Environmental conditions within storage areas and facilities have a major impact on the preservation or deterioration of physical records and particular formats (e.g. magnetic tape and photographic media). Poor storage and environmental conditions will result in the deterioration of records and their potential loss, or the necessity of undertaking conservation work at considerable cost to the public office.

All records should be sentenced for disposal using the appropriate retention and disposal authorities before the records are transferred to a storage area or facility. Understanding how long a record is required to be kept before it can be disposed of or transferred to NSW State Archives and Records will ensure that records are stored in the correct type of storage with appropriate environmental storage conditions.

NSW State Archives and Records recognises that many public offices have difficulties in implementing and maintaining appropriate storage environment conditions. We recommend that public offices implement the storage environment conditions and housing requirements as practically and sustainably as possible, and prioritise/implement the best storage environment conditions possible for those long term records and State archives in their control.

Short and medium term records, i.e. records that are only to be retained for 30 years or less, should be stored in good storage conditions until they are authorised for destruction. Conditions for short term records are not as exacting as the conditions for long term records/archival storage. See Table A - Storage environment conditions and housing requirements for short and medium term temporary records.*

Long term records, i.e. records that are retained for 30 years or longer or those records required to be transferred as State archives, should be stored in the best environmental conditions possible. See Table B - Storage environment conditions and housing requirements for long term temporary records and State archives.*

* These requirements are based on temperature and humidity controls defined in international or Australian standards. These tables are also available in the Standard on the physical storage of State records.

4.1  Temperature and humidity

Temperature and humidity are two of the most vital components in a records storage program. Temperature helps to determine the rate of chemical change in materials and is also an important factor in biological and physical deterioration. Increases in temperature lead to increased rates of change and deterioration.

Relative Humidity (RH) affects the rate of deterioration. Moisture is a requirement in many deterioration reactions and is crucial to the germination and growth of mould.

When major fluctuations in temperature and humidity levels occur, moisture is absorbed and released frequently, causing deterioration to records.

There should be regular monitoring of temperature and humidity levels in storage areas and facilities. Action and mitigation strategies should be taken to address any fluctuations in temperature or humidity levels.

A stable storage environment can be achieved through building design and construction, insulation from the external climate, and a suitable location for the storage area/facility, rather than dependence on air conditioning.

Where possible the storage environment should be based on the requirements of the records being stored. High sensitivity items (e.g. photographic media, magnetic media, optical media and mixed media items) require more stringent environmental controls and should be separated from the other records so that their special requirements can be met in an isolated storage facility, e.g. photographic media (black and white, or colour), magnetic media, optical media and mixed media items, should be stored separate to paper-based records and require more rigorour temperature and humidity controls.

Records identified as long term temporary or as State archives should be removed from short term temporary records storage and placed in environmentally controlled storage and maintained at temperature and humidity levels as described in the Standard on physical storage of State records (see Table B - Storage environment conditions and housing requirements for long term temporary records and State archives).

Records subject to ‘still in use’ determinations that are of archival value and should be stored according to Table B (see Table B - Storage environment conditions and housing requirements for long term temporary records and State archives).

How to achieve stable temperature and humidity levels in storage areas?

Public offices can achieve stable temperature and humidity levels in a number of ways:

1. Choose the location of the storage area/facility carefully. Is the location prone to major changes in temperature or humidity?
2. Choose the location of the storage area within the building carefully. For example, is the storage area located on the western side of building and likely to bake in the hot summer afternoon sun? Is the room well insulated?
3. Choose a building with a high thermal mass, that is, a building which is made of materials which respond slowly to the external climate.
4. Insulate the external walls, roof and floor of the storage area or facility from the external climate, for example put insulation batts into the ceiling and walls.
5. Use portable dehumidifiers, silica gel or moisture absorbing crystals, and ceiling fans to regulate humidity and provide good ventilation. [12]

Monitoring stability of temperature and humidity

Monitoring the temperature and humidity within the storage area or facility is critical. Public offices should create temperature and humidity logs for storage areas, or obtain regular reports from the commercial storage provider. Information from monitoring allows you to know:

• what is happening in the storage area or facility, so that you can take the appropriate action
• when your storage area or facility is undergoing major fluctuations. The change to summer or winter, or a period of wet weather after dry weather, are particularly important times
• if air-conditioning is working appropriately in the storage areas, and
• which storage areas function well and are stable and which ones are not (this will allow you to determine which storage areas to use for records of archival value). [13]

4.2  Light

All forms of light can damage records. Protecting records from direct sunlight and minimising light in storage areas will minimise damage to records.

ISO 11799 notes that storage areas should “not be illuminated more than is necessary for retrieval and replacement of documents, room inspection and cleaning.”[14]  Ideally storage areas should not have external windows or skylights.

To protect records:

• prevent sunlight entering storage area, by covering windows and skylights
• use movement-activated or time-limited lighting in storage areas, so there is lighting only when required
• store records in boxes to reduce their exposure to light
• use soft and diffused lighting, and
• use low ultra-violet emitting bulbs or place filters over the lights.[15]

At the minimum, lighting should be ambient (soft and diffused) for short term records. UV filtered fluorescent lighting and timer controlled switches should be installed for records that are either long term temporary records or State archives.

4.3  Air quality

Good ventilation within storage areas and facilities is important. Air must be able to freely circulate within the storage space to prevent ‘pockets’ of stagnant air. Good air circulation also assists in maintaining constant temperature and humidity. There should also be intake of fresh air. Good ventilation in the storage area can be achieved by using fans or air conditioning.

It is important that the air entering and circulating through the storage area or facility is ‘clean air’ and does not contain dust, pollen or pollutants which will cause deterioration to records. A ‘clean air environment’ can be achieved through:

• careful selection of the location of the storage area or facility so that its not near heavy industrial locations (see Section 3 Location of storage areas and facilities)
• use of filtration systems to exclude dust, sulphur dioxide, carbon monoxide, and pollutants[16], and
• placing inflow ducts so that they do not draw in air from car parks or busy roads.

Air quality should be periodically monitored to check for dust and, acidic and oxidising gases.[17]

4.4  Pest management

Records, particularly paper records, are an attractive food source for a range of pests and vermin including termites, cockroaches, spiders, silverfish, paper lice, rats and mice. The biggest threats are rats and mice, cockroaches and silverfish.

The presence of rats or mice and cockroaches is very obvious. Records will be chewed, there will be droppings and there will be evidence that the paper records are used for nesting sites for rats and mice. Silverfish infestations are only apparent when the habitat is disturbed or items are removed from boxes and examined. Silverfish eat the starch in coated papers (i.e. glossy papers) and ink. Evidence of silverfish includes holes in paper and missing letters on documents (i.e. the ink has been eaten).

Silverfish, source: http://www.flickr.com/photos/bettaman/3302148003/

Severe insect damage, source: NSW State Archives and Records

An integrated pest management approach is based on a range of preventative measures. It is a low-toxicity means to control pests and mould, and includes:

• a risk assessment of the storage area/facility to identify possible food sources or environmental conditions which would encourage pests and rodents and any current pest activity
• good housekeeping practices
• implementing preventative measures to control pests and rodents (see below)
• isolating and treating affected records, and
• as a last resort, active intervention measures.[18]

Preventative measures include:

• maintaining a cool, dry, ventilated, and clean environment
• perimeter spraying of the building to discourage pests and vermin
• preventing the accumulation of rubbish or food in the storage area (this will remove food sources from the storage area)
• carefully selecting furnishing materials and floor coverings to exclude those that attract insects
• configuring the shelving so that the bottom shelf is 100-150cm from the floor to enable cleaning and air circulation
• designing the storage operation/processes so that records are inspected for infestation before they come into contact with records already in storage
• regularly inspecting the site for rats, mice, silverfish and cockroaches (see also Section 6 Maintenance), and
• using pest control traps and baits.

Fumigation of the facility/storage area and records should be a last resort. If it is necessary to spray to control an infestation, you should ensure that the pest control agency does not spray the records. It may be necessary to supervise the work. All staff and visitors should be notified if fumigants are to be used to ensure that they do not go into unsafe areas or come into contact with contaminated surfaces. All affected air conditioning systems and very early smoke detection devices (VESDA) should be shut down while fumigation takes place.

4.5  Magnetic fields

Magnetic fields can distort the data contained in some record formats, such as computer tapes and disks, video tapes, audio tapes and mini disks.

Storage areas should be protected from magnetic fields. Magnetic media should be stoed on non-magnetisable shelving and stored in non-magnetisable sealed contains, cassette cases or sleeves. See Table A and Table B.

Magnetic fields include:

• high intensity electro-magnetic fields, e.g. high voltage power lines
• lightning conductor systems
• electric generators and motors, and
• electrical wiring.

4.6  Keeping records about environmental conditions

It is important to keep records of the management of environmental conditions in each storage area and facility. Examples of the types of documentation include:

• reports which identify the types of records to be stored in each area/facility, the appropriate storage conditions for their retention periods, assessments of the respective storage area/facility and its capacity to provide appropriate storage
• documentation of temperature and humidity levels within each storage area / facility (thermohygrograhic logs etc.)
• reports of monitoring of temperature and humidity in each storage area / facility
• risk assessment reports on how the impact of sunlight and UV light on records has been minimised
• documentation of maintenance for any air circulation system in use
• risk assessment reports on how magnetic storage media has been protected from the effects of magnetic fields
• information about the integrated pest management system in the organisation’s storage plan, and
• reports/documentation of pest inspections and monitoring.

[12] ISO 11799, section 4.2 Indoor climate stability; Elizabeth Hadlow, “Preservation” in Keeping Archives, 3rd Edition, ed. Jackie Bettington, Kim Eberhard, Rowena Loo and Clive Smith, Australian Society of Archivists, 2008, p. 103

[13] Hadlow, “Preservation”, p. 104

[14] ISO 11799, clause 5.5.1 Illumination

[15] Hadlow, “Preservation”, p.104; National Archives of Australia, Storing to the Standard, pp. 20-21

[16] Ted Ling, “Buildings & Storage” in Keeping Archives 3rd Edition, ed. Jackie Bettington, Kim Eberhard, Rowena Loo and Clive Smith, Australian Society of Archivists, 2008,p. 70

[17] ISO 11799, section 5.5.3 Ventilation and air quality

[18] National Archives of Australia, Integrated Pest Management, see http://www.naa.gov.au/information-management/managing-information-and-records/preserving/physical-records-pres/integrated-pest-management.aspx; Hadlow, “Preservation”, pp. 116-118