If the building owner wants a reduction in insurance premiums the plans would need to be sent to ISO. Since the insurance company, Chubb I worked for was not a member of ISO we did not use ISO building rates, we used our own rates. Most large insurance companies do not use the ISO rating system. At one time if ISO did not witness the annual main drain test they would withdraw the sprinklered rate. I have been out of the loop since 2015 when I retired and do not know if this is still being done.
ISO/Verisk is only aware of sprinklered buildings within a jurisdiction, when they have physically visited the building on the behalf of an insurance carrier (or did the plan review). Many of the larger insurance companies have their own engineering field staffs (examples include; FM, XL GAPS, Zurich, AIG, etc.) Not all insurance carriers utilize ISO services or information. They have a group that does the sprinklered building evaluations, and a separate group that does the municipal rating system. As for premium rate increases / or reductions, the plans should be sent to whom the insurance carrier uses, and this could be either the insurance carrier's engineering group, or ISO. If the insurance carrier does not utilize ISO's rate structure or services, you gain nothing with one's current carrier by sending the plans to ISO.
