New directive on electromagnetic emissions

Directive 2004/40/EC sets out limits for currents induced in the human body, ranging from 40mA/sq m up to 1Hz to frequency divided by 100 mA/sq m up to 10MHz and also cites maximum figures for specific energy absorption rate or SAR. There are also values for maximum electric and magnetic field strengths, magnetic flux density, equivalent plane wave power, contact current and limb induced current. We first heard of these from Richard Hulmes, Chief Executive of the Safety Assessment Federation addressing a seminar organised by INITA, the Independent National Inspection and Testing Association. He said that that all organisations will be required to declare themselves to be free of harmful electromagnetic emissions, despite that fact that nobody seems to have decided what harm low level electromagnetic emissions actually cause. “The jury is out”, he said in response to our question about this. He told his audience that they would be relieved to know that all mobile phones, laptops, PCs and similar items were already on an exempt list. Makers and users of MRI machines, on the other hand, have shown concern that the directive might outlaw what they do, but there is no exposure limit provided for static magnetic fields. Makers of high power microwave and broadcast equipment are, Hulmes said, already aware of the hazards associated with their equipment, but when he was asked about possible hazards associated with mobile phone base stations, he had no answer. Looking at the limits cited for magnetic field strength and flux density, which come to only 0.4A/m and 0.5 micro Tesla at 50Hz, we are not sure where this puts large electric motors and generators, whether this creates a problem, and whether these regulations are ever going to be really enforced. More information from The Health Protection Agency