Appendix A — Explanatory Notes to Part 2

Listing of Objectives Any gaps in the numbering sequence of the objectives are due to the fact that there is a master list of objectives covering the Building Code, Fire Code and the National Code Documents (National Building Code of Canada 2020, National Plumbing Code of Canada 2020 and National Fire Code of Canada 2020) but not all objectives are pertinent to all Codes. The Building Where the term “the building” is used in the wording of the objectives, it refers to the building for which compliance with the Building Code is being assessed. Emergency The term “emergency" - in the context of safety in buildings - is often equated to the term “fire emergency”; however, the wording of objectives OS3.7 and OS5.9 makes it clear that the Code addresses any type of emergency that would require the rapid evacuation of the building, such as the release of hazardous substances or the presence of intruders.

The intent of Part 2 is to set forth measures to ensure the safety of persons in farm buildings.

The following are examples of the agricultural major occupancy classifications described in Table 2.1.4.1.: Group G, Division 1 Farm buildings housing livestock with a below-floor storage area for liquid manure Feed mills Grain elevators Rooms for the bulk storage of dangerous goods classified as flammable gases or compressed gases Rooms for the bulk storage of flammable liquids Rooms for the bulk storage of reactive materials Group G, Division 2 Animal exercise facilities Animal housing facilities, including, but not limited to, facilities for livestock, facilities for alternative livestock and game animals, facilities for fur-bearing animals, and facilities for cultured fish and shellfish Animal training facilities Facilities for the packaging and processing of agricultural products Facilities for the production of plants and fungi, excluding greenhouses Farm workshops Feed preparation centres Feed storage facilities Fruit and vegetable storage facilities Grain, forage and feed structures Milking facilities Storage facilities for farming equipment, implements and machinery Viniculture facilities Group G, Division 3 Greenhouses Group G, Division 4 Biomass facilities By-product facilities Digesters Grain bins Horizontal silos Storage bins Vertical silos Page 16 Appendix A • Volume 2

It is intended that portions of farm buildings that contain permitted major occupancies other than agricultural major occupancies be subject to the requirements of Part 3. Unless specifically referenced in Part 2, the requirements of Part 3 are not intended to be applied to portions of farm buildings meeting the criteria for the application of Part 2. (See Articles 2.1.2.1. and 2.1.2.2.)

The materials used in the construction of fire separations and closures in farm buildings should be selected to minimize deterioration caused by exposure to corrosive or humid environmental conditions.

Sentence 2.2.1.8.(1) is not intended to prohibit a concealed attic or roof space from being used as a supply air plenum for the distribution of air through a porous ceiling or ceiling inlets to the space below.

The protection required by Sentence 2.2.1.15.(2) is intended to prevent rodents from damaging electrical wiring that is installed in a concealed space, such as a space within an assembly, an attic space, or a service space.

The intent of Sentence 2.2.7.1.(1) is that each floor level be served by its own exits. This approach to providing exits is consistent with that in Part 3.

Overhead doors and sliding doors are not permitted to be used as exits from farm buildings with human occupants because such doors could delay their egress.

Where a farm building housing livestock with a below-floor storage area for liquid manure is provided with a ventilation system in accordance with Article 2.2.8.3., the requirements of Sentences 2.2.8.2.(1) and (2) are considered to be satisfied with respect to the fire and explosion hazard posed by manure gases. Should other hazardous substances or conditions be present in the farm building, the requirements of Sentences 2.2.8.2.(1) and (2) must be applied with respect to those substances or conditions.

The following are examples of manure-handling equipment and systems that are not considered to be below-floor storage areas for liquid manure: • gutters, pumps and pump chambers designed to be emptied or flushed every few days • shallow gutters • gutters scraped with an alley scraper or stable cleaner • gutters equipped with a belt manure removal system • normally empty transfer gutters and pipes

The room referred to in Sentence 2.2.8.4.(1) is a space where significant and regular welding and cutting operations are routinely performed, such as a welding shop supporting the farm operation. Sentence 2.2.8.4.(1) is not intended to apply to occasional welding and cutting operations, such as those carried out during repairs of farm machinery. Refer to Section 5.2. of Division B of the NFC for requirements relating to hot works, including cutting, welding, soldering, brazing, grinding and adhesive bonding. Appendix A • Volume 2 Page 17

Examples of liquids that are capable of releasing hazardous gases or vapours include liquid manure, wash water from a milking facility, and waste water in a septic system.

Information on the design of bins and silos can be found in the Commentary entitled Farm Buildings in the “Structural Commentaries (User's Guide – NBC 2020: Part 4 of Division B”.

The bulk densities, ρ, of agricultural products listed in Table A-2.3.2.3.(1) can be used to determine the specific weight, γ, of the products as follows: where γ = specific weight, in N/m3, ρ = bulk density, in kg/m3, and g = gravitational acceleration, in m/s2. Page 18 Appendix A • Volume 2 Table A-2.3.2.3.(1) Bulk Densities of Agricultural Products Agricultural Product Bulk Density, kg/m3 Agricultural Product Bulk Density, kg/m3 Grains and Seeds(1) Grains and Seeds(1) Alfalfa 750 Peanuts Alsike 740 shelled 640 Barley 620 unshelled 240 Beans Peas 770 castor 590 Rapeseed (see Canola) lima 720 Red top 390 navy 770 Reed canary grass 380 snap 380 Rice Bentgrass 450 hulled 770 Birdsfoot trefoil 740 rough 580 Bluegrass Russian wild rye 250 Canada 270 Rye 720 Kentucky 280 Ryegrass rough 270 annual 360 Bromegrass 170 perennial 300 Buckwheat 640 Safflower seed 720 Canola 640 Sainfoin 360 Argentine rape 640 Soybeans 770 turnip or Polish rape 770 Sunflower seed 310 – 410 Clover Timothy 580 red 750 Wheat 770 sweet 780 Concentrated Feeds white 760 Alfalfa Corn meal 250 – 350 ear-husked 450 pellets 650 – 700 shelled 720 Barley Cottonseed 410 ground, meal 380 – 450 Cowpeas 770 malt 500 Fescue Beet pulp, dried 180 – 250 chewings 240 Bone meal 800 – 960 meadow 290 Bran, rice-rye-wheat 260 – 320 red 220 Brewer's grain tall 280 spent, dry 220 – 290 Flaxseed (linseed) 700 spent, wet 880 – 960 Grain sorghums 720 Corn Lentils 770 cobs, ground 270 Milkvetch 820 cobs, whole 190 – 240 Millet 640 cracked 640 – 800 Mustard 640 germ 340 Oats 420 grits 640 – 720 Orchard grass 200 meal 510 – 640 Column 1 2 3 4 Appendix A • Volume 2 Page 19 Table A-2.3.2.3.(1) Cont’d Bulk Densities of Agricultural Products Agricultural Product Bulk Density, kg/m3 Agricultural Product Bulk Density, kg/m3 Concentrated Feeds Fruits and Vegetables Corn oil, cake 400 Beans Crumbled ration 550 shelled 800 Fish meal 560 – 640 unshelled 400 Flaxseed oil (linseed oil) Beets 700 cake 770 – 800 Blackberries 610 meal 400 – 720 Cabbage 500 Malt Carrots 550 dry, ground 320 – 480 Cauliflower 320 meal 580 – 640 Corn, cob 450 Meat meal 600 Cranberries 480 Oats Cucumbers 620 crimped 300 – 420 Onions, dry 650 crushed 350 Parsnips 500 rolled 300 – 420 Peaches 620 Pelleted ration 600 Pears 640 Salt 1000 – 1100 Peas 390 Soya bean meal 550 – 650 Peppers 320 Wheat Plums 720 cracked 640 – 720 Potatoes 670 germ 350 – 450 Pumpkins 600 Roughage Feeds and Bedding Squash 600 Hay (air-dried) Sweet potatoes 700 baled 160 Tomatoes 680 chopped 160 Turnips 600 long 80 Miscellaneous wafered 325 Eggs in cases 200 Straw Fertilizer 950 – 1 000 chopped 100 – 130 Tobacco 550 field-baled 130 Wool long 60 compressed bales 775 Wood shavings, baled 320 uncompressed bales 200 Fresh manure (feces and urine Fruits and Vegetables 1000 mixed) Apples, bulk 600 Apricots 620 Column 1 2 3 4 Notes to Table A-2.3.2.3.(1): (1) The bulk densities of grains listed in Table A-2.3.2.3.(1) are determined by filling a small container with grain and weighing the filled container. If grain is dropped from a distance into a bin, the bulk density may be up to 5% higher than the listed density. If a grain spreader is used to load the grain into the bin, the bulk density will be even higher (but wall pressures in the bin will be more uniform and slightly lower). Therefore, it is recommended that the listed density be multiplied by a factor of 1.06 for grain stored in a bin. Page 20 Appendix A • Volume 2

The lateral ice pressure in liquid manure storage tanks in an Ontario region has been found to reach 50 kPa acting over an ice thickness of 0.5 m. The ice thickness, and therefore the lateral ice load, depends on the geographic location. To calculate the lateral ice load for a particular location, a lateral ice pressure of 50 kPa is applied over the ice thickness expected in that location, which can be estimated from the location's degree-days below 18°C listed in Table 2 of Supplementary Standard SB-1 as follows: ice thickness (location) = 0.5 m × (degree-days below 18°C (location) / degree-days below 18°C (location))

The lateral earth pressure referred to in Clause 2.3.2.5.(4)(a) should be based on the equivalent fluid density of the earth surrounding the liquid manure storage tank. Equivalent fluid densities for different types of soil are listed in Table A- 2.3.2.5.(4)(a). Table A-2.3.2.5.(4)(a) Equivalent Fluid Densities for Soil Type of Soil Equivalent Fluid Density, kN/m3 Clean sand and gravel, well-drained 4.7 Sand and gravel with fines, restricted permeability 5.7 Stiff residual silts and clays 7.0 Soft silts and clays, poorly drained 16.0 2.3.2.5.(6) Design of Liquid Manure Storage Tanks to Minimize Leakage. In designing walls and bases of liquid manure storage tanks to minimize leakage of liquid manure, all factors that may influence the formation of cracks should be taken into account, including thermal effects, concrete shrinkage, structural movement, and material choice and installation. The control of crack formation to minimize leakage is particularly important for reinforced concrete structures to prevent corrosion of the reinforcing steel.

Research has shown that sloped roofs covered with pre-painted steel have reduced snow loads relative to roofs covered with asphalt shingles. Sentence 2.3.3.1.(1) allows a reduction of the slope factor, Cs, for unobstructed slippery roofs of farm buildings where the roof slope, α, is greater than 15° but not greater than 60°. Figure A-2.3.3.1.(1) shows the Cs versus α curve calculated in accordance with Sentence 2.3.3.1.(1). Before using the reduced slope factor, the designer should carefully examine the proposed roof configuration to ensure that snow will freely slide off the roof. The reduced slope factor does not apply to sloped roofs terminating at grade, at a roof valley, or at another roof of lower slope because the snow may pile up or not slide freely at the transition in slope. The reduced slope factor also does not apply to roofs with obstructions, such as chimneys, silos or ice guards. Appendix A • Volume 2 Page 21 Figure A-2.3.3.1.(1) Curve for Slope Factor, Cs, Versus Roof Slope, α, for Unobstructed Slippery Roofs of Farm Buildings

Information on the seismic design of above-ground liquid manure storage tanks can be found in the Commentary entitled Farm Buildings in the “Structural Commentaries (User's Guide – NBC 2020: Part 4 of Division B)”.

Information on SFRSs with RdRo ≥ 3.0 for farm buildings in Seismic Category SC2 can be found in the Commentary entitled Farm Buildings in the “Structural Commentaries (User's Guide – NBC 2020: Part 4 of Division B)”.

Guidance on ventilation in farm animal housing and indoor plant agriculture facilities can be found in the chapter entitled Environmental Controls for Animals and Plants in the “ASHRAE Handbook – HVAC Applications”.

Controlled-atmosphere storage areas are typically used to preserve fruits and vegetables and are not intended to contain hazardous gases.

In enclosed horizontal silos, gases produced by tractors during loading and unloading operations and by silage fermentation present a hazard. Providing openings at both roof or eave level and floor level in horizontal silos promotes airflow to remove these gases, most of which are heavier than air.

The requirement of Clause 2.4.2.4.(3)(b) can be met by providing a single opening at floor level, which may also serve as a tractor access opening.

The ventilation requirements of Article 2.4.2.5. are intended to address the specific hazards due to manure gases in farm buildings housing livestock with below-floor storage of liquid manure. Where these requirements are met, it is not necessary to apply the provisions of Articles 6.3.1.5. and 6.9.1.2. with respect to manure gases. However, where the farm building contains other hazardous substances (air contaminants or hazardous gases, dusts or liquids), the provisions of Articles 6.3.1.5. and 6.9.1.2. must be applied with respect to those substances.

The minimum ventilation rate required by Sentence 2.4.2.5.(1) is intended to limit the concentrations of flammable gases and toxic gases produced by the decomposition of liquid manure. Higher ventilation rates may be necessary to promote farm Page 22 Appendix A • Volume 2 animal health and production. Where requested by the authority having jurisdiction, compliance with Clauses 2.4.2.5.(1)(a) and (b) can be demonstrated through periodic in situ monitoring of gas concentrations or through calculation of gas concentrations using a reliable method (such as that described in the following publication: Massé, D.I., Croteau, F., Patni, N.K. and Masse, L. Methane Emissions from Dairy Cow and Swine Manure Slurries Stored at 10°C and 15°C. Canadian Biosystems Engineering, Vol. 45, pp. 6.1–6.6, 2003).