I think this Kodak info will roughly connect lux to an exposure, although I didn't try to work it out.

http://www.kodak.com/cluster/global/...am105kic.shtml

I don't know about surveyors, but inside of buildings, there are standard guidelines for light levels at various workstations, as well as regulated minimums in hallways, stairwells, etc. So it's a common industrial thing to verify light levels. The meters I've seen used are typically incident type, with a flat diffuser. They would be placed on a desk surface or the like. I think the kodak document implies that such a meter, intended for visual purposes, may not necessarily agree with an exposure meter, especially under different types of light. I'd personally rather have an exposure meter.