I don't know about a "fire suppression P.E."... I do agree with benbo that if you have adequate training, use your discression to sign off. Your state may have specific rules governing the stamping of fire suppression systems. Can you get on line and read the State regulations? For Missouri, it just requires that a P.E. stamp them... Here's the verbiage:
Title 4.DEPARTMENT OF ECONOMIC DEVELOPMENT
Division 30.Missouri Board for Architects, Professional Engineers, Professional Land Surveyors, and Landscape Architects
Chapter 21.Professional Engineering
4 CSR 30-21.010 Design of Fire Suppression Systems
PURPOSE: This rule requires the design of fire suppression systems to be designed, prepared, and sealed by a professional engineer.
(1) Pursuant to section 327.181, RSMo the design of fire suppression systems is engineering and therefore the plans for those systems must be designed, prepared, and sealed by a professional engineer. This can be accomplished two (2) ways:
(A) The design engineer seals the construction documents that specify the design and criteria for the fire suppression system, including sprinklers, fire alarms, and other suppression systems. The layout and sizing of these systems, done by a Level III Technician certified by the National Institute for Certification in Engineering Technologies (NICET) or a professional engineer, can be submitted as a shop drawing. These shop drawings may be sealed by a professional engineer. The design engineer must review and approve the shop drawings for compliance with the design and specifications shown on the construction
documents; and
(B) If there is no design engineer for the fire suppression system, then the shop drawings for the sprinklers, fire alarms, and other suppression systems must be designed and prepared under the immediate personal supervision of a professional engineer. These shop drawings must be sealed by the profes-
sional engineer who prepared them.
(2) Nothing in this section shall prohibit the design engineer, at his/her discretion, to specify and require the shop drawings to be designed, prepared, and sealed, by a professional engineer.