We had a meeting with the Pre-Fab association and they confirmed some important points. First, the recent talk about an “exemption” for using JAS materials was incorrect. It was not an exemption, but there is actually a provision written into the Building Standards Law that allows construction to disregard the BSL provisions for a period of one month after a major disaster. Furthermore, while it is only for one month, in practice MLIT allows this to continue until all of the temporary housing is completed. In the case of Kobe, this took 7 months and the Pre-Fab Association expects that it will be at least until the end of August this time.
All of this is written into Article 85-1. One concern is that the period after the first month is not expressly written into the Article 85. However, as the Pre-Fab Association explained without such an extension no temporary housing could be built past one month.
The Pre-Fab Association did say that they officially “recommend” to their members that they use JAS, etc. compliant materials even in temporary housing, but it is up to the individual members to actually purchase materials. Depending on shortages and other factors, they may or may not be following this voluntary guideline set by the association.
The one thing that they did warn us about was the risk of sick-house syndrome. This was a major problem in the Kobe temporary houses so they feel that officials will be watching for this. Therefore, even if materials are not JAS, you should try to determine if they would be similar in performance so as to not cause a problem later with formaldehyde emissions. This is of course more of a concern with the materials that face the inside living space.