In our lab, warning signs (Figure 15.1) and coloured bands are displayed in areas where the field exceeds 5 Gauss; the location of the 10 Gauss region is located slightly inside the 5 Gauss region:
10 GAUSS WARNING - between RED and ORANGE BAND (Figure 15.2) STRONG MAGNETIC FIELD
Figure 15.1 Warning sign
Pacemaker, Metallic Implant hazard
Strong magnetic and RF fields can cause serious injury that may result in death of people with implanted or attached medical devices, such as pacemakers and prosthetic parts. Such people must not go closer to the magnet than this sign until safety at a closer distance is identified by a physician or device manufactures.
Magnetic Media, ATM/Credit Cards
Strong magnetic and RF fields are present that can erase magnetic media, disable ATM and credit cards and damage some watches. Do not take such objects closer to the magnet than this sign.
5 GAUSS WARNING – between red and green band (Figure 15.2.b)
STRONG MAGNETIC FIELD
Tools and Equipment
Strong magnetic and radio frequency fields are present that can cause magnetic items suddenly fly toward the magnet, which could cause personal injury or serious damage. Do not take tools, equipment or personal items containing steel, iron or other magnetic materials closer to the magnet than this sign.
The warnings at the NMR Lab door are shown below in Figure 15.2.a:
Figure 15.2 NMR room warning signs (a), NMR spectrometer warning signs and bands (b)