Equipment Safety

At the start of the introductory section pertaining to "Laboratory Equipment" in Prudent Practices (1995) is this statement: "Proper use of laboratory equipment is required to work safety with hazardous chemicals. Maintenance and regular inspection of laboratory equipment are an essential part of this activity. Many of the accidents that occur in the laboratory can be attributed to improper use or maintenance of laboratory equipment."

Requirements and recommendations concerning safety with equipment commonly located in chemical laboratories appear below.

Water-cooled equipment (e.g., distillation apparatus):

The major problem with cooling water is localized flooding due to the disconnection of tubing supplying water to the condenser. Tubing connections should be checked frequently, and the entire apparatus should be operated when the laboratory is occupied.

Electrically-powered equipment (including fluid and vacuum pumps, lasers, power supplies, both electrophoresis and electrochemical apparatus, stirrers, hot plates, water baths, heating mantles, microwave ovens and ultrasonicators):

The major hazard is electrical, as a shock hazard and as a source for flammable or explosive vapors. All electrical equipment must be installed and maintained according to the provisions of the National Electric Code (NEC) of the National Fire Protection Association (NFPA, 1991a).

All repair and calibration work must be carried out by properly trained and qualified personnel. Before modification, installation, or even minor repairs of electrical equipment are carried out, the devices must be deenergized, and all capacitors, discharged safely.

All 110-volt (V) outlet receptacles should be of the standard design that accepts a three-prong plug and provides a ground connection. The use of two-pronged adapters to connect equipment with three-pronged grounded plugs to two-wire outlets is prohibited. Ground fault circuit interrupter circuits should be located where appropriate, i.e., receptacles less than 6 feet from sinks.

Receptacles that provide electric power for operations in hoods should be located outside the hood, a step which prevent the production of electric sparks inside the hood. In addition, cords should not dangle outside the hood in such a way that they accidentally can be pulled out of their receptacles or tripped over.

Equipment plugged into an electrical receptacle should include a fuse or other overload protection device to disconnect the circuit if the apparatus fails or is overloaded.

General precautions for working with electrical equipment:

1. All equipment must be insulated properly. During equipment use, if frayed or damaged cords are found, they must be replaced before further use of the equipment is permitted. The complete electrical isolation of electrical equipment and power supplies must be ensured to prevent the possibility of accidental contact with electrical circuits.
   
   
2. The isolation of electrical equipment which may generate sparks from volatile solvents must be ensured.
   
   
3. To minimize the possibility of electrical shock, adequate grounding will be provided for all electrical equipment.
   
   
4. Pieces of equipment should be unplugged prior to adjusting, modifying or repairing them. If it is necessary to power this equipment, hands must be dry and, if feasible, nonconductive gloves and shoes with insulated soles should be worn.
   
   
5. Lab supervisors and students must be made aware of the location and operation of power shutoffs (i.e., main switches and circuit breaker boxes) for areas in which they work.

Personal safety techniques for use with electrical equipment:

1. Contact with energized electrical circuits must be avoided. Electrical equipment should be serviced by only qualified individuals, and only after power has been disrupted and capacitors are discharged. Before electrical equipment is reconnected to power after servicing, it must be tested to ensure proper grounding.
   
   
2. If a circuit breaker "trips," steps must be taken to assure that the overload or short-circuit which caused the failure is corrected.
   
   
3. Ground-fault circuit interrupters must be in place where required, particularly if an electrical device is hand-held during a lab operation.
   
   
4. If a person contacts a live electrical conductor, the power source first must be disconnected before the person is removed from the contact and first-aid is administered.
   
   Electrical equipment used in ISAT laboratories requiring special precautions:
   
   
   Ultrasonicators:
   
   
   • When ultrasonic equipment is operated in the laboratory, the apparatus must be enclosed in a 2-cm-thick wooden box or in a box lined with acoustically absorbing foam or tiles to substantially reduce acoustic emissions.
     
     
   • Direct contact of the body with liquids or solids subjected to high-intensity ultrasound should be avoided.
   
   
   Centrifuges:
   
   
   • Centrifuges should be properly installed and must be operated by only trained personnel.
     
     
   • The load must be balanced each time the centrifuge is used, and the lid must be closed while the rotor is moving.

Electrical Instruments and Appliances (e.g., circuit testing equipment, electrophoresis power supplies, microscopes, ovens, water baths, hot plates and stirring devices, top-loading and analytical balances, microwave ovens, pH and specific ion meters, vacuum pumps, refrigerators and freezers):

• For all equipment, a chassis ground must be in place.
  
  
• Special precautions should be taken to avoid the possibility that water or other chemicals could be spilled onto these instruments.
  
  
• Only qualified individuals should make repairs.

Electromagnetic Radiation Hazards (e.g., UV sources, lasers, microwave sources)

• Overexposure to UV light, direct or reflected, should be minimized. Lamp sources should be sealed or enclosed whenever possible, and appropriate eye protection and/or face shields should be worn. Long-sleeved clothing and gloves should be worn to protect arms and hands.
  
  
• Lasers:
  
  
  • Users of class III A and B, and class IV, lasers must wear appropriate eye protection and clothing to prevent damage to eyes and skin when direct laser beam exposure is remotely possible. NOTE: When laser demonstration laboratory exercises are in process in an ISAT laboratory, if the laser beam is split by means of a diffraction grating so that several low-energy beams can be projected onto a surface, safety glasses may be set aside to facilitate the laboratory activity. However, precautions must be taken so that it is ensured that operators of laser equipment, as well as observers, do not look directly into the beam with unprotected eyes, and that the laser points only at the intended projection wall or screen.
    
    
  • Area where a laser is in operation must be posted accordingly.
    
    
  • Anyone who is not the authorized operator of a laser system, or who is not authorized to be present by the operator, should not enter a posted laser-controlled laboratory if the laser is in use.
  
  
  
• Microwave sources must be operated only with appropriate microwave generator shielding in place. Avoid metal in microwave ovens, since arcing may occur, causing the ignition of any solvents present. Since superheating of liquids can occur, capping of vials and other containers can result in explosion from pressure buildup within the vial. Use only selected plastic containers that will resist melting.

Robotics

• Sources of hazards include human error in programming/operation and installation, control faults and power system malfunctions, mechanical failures, environmental problems (e.g., electromagnetic or radio-frequency interferences), and unauthorized access into a robot's safeguarded area.
  
  
• General types of accidents:
  
  
  • Those caused by robotic arm or controlled tool;
    
    
  • Those in which the robotic arm or controlled tool place an individual in a risk circumstance;
    
    
  • Those caused by failure of mechanical parts if a robot; and
    
    
  • Those caused by the uncontrolled activity of a power supply.
  
  
  Accidents may involve impact or collision, caused by unpredicted movements, component malfunctions, or unpredicted program changes; crushing and trapping, involving a worker's limb or other body part; failure of mechanical parts; other accidents, such as pressurized fluid hazards, arc flashing, metal spatter, dust, electromagnetic or radio-frequency interferences, and those related to equipment and power cables stretched over floors.
  
  
• Robotics safety begins with proper installation. Installation of any units housed in any ISAT laboratory will be done with the oversight of qualified persons.
  
  
• For the planning stage, installation, and subsequent operation of a robot or robot system, these control and personnel safeguarding consideration will be kept in mind:
  
  
  • At each stage of development of the robot and robot system, a risk assessment will be performed.
    
    
  • Personnel safeguards may include mechanical limiting devices, nonmechanical limiting devices, presence sensing safeguarding devices, fixed barriers (which prevent contact with moving parts), and interlocked barrier guards.
    
    
  • Awareness devices, such as chain or rope barriers, will be used in conjunction with other safeguarding devices.
    
    
  • Teacher safeguards will be put into place as necessary, especially when the person is within the robot's restricted envelope, as the robot is being "taught" (programmed) for operation.
    
    
  • Operator safeguards should be in place during all operations performed by the robot. When the robot is operating automatically, all safeguarding devices should be activated, and at no time should any part of the operator's body be within the robot's safeguarded area.
    
    
  • During attended continuous operation, when a person is permitted to be in or near the robot's restricted envelope, the robot will be operated in "teaching mode" at a slower, safer speed.
    
    
  • Maintenance and repair personnel must take special precautions, since their work likely places them in the robot's restricted envelope during operation of the system.
  
  
  
• Maintenance should occur during the regular and periodic inspection program for a robot or robot system. An inspection program should include, but not be limited to, the recommendations of the robot manufacturer and manufacturer of other associated robot system equipment. These recommended inspection and maintenance programs are essential for minimizing the hazards from component malfunction, breakage, and unpredicted movements or actions by the robot or other system equipment.
  
  To ensure proper maintenance, it is recommended that periodic maintenance and inspections be documented along with the identity of personnel performing these tasks. In addition, OSHA's Lockout/Tagout standards must be followed for servicing and maintenance.