Air measurements in your archive

Include gases when you plan tests for the air in your store. Reactive gases are gases that react with materials. Their effects on objects are covered on Museums and libraries.

Set out what you need the report to answer. Do you want to check a gas limit? Or test whether a filter meets the agreed target? Write this down before you book the work.

Sampling in the air handler and store

A tender for the Dutch National Archives and Regional Historical Centres uses air samples to assess the store against article 51 of the Archiefregeling. This is a Dutch source, written in Dutch. We use the Dutch legal values as a reference. The Canadian Conservation Institute advises testing how well filters work at the site.

Ask for sampling points to be agreed in advance. Include the air-handling unit, which treats the air for the store. Take samples in the store too, so that the tests cover how the system works with gas sources inside the room.

Questions for the lab

• Ask which gases it can test for and which method it uses.
• Ask how it measures low gas levels.
• Agree when to take each sample and how long to sample for.
• Ask how the results can be set against an annual mean.
• Check which approval the lab has for the exact test you need.

Specify the place and sampling period in your request. Ask how the report deals with results too low for a reliable reading.

What the report should show

The tender mentioned calls for a report on air purity for the substances named in the Archiefregeling. The rule expresses the gas limits as annual means. Read the archive gas reference values.

Ask for each result with its unit. The report should explain the sampling period and which limit it uses for comparison. Agree who will deal with a result above the limit. Ask for context before you compare one reading with a yearly limit.

Testing after filters are fitted

A gas filter may become full and lose some of its effect. Ask for tests on both sides of the filter to track this. Discuss filter resistance as part of maintenance too. State in the contract what the filter must achieve and what proof you need when the contract ends.

For a guide to filter stages, see Archive air filtration. To discuss tests, send your current report with the question you still need to resolve.