FAQ

Combine Conditions with caution. As we cannot determine the effects of different conditions

1. View the graphic display of the aggregate Rating, and
2. expand and examine ratings to avoid such misleading DCRG average Rating.

To expand a the Ratings when you have selected multiple Conditions:

• Click the triangle (▶) to the right of the chemical to see an Ratings for each Condition chosen.
• Click any rating cell in the table to view the individual Ratings from References.

For each Chemical selected, the Conditions offered are based on ratings available for the selected Materials. Adding or changing a Material would require new decisions of Conditions for each Chemical. For this reason, once the Material list is finalized, it cannot be changed.

It is quick and easy to select Materials. If you need another or different Materials, you can: 1) Continue to generate a table with your current set of Materials and create a second table with the missing Material(s) or 2) Click restart and define the Materials list with the new Material.

Including multiple conditions can result in misleading averages. For example, adding Conditions for room temperature and 100°C, there are many more Ratings at room temperature and high temperature typically adversely affects resistance. This could result in a reported rating (A or B), i while exposure at 100C could be unacceptable (?). This would be seen by examining the graphic display of Ratings, which should always be done for every Rating in your custom table. [see “Warning when combining widely varying Conditions”]

NOTE: The exception to this is when simply combining different room temperature rating [20C-22C, 68F-74F] when these are explicitly identified. [In the future, users will be able to define the range they consider room temperature to reduce this effect.]

Sometimes the names are the same, sometimes they are different. Each name serves a purpose: one for convenience, and one for consistency. The first name identifies the name you select to identify a Chemical or Material. The second name, which we call the Primary name, is the name that DCRG uses to identify the item. This is necessary to present you with data from all synonyms of the name that you search for. Sometimes these two names are the same, when there are no synonyms in our tables or you have searched for our Primary name, but two names are always shown for consistency.

Many Materials and Chemicals can be referred to with equivalent names, or synonyms. Such as the Chemical Methyl Ethyl Ketone, MEK, or Butanone; or the Material: Buna-N and Nitrile. We have identified these synonyms to be able to retrieve Ratings for all representations of the Chemical or Material you seek, without you needing to know synonyms for the name by which you know the Material or Chemical. We first list the name you search for, followed by the name by which we identify the Chemical.

When using traditional stand-alone Chemical Resistance tables, a single Rating is shown for each Material/Chemical+Condition. Although most tables use a 4-level Rating ( or ), some use 2-level (, or 3- or 5-level Ratings. When we report data we retrieve frm 50 tables, they are rarely identical. To provide you a report as a table, we need to define an average rating. We call the average we report a DCRG average. As with any average, this can hide information. The side effect is that bad ratings could be hidden.

The most obvious occurs if varied conditions are selected. For example, if you combine Ratings for room temperature and 100C, there are likely to be far fewer Ratings for the 100C. If 12 Room Temperature Ratings are  A and 3 100C Ratings are D the average Rating reported will be A, which does not accurately reflect the worst-case chemical resistance scenario if the chemical is at 100C. The application should not be run at 100C.

Unfortunately, even for exactly the same request, different tables can provide Ratings. As an example, the Ratings for Polyethylene and Acetone are found in only three of our 50 table, and those ratings are 2, C, and A, represented in DCRG graphic representation below.

When defining Conditions, DCRG represents them in three boxes

Conditions can be complex. We devide all conditions into three groups: Temperature, Concentration, and Other, and represent them in three boxes

Although Temperature and Concentration seem obvious, they can be represented not only by quantitative levels, such as 100C or 50%, but also using descriptive terms, such as hot or concentrated. Then there are other terms often describing a Chemical, such as anhydrous liquid, aqueous, or dry gas.

Thus DCRG represents Conditions in three boxes:

Temperature	Concentration	Other
Conditions related to temperature	Conditions related to concentration	All other conditions
100C, hot, molten, 50°F, warm, &ellip;	3 Molar, concentrated, 6%, concentrate, …	dry gas, 40 vol, anhydrous liquid, bleached, up to 50% aromatic, …

Examples of Conditions representation:

Original	Standardized
Acetic Acid (10-50%, 100°F Max.)
Ammonium carbonate (aq) 20C (70F)/60C (140F)
Hydrochloric Acid, Concentrated to 158°F bec

A	B	C	D
Best Resistance			Worst Resistance

A	B	C	D	M
Best Resistance			Worst Resistance	Mixed

The majority of Chemical Resistance Charts available provide four levels of resistance, and these are qualitative. These are represented A-B-C-D, E-G-F-P, 1-2-3-4, etc. For all these Charts, the meaning of these Ratings is defined in qualitative terms, such as ("Excellent, Good, Fair, Poor") or ("No effect, Minor effect, Moderate, Severe"), if they are defined at all. We use this common 4-level representation, “A-B-C-D,” and have developed an algorithm that represents an average Rating, a DCRG Rating, for all the Rating in our repository for the Chemical/Material/Conditions that you selected. What about the M Rating???? For this, see FAQ What is an M Rating?

This Rating is not standard, so we don’t label the four levels like most published tables do. Also, since this single letter often represents combination of different Ratings, we present a graphic display of all Ratings we found for your combination. We strongly recommend that you examine this for EVERY Chemicals/Materials/Conditions in your custom DCRG table. [see also: MULTIPLE]

NOTE: The exception is Chemical Resistance Charts for gloves. These tables typically include quantitative measures such as Penetration and Breakthrough time. They have not, at this time, been incorporated into our dataset. For chemical resistance of gloves, use of a table specific for the glove manufacturer is strongly recommended.