In December 2018 the AICCM National Council ratified the AICCM Environmental Guidelines for Australian Cultural Heritage Collections (2018) and endorsed the Heritage Collections Council (HCC) Guidelines for Environmental Control in Cultural Institutions (2002). This followed a year of public consultation, a national industry survey, conference presentations, publication of the AICCM Bulletin paper ‘Environmental Guidelines – An Australian Perspective’, and regular updates published in industry newsletters. Both of these guidelines are now published on the AICCM website.

In ratifying the AICCM Environmental Guidelines for Australian Cultural Heritage Collections (Table 1) and endorsing the HCC Guidelines for Environmental Control in Cultural Institutions (Table 2) the National Council has responded to the IIC and ICOM-CC 2014 Declaration on Environmental Guidelines. Specifically that,

  • Temperature and relative humidity guidelines for environmental conditions for collections should be achievable for the local climate.
  • Cultural heritage organisations should seek to reduce their environmental impact to mitigate climate change.
  • Passive solutions and low-energy technology should be prioritised strategies for climate control. (ICOM-CC 2014)

AICCM recognises the importance of publishing temperature and relative humidity guidelines that promote and support sustainable practices within the cultural heritage profession. However, this is the first step in an ongoing process. The AICCM guidelines outline parameters that, although an expansion upon the narrower convention of 50 or 55%RH ±5 and 20 or 21ºC ±2, remain conservative.

Environmental Guidelines

Table 1. AICCM Environmental Guidelines for Australian Cultural Heritage Collections (2018)
Climate Type Temperature Range RH Range
Temperate 15 – 25ºC 45 – 55% RH ± 5
Total Temperate Range 40 – 60%
Subtropical / Tropical 15 – 25ºC 50 – 60% RH ± 5
Total Subtropical / Tropical Range 45 – 65%
It is recommended, where possible, that relative humidity remain within the set-ranges of 45-55% (Temperate) and 50-60% (Subtropical / Tropical) for the majority of the time. Short term, ±5% fluctuations ≤24 hours duration into the outer limits of the total RH ranges are acceptable.
It is recommended, where possible, that temperature remains within the specified range. Short term fluctuations of no greater than 4ºC for ≤24 hours duration within the total temperature range are acceptable.
It is recommended that where seasonal adjustments are applied that the temperature and relative humidity remains within the total ranges.
Temperature and relative humidity parameters for preservation of cultural materials will differ according to their material, construction and condition, but constant conditions maintained within the parameters described above are generally acceptable for most objects in stable condition

The HCC Guidelines for Environmental Control in Cultural Institutions, published in 2002, was written by Professor Colin Pearson and members of the Consortium for Heritage Collections and Their Environment following two years of research and field work. The work was undertaken in response to the Cultural Ministers Council and HCC report, National Conservation and Preservation Policy and Strategy: Australia’s Heritage Collections (1998).

Table 2. HCC Environmental Guidelines for Australian Cultural Heritage Collections (2002)
Climate Type Temperature Range RH Range
Temperate 18 – 24ºC 45 – 65% RH
Hot Dry 22 – 28ºC 40 – 60% RH
Hot Humid 22 – 28ºC 55 – 70% RH
It is recommended, where possible, that levels of temperature and relative humidity should, on a daily basis, be kept within the boundaries given. If this is not possible then it is necessary to minimise periods at high or low levels and fluctuations in temperature and relative humidity.
Other considerations:
An increase in temperature will increase chemical reaction rates which will affect materials prone to auto-catalytic and self-perpetuating deterioration.
Diurnal variations in temperature are small in hot humid climates and large in hot dry and temperate climates. Large diurnal variations in temperature and relative humidity are more likely to damage objects composed of restrained layers through the action of expansion and contraction.
Above 70% RH there is a reasonable probability of fungal growth, corrosion of unstable metals and crizzling of unstable glass.
Below 40% RH there is a reasonable probability that organic materials will begin to desiccate.
Few materials respond to rapid, wide fluctuations of relative humidity that are less than 1 hour in duration.
Wet season cycles, where around 80% of the annual rainfall occurs over a few months will cause extreme daily relative humidity levels sufficient to cause damage to materials, requiring a range of precautions to be considered.

(HCC 2002, pp.10-16)

Guiding Principles

AICCM’s position on environmental guidelines for the care of cultural heritage collections in Australia is governed by three guiding principles:

Sustainability and resilience
AICCM recognises that sustainable and resilient conservation practice comes from an ability to balance advocacy for and practice in collection care in response to other priorities such as an organisation’s mission, function, programming and resources.

Adaptive and proactive practices
AICCM supports a pragmatic approach to the use of wider parameters for the management of the collection environment and encourages the adoption of environmental parameters that address individual needs and circumstances. The published guidelines provide recommendations that are not intended to be prescriptive or inflexible.

Maintaining relevance
AICCM will periodically review the Environmental Guidelines for Australian Cultural Heritage Collections to ensure that the guidelines remain current and applicable to the national cultural heritage profession, collection care practices, climate change, and local climatic conditions.

The difference between a set-range and a median set-point

The AICCM guidelines describe temperature and relative humidity as specific set-ranges. In the case of relative humidity set-ranges, the acceptable fluctuations of ±5% beyond the set-ranges expand the total relative humidity ranges to 20%. In the past temperature and relative humidity parameters have been described as median set-points. For comparison, Table 3 shows how the current AICCM guidelines would be described as set-ranges and median set-points.

Table 3. AICCM guidelines comparing set-range with median set-point
AICCM Guidelines Set Range Median set-point
Temperate temperature 15 – 25ºC 20º±5
Temperate RH 45 – 55%±5 50%±10
Subtropical / Tropical temperature 15 – 25ºC 20º±5
Subtropical / Tropical RH 50 – 60%±5 55%±10

AICCM has chosen to describe the temperature and relative humidity parameters as set-ranges as there is the possibility of achieving some gain in heating, ventilation and air conditioning (HVAC) energy efficiency when applying a set-range instead of a median set-point.

Widening temperature and relative humidity deadbands is a technique used to improve the energy efficiency of HVAC systems. The deadband is the range around a set target point, for example to achieve conditions of 50%RH ±10, 50%RH is the target point and the deadband is up to 60% and down to 40%. However, additional energy efficiency could be gained through the use of a set-range as the target. Correcting back to a range instead of a median point may require smaller and fewer corrections and therefore less HVAC energy consumption.

Not all HVAC systems may be able to accommodate the use of set-ranges over set-points. AICCM recommends that organisations consult their facilities management staff and/or HVAC agents to discuss operations of in-house HVAC systems.

How to read the guidelines

The following tables provide simplified illustrations of the AICCM guidelines and a comparison of the AICCM guidelines, the HCC guidelines and the Bizot Green Protocol for loans against the American Society of Heating, Refrigerating and Air-Conditioning Engineers classification system for museums, galleries, archives and libraries (ASHRAE 2019).

Table 4 visually illustrates the two AICCM climate type guidelines – Temperate and Subtropical/Tropical. The table illustrates the core set-ranges and the zones of acceptable, short term fluctuations coloured with diagonal stripes.

AICCM Environmental Guidelines for Australian Cultural Heritage Collections

The purpose of the AICCM guidelines is to provide a statement and parameters with which organisations can determine an approach for establishing a preservation environment that suits their collection in conjunction with their functions and operations. The guidelines can be applied either as fixed annual parameters or adjusted seasonal parameters.

Fixed annual parameters

Fixed annual parameters refers to the adoption of the guidelines with no seasonal variation. This would suit locations where seasonal temperature and relative humidity changes are small, or where mechanical environmental control is maintained within a set range year-round.

Adjusted seasonal parameters

In locations where seasonal temperature and relative humidity changes are more pronounced the use of incrementally adjusted parameters may be considered. Where seasonal variation in temperature and relative humidity parameters are in use it is recommended that the variance remain with the guidelines total ranges.


AICCM encourages the setting of a temperature range within the total range of 15-25ºC. The temperature range will depend on the geographic location, buildings, environmental control strategies and collection needs. Short-term fluctuations in temperature should be limited to within the total range, if possible.

Relative humidity

AICCM encourages the selection of a relative humidity range that takes into account the buildings, environmental control strategies, collection needs and specifically the geographic location of the organisation. Consideration should be given to the local ambient seasonal relative humidity modes and this should be reflected in the selection of the appropriate climate type as defined in the guidelines.

Geographic climate information is available from the Bureau of Meteorology website:

Table 5 visually illustrates the total ranges of the AICCM, HCC and Bizot environmental guidelines against the ASHRAE guideline classification system. This is a very simplistic comparison and only compares total temperature and relative humidity ranges and does not incorporate each guideline’s specific provisions.

The AICCM Temperate and Subtropical/Tropical guidelines, the HCC Temperate guideline, and the Bizot Green Protocol for loans all correspond to ASHRAE category A, which defines precision control of temperature and relative humidity. These guidelines, although broader than the narrow conventional guideline of 50 or 55%RH ±5 and 20 or 21ºC ±2 are still relatively conservative and will best suit purpose built buildings and rooms. The HCC Hot Dry and Hot Humid guidelines correspond with ASHRAE category B, which defines limited control and may suit repurposed and heritage buildings and organisations looking to reduce their energy consumption.

A ‘fit for purpose’ approach

AICCM encourages the flexible and adaptable adoption of environmental guidelines. The results of the AICCM Collection Environment survey (2018) indicate that this type of approach is in practice within the profession. The survey showed that the AICCM interim guidelines, published in 2014, were in use within the profession and that some organisations, while referencing the guidelines, had adopted customised parameters to meet the specific needs of collections and the ability of buildings to maintain conditions.

Before adopting new strategies and procedures for collection care an organisation should consider the internal and external factors that are likely to influence their objectives. These factors can be described as uncertainty and are often measured as levels of risk. The Australian and New Zealand Standard AS/NZS ISO 31000:2018 Risk Management – Guidelines describes a systematic and logical framework for decision-making and states that,

All activities of an organization involve risk. Organizations manage risk by anticipating, understanding and deciding whether to modify it. Throughout this process they communicate and consult with stakeholders and monitor and review the risk and the controls that are modifying the risk. … Although the practice of risk management has been developed over time and within many sectors to meet diverse needs, the adoption of consistent processes with a comprehensive framework helps ensure that risk is managed effectively, efficiently and coherently across an organization. 

Within the Conservation profession risk assessment tools of varying complexity are used to carry out audits to determine the specific vulnerabilities and needs of collections.  Risk assessments will help to determine the most influential agents of deterioration and the types and frequency of risk created by these agents.

Two recently published decision making models that have been designed specifically for the preservation environment can be found in the following resources:

  • Ankersmit, B. and Stappers M.H.L. (2017) Managing Indoor Climate Risks in Museums. Springer: Switzerland.
  • GCI (2019) ‘Updated ASHRAE Chapter on Museums, Galleries, Archives and Libraries’, Conservation Perspectives – The GCI Newsletter, 34:1 Spring 2019, p. 28.
  • ASHRAE (2019) ‘Museums, Galleries, Archives and Libraries’, ASHRAE Handbook – HVAC Applications, Atlanta: ASHRAE.

A note about mould

Mould is a naturally occurring fungus that under specific conditions will grow on some surfaces. Mould becomes problematic when it is found growing on the surface of objects in cultural heritage collections. Damp, high humidity, warm temperatures, poor air flow, and accumulation of dust and grease on surfaces will contribute to an environment that encourages mould growth.

In order to reduce the risk of mould outbreaks it is recommended that cultural heritage collections are kept in clean, dry storage and displayed environments with good air circulation. To prevent mould growth relative humidity should be maintained below 70% (Ankersmit 2017; ASHRAE 2019; HCC 2002; Kalamees 2016; Smithsonian 2013). The AICCM guidelines recommend a conservative upper limit of 65% relative humidity for the care of cultural heritage materials.

Lending and borrowing cultural heritage objects

Green and sustainable cultural heritage industry practice has been a topic of international discussion for some 25 years. While there has been slow but progressive uptake of wider temperature and relative humidity parameters for collection display and storage, there has been almost no changes to parameters for loans. In their paper ‘Managing Environments for Collections: The Impact of International Loans on Sustainable Climate Strategies’, Taylor and Boersma (2018), investigating the prevailing impediments note that,

Despite this evolution in thinking about environmental conditions, the ghost of ‘ideal conditions’, particularly 50% or 55% RH, remains implicitly if not explicitly in loan conditions, environmental targets, and policy. Not only is this assumption impractical and imbalanced, but potentially damaging for objects outside median climate profiles. Highly technical specifications that require a scientist to understand, or an HVAC system to implement, do not represent the majority of loan situations.

Recognising that to make progress on the issue of environmental guidelines for lending and borrowing, a paper recommending adoption of wider temperature and relative humidity parameters for loans was submitted to the Council of Australian Art Museum Directors (CAAMD) for consideration at the March 2019 meeting. The paper was prepared by the Coordinator of the AICCM Environmental Guidelines Project and signed by the Heads of Conservation from the Art Gallery of New South Wales, the National Gallery of Australia, the National Gallery of Victoria, and the Queensland Art Gallery|Gallery of Modern Art. The CAAMD Directors unanimously agreed to adopt the Bizot Green Protocol guidelines for loans (Table 6) and to implement these guidelines to manage works of art on loan between the CAAMD member organisations. These guidelines were established by The International Group of Organizers of Major Exhibitions (also known as the Bizot Group) and have been endorsed by the National Museum Directors’ Council (United Kingdom) and implemented in art museums such as the Tate, the Victoria and Albert Museum, and the Los Angeles County Museum of Art.

Table 6. BIZOT Green Protocol guidelines for loans (2015)
Temperature Range Relative Humidity Range
16-25ºC 40-60%RH
For many classes of object containing hygroscopic material (such as canvas paintings, textiles, ethnographic objects or animal glue) a stable relative humidity and temperature is required within the prescribed ranges.
Fluctuations of no more than ±10%RH per 24 hours within the range.
More sensitive objects will require specific and tighter RH control, depending on the materials, condition, and history of the work of art.
A conservator’s evaluation is essential in establishing the appropriate environmental conditions for works of art requested for loan.

(Bizot 2015)

The implementation of environmental guidelines, whether the Bizot Green Protocol, the AICCM guidelines, or the HCC guidelines must be considered within the context of their specified provisions. The paper to CAAMD outlined a number of specific considerations that helped to frame the Heads of Conservation recommendation to adopt wider parameters for loans. Some of these considerations included:

  • Collective review of loan agreement terms and conditions would be necessary to develop new wording that focuses on broad principles of preservation and care of objects on loan.

In the era of sustainability and climate change it is imperative that the conservation profession take a leading role in reviewing our collection care and collection access practices. The adoption by CAAMD of wider environmental guidelines for loans is a first step towards a national review of borrowing and lending procedures. It is hoped that this change in practice by national and state art galleries will encourage other organisations to rethink their approach to environmental requirements for lending and borrowing of cultural heritage.

Other Australian guidelines and resources for cultural heritage collections


International and foreign environmental guidelines and resources for cultural heritage collections


  • BS EN 16893:2018 Specifications for location, construction and modification of buildings or rooms intended for the storage or use of heritage collections.
  • PAS 198:20212 Specification for managing environmental conditions for cultural collections. (DISCONTINUED)
  • BS EN 16141:2012 Guidelines for management of environmental conditions. Open storage facilities: definitions and characteristics of collection centres dedicated to the preservation and management of cultural heritage.
  • BS EN 15757:2010 Specifications for temperature and relative humidity to limit climate-induced mechanical damage in organic hygroscopic materials.

Some other resources to look at

  • AICCM Collection Environment survey 2018 – summary results [PDF – 162 KB]
  • Brimblecombe, P. and Brimblecombe, C. (2016) ‘Climate Change and Non-mechanically Ventilated Historic Interiors’ in APT Bulletin: The Journal of Preservation Technology, 47:1 Special Issue on Climate Change and Preservation Technology, pp. 31-38.
  • Haasnoot, M., Kwakkel, J.H., Walker, W.E. and ter Maat, J. (2013) ‘Dynamic adaptive policy pathways: A method for crafting robust decisions for a deeply uncertain world’ in Global Environmental Change, 23, pp. 485-498.
  • Lukomski, M., Beltran, V., Boersma, F., Druzik, J., Freeman, A., Strojecki, M., Learner, T. and Taylor, J. (2018) ‘Monitoring Acoustic Emission in an Epidemiological Pilot Study of a Collection of Wooden Objects’ in Studies in Conservation, 63: sup1, pp. 181-186.
  • MacLeod, I. (2015) ‘Micrometeorological assessment of passive climate controls for museums’, in AICCM Bulletin, 36:1, pp. 33-43.
  • Sterrett, J. and Piantavigna, R. (2018) ‘Building an Environmentally Sustainable San Francisco Museum of Modern Art’, in Studies in Conservation, 63: sup1, pp. 242-250.


  • Ankersmit, B. and Stappers M.H.L. (2017) Managing Indoor Climate Risks in Museums. Springer: Switzerland.
  • ASHRAE (2019) ‘Museums, Galleries, Archives and Libraries’, ASHRAE Handbook – HVAC Applications, Atlanta: ASHRAE.
  • Bizot Group (2015) ‘Bizot Green Protocol’ in Environmental Sustainability: Reducing Museums’ Carbon Footprint, London: National Museum Directors’ Council, viewed 8 May 2019, <>
  • Cultural Ministers Council and Heritage Collections Council (1998) National conservation and preservation policy and strategy: Australia’s heritage collections, Canberra: Commonwealth of Australia on behalf of the HCC.
  • ICOM-CC (2014) Environmental Guidelines ICOM-CC and IIC Declaration, viewed 8 May 2019, <>
  • Kalamees, T., Vali, A., Kurik, L., Napp, M., Arumagi, E. and Kallavus, U. (2016) ‘The influence of indoor climate control on risk for damages in naturally ventilated historic churches in cold climate’ in International Journal of Architectural Heritage, 10:4, pp. 486-498.
  • Smithsonian Museum Conservation Institute (2013) Mould and Mildew, viewed 8 May 2019, <>
  • Standards Australia and Standards New Zealand (2009) AS/NZS ISO 31000:2009 Risk Management – Principles and Guidelines, Sydney and Wellington: Standards Australia and Standards New Zealand.
  • Taylor, J and Boersma, F (2018) ‘Managing Environments for Collections: The Impact of International Loans on Sustainable Climate Strategies’, Studies in Conservation, vol 63: sup1, pp. 257-261.

Author: Amanda Pagliarino
Date: 26 May 2019