Having worked on various trusses of the ISS, I will agree with Paul's comments. I think of all the exposed fluid lines and power cables on the solar power trusses (S4, S6, P4, and P6 if you're being technical) and I would agree with him. The fluid lines have insulation around them, but it's tight and the power cables definitely are shielded and insulated, but the rest is open truss work.