[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Preservation Index/Time-Weighted Preservation Index



Title: Preservation Index/Time-Weighted Preservation Index

Colleagues -

I've been reading New Tools for Preservation: Assessing Long-Term Environmental Effects on Library and Archives Collections by the Commission on Preservation & Access (1995).  I am a bit confused about the Preservation Index and the Time-Weighted Preservation Index.  I am in the process of garnering institutional support to improve our environmental conditions and I am looking to provide some information to convince the administration of the need to have better control over our temp and RH. 

This is where my confusion comes in.  According the the PI chart, our materials have an approximate predicted lifetime of 47 years, based on our current temp and RH (67 and 50%).  I would like to show that investing in a better HVAC system and some building upgrades will allow us to change the temp and RH and lengthen the predicted lifetime of the materials.  Basically, I'm looking for a justification for the expense (to justify it to them - I don't need much convincing).

The question I've already been asked is:  If the PI chart is right, how come our collections (dating to 1860 and before) aren't dust already?

I'd appreciate it if someone could point out my faulty logic or better explain the value of the PI and TWPI charts.

Much obliged for any assistance, and I will post a summary if there is enough interest.

Jamie Nelson

Jamie Nelson
Special Collections Librarian
Augustana College