Spanish to English Tech/Engineering Construction / Civil Engineering suspended ceilings

I'm translating maintenance instructions for a new building and in the section related to the suspended ceilings they're talking about hanging objects from the ceiling, but they use a term that I've not been able to find much information about. I'm also slightly confused by the structure of the sentence. If anyone can help I'd very much appreciate it!

Si es necesario suspender algún elemento ligero del mismo (como por ejemplo una lámpara) deberán utilizarse únicamente hembrillas de acero galvanizado con dispositivo de apertura interior. Deberá comprobarse asimismo que el agujero no coincida con un elemento de fijación y que no exista ninguna instalación en la profundidad a *trepanar*.