ASTM recently published revisions to E2026 Standard Guide and E2557 Standard Practice for assessing seismic risk to buildings. Among other changes, E2557-16a now recommends the inclusion of a new appendix, X5, to help clients better understand the limitations of probable maximum loss studies.
What’s in the Form?
The form begins with a reminder that seismic risk assessments are performed for specific clients and for specific purposes. They may not meet the needs of other clients and should never be used for anything other than the intended purpose.
Not surprisingly, the appendix recommends that the assessment be based on the referenced ASTM standards. The standards provide a sound basis for describing the work, and terminology included in ASTM E2026 has become increasingly accepted in the industry. This improves the transparency of evaluations, so is useful for users to describe that they need and consultants to describe their assessment and conclusions.
General guidance concerning what to look for in reports includes:
- Property information and description of buildings,
- Review of seismic hazards at the site,
- A list of documents reviewed, such as design drawings,
- The level of Review provided by the report,
- Estimation of building loss, including the specific loss definition
- Identification of the analysis and methods used to determine loss,
- Evaluation of building stability (collapse potential) and methods used to reach opinion, and
- Qualifications of the senior and field assessors who completed the work.
Levels of Assessment
An understanding of the level of investigation performed is also important to interpreting Probable Maximum Loss Reports. ASTM E2026 defines three to four levels of assessment in five different categories; ground shaking, site stability, building damageability, content damageability, and business interruption. Most probable maximum loss studies exclude the evaluation of business interruption and content damageability. The evaluation of other issues may range from screening assessments (Level 0), through cursory engineering assessment (Level 1), detailed evaluation (Level 2), to exhaustive review and analysis; each level providing an increasing degree of certainty.
A discussion of the qualifications for assessors performing is also provided. Other items include reminders that:
- Relying on an estimate of Probable Maximum Loss (PML), alone, may not provide a complete picture of seismic risks. It’s necessary to read the entire report to fully understand the findings.
- Seismic Risk Assessments can change. Changes to the property and changes in our understanding of building performance and seismology can result in different conclusions over time.
- Most findings are professional opinions.
Have Questions About the ASTM Updates?
We recently hosted a webinar on the ASTM updates, which addressed the importance of understanding the level of investigation when ordering seismic risk assessments as per the new standards. The webinar is now available on demand until September 29. Please REGISTER NOW to learn more about how to ensure your seismic risk policy reflects the appropriate scope of work for your purposes.