Can I rely on test data from the brick supplier or should I have the brick tested in a lab?
If test data furnished by brick suppliers are current and if brick suppliers are reputable, you can rely on their test data. If, however, the test results are more than 1 year old, have the brick tested in a lab. Because brick is made from natural clays occurring in the earth, the clay vein--and corresponding test results--may vary from year to year.