From what I can tell, 501.105(B)(4) doesn't require a solenoid to be rated for hazardous locations because it does "...not incorporate sliding or make-or-break contacts..."

I'm not sure if the class of coil is a limiting factor, or if there's something elsewhere that would have an affect on this. I'm familiar with the "T" rating relative to installation location but that's not what I'm concerned with.