"At 25=B0C the accepted values with their uncertainties for=0A= conductivity, =EA and its reciprocal, resistivity, =F1, are:=0A= =EA =3D 0.05501 =B1 0.0001 =ECS/cm at 25.00 =B0C=0A= =F1 =3D 18.18 =B1 0.03 M=D9=B7cm at 25.00 =B0C"=0A= =0A= Standardized Result: 18.18 M=D9=B7cm=0A= unit resistivity per area/length.??=0A= http://hypertextbook.com/facts/2006/SamTetruashvili.shtml=0A= =0A= =0A= =0A= =0A= On 9/8/11, cdb wrote:=0A= > I've been looking at the specifications for a domestic water heater and = in=0A= > the sales bumph they specify the minimum water resistivity required (2K79= 5=0A= > x inches or 1K1 x cm's). I've never seen such a specification before for= =0A= > this kind of water heater nor the unit resistivity per area/length.=0A= >=0A= > I can find no documents on the interrent apart from those referring to=0A= > measurement devices for analytical purposes.=0A= >=0A= > Colin=0A= > --=0A= > cdb, 8/09/2011=0A= >=0A= > --=0A= >=0A= >=0A= >=0A= >=0A= > colin@btech-online.co.uk=0A= >=0A= > --=0A= > http://www.piclist.com PIC/SX FAQ & list archive=0A= > View/change your membership options at=0A= > http://mailman.mit.edu/mailman/listinfo/piclist=0A= >=0A= =0A= -- =0A= http://www.piclist.com PIC/SX FAQ & list archive=0A= View/change your membership options at=0A= http://mailman.mit.edu/mailman/listinfo/piclist=0A= .