A step-by-step guide - Chemical damage tool

General

Select Modules from the start-up page and then select Incorrect relative humidity or Incorrect temperature as agents of deterioration. A list of deterioration processes for which risk may be quantitatively assessed by means of available tools is displayed. Select the Chemical degradation tool.
Alternatively, select Tools in the upper menu line and select the Chemical degradation tool from the list. The list of data sets available for calculations is displayed with the average levels of relative humidity and temperature over the period covered by the data. You can view plots of each data set by selecting Graph. From the list, select one or more data sets to perform calculations. You can select between five ways of obtaining quantitative measures of climate-induced chemical damage risk to materials for the environmental data contained in the uploaded data set:

• press Relative lifetimes – data-based or Relative lifetimes – constant climate to calculate relative lifetimes expected for four categories of low stability materials,
• press Lifetime – paper to calculate the lifetime of unstable paper materials,
• press Lifetime – cellulose acetate to calculate the lifetime of cellulose acetate undergoing hydrolytic decomposition,
• press Time to discoloration – poly(vinyl chloride) to calculate the time to reach specific color changes of PVC-based materials,
• press Time to lining – canvas to calculate the time to reach the fragile and very fragile conditions of canvases.

Relative lifetimes

Relative lifetimes of paper materials/canvas, cellulose acetate, poly(vinyl chloride), or a general category of low-stability organic materials are displayed for each selected data set together with the average levels of relative humidity and temperature over the period covered by the data.
You can use Relative lifetimes – constant climate at selected constant environmental conditions. Enter the values of temperature and relative humidity of interest and press Calculate relative lifetimes.

Lifetime – paper

Enter the name of your paper material, its current and critical polymerization degrees of cellulose DP and its acidity – reflected in the cold water extract pH value. Press Calculate lifetime. Lifetimes of the paper material are displayed for each data set selected.

Lifetime – cellulose acetate

Lifetimes of cellulose acetate are displayed for each data set selected together with the average levels of relative humidity and temperature over the period covered by the data.

Time to discoloration – poly(vinyl chloride)

Enter the name of your PVC material, its current plasticizer content, and the current molecular weight of PVC. Press Calculate lifetime. Times to just noticeable difference (JND) and lifetimes of the PVC material are displayed for each data set selected.

On each of the pages you can view plots of the results by selecting Graph. You can graphically explore your data in two ways. Move the cursor over the plot to dynamically display the time/parameter coordinates of data points. Zoom in by selecting a fragment of the plot. A double click resets the zoom in selection. After viewing the data, click Back above the plots to return to the respective results page.

Time to lining – canvas

Enter the name of your painting, its current polymerisation degree of cellulose DP, and its acidity, reflected in the cold water extract pH value. Press Calculate the time to lining. The values of the time to fragile and very fragile conditions of the canvases are displayed for each data set selected.