Per ANSI/TPI 1-2022 (National Design Standard for Metal Plate Connected Wood Truss Construction), Section 6.2.2.5, trusses with an overall span of 18 ft or greater must be evaluated for a 300 lb concentrated person load applied at the midpoint of any chord panel that is not sheathed with structural wood sheathing. This load shall be applied concurrently with dead load only (Person Live Load Case(s)) and shall not be combined with other loads. A load duration factor of 1.6 is used in Person Live Load case(s).
This check is performed as a moving load applied at mid-panel points in separate load cases. If any of these combinations govern, member sizes and/or plate requirements may change. This check is automatically performed by MiTek engineering software when ANSI/TPI 1-2022 provisions are applied. [For all images, See PDF or View in Full Issue.]
The TPI Technical Advisory Committee (TAC) issued a Technical Interpretation of Section 6.2.2.5 (Person Loading), updated April 2, 2026, to further clarify the application of this requirement.
For roof trusses spaced at 30 inches on center or less, the 300 lb concentrated load may be distributed across two adjacent trusses, with 150 lb applied to each. The load shall be applied at the midspan of the chord panel and concurrently with dead load only.
The person load applies only to chord panels meeting the following criteria:
Bottom Chord Applicability Criteria
- Accessible Panel Geometry
The bottom chord panel must be capable of accommodating a rectangular space measuring 42 inches in height by 24 inches in width within the panel.
- Horizontal Bottom Chords Only
The bottom chord must have a slope less than 2/12.
Top and Bottom Chord Applicability Criteria
- Absence of Sheathing or Wide Spaced Purlins
The person load is applicable only where there is no structural wood sheathing, or where purlins or bracing members are spaced greater than 24 inches on center.
Within this provision, the term “spanning” refers to the distance between bearings and should not be interpreted as the overall truss length.
These updates are included in the MiTek Engineering software.
For additional information, or if you have questions, please refer to TPI Technical Advisory Committee (TAC) Technical Interpretation ANSI/TPI 1-2022 – Section 6.2.2.5 Person Loading (Updated 4/2/2026) or contact the MiTek Engineering department.