The ATC 20-1 Field Manual: Postearthquake Safety Evaluation of Building (2nd Edition), was introduced in 1989 as a companion document to the ATC-20 report. The second (2005) edition of the Field Manual has been updated to include:

• the RESTRICTED USE placard, which was introduced in 1995 (replacing the LIMITED ENTRY placard),
• updated evaluation forms, which were also introduced in 1995,
• new examples,
• more information on steel moment-frame buildings,
• a chapter on mobile homes and manufactured housing,
• guidance on aftershocks and entering damaged buildings,
• new information on barricading, and
• resources available on the internet pertaining to post earthquake safety evaluation.

The pocket-sized Field Manual summarizes the post earthquake safety evaluation procedures in brief concise format designed for ease of use in the field.