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Codes and Loads
All buildings, including Metal Building Systems, must be engineered to meet certain building code and load requirements defined by the municipality or jurisdiction in which the building is located. At Norsteel, all of our buildings are custom-made to order so that our certified engineers can design a building that accommodates your design requirements while still adhering to your local building code and load requirements.
What Are Building Codes and Loads?
Buildings provide shelter for people and property. While a building should have many desirable characteristics, including an attractive appearance, long life, flexibility of use and economy, its basic requirement must be one of protection.
To break this down even further, we can consider two kinds of protection that buildings provide:
1. Protection against forces or loads that may be exerted upon the building
Unless the structure can offer adequate resistance against various loading conditions, the safety of people and the value of property are endangered. This is where sound design considerations must be given as to the strength of the building and particularly, to the structural system.
2. Protection against the elements - rain, wind, heat and cold:
Any of these can contribute to personal discomfort and cause a decrease in the value of contents and property. The degree of protection against the elements is determined by the weather tightness and thermal efficiency of a building. These factors greatly influence the design of a structure’s roof and walls.
Now that we understand the two broad types of load requirements, let’s examine each in detail so we can outline some of the specific loads that are taken into consideration when designing and constructing a new building.
Protection from Loads Exerted on the Building
The Dead Load is the total weight of the metal building system, including elements like the roof, framing, insulation, and covering members. The specific and detailed distribution of a structure’s weight must be taken into consideration when designing a building so that the structural integrity of the building itself isn’t compromised.
The Live Load refers to any temporary load imposed on a building (that is not wind load, snow load, seismic load or dead load), that will be present during construction, maintenance, or present at different points throughout the life of the building. A few examples of a live load are workers, equipment and materials. The minimum Live Load per code is 20.89 PSF.
The Collateral load refers to the weight of additional permanent materials, other than the weight of the metal building system, such as sprinklers, mechanical and electrical systems, and ceilings. Collateral loads in a building are evenly distributed suspended loads inside the building. A normal (minimum) collateral load is 2 PSF, which takes into consideration roof insulation and normal lighting. Sprinkler systems add 3 to 4 PSF, suspended ceilings add another 4 PSF.
At Norsteel we design all structures with a minimum collateral load of 3 PSF – Although lowering the collateral load will decrease the initial cost of a structure, the cost to reinforce the building once it has been manufactured and erected outweighs any initial savings. The collateral load should be clearly indicated on costing sheets.
Concentrated or Point Loads
Concentrated loads, occur either from roof top units or are loads that are suspended inside the building. Roof top units are typically things like air conditioners and make-up air units. Suspended loads can be from heaters, ductwork, cable trays or support strapping, basketball nets, mechanical piping, suspended walkways or conveyors, roof top units. All concentrated loads need to be considered in the building’s design. Although they are technically dynamic live loads (e.g., cranes and material handling systems), Auxiliary Loads also fall under this category and must be given careful consideration in the design of the structure.
Protection from the Elements
Structures must be designed to resist the forces imposed by the wind blowing from any direction. There are 3 specific concerns to be aware of regarding wind: Speed, Exposure and Enclosure.
1. Wind Speed: Wind speeds vary greatly depending on a building’s physical location and surrounding geographic area. As a result, these loads are imposed by the building codes for the building site within the designated municipality.
2. Wind Exposure: Wind exposure is determined by the specific location of the structure itself on the site, and what features are near the building.
- Obstructions: Trees, buildings, terrain features
- Exposure B: Obstructions within ½ mile zone
- Exposure C: No obstructions on any side within ½ mile zone
3. Wind Enclosure: Wind enclosure speaks to the effect of wind as determined by the openings on the building itself.
- Enclosed: All openings can be relied on to be closed during a storm
- Partially Enclosed: One wall more open than the sum of the others; creates a ballooning effect
- Open: Buildings with all walls at least 80% open; openings will remain open during storms
Technically speaking, the snow load refers to and addresses the vertical load induced by the weight of snow, assumed to act on the horizontal projection of the roof of the structure. This environmental load varies greatly depending on locality and site conditions. Note: Very wet snow 6” deep is equal to one inch of water. One inch of water on a square foot of surface weighs five pounds.
The load or loads acting in any direction on a structural system due to the action of an earthquake.
Who Determines Building Codes and Loads?
Building Codes and Loads are determined Nationally and Internationally, and imposed by our local municipal permit offices. When we design a structure, we use the job site location and specifically the postal code to determine the National (or International) Building Code and Loadings for the specific municipality of the job in question. This takes care of mother nature’s influence. But remember that there are particular considerations that will be specific to your site location and where you want to place your building on the site.
When pricing out your steel building, ensure that your building provider is asking the questions that are important in ensuring the integrity of your building and the safety of everything you will be protecting.
Remember that pre-engineered buildings are custom designed and manufactured to your specific requirements. Each component is carefully engineered to ensure that it can withstand the elements for your specific circumstance. This is why there are no genuine clearance buildings and why customers should be very weary of buying a building that was designed for someone else. The design of your building relies on the information that you provide about its purpose, content and about the site itself. At Norsteel, regardless of a job’s location, we always demand a series of minimum requirements for our building projects to ensure a consistent level of quality construction.
The types of loads and their magnitudes are critically important to the design and construction of your steel building. At Norsteel we’ll work with you on your building project from start to finish to ensure the proper building codes and loads are used, without sacrificing on the design elements and functionality that you need from your steel building.
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