1 August 1998
c. Drawings. Control drawings are an extension of the performance specification and should be
used to illustrate project requirements not completely identified or illustrated in the specification.
Excessive detailing should be avoided since the advantage of using a Metal Building System is lost if the
manufacturer is forced to use details other than those which have made standard for its product.
Architectural drawings should provide basic floor plans and building elevations. Roof slopes, door and
window openings, and areas that must remain devoid of bracing must also be indicated. Structural
drawings should include a foundation plan (based on a preliminary design), a floor slab plan (showing
joint layout), and structural elevations where unusual bracing requirements exist. Working clearances
discussed earlier can be shown on architectural or structural drawings as appropriate, but should not be
shown on both.
d. Design Requirements. The designer/specifier must be familiar with all referenced design
standards and codes, especially when specifying large complicated structures, so that the specification
contains the appropriate choice for the structure being procured.
\ text deleted/1/ These decisions
should receive special attention during the Independent Technical Review process.
(1) Collateral loads are an estimate of the miscellaneous loading, expressed as a uniform
load applied to the entire structure, that account for small miscellaneous items such as lights, ducts, etc.,
that are hung from the structural frame or secondary framing members. Collateral loads should not be
increased to account for heavy items, i.e., those with a mass more than 25 kg (55 lb.) Hanging from the
framing, since that would impose a significant penalty on members that do not support the heavy loads.
Instead, large equipment should be shown on the contract drawings and tabulated on the structural
drawings with descriptions, estimated weights (to be verified by the contractor), plan dimensions, drawing
references for locations, and any unusual access requirements. Secondary members should be
increased appropriately in size or number to support the heavier loads.
(2) Wind loads are frequently subject to miscalculation even by experienced engineers and an
error, if undetected, could result in costly redesign and resubmittal. Relying on code references alone
and allowing the manufacturer to calculate pressures may be safe for small uncomplicated structures,
but it is preferable to calculate pressures and illustrate the limits of these pressures on the control
drawings for large complicated structures. The use of tables and isometric drawings to illustrate all
significant design pressures, the extent of all high pressure areas, and the pressures for parts and
portions of the structure along with their tributary area limitations is recommended.
(3) Seismic loads rarely control the design of lightweight flexible steel structures. These loads
become more of a concern if rigid masonry or precast elements are attached to the structure as
cladding./1/ text deleted/1/
(4) The foundations paragraph in the guide specifications contains written criteria the
contractor will use to design the building foundation. Additional supporting criteria, to include required
details of construction, should be shown on the structural plates of the contract drawings. Examples
include: details of integral slab footings, details of separate wall or column footings, minimum thickness
slabs at edges, dimensions of turn-down portion of slabs, details of hair pins or tie rods for lateral thrust
(5) If Structural Standing Seam Metal Roofing is to be used on the structure, then purlin
spacing of 750 mm (30 inches) maximum at corner, edge, and ridge zones and at 1500 mm (5 foot)
maximum for the remainder of the roof are required and must be clearly shown on the drawings, or in the