What’s Important to Know about Steel Building Codes

Types of Loads On Your Steel Building

Over the years, building codes have become more and more accurate due to life experience in the field of steel building engineering, construction, and data collection. Together, building codes as revealed by your ZIP code and confirmed by your local building department, along with steel building fabrication technologies, serve to alleviate concerns regarding our safety.  In order to understand the need for accurate building codes, we begin with a short course about the types of loads put upon a steel building structure.

Dead Loads

Steel, by the nature of its own strength, carries a heavier dead load than a wood frame building…meaning, capacity to carry the weight of its own material alone.  Steel building structures can carry their own load of the framework, wall, and roof panels without the use of interior load-bearing support columns for building widths up to 300’ wide.

Collateral Loads

The standard minimum collateral load is 0.5 psf which allows for insulation and lightweight lighting to be attached to the ceiling.  However, if you intend to finish the interior of your building with materials, such as acoustical tile, sheetrock, heavier lighting, sprinkler systems, ductwork, etc., then be sure to note the increased requirements which you have confirmed with your building department.

Environmentally Speaking…

In addition to holding its own loads for structural, wall, and roof panels, the pre-engineered metal building system must also carry the load of snow, ice, water, wind forces, and seismic factors.  These loads vary by location, of course, as affected by climate and soil conditions throughout the year. Over the years, data has been collected for these variables and are built into Metal Building Software (MBS pricing and engineering programs) based on ZIP codes that your broker uses to design and quote your building.

Roof Snow Load – per Square Foot

Typical snow loads in the United States range from 4 – 60 lbs depending on precipitation.  Obviously, in warmer climates, there are 0 lb minimum snow load requirements, whereas, in colder states where snow and ice hardly have a chance to thaw before the next storm, roof snow loads can be greater than 60 lbs per square foot.  In addition, snow tends to drift and accumulate heavier in some spots than others, which is why snow loads are a factor in addition to the standard dead loads of a building.

Consider this; 1 cubic foot of water weighs approximately 62.4 lbs. (that’s about 7.5 gallons of water).  According to FEMA Snow Load Safety Guide, “The weight of one foot of fresh snow ranges from three pounds per square foot for light, dry snow, to 21 pounds per square foot for wet, heavy snow.”   Thus, the weight of 1 cubic foot of ice and snow approaches 62.4 lbs, yet won’t reach this weight if melting occurs.  This is why maintenance and snow removal still may be necessary during the winter months in your area.   It’s the build-up that begins to become excessive of the maximum load requirements that your steel building was designed to carry which could potentially invalidate the structural lifetime warranty offered with your building purchase.

Wind Codes – Miles per Hour

Wind load is also determined by patterns of climate local to your building site. Wind speed codes normally range from 85 mph to over 170 mph winds.

Wind, unlike snow, will affect different portions of the building not limited to only the roof.  The wind’s effects on your steel building structure will vary depending on your building design and how it sits on your property.  During the software designing process, strength factors are determined by building height, the size and number of large framed openings, and even the location of those openings.

Wind Exposure B or Wind Exposure C

Also in relation to the wind is the exposure of your building. Exposure B or C is site-specific.  For example, in gusty areas, your local building department may require Exposure C if there are no windbreaks provided by your surroundings, such as trees or neighboring buildings. Wind exposure also affects how snow tends to drift and accumulate on your building structure.  Your local building department can advise you as to whether or not your specific steel building erection site is requiring Exposure B or Exposure C.

Seismic Factors

Most buyers don’t generally know their seismic measures, however, they do play a significant role in the design of the building and are revealed by building site ZIP codes.  If you will be building near a fault line, for example, expect strong seismic factors to be incorporated into your building components for added strength. You don’t necessarily need to know these numbers, as they will default in the design software and be reflected in the measurements required for strong building components which may or may not cause price fluctuations as necessary