Wis. Stat. § 145.175: Automatic fire sprinkler-maintenance only registration.

An automatic fire sprinkler-maintenance only registration certificate is required before any business establishment may maintain or repair existing automatic fire sprinkler systems in its physical facilities. The department shall, by rule, specify the qualifications for issuing an automatic fire sprinkler-maintenance only registration certificate. The department shall, by rule, specify the activities in which a person holding a registration certificate under this section may engage.