It¹s 2 1/2. http://www.unistrut.us/DB/PDF_Archive/No_12.pdf (Bottom of Page 67, also the first google response to "safety factor of P1000" Justin On 2/26/15, 3:00 PM, "stagecraft-request at theatrical.net" <stagecraft-request at theatrical.net> wrote: >Re: [SML] Unistrut safety factor specs?