TLV's for Static Magnetic Fields

[Tad_Blanchard@ccmail.gsfc.nasa.gov]

Please correct me if I'm wrong.  Is this the correct interpretation of 
the ACGIH Threshold Limit Values for Static Magnetic Fields?  (I have a 
1994 edition of the TWA booklet that listed this information as 
"Proposed Changes".)  
------------------------------------------------------------------------

Persons who wear pacemakers or other medical devices 
(Includes medical implants such as sutures, clamps, etc)  =  5 Gauss (G)

Ceiling value for workers (ceiling value)*                =  20,000 G

Time Weighted Average       Whole Body         Extremities

8-Hour TWA                      600 G            6,000 G
4-Hour TWA                    1,200 G           12,000 G
2-Hour TWA                    2,400 G           20,000 G*
1-Hour TWA                    4,800 G           20,000 G*
15-Minute TWA                19,200 G           20,000 G*


We are evaluating the construction of a building which will be used by 
researchers who will be using superconducting magnets.  We want to be 
sure that adequate warning is provided to pacemaker/implant wearers that 
magnetic fields are being produced.


************************* /^\   /^\ *****************************
Tad Blanchard            /___\ /___\  NASA-Goddard Space Flt Ctr  
Nat'l Health Svc, Inc         O       Greenbelt, Maryland        
Sr Health Physics Tech       / \      Phone: 301-286-9157         
                            /___\                                 
               Tad_Blanchard@ccmail.GSFC.NASA.gov                   
*****************************************************************