Span Charts — Estimating Guidelines CAUTION!The material shown on the charts has been prepared as a general guideline for estimating purposes only. While they are in accord with recognized engineering principles and sound judgment, the charts are not to be used in lieu of job-specific designing provided by a licensed Structural Engineer whose requirements shall prevail in all cases. The information disclosed in these charts is subject to approval by the local building code authority or a structural engineer who is trained and licensed to interpret the information show. LiteForm International, American PolySteel, nor any of their employees or representatives makes any warranty, guarantee or representation, expressed or implied, for the direct or indirect damages arising from the use of the information show.