Weighing Chemicals

1. Completed by: Dr Mary Beilby
Safe work procedure
Staff number:
The Writing Safe Work Procedures Guideline (OHS027) should be consulted to assist in the completion of this
Document number
School of Physics/ Biophysics Group
Initial Issue date
Current version
Current Version
Issue date
Next review date
Safe work procedure title and basic description of activity
Title: Weighing of Chemicals using analytical balance
Description of activity:There are three main objectives when weighing out chemicals:1. To accurately weigh out the chemical
2. To not spill any chemical.
3. If a chemical is spilled, to ensure clean up all of the chemical immediately (see SWP Chemical Spills)
Very few of the chemicals we use are very hazardous. They present the greatest risks at the point of weighing
otherwise others are pose little risk The balance of surrounding area are cleaned after every use.
MSDS are located in the Laboratory’s OH& S document section.
List Hazards and risk controls as per risk assessment
Associated risk
number and
location: G12
Potential Hazard
of being
exposed to
chemicals by the
skin, eyes,
inhalation and
All staff and students are trained to use the specific weighing
equipment and are aware of the chemicals used.
Chemical Lists and MSDS are located in the Laboratory as a risk
management procedure.
Laboratory induction and regular OHS discussions at Lab Meetings to
reinforce the potential hazards.
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OHS026 safe work procedure
Current Version: 3.0, 04/03/2011
List resources required including personal protective clothing, chemicals and equipment needed
PPE (long sleeve lab gowns, latex gloves and eye protection) must be worn at all times when weighing out or
decanting chemicals in the Laboratory
Weigh Balance
Spatulas for weighing
List step by step instructions or order for undertaking the task
Weigh Balance Use & Care
1. Ensure Balance is sitting level on surface by observing the level bubble in window. Adjust if necessary.
2. Turn balance power to ‘on’ by pressing the on/off button on the front face of the balance.
3. Use the Tare button to re-zero the balance.
4. Always use some type of weighing tray on the balance pan.
5. If weighing another type of non-chemical item, please cover the balance pan with paper towelling.
6. Hold the chemical bottle as close as possible to the balance pan to help prevent spills.
7. It is preferable to use a spatula as simply just tipping out chemicals will often spill out onto the pan, the
balance area and also around the outside of the balance. This will then require chemical clean-up.
8. If it is not recommended to use a spatula during the weighing out of chemicals for RNA or DNA work,
please remember to gently tip out the chemical with extreme caution.
9. Using a spatula scoop up sensible amounts of chemical from bottle and transfer to the weigh boat on the
balance pan. The Labs has different sized spatulas to deal with all amounts of chemicals.
10. If you remove too much chemical, avoid tipping the excess chemical back into the stock bottle, as this
practice often risks contamination of chemicals.
All spills must be cleaned immediately!!!
List emergency shutdown procedures
All items of weighing equipment have “OFF” switches that can be used in emergency. Shut all electrical
equipment off at powerpoint in case of emergency.
List Clean up and waste disposal requirements
Make sure the weighing equipment is turned off after use. Report any faults in the weighing equipment to the
Laboratory Manager.
List legislation used in the development of this SWP
NSW OHS Act 2000
NSW OHS Regulation 2001
Australia Dangerous Goods Code
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OHS026 safe work procedure
Current Version: 3.0, 04/03/2011
Code of Practice for the Labelling of Workplace Substances
AS/NZS 2243.2:2006. Safety in laboratories. Part 2: Chemical aspects
Australian Standard AS2243.6-1990. Safety in laboratories. Part 6: Mechanical Aspects.
Australian Standard AS2243.7-1991. Safety in laboratories. Part 7: Electrical Aspects.
AS/NZS 2161.1:2000 Occupational Protective Gloves – Selection, Use and Maintenance
Safe Work Procedure Form (OHS026)
UNSW Hazardous Waste Disposal Procedure
List competency required – qualifications, certificates, licensing, training - e.g. course or instruction:
Laboratory induction and regular OHS discussions at Lab Meetings to reinforce the potential hazards.
List competency of Assessor
Supervisory approval, And review
Responsibility for SWP review:
Date of review:
SWP Sign off sheet
SWP name and version:
In signing this section the assessor/ authorisor agrees that the following persons are competent in
following this SWP
Name of
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OHS026 safe work procedure
Current Version: 3.0, 04/03/2011
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OHS026 safe work procedure
Current Version: 3.0, 04/03/2011