16.14.1 Glassware and Plasticware

• Borosilicate glassware (i.e. pyrex) is recommended for all lab glassware, except for special experiments using UV or other light sources. Soft glass should only be used for things such as reagent bottles, measuring equipment, stirring rods and tubing. 
• Any glass equipment being evacuated, such as suction flasks, should be specially designed with heavy walls. Dewar flasks and large vacuum vessels should be taped or guarded in case of flying glass from an implosion. Household thermos bottles have thin walls and are not acceptable substitutes for lab Dewar flasks. 
• Glass containers containing hazardous chemicals should be transported in rubber bottle carriers or buckets to protect them from breakage and contain any spills or leaks. It is recommended to transport plastic containers this way as well since they also can break or leak. 

16.14.2 Preparation of Glass Tubing and Stoppers

• To cut glass tubing:
  • Hold the tube against a firm support and make one firm quick stroke with a sharp triangular file or glass cutter to score the glass long enough to extend approximately one third around the circumference. 
  • Cover the tubing with cloth and hold the tubing in both hands away from the body. Place thumbs on the tubing opposite the nick 2 to 3 cm and extended toward each other. 
  • Push out on the tubing with the thumbs as you pull the sections apart, but do not deliberately bend the glass with the hands. If the tubing does not break, re-score the tube in the same place and try again. Be careful to not contact anyone nearby with your motion or with long pieces of tubing.
• All glass tubing, including stir rods, should be fire polished before use. Unpolished tubing can cut skin as well as inhibit insertion into stoppers. After polishing or bending glass, give ample time for it to cool before grasping it. 
• When drilling a stopper:
  • Use only a sharp borer one size smaller than that which will just slip over the tube to be inserted. For rubber stoppers, lubricate with water or glycerol. Holes should be bored by slicing through the stopper, twisting with moderate forward pressure, grasping the stopper only with the fingers, and keeping the hand away from the back of the stopper. 
  • Keep the index finger of the drilling hand against the barrel of the borer and close to the stopper to stop the borer when it breaks through. Preferably, drill only part way through and then finish by drilling from the opposite side. 
  • Discard a stopper if a hole is irregular or does not fit the inserted tube snugly, if it is cracked, or if it leaks. 
  • Corks should have been previously softened by rolling and kneading. Rubber or cork stoppers should fit into a joint so that one-third to one–half of the stopper is inserted.
• When available, glassware with ground joints is preferable. Glass stoppers and joints should be clean, dry and lightly lubricated.

16.14.3 Insertion of Glass Tubes or Rods into Stoppers

The following practices will help prevent accidents:

• Make sure the diameter of the tube or rod is compatible with the diameter of the hose or stopper. 
• If not already fire polished, fire polish the end of the glass to be inserted; let it cool. 
• Lubricate the glass. Water may be sufficient, but glycerol is a better lubricant. 
• Wear heavy gloves or wrap layers of cloth around the glass and protect the other hand by holding the hose or stopper with a layered cloth pad. 
• Hold the glass not more than 5 cm from the end to be inserted.
• Insert the glass with a slight twisting motion, avoiding too much pressure and torque. 
• When helpful, use a cork borer as a sleeve for insertion of glass tubes. 
• If appropriate, substitute a piece of metal tubing for glass tubing. 
• Remove stuck tubes by slitting the hose or stopper with a sharp knife.

16.14.4 Assembling Apparatus

Following these recommendations will help make apparatus assembly easier and equipment safer:

• Keep your work space free of clutter. 
• Set up clean, dry apparatus, firmly clamped and well back from the edge of the lab bench making adequate space between your apparatus and others work. Choose sizes that can properly accommodate the operation to be performed. As a rule, leave about 20% free space around your work.
• Use only equipment that is free from flaws such as cracks, chips, frayed wire, and obvious defects. Glassware can be examined in polarized light for strains. Even the smallest crack or chip can render glassware unusable. Cracked or chipped glassware should be repaired or discarded. 
• A properly placed pan under a reaction vessel or container will act as secondary containment to confine spilled liquids in the event of glass breakage. 
• When working with flammable gases or liquids, do not allow burners or other ignition sources in the vicinity. Use appropriate traps, condensers, or scrubbers to minimize release of material to the environment. If a hot plate is used, ensure the temperatures of all exposed surfaces are less than the autoignition temperature of the chemicals likely to be released and that the temperature control device and the stirring / ventilation motor (if present) do not spark. 
• Whenever possible, use controlled electrical heaters or steam in place of gas burners. 
• Addition and separatory funnels should be properly supported and oriented so that the stopcock will not be loosened by gravity. A retainer ring should be used on the stopcock plug. Glass stopcocks should be freshly lubricated. Teflon stopcocks should not be lubricated. 
• Condensers should be properly supported with securely positioned clamps and the attached water hoses secured with wire or clamps. 
• Stirrer motors and vessels should be secured to maintain proper alignment. Magnetic stirring is preferable. Only non-sparking motors should be used in chemical laboratories. Air motors may be an option. 
• Apparatus attached to a ring stand should be positioned so that the center of gravity of the system is over the base and not to one side. There should be adequate provision for removing burners or baths quickly. Standards bearing heavy loads should be firmly attached to the bench top. Equipment racks should be securely anchored at the top and bottom. 
• Apparatus, equipment, or chemical bottles should not be placed on the floor. If necessary, keep these items under tables and out of aisleways to prevent creating a tripping hazard. 
• Never heat a closed container. Provide a vent as part of the apparatus for chemicals that are to be heated. Prior to heating a liquid, place boiling stones in unstirred vessels (except test tubes). If a burner is used, distribute the heat with a ceramic-centered wire gauze. Use the thermometer with its bulb in the boiling liquid if there is the possibility of a dangerous exothermic decomposition as in some distillations. This will provide a warning and may allow time to remove the heat and apply external cooling. The setup should allow for fast removal of heat. 
• Whenever hazardous gases or fumes are likely to be evolved, an appropriate gas trap should be used and the operation confined to a fume hood. 
• Fume hoods are recommended for all operations in which toxic or flammable vapors are evolved as is the case with many distillations. Most vapors have a density greater than air and will settle on a bench top or floor where they may diffuse to a distant burner or ignition source. These vapors will roll out over astonishingly long distances and, if flammable, an ignition can cause a flash back to the source of vapors. Once diluted with significant amounts of air, vapors move in air essentially as air itself. 
• Use a hood when working with a system under reduced pressure (which may implode). Close the sash to provide a shield. If a hood is not available, use a standing shield. Shields that can be knocked over must be stabilized with weights or fasteners. Standing shields are preferably secured near the top. Proper eye and face protection must be worn even when using safety shields or fume hoods.

16.14.5 Mercury Containing Equipment

Elemental Mercury (Hg) or liquid Mercury is commonly seen in thermometers, barometers, diffusion pumps, sphygmomanometers, thermostats, high intensity microscope bulbs, fluorescent bulbs, UV lamps, batteries, Coulter Counter, boilers, ovens, welding machines, etc.

Most of these items can be substituted with equipment without Mercury, thus greatly decreasing the hazard potential. Larger laboratory equipment may be more difficult to identify as “Mercury containing” due to the fact that mercury can be hidden inside inner components such as switches or gauges.

The concerns surrounding mercury containing equipment are:

• It is difficult to identify exposures or cross-contamination due to Mercury leaks or spills. 
• The amount of Mercury used is usually much greater than the Department of Environmental Conservation (DEC) reportable quantities for releases to the environment. 
• People may be unaware of the Mercury and thus may not be properly trained for use, maintenance, spills, transport or disposal or may not use the appropriate engineering controls or Personal Protective Equipment (PPE). 
• There is legal liability if human health and the environment are not properly protected.

To minimize the potential for Mercury spills and possible exposures, laboratory personnel is strongly encouraged to follow these recommendations:

• Identify and label “Mercury Containing Equipment”.
• Write a Standard Operating Procedure (SOP).
• Train personnel on proper use, maintenance, transport and disposal.
• Conduct periodic inspections of equipment to ensure no leaks or spills have occurred.
• Consider replacing Mercury with electronic or other replacement components.
• Have available proper PPE such as nitrile gloves.
• Use secondary containment, such as trays as a precaution for spills.
• Plan for emergency such as a spill or release of mercury.
• Decontaminate and remove Mercury before long-term storage, transport or disposal.
• For new equipment purchases, please attempt to procure instruments with no or little Mercury