Specifiers, contractors, and owners should consider a qualitative and quantitative process for selecting repair materials. The system developed by ConSpec Associates, the Material Selection Criteria (CSA-MSC), includes three primary functions.
First, it provides a selection process where the specifier uses a thoughtful and a tactile process to review all of the properties of the repair materials being considered, and produces a forced ranking of the products in order of anticipated performance. Second, if and when a contractor supplies a substitute material, the system allows for the objective, not subjective, review of the material. Acceptance or rejection is objectively based on a material having a mathematically greater number than the material specified. Third, in the case of the failure of a specified material, the system provides documentation for the review process undertaken by the specifier which can only reduce his or her liability when done properly.
Specification and selection
For years, manufacturers would use slightly or totally different ASTM or other test methods to make the specification and selection of materials unique. More recently, with the adoption of data sheet protocols, this practice can be almost eliminated so that all material suppliers are held to the same standards. Table 1 shows the discontinuities in the older product data sheets.
While the data sheet protocols provide this level playing field, the specifier still must choose from a substantial list of potentially acceptable materials. This is where the CSA-MSC system requires the specifier or the contractor, when a substitute is given for consideration, to place the property values in order of their anticipated performance for the repair at hand. Further by providing individual cards for each material property (test method) the specifier is required to actually handle the cards and place them in the order of priority for the repair being considered, then place these properties in that order in the CSA-MSC Spreadsheet (spreadsheet and cards ). For example, while surface abrasion is not a key characteristic for an overhead repair, it would be the obvious choice for the first or second ranked material property when being considered for a warehouse floor repair. If there are four materials being considered then the highest rated material would receive a rank of 4 while the lowest would receive a 1. Then the highest ranking property would have a value, in the system, of 10 therefore giving the best material for this property a value of 40 (4X10) and the least a 10 (1X10). (See Table 1)
The system also allows for the removal from consideration of a material when it does not fall within a particular range of values or it exceeds a maximum or minimum value. An example of these would be setting a range of values for compressive strength characteristics or in the case of shrinkage—a maximum value. This would be the most severe restriction, that is, totally eliminating a product, but an alternative might be providing a zero value on the appropriate ranking line for the particular product, therefore potentially taking it out of consideration, but not guaranteeing its removal. As in the preceding calculation (0X10) equals zero.
Using the CSA-MSC spreadsheet allows for the comparison of up to five or more products with the specifier only including the top three in the specification. One of the unique attributes of the card system is that test methods may not only be added or removed as necessary, but the system is also adaptable to other materials such as sealants and grouts where valid test methods with values established can be compared.
The review process
As specifiers review each new project the use of a “cut and paste” mentality may not provide the owner with the best solution for a particular repair project. The final decision process need no longer be based on the best salesperson, the last manufacturer interviewed, or even the manufacturer the specifier has been most comfortable with in the past. All of these subjective criteria can, of course, be included in the initial selection of materials to be considered, but to be most appropriate for the project a totally objective review is essential.
The review process then starts with selecting those manufacturers that provide a set of test data that have the same test methods so values can be compared. The list is then pared down to those that are to be considered for the project.
This list of materials shown in the examples is from data sheets that are a few years old. Once the data sheet protocols, currently being reviewed by ICRI, are established, many more materials will have almost all the needed property values listed. Without this spreadsheet it will be significantly harder to objectively find the best potential repair products for the project.
Again, whether you are a specifier looking for the best materials for your next repair project or a contractor asking for a material that you have a lot of experience with to be considered, this system offers a fair and relatively easy way for an objective decision to be made and is fair to the specifier, contractor, and owner.
For example, if the contractor submits a material that has the required test data, the chart is recomputed and if the new material is now one of the top three then there is substantial objective documentation that the material should be considered.
Whether you are a specifier, contractor, or owner think about considering this system for your next repair or restoration project.
PJ Morrissey has been in the repair/restoration business as a materials consultant for almost 35 years and has been involved with many industry organizations including ICRI, APT and ASTM.