There is no legal requirement to keep a chemical storeroom at a particular temperature. However, there is a legal obligation to store chemicals in a safe manner. AS/NZS 2243.1:2005 ‘Safety in laboratories – planning and operational aspects’ recommends that in a (working) laboratory the temperature is maintained at 22 °C ± 2 °C.1 However, due to varying storage requirements for a diversity of chemicals, no specific temperature range is given for a chemical store.
To maintain the quality of chemicals and their containers, it is important to store them within a consistent, narrow temperature range and particularly, for many chemicals, to avoid high storage temperatures. Due to the wide variety of chemicals stored in schools, each with its own ideal storage conditions, it is difficult to choose a storage temperature range that works well for all the chemicals in the storeroom. Taking into consideration the large variation in climate conditions in Australia, and the nature of the chemicals stored in schools, Science ASSIST recommends:
- maintaining the chemical storeroom temperature below 30 °C and at a consistent cool temperature, with the average ambient temperature being within the range 10–24 °C;
- climate control systems be considered to maintain ambient temperatures where a chemical storeroom experiences:
- temperatures which are consistently at or above 30 °C or,
- temperatures which are consistently low, and which adversely affect the quality, physical characteristics and/or performance of a particular chemical or chemicals.
The stability or deterioration of a chemical is influenced by the environment in which it is stored. Chemicals should be stored segregated from incompatible chemicals in a well-ventilated, cool and dry location. It is recommended to avoid exposure of chemicals to heat, direct sunlight and ignition sources.2
An important environmental aspect of safe chemical storage is to ensure that chemicals are kept at an appropriate temperature all year round. For some chemicals, this may also include controlling temperature levels so that chemicals are stored within the range specified by the manufacturer.
AS 2243.10 states:
“(l) Substances which are unstable at ambient temperature shall be kept in a controlled temperature environment set to maintain an appropriate temperature range.”3
If the temperature goes outside these limits the chemical may be affected so that it: becomes unusable, undergoes changes in its composition, reaches its autoignition range, or becomes otherwise hazardous. It is generally recommended to keep the temperature in a chemical storeroom as stable as possible.
Determining a safe storage temperature range
The appropriate chemical storeroom temperature range depends on the nature of the chemicals stored within. To determine an appropriate storage temperature range, a risk assessment should be conducted, beginning with the identification of the hazards of the stored chemicals. Particular consideration should be given to chemicals such as organic peroxides, volatile flammable substances and oxidising agents (NB: Science ASSIST does not recommend the use of organic peroxides in schools).
It is essential to consult the Safety Data Sheet (SDS) for a chemical and its container label for specific storage requirements including any specific temperature conditions. The relevant sections of the SDS include:
- Section 7: Handling & Storage,
- Section 9: Physical & Chemical Properties, and
- Section 10: Stability and Reactivity.
Chemicals that degrade or become unstable under certain conditions should be regularly monitored to ensure their quality and stability.4
Recommendations for chemical storerooms in other countries
Temperature ranges for school chemical storerooms, as recommended by overseas authorities, include 0 °C to 28 °C for the UK,5 10 °C to 25 °C also in the UK6 with a qualification that up to 30 °C should not cause problems,6 and for schools in New York, 18 °C to 27 °C.7
Problems with fluctuations to high temperatures
Storage temperature maxima generally have more bearing on chemical safety than temperature minima. Some chemicals, if stored in hot conditions or at temperatures above their recommended temperature range, are at risk of becoming degraded, unstable, more volatile, potentially dangerous and unusable. Examples include:
- the rate of decomposition of hydrogen peroxide increases with temperature. Storage in a vented container is necessary to prevent the increased pressure in the container due to the build-up of oxygen;
- increased vaporisation of flammable liquids at higher temperatures, which may lead to the build of pressure in containers, may cause an inhalation hazard or may lead to the formation of a combustible atmosphere;
- the rate of peroxide formation increases with temperature in peroxidisable chemicals;
- the rate of absorption of CO2 by hydroxides increases with temperature;
- organic peroxides can undergo self-accelerating decomposition if exposed to heat. Arkema Inc.8 recommends a storage temperature of below 30 °C for organic peroxides, and a maximum storage temperature of 38 °C;
- the viscosity of liquids is also generally decreased with an increase in temperature;
- many oxidisers combust or decompose explosively on exposure to intense heat and contamination (with combustible material), which may lower the decomposition temperature.
Problems with fluctuations to low temperatures
Some chemicals, if kept below their recommended temperature range, are at risk of freezing, becoming difficult to handle, or even unstable. If the chemical freezes, it may expand and possibly cause its container to split or crack. Examples include:
- glacial acetic acid, which freezes below 16 °C;
- tert-Butyl alcohol, which has a melting point around 25 °C, and may need to be warmed in cool weather before use;
- some liquids may become too viscous to work with;
- if peroxidisable liquids are stored below the melting point of their peroxide, the peroxide may freeze, thus increasing its sensitivity to heat and friction.
Providing temperature control for stored chemicals
In Australia, there is a wide variation in climate conditions between different geographical regions. If schools are located in regions that consistently experience low or high temperatures, then consideration should be given to providing heating or cooling to achieve a consistent ambient temperature range in the chemical store. Generally, but not always, chemical storerooms are located within the science building in schools and are not likely to be subject to the extremes of the outside temperature.
There are several ways to control the temperature levels for chemical storage.
- Provide extractive ventilation within the store by local exhaust or mechanical means. Ventilation minimises the build-up of any heat and therefore provides a safer working atmosphere by keeping any concentrations of hazardous vapours, fumes etc. within allowable limits.
- Consider the use of spark-proof refrigerators for certain chemicals.
- If logistically feasible, and room permits, relocate the chemical store to a cool, dry environment in another part of the school.
- The installation of a commercial, spark-free, temperature-control product designed for chemical stores.
- Obligations under the harmonised Work Health and Safety legislation for persons conducting businesses or undertakings toward the management of the risks associated with the use, handling, generation and storage of hazardous chemicals are described in Regulations 351 to 356 of the Model Work Health and Safety Regulations
- General guidance on the requirements for the storage of chemicals in schools can be found through the following links:
- Detailed information relating to the storage of chemicals is provided in:
- Australian Standard AS/NZS 2243.10 – Safety in Laboratories: Storage of Chemicals.
- Science ASSIST has also previously answered questions relating to the storage of chemicals, see:
1 Standards Australia. 2005. AS/NZS 2243.1:2005 Safety in laboratories Part 1: Planning and Operational Aspects. Standards Australia: Sydney
2 Queensland Government, Department of Education, Training and Employment. 2013. Guideline for Managing Risks with Chemicals in DETE workplaces’ Education Queensland website, http://education.qld.gov.au/health/pdfs/healthsafety/guideline-managing-chemicals.pdf (November 2013)
3 This extract is from AS/NZS 2243.10:2004 Safety in Laboratories, ‘Storage of chemicals’ reproduced with permission from SAI Global Ltd under Licence 1407-c117
4 ‘Chemical Storage and Transport’, University of Sydney website. http://sydney.edu.au/science/chemistry/local-safety/chemical-storage-and... (Accessed November 2016)
5 CLEAPSS. 2009. CLEAPSS Laboratory Handbook – Section 7: Chemicals. CLEAPSS website, http://science.cleapss.org.uk/Resource-Info/Handbook-Section-7-Chemical-... (Link updated February 2017, requires membership).
6 Piggott, A. 2013. The Chemicals Store – Design of storage accommodation for chemicals in School Science Departments, Gratnells Ltd and Timstar Ltd:UK, ASE website, https://web.archive.org/web/20160519052335/https://www.ase.org.uk/docume... (The original of this document is no longer freely available. This version made available through the Internet Archive's Wayback Machine as of August 2018).
7 The University of the State of New York. nd. Chemical storage guidelines, New York State Education Department website, http://www.nysed.gov/curriculum-instruction/school-chemical-management-a... (Updated August 2018)
8Arkema Inc. 2007. ‘Organic Peroxides Storage Temperature, SADT and Storage Stability Guide’ Luperox website, https://www.luperox.com/export/sites/organicperoxide/.content/medias/downloads/literature/storage-temperature.pdf
Arkema Inc. 2007. Organic Peroxides: Their safe handling and use, Luperox website, https://www.luperox.com/export/sites/organicperoxide/.content/medias/downloads/literature/their-safe-handling-and-use.pdf
‘Hazardous chemical storage’ Flinn Scientific Inc. website, https://www.flinnsci.com/teacher-resources/safety/laboratory-chemical-safety/hazardous-chemical-storage/ (Accessed March 2016)
‘HS404 Dangerous Goods Storage Guideline’, University of NSW website. https://www.gs.unsw.edu.au/policy/documents/HS404.pdf (April 2014)
‘Optimum Temperature Chemical Storage’ Chemstore website, http://www.chemstore.co.uk/knowledge-store/optimum-temperature-chemical-storage/ (January 2015)
Safe Work Australia. 2012. Managing risks of hazardous chemicals in the workplace – Code of Practice July 2012, Safe Work Australia website http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documen... (July 2012)
Standards Australia. 2004. AS/NZS2243.10:2004 Safety in Laboratories – Storage of chemicals, Standards Australia; Sydney
Victorian Department of Education and Early Childhood Development. nd. Guidance sheet 1: Chemical storage’, DEECD website, www.education.vic.gov.au/Documents/school/principals/management/guid1chemst.docx (Accessed March 2016)
U.S. Consumer Safety Product Commission. 2006. School Chemistry Laboratory Safety Guide, CDC Workplace Health Safety and Health website, https://www.cdc.gov/niosh/docs/2007-107/pdfs/2007-107.pdf (October 2006)