BS 9991:2015 provides guidance on where watermist systems are recommended and where they are not recommended depending on the application. If an application for watermist is not recommended in BS 9991 then it is also not recommended for Automist.
As with any guidance document, it is a experience based, best practice knowledge base which aids in decision making when specifying and approving, it is not the law. To avoid the use of guidance documents to justify it's suitability, a fire engineering analysis would need to be carried out for the specific project in question.
An extract of BS 9991 with the main applications for which Automist Smartscan is equally suitable to a BS 8458:2015 watermist system can be seen on Automist's Smartscan DIOM (Design, Installation, Operation and Maintenance) Manual, Appendix B.