Metal Shipping Containers as Additional Storage
Metal shipping containers are often used for short and long term storage during museum expansion, renovation as well as a solution to limited permanent storage solutions. While shipping containers are widely available and inexpensive, their lack of climate control and buffering capacity may actually cause catalyze deterioration unless codified. Several case studies have shown that unsealed and uninsulated containers cause more damage then was present before storage.
Therefore, if you chose to use metal shipping containers as a storage option, there is a few adjustments that need to be made to ensure that the container is safe to store museum objects.
Acquiring a Used Container
The container needs to be assessed before purchased to ensure that it is in good condition. There should be no rust, gaps or leaks. The doors should be checked to ensure that they move freely and form a tight seal when closed. The container must be able to sustain a sealed internal environment to ensure stable conditions and to protect against the intrusion of weather, dust and dirt, insects and other pests. The easiest way to tell if a container has any leaks is to see if any daylight enters the container when its doors are closed.
Preparing the Site
When choosing a site for the container, you should ensure that it is level with good drainage (i.e. gutters or ditches), so that water flows away from it quickly. The containers should not be located next to creeks, rivers, lakes, near an exposed storm water drain or on a flood plain. The site should also be cleared of all pests, vegetation, including tree stumps. Ideally, the surrounding area should be paved or concrete.
The container should be placed on piers or blocks (bricks or concrete) and not on the ground (See How to Build a Level Foundation for your Shipping Container). Elevating the container will enable greater air circulation underneath and will reduce the possibility of rodents, snakes and other pests nesting or living underneath the container. If possible, the space between the container and the ground should be fenced with a mesh material, like chicken wire, so you can see below the container. The entrance should be protected from the elements, when possible. This can include orientating the entrance away from typical wind and sun directions, or even building a verandah where a quality mat can be stored to help to keep dirt and dust from being tracked into the container.
To help with circulation, ‘whirlybird’ ventilators can be installed on the top of the container. However, if these vents are installed, you need to ensure that any holes created to insert the vents are sealed shut to prevent the intrusion of water or dust.
Since the container has a flat roof, a car-port-type structure should be built over it to protect it from the elements. The room should be titled to ensure rapid rainwater runoff. Ideally the roof should be made of steel or plastic. The roof line should extend past all sides of the container by at least 3 feet to provide further protection. The roof water and surface runoff should be directed away from the container either by gutters or ditches. Additionally, a gap of 2-3 feet should be created between the roof structure and the container to allow air to circular between the two.
Finally, if a general purpose container is being used, the exterior walls and roof should be coated with a highly insulating material. This material should be weatherproofed.
The Interior of the Container
It is important that the storage containers be wired for electricity to help with environmental monitoring.
Containers generally do not have internal lightening and several light fittings many have to be installed. Consider using emergency lights or LED lights to reduce Lux levels or alternatively simply use torches when accessing the container.
Portable dehumidifiers can be installed to help control humidity levels. In the winter, heaters should be placed in the container to ensure that temperatures remain stable.
Environmental conditions within the container should be monitored regularly. This can be done in a number of ways. Portable electronic data loggers can be used. Only one or two would be needed. They are powered by a lithium battery and can monitor conditions without interruption for over a year. The results can then be downloaded to a computer system (Which MAS can help you with). Older style thermohygrographs can also be used but they need to be monitored more closely, with readings noted and the graph paper replaced.
Boxes and objects should ideally be placed on shelving or racking and not simply stacked on top of each other. While it is possible to stack them seven or eight high, there is always the risk that the bottom layers will be crushed under the weight. If this method has to be adopted thick layers of cardboard across each level should be used in order to distribute the weight. The benefit from not using racking means that a larger number of boxes can be stored cheaply. The disadvantage is that should access be required to a particular box – for example, the box on the bottom level – the set up will have to be dismantled to gain access to that box. Ideally, when the boxes or objects are placed on shelves, they should not touch each other or the outer walls so that ventilation can occur. Ultimately, a balance needs to be created between maximum storage capacity, ease of access and retrieval and good ventilation.
As boxes and objects are bring brought into the container they should be inspected to ensure there is no evidence of damp, mould or pest infestations. Otherwise, a problem could easily be imported. Once established, boxes of moisture-absorbing crystals such as Damp Rid TM or Closet Camel TM should be placed inside the container to help keep excess moisture under control. Baits and blunder traps should also be included for insects and other pests. These items should be checked regularly and replaced when necessary.
Remember, the objects and artifacts being placed into the shipping container, should also be stored properly using conservationally sound materials and practices. This will go a long way to ensure protection of the artifacts when they are placed into the container.
For More Information about Converting a Shipping Container into Storage, See:
“Home.” Container Technology Inc. 2016. Website: http://containertech.com
“How to Build a Level Foundation for your Shipping Container.” Premier Box. Jnuary 30, 2013. Website: http://premiershippingcontainers.com.au/the-best-way-to-build-a-level-foundation-for-your-shipping-container.html
Oster, Joseph. “Home” ContainerCore.org. 2016. Website: http://www.containercore.com
For Case Studies, See:
Ling, Ted. “The Darwin Shipping Container Trail” Report and Results.” National Archives of Australia. Pacific Regional Branch of the International Council on Archives. Nov. 2002. Website: http://www.ica.org/sites/default/files/PARBICA_2002_report_conservation_EN.pdf
Ling, Ted. “Using Shipping Containers for Record Storage: Specification and Description.” National Archives of Australia. Pacific Regional Branch of the International Council on Archives. Nov. 2002. Website: http://www.ica.org/sites/default/files/PARBICA_2002_guide_conservation_EN.pdf