of farming (larger and more complex buildings and equipment), as well as discrepancies between the requirements applicable to agricultural versus non-agricultural buildings.
NBC 2020: Heating, ventilation and air-conditioning (HVAC)
The heating, ventilation and air-conditioning requirements for farm buildings are included in Section 2.4., which is divided into Subsections:
- General
- Ventilation
- Heating Appliances
Part 6 of the NBC forms the basis for requirements in Section 2.4. as outlined in the general requirements of Subsection 2.4.1. However, given the unique nature of the operations within farm buildings, the low human occupancy level inherent in the definition of agricultural occupancy, and the objectives of the farm building requirements to provide occupant safety, some exemptions are provided to the requirements of NBC, Part 6.
NFC 2020: Additional requirements
The NFC already applied to farm buildings, as farm buildings fit within the application statements of this Code. So, specific requirements for farm buildings have been introduced in the existing Parts of the NFC 2020.
Additional requirements for farm buildings are provided in:
- Part 2, Building and Occupant Fire Safety, and
- Part 4, Flammable and Combustible Liquids.
A few changes to note include:
- requirements for the inspection of mechanical and electrical equipment at regular intervals in order to control the risk of fire hazard caused by a mechanical or electrical malfunction,
- the addition of requirements specific to the control of gases and vapours for farm buildings having under-floor liquid manure storage to mitigate the atmosphere of dangerous gases created in these buildings, and
- the introduction of specific requirements for the storage of flammable and combustible liquids on farms.
NFC 2020: Application of objectives
When considering the application of the NBC 2020 and NFC 2020 to farm buildings, it should be noted that:
- The farm building provisions for Part 2 of the NBC were assigned life safety objectives only in accordance with the direction provided by the Canadian Commission on Building and Fire Codes.
- The entire NFC applies to farm buildings; however, in applying the requirements, the only objective should be human safety. Thus, the NFC specifically excludes any property protection objective assigned to any requirement that is applied to farm buildings.
The application of objectives for farm buildings in the NBC and the NFC are consistent.
NFC 2020: Inspections
The requirements for mechanical and electrical inspection have also been added to the NFC as one of the measures aimed at reducing the frequency of fires in farm buildings.
The inspection requirements have given great consideration to:
- frequency, especially for farm buildings containing wet or corrosive environments;
- application to farm buildings greater than 600 m2 in building area or greater than three storeys in building height, and
- the person who is qualified to perform such inspection.
The additional inspection requirements are very important in reducing fire starts due to mechanical and electrical failures, which was noted to represent a significant cause of farm building fires.
The impact
Farm buildings do not have the same risks as buildings with other occupancies already established in the National Model Codes (e.g., industrial occupancies). Every provision was reviewed or developed with regard to the different level of risk for different types of farm buildings, and an agricultural occupancy-specific classification was developed based on risk and intended use.
Generally, the requirements for farm buildings tend to include some relaxations of similar requirements for any other occupancy. The requirements provide an acceptable minimum level of safety commensurate with the expected risk, making compliance more cost-effective compared to the classification of a farm as an industrial occupancy.
The direct introduction of the technical requirements for farm buildings in the NBC and the NFC ensures that these provisions benefit from the same Code development process as all other technical requirements in the National Model Codes.
The farm building provisions include all intent statements, objectives and functional statements required to make the farm building provisions objective-based. This results in clarification of the intent of the requirements, as well as the opportunity to propose and evaluate alternative solutions as an optional compliance path. This allows designers to seek and pursue innovation in farm building design and construction while meeting the intended level of safety to human occupants.
Since the NFBC was last published in 1995, a benefit of the changes to the NBC 2020 and NFC 2020 results from updating the farm building provisions to include comprehensive requirements that reflect current practices in the farm building construction industry. This manifests in the provisions through relaxations recognizing enhancements in protection features, flexibility in building size, geometry and layout, which enable farm buildings to be designed to better suit the nature of their intended occupancies.
The requirements for large farm buildings in the NBC 2020 and NFC 2020 re-establish farm building provisions as a recognized part of the National Model Codes that are specific to the uniqueness of farm buildings.
Conclusion
This concludes the presentation about important changes related to large farm buildings in the 2020 editions of the National Building Code of Canada and National Fire Code of Canada.
How to get involved
To participate in the code development process, visit the CBHCC’s website to find information about upcoming events and meetings, to submit a code change request, to comment on proposed changes during an open public review, or to volunteer to participate on a code development committee.
How to access the Codes
The National Model Codes are published by the National Research Council of Canada.
Visit Codes Canada publications web page on the NRC’s website to purchase a paper copy of the Codes or to access them in free electronic format.
Thank you.