Safety

The Rules

All users must complete the MR safety I and II training, and sign and submit the MR Screening Form and the Biochemistry NMR Safety Form, before they are permitted to enter the magnet rooms or request NMR training. There will be no exception to this rule. Anyone who let an unauthorized person into a magnet room, such as lending your key or opening the door for that person, will be held accountable and face disciplinary and/or possible legal actions.

Regardless of your prior NMR experience, users who are new to this facility must complete a formal training with the facility manager on an instrument before they are allowed to operate on that instrument, including inserting samples in the spinners or placing samples in the sample tray or on top of the magnet. There will be no exception to this rule. Anyone who allows an untrained person to use the instrument will be held accountable for any resulting damages and lose NMR privileges.

Magnet Safety

Modern NMR instruments are equipped with high field superconducting magnets. They are always on and exhibit strong attractive force on ferromagnetic objects when these objects come within the 5-gauss lines of the magnets. For shielded magnets such as the AN400 and MR400, the 5-gauss lines only extend to about where the magnet legs are. However, for unshielded magnets such as the UI500, the 5-gauss line is about 10 feet from the center of the magnet and poses a much greater danger.

1. Individuals with ferromagnetic objects or medical devices in or on their bodies, such as metal fragments, cardiac pacemakers, orthopedic implants, prostheses and hearing aids, must be cleared by their doctors as well as the University’s MR safety screening before they are permitted to enter the magnet rooms or request NMR training.
2. Except for your personal items, do not bring any other ferromagnetic objects into the magnet rooms, including gas cylinders, stapler/staples, paper clips, scissors, tools of any kind, and metal chairs or carts. Always leave your personal items such as phones, wallets, and watches on the computer tables upon entering the magnet rooms.

Cryogen Safety

Superconducting magnets are cooled and maintained by liquid helium (L-He, ~100 Liters) and liquid nitrogen (L-N2, 100 – 130 Liters). In the event of a magnet quench when the magnet’s superconductivity is lost for some reason, all its stored energy converts into heat in an instant. Most of the cryogens in the magnet will boil off and vent through the top of the magnet within a matter of seconds, filling the magnet room with a huge amount of helium and nitrogen gases due to their large liquid to gas expansion ratios (757 for helium and 696 for nitrogen). This may create a potentially dangerous oxygen deficient environment, which could lead to asphyxiation.

1. An oxygen sensor has been installed in L4.504, and one will be installed in our future 600 MHz magnet room in L1.100. Normally it should read 20.9%, but a 2-level alarm will sound if the oxygen level in the room drops to below 19.5% (level 1, orange LED) or below 18.0% (level 2, red LED). When the oxygen sensor’s alarm is activated, leave the room immediately.
2. In the event of a magnet quench where a big cloud of helium and nitrogen gases is formed above the magnet, leave the room immediately.

Other Safety

• No radioactive or other highly dangerous samples are allowed on any instrument in the facility. Check with the manager if you are not sure.
• High and low pressure samples and experiments are not allowed without the explicit permission of the manager.
• Training is required before a user is allowed to change probe temperature. VT experiments higher than 50 degrees C must be cleared with the manager in advance.
• Handle NMR tubes with care. They have very thin walls and break easily, which can result in cuts and other injuries.