wireless-iconISA has released the 100.11a standard on September 9th 2009.  I’ve update the Wikipedia entry for it.  I’m going to a conference and several classes at ISA Expo 2009 this year that cover the new standard.  Hopefully this standard will bring some order to the wireless gas detection and industrial control industries for wireless devices.  It uses IEEE 802.15.4 for the lower level which dictates a center frequency 2.4 GHz and uses DSSS for the modulation technique.   It also uses some of TSMP from Dust Networks for the mesh and networking protocol.  This should allow for battery operated devices with automatic routing capability, via time synchronized sleeping.