Page 130 - The Veterinary Laboratory and Field Manual 3rd Edition

The selection, use, maintenance and quality control of laboratory equipment and supplies 99

protected against penetrating liquids by a valve circumstances be disposed of in a domestic
with a membrane. glass recycling stream (for example, bottle
banks), since its high melting point makes
• The pipetting aid is attached to the top of the it incompatible with other glass (soda-lime
pipette. glass) for recycling. The correct method of
• Press the ‘fill’ button (the intake rate is vari- disposal is to include it in with general waste
able by trigger pressure). in accordance with the relevant guidelines,
• Press the ‘deliver’ button. The discharge rate provided that the glass is free of any harmful
is variable by trigger pressure. One can choose chemical contamination.
between ‘free delivery’ and ‘power delivery’. • Never use excessive force to fit rubber bungs
into the neck of glass aspirators, test tubes,
conical flasks, and so on.
2.7 Care, maintenance and cleaning • Never use excessive force to connect a rubber
of laboratory ware hose or tubing.
• Lifting or carrying large glass flasks, beakers
Good quality labware is expensive and must be or bottles by the neck or rim can be very dan-
handled with care. Clean and sterile glassware gerous. It is best to provide support from the
should always be available in a laboratory and base and sides.
stored in a cupboard that offers protection from • When stirring solutions in glass vessels, such
dust and from accidental breakage. as beakers and flasks, avoid using stirring
rods with sharp ends which can scratch and
weaken the glassware.
care and maintenance of laboratory • Do not mix concentrated strong acids with
glassware water inside a glass measuring cylinder. The
heat of reaction can break the seal at the base
General precautions of the cylinder.
• We recommend that all glassware is washed
To obtain maximum life and performance of your before it is first used.
glassware, correct handling is essential. The fol- • Wash glassware promptly after use to avoid
lowing notes will serve as a guide to new users hard dried residues. Use a biodegradable,
and to remind more experienced handlers of the phosphate free detergent, specially formu-
recommended procedures. lated for laboratory use.
• Do not use cleaning brushes which are badly
• Before using any piece of glassware, take time worn and where the metal spine may scratch
to examine it carefully and ensure that it is the glass.
in good condition. Do not use any glassware
that is scratched, chipped, cracked or etched.
Defects like these can seriously weaken the Heating and cooling
glass and make it prone to breakage while in • The maximum recommended working tem-
use. perature for Pyrex glassware is 500°C (for
• Dispose of broken or defective glassware short periods only). However, once the tem-
safely. Use a purpose-designed disposal bin perature exceeds 150°C special care should
that is puncture resistant and clearly labelled. be taken to ensure that heating and cooling
• Pyrex laboratory glassware should under no is achieved in a slow and uniform manner.

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