1. Reasons for revision and main contents

In a situation where the durability evaluation items for long-lasting housing certification are divided into grading standards (which have been borrowed from those provided under the relevant standard specifications) and design standards, the durability-related standards stipulated in concrete standard specifications, etc. have been continuously strengthened. However, the durability evaluation items referred to in the relevant Ministerial notice have remained at the current level since August 2018. Therefore, the proposed amendment aims to resolve the inconsistencies arising from this and to improve the long-lasting housing construction and certification standards and bring them into line with reality by deleting some evaluation items that can only be assessed at the construction stage and considering that long-lasting housing certification is determined by a document review.

a. Update of the performance grade standards within durability evaluation items (Appendix 1, 1) Durability ② Evaluation criteria)

1) The proposed revision matches the minimum standard (Class 4) for rebar covering thickness and concrete design strength with those under the standard specifications; and differentiates the grades according to quality (strength and thickness).

2) The design strength of concrete is differentiated according to saltwater hazard areas, and the confusing part of the text concerning the calculation of cover thickness has been removed and reflected in the performance rating table.

3) It also deletes items that cannot be evaluated at the design stage (slump, amount of unit cementing materials, ratio of combining materials, air content, and chloride content).

b. Clarification of the durability evaluation grade criteria (Appendix 1, 1) Durability ① Evaluation grade).

1) The proposed revision improves the existing classification criteria based on useful life by classifying it based on durability evaluation items, such as required essential conditions and concrete quality reinforcement.

c. Easing of the criteria for “best” and “excellent” grades (Appendix 3 of the draft).

1) The score criterion for the “best” grade has been lowered from the current 90 points or more to 80 points or more; while the score criterion for the “excellent grade” has been lowered from the current 80 points or more to 70 points or more.