Minimum Loads [6.6.4]

All building designs must be in compliance with the local building code requirements. The required Building Code and Loading information may be obtained by consulting the local building official. It is the responsibility of the builder to determine this data. In the absence of a legally binding building code, designs will be based on the 1996 edition of the MBMA Low Rise Building Systems Manual.

Snow Drifting / Stepped Elevations [6.6.5, 6.6.18, 6.10.5]

Whenever two structures of unequal height are located in close proximity (within 20'), the lower structure and its components are subjected to increased roof snow load. These increased loads may be due to drifting from blowing snow, sliding snow, or valley accumulations. The location of the building in close proximity to a natural site feature such as a hill or escarpment may also produce the same phenomena. It is the builder's responsibility to identify on the existing building data sheet or on another sketch other structures or site features in close proximity to the proposed new building. Required information includes heights and height differentials, distance from proposed building, and size (width and length) and orientation of the structure / feature. This will enable the Metal Building designer to properly account for additional snow loads.

Building End Use [6.6.6]

Common sense dictates that a structure designated to house a medical treatment facility is at a higher risk for catastrophic loss of life than an agricultural building in the event of collapse. Thus, building codes dictate that a higher factor of "importance" or "safety" be applied to certain categories of structures. For example, a fire or police station may require a snow load importance factor of 1.2 while an agricultural building may only require a factor of 0.8. This particular example reflects a difference in importance of 50%, resulting in increased loading designed for the structure, and is indicative of the relative risk for catastrophic loss of life. Projects comprised of multiple, interconnected buildings should generally be ordered using only one Use Category. Buildings, which have a physical separation between buildings, may be ordered with different Use Category, in accordance with actual usage.

Note: The application of Importance Factors based on end use may affect all structural elements of a building. Not only will the metal building members be affected, but the changes in column reactions may influence the foundation design. Raising the importance factor has the same effect as increasing the base load rate to which the factor is applied. Purlin and girt depths may increase, and column and rafter sizes may increase as well. In this sense, available building volume may be impacted by a change in Importance Factor.

Wind and Snow Exposure factors [6.6.7]

Wind exposure factors "B", "C", and "D" are defined in the IBC Loads help screen.  Exposure "B" represents urban and suburban areas, or wooded areas, while exposure "C" represents open terrain with scattered obstructions having heights generally less than 30' and exposure "D" represents flat, unobstructed areas exposed to wind flowing over large, open, bodies of water.  Specifying wind exposure on the purchase order is required.

Snow exposure categories are defined as follows:

Fully Exposed are roofs exposed on all sides with no shelter afforded by terrain, higher structures, or trees.

Sheltered are roofs located tight in among conifers that qualify as obstructions.

Partially Exposed are all roofs except as previously defined.

We assume that the building will be a heated structure. It is the builder's responsibility to so note on the Work Order if this is not the case.

We recommend you consult with your Professional of Record to determine the proper Wind and Snow exposure categories.

Serviceability Requirements [6.6.8]

Serviceability issues relate to the occupancy and function of a building. In general, these issues involve the response of people and objects to the behavior of the structure under load. Whether a building has exceeded a serviceability limit is based on judgement and is frequently non-technical. The manufacturer will size and locate members to be in compliance with the deflection limits specified in the appropriate building code, unless otherwise instructed. If stricter limits are required either by occupancy or because of the properties of supported materials, then these more stringent requirements must be incorporated into the  Notes section before the project is quoted.

Review and advise special serviceability requirements in the Notes section of the Quotation/Contract.

Seismic Design [6.6.17]

Review and advise of the appropriate Seismic Design Information.

Note: The Design Engineer will conform to the dictates of the Building Code specified unless any additional information can be provided. Such additional information may take the form of soil property analysis or distance to a known seismic source.

Expandable Endwalls [6.10.1]

If an expandable endwall is requested, the main end frame will be designed for an expansion bay length equal to the end bay length at that end of the building unless noted on the contract. If a non-expandable main end frame is requested, it will be designed with a tributary bay spacing equal to one-half of the end bay length at that end of the building.

Collateral Loads [6.10.4]

In order to properly assess the impact of collateral loads on the building design, it is necessary to know the source of the components of the loading. Future or speculative collateral loads must not be used to resist wind uplift forces required by the code.

Review and advise of the collateral load sources in the Notes section of the Quotation/Contract.

Building Porosity [6.10.9, 6.10.24]

Large internal pressures may develop in a building, which has a large percentage of openings in the windward side and a relatively small percentage of openings in the remaining building envelope. The builder is responsible to define all roof and wall penetrations so that the Design Engineer may properly assess the building porosity. For design wind loads, all doors and windows are considered to be closed and wind resistant, and framed opening materials and collateral wall materials are considered to be properly designed and constructed to be wind resistant. In this case, wind resistant means able to safely resist the Code specified wind loads. Louvers, and fan openings are considered as openings.

Walls Open for Materials by Others

Weights of wall materials are needed for Seismic and Dead load calculations. Deflection limit information is necessary for determining stiffness of spandrels or girts supporting these materials.