What’s Your Sign? A Look at NFPA 25 Signage Requirements

September 8, 2025

What’s Your Sign?
A Look at NFPA 25 Signage Requirements

By Vincent Powers

When it comes to the inspection, testing, and maintenance (ITM) of sprinkler systems, signage isn’t usually the first thing that comes to mind. Yet proper signage plays a critical role in ensuring that water-based fire protection systems can be quickly understood and operated during an emergency.

NFPA 25 That said, there’s often confusion in the field about which signs are actually required under NFPA 25: Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems. Many technicians mistakenly cite deficiencies that don’t exist—while overlooking the signage that NFPA 25 does require.

Let’s clear up the most common misconceptions.

Signs You Don’t Have to Maintain Under NFPA 25

Some signage is required at installation by NFPA 13, but not by NFPA 25 for ongoing maintenance. Common examples include:

Main drain signs
Inspector’s test connection signs
Airline signs
Alarm line identification

These signs are useful for system understanding, but they are not enforceable under NFPA 25 inspections. If they’re missing, they should be documented as observations, not deficiencies.

Signs You Must Maintain Under NFPA 25

Control Valve Signs (13.3)

Every control valve must have a sign showing which part of the building it serves.
If more than one valve must be shut to isolate a system, cross-referencing is required.
- Example: In a high-rise with looped mains, the valve in Stair A must reference the valve in Stair B.
NFPA 25 does not specify a frequency, but valve inspections (weekly, monthly, or quarterly, depending on supervision) are the right time to verify signage.

Hydraulic Design Information Sign (5.2.5)

Required at each system riser and inspected annually for legibility and attachment.
Applies to hydraulically designed systems. Pipe schedule systems have slightly different requirements but must still have a sign attached to the system riser.

Information Sign (5.2.7 / 4.1.9)

Inspected annually.
Required at each system riser for auxiliary systems such as antifreeze, dry, or preaction.
Must clearly state the area controlled by the associated control valve.
Important: The definition of “system riser” was clarified in the 2022 edition of NFPA 13 and the 2023 edition of NFPA 25 as the piping between the water supply and check valve.

General Information Sign (5.2.8)

Required by NFPA 13 since 2007, but NFPA 25 began enforcing it in the 2014 edition.
This is not the same as the Information Sign.
Includes detailed system data, which may prompt follow-up between owners and contractors.
Annex A.5.2.8 clarifies that this sign should also satisfy the Information Sign requirements noted above.

Antifreeze Sign (5.2.9 / 4.1.10)

Added in the 2017 edition of NFPA 25.
Must include:
- Manufacturer of the antifreeze
- Volume of the system
- Type/brand
- Percentage of solution

Fire Department Connection (FDC) Identification (13.8)

The FDC must clearly indicate what system it serves and whether it is automatic or manual (sprinkler, standpipe, or combination).
Manual standpipes are often overlooked—if manual, the sign must state whether it is wet or dry.
If the fire department must pump above 150 psi, that pressure must also be posted at the FDC.

A Special Note on Control Valve Lists

NFPA 25 Section 4.1.8 requires building owners to maintain a list of all control valves at each system riser and other approved locations.

This is not a signage requirement and cannot be cited as a deficiency. It is the owner’s responsibility. Inspectors should document it as an observation if missing, but it does not carry the same enforceability as the signage requirements listed above.

Wrapping It Up

NFPA 25 signage requirements are straightforward once you separate them from NFPA 13 installation requirements. If it’s listed in Chapters 5 through 14 of NFPA 25, it’s enforceable as a deficiency. If it only appears in NFPA 13—or in other chapters of NFPA 25—it can be recommended to the owner, but not cited.

Always remember: “If it’s not in the table, you’re not able.”