In reply to muppetfilter:
I agree, I've never bolted anything but I obvs have used bolts climbing, they are designed to hold a fall every now and then, where I imagine for window cleaning they will be under constant load on a regular basis.
Also in office buildings I've worked in I've seen window cleaning bolts, they don't look anything like climbing bolts, they are larger ands rounded. They also tend to have a sticker attached saying when they were last checked and with a load of regulatory crap on them.
The construction industry would be where to go for this, a fall protection company I imagine.