From Inside the Vaults Blog

From Inside the Vaults: Temperature and Relative Humidity Monitoring

From Inside the Vaults is a monthly blog that gives insight into best practices for collections stewardship, curation, and archaeological collecting institutions.

How Should Archaeological Collections Be Stored?

Preventative conservation, as we’ve discussed this year, includes many different tasks that are performed by Collections Managers to keep collections and storage spaces safe. Monitoring temperature and relative humidity levels in collections spaces and places where artifacts are housed is an incredibly important part of preventative conservation. Not all collections are the same, so it is important to take this into consideration when researching temperature and relative humidity monitoring for your artifacts.

Levels of Climate Sensitivity in Archaeological Collections

Archaeological collections are usually made up of many different types of materials. The National Park Services Museum Handbook recommends organizing archaeological collections by site and material class. Based on these NPS guidelines, there are three categories the collections lab considers when organizing collections:  Artifacts that are considered negligibly climate-sensitive materials, those that are climate-sensitive materials, and collections that are significantly climate-sensitive materials. The bulk of SDAC’s collections are considered negligibly climate-sensitive, which reduces the risk of damage due to fluctuating temperatures and relative humidity because of the stability of the artifacts.

How Temperature and Relative Humidity Are Monitored

Having a preservation plan in place is pertinent to any collecting institution. At the SDAC, there is a Temperature and Relative Humidity Monitoring program that helps ensure the safety of collections housed at the Center. In order to record existing environmental conditions throughout the building, temperature and RH (relative humidity) must be measured and recorded with instruments designed for that purpose. The focus of most monitoring programs is on storage spaces, but keeping track of the Museum gallery and staff spaces as well, provides a better overall picture of conditions throughout the entire building. All of the collections spaces and vaults are equipped with temperature and RH controls. These spaces are monitored by Center staff each day. Weekly, this data is entered into a graph where the RH and temperature are tracked. Once enough data is collected (usually one to two years after the monitoring program is put in place), quarterly reports can be produced that allow for long-term observation. Annually, the Collections Manager compares data from previous years to see if adjustments and improvements need to be made throughout the building. By keeping the RH in these spaces above 30% and below 65%, and temperatures between 50-75 degrees Fahrenheit, collections can remain stable and the rate of deterioration is lessened greatly. If RH levels rise above 65%, the chance of deterioration may become heightened. Additionally, the higher temperatures rise, the faster deterioration of artifacts will occur.

Best Practices

It is recommended that one staff member records, monitors, and analyzes the environmental conditions in collections spaces. Even so, there should be a backup staff member in place to fill in when needed so that data is being recorded constantly. Because temperature and RH of the vaults and Museum galleries are recorded and monitored daily, the collections department is able to analyze and mitigate any problems caused by fluctuations or increases.

The collections department is able to make improvements to collections spaces because of the data collected during daily monitoring. Looking for ways to improve climate conditions for the Center’s lab, library, vaults, and Museum galleries is always a top priority.      

By Jessica McPheters, Collections Manager

Volunteers work in the Center’s Research Library, cataloguing materials and organizing on a computer-based system.

Marketing and Administrative Volunteers assist the Development Office or Administration Office with data entry, updating marketing materials and clerical tasks. Computer experience is a plus.

Docents welcome visitors and answer general questions regarding the Center and exhibits. Docents staff the gift shop and help out with administrative and curatorial tasks.

Volunteers support event activities at the Center, such as the Annual BBQ, lectures, workshops, and fundraising events. Be a part of the party!

Volunteer provide support for K-12 programs offered at the Center. These are fun, hands-on programs that kids really enjoy. Teaching experience is a plus, but not required. Background checks are required.


With the assistance of Center staff, the intern will use photogrammetry to prepare one or more archaeological collections for digital preservation, as well as create a virtual museum exhibit for our Public Archaeology department. Per approval, special projects of the intern’s choosing are also available. During the research and planning, the intern will receive guidance as appropriate to their selected project. Prospective interns should already be familiar with photogrammetric procedures, and Agisoft Metashape.

Collections Management

With the assistance of Center staff, the intern will prepare one or more archaeological collections for curation. During the course of the internship, the intern will learn to identify artifacts and ecofacts common to the San Diego region, including lithics, ceramics, historical objects, and faunal, botanical, and mineral specimens. Center staff will instruct the intern on archaeological laboratory procedures such as basic artifact analysis, manual and computer cataloguing, storage requirements, and preventative conservation. In addition, the intern will become familiar with historical trends in archaeological practice in the San Diego area and will be introduced to current legal and ethical issues in archaeological curation as well as the concerns and rights of culturally affiliated groups with regard to archaeological materials.

Development and Marketing

Under the direction of Center staff, the intern will support the department in various activities, including, but not limited to, fundraising and grant research; e-newsletter development; social media marketing; and website maintenance. This internship will give the intern valuable, real-world experience in non-profit fundraising and marketing.

Geographical Information Systems in Archaeology

Prospective Interns must have completed three courses: Introduction to GIS, GIS Database Management, and Intermediate/Advanced Methods in GIS. The intern will be assigned a project where they will create shapefiles and maps for curated archaeological collections, museum exhibits, and/or public outreach using ArcGIS 10.6. Center staff will instruct the intern on archaeological GIS laboratory procedures such as computer cataloguing, storage requirements, and database management.

Library Science

With the assistance of Center staff, the intern will arrange and catalog materials in the Center’s library. During the course of the internship, the intern will take a leading role in the cataloging, sorting and storing of research files and creating user guides for these collections. Center staff will instruct the intern on archival procedures, computer cataloging, storage requirements, and preventative conservation.

Public Archaeology

Harness your passion for Public Archaeology and gain hands-on experience with K-12 museum field trips, lectures, and public outreach. Additional projects may include creating virtual museum exhibits and activities, assisting in the development and implementation of K-12 curricula programs, planning and presenting public facing content, or educational field trip content of your own design. Must be able to pass a Live Scan.