What are some common fire ratings that are used in the ASTM E119 test?

The ASTM E119 test is a standardized fire test conducted by the American Society for Testing and Materials (ASTM) to evaluate the fire resistance of various building components. The test measures the time duration for which a specimen can withstand exposure to fire and maintain its structural integrity. The fire ratings are typically designated by the duration of fire resistance provided by the tested materials. Here are some common fire ratings used in the ASTM E119 test:

1. Hourly ratings: This is the most common fire rating system used in the ASTM E119 test. It indicates the number of hours a specimen can withstand fire exposure without failure. For example, a material with a 1-hour fire rating can endure fire exposure for one hour.

2. Two-hour, three-hour, and four-hour ratings: These ratings follow the same principle as hourly ratings, indicating the duration for which materials can resist fire exposure.

3. Intermittent fire ratings: Some materials display intermittent fire resistance, meaning they can withstand fire exposure for a specific time period and then cool down before being exposed to fire again. These ratings are expressed as "X hours of fire followed by X hours of cooling."

4. Temperature rise ratings: In addition to duration-based ratings, the ASTM E119 test also assesses temperature rise in building elements. This rating measures the maximum permissible temperature increase on the unexposed surface after a specified time period of fire exposure.

It's worth noting that fire ratings are subject to local building codes and regulations, and specific requirements may vary across different jurisdictions.