This wiki is on far field magnetic AC fields. The area within 3 wave lengths is called the near field. The area beyond 3 wave lengths in called the far field. Information on near field is in the shielding: magnetic: near field wiki.
Power lines, power grid, appliances and over the horizon radar emit alternating current (AC) magnetic fields. AC magnetic fields include ELF and VLF. AC Magnetic Fields are considered low frequency electromagnetic radiation. (5 Hz – 400,000 Hz). 400,000 Hz = .4 MHz.
http://www.slt.co/Education/ACElectromagneticFields.aspx
Extremely low frequencies (ELF) is 0 - 300 Hertz). Very low frequencies (VLF) is 300 - 100,000 Hertz).
http://www.ifp.illinois.edu/~hasegawa/emma/node2.html
Frequencies above 1 MHz are radiofrequency. See the three shielding: radiofrequencies wikis.
ELF waves can also penetrate significant distances into earth or rock, and "through-the-earth" underground mine communication systems use frequencies of 300 to 3000 Hz. The frequency of alternating current flowing in electric power grids, 50 or 60 Hz, also falls within the ELF band, making power grids an unintentional source of ELF radiation....United States Government agencies, such as NASA, describe ELF as non-ionizing radiation with frequencies between 0 and 300 Hz.[14] The World Health Organization (WHO) have used ELF to refer to the concept of "extremely low frequency (ELF) electric and magnetic fields (EMF)"[17] and have also referred to "ELF electric and magnetic fields in the frequency range >0 to 100,000 Hz (100 kHz)."[18] The WHO also stated that at frequencies between 0 and 300 Hz, "the wavelengths in air are very long (6000 km at 50 Hz and 5000 km at 60 Hz), and, in practical situations, the electric and magnetic fields act independently of one another and are measured separately."[17]..ELF waves can also travel considerable distances through "lossy" media like earth and seawater, which would absorb higher frequency radio waves.
https://en.wikipedia.org/wiki/Extremely_low_frequency
[Shielding: Magnetic: AC] Test comparing iron, low carbon steel and aluminum shielding 50 Hz by Global EMC
[J] [Shielding: Magnetic] Magnetic Shield Effectiveness in Low Frequency
https://www.reddit.com/r/Electromagnetics/comments/5r5mwj/j_shielding_magnetic_magnetic_shield/
Metals that do not shield ELF magnetic fields
Magnetic fields are not shielded by trees, buildings or iron roofs.
Shielding from ELF Magnetic Fields Emanating from Power Plants in Large Facilities
http://link.springer.com/article/10.1007/s10669-005-4285-7
Lead is very good at shielding x-rays, but has no special shielding properties for ELF fields. Like other metals, lead is a conductor and so can shield electric fields. However, it does not shield magnetic fields. Special grades of steel or alloys are required to shield magnetic fields.
Electric and Magnetic Fields and Your Health by National Radiation Laboratory, Ministry of Health, New Zealand.
www.who.int/peh-emf/project/mapnatreps/nznrl_emfbookl
Unfortunately, aluminum foil is extremely inadequate against low frequency magnetic fields, where thick steel or highly permeable ferrite material provides more adequate shielding.
Replies
Even though it does a great job of blocking x-rays, lead has no octordle particular qualities as a shield against electromagnetic fields below 100 Hz. Lead, like other metals, is a conductor and can protect against electric fields. It does not, however, protect against magnetic fields. The only way to effectively block magnetic fields is to use specialized steels and alloys.