Signs for main drain and inspectors test valves hanging from fire sprinkler pipes

The durable signage required by NFPA 13 preserves fire sprinkler systems and the buildings they serve by providing system information and the locations of critical components

The National Fire Protection Association (NFPA) has complex requirements for labeling the components of a fire sprinkler system. NFPA 13: Standard for the Installation of Sprinkler Systems contains 12 sections detailing the different signs required for a system, with many more specific information requirements for each sign. Despite this guidance, some contractors and building owners fail to install or account for all of these signs, which can cause problems beyond a code violation. Missing fire sprinkler signs can result in system damage, liability, or the worst possible outcome: a sprinkler system that fails in the event of an emergency.

In an article at Sprinkler Age, fire protection engineer John Denhardt wrote about some of the signage problems he’s witnessed as a fire safety contractor, including one that resulted in "over $500,000 in property damage for one property owner." The culprit? A missing sign that should have indicated the presence and location of a second control valve. "In an emergency, the control valves were not able to be turned off in a timely manner and no one on-site knew the location of the second control valve."

Half a million dollars in damage may have been prevented by investing in a sign that costs a few dollars. Clearly, it’s a good investment.

This article will examine the code requirements for fire sprinkler signs according to NFPA 13, simplifying the subject for contractors and building owners.

Are you looking to buy signs to mark your fire protection system? If so, feel free to skip directly to our selection of standard fire signs.

Fire sprinkler system with main drain and control valve signs

This collection of fire sprinkler valves has signs for a main drain and control valve. Assemblies like this are often found in riser rooms.

Most fire sprinkler system valves must be identified with metal or rigid plastic signs

Section 6.6.4 of NFPA 13 stipulates sign requirements for “All control, drain, venting, and test connection valves,” while section expands on the guidance for control valves.

From the 2016 Edition of NFPA 13

6.6.4* Identification of Valves. All control, drain, venting, and test connection valves shall be provided with permanently marked weather-proof metal or rigid plastic identification signs. The identification sign shall be secured with corrosion-resistant wire, chain, or other approved means. The control valve sign shall identify the portion of the building served.* Systems that have more than one control valve that must be closed to work on a system or space shall have a sign referring to existence and location of other valves.* Control Valves. Control Valve Identification. Identification signs shall be provided at each valve to indicate its function and what it controls.

Control valve signs

As the name implies, control valves control the supply of water to an automatic fire sprinkler. For the system to work in an emergency, they must remain open.

Closed control valves are a leading cause of sprinkler failure during a fire; if a valve is shut off during testing or installation and a contractor fails to find and reopen it, the sprinkler won’t perform. If components of the sprinkler system are improperly installed and someone needs to cut off the water supply, failing to find a control valve could result in damage to the system and building. And, if a fire has been controlled and the sprinklers need to be stopped to minimize water damage, it’s essential to know where every control valve is located and what portion of the building it serves.

White rectangular sign with letters reading "Control Valve"

Control valve signs help minimize flooding and fire sprinkler system malfunction.

Drain valve signs

A standard interpretation of NFPA's requirements for drain valves is that a sign needs to identify the main drain valve assembly, which serves to drain water from the system and provides a way to measure water flow during the main drain test. Knowing where the system drains is essential for fire sprinklers that need to be taken out of service for any period of time (for testing or repair), or for systems that must be drained to avoid damage from water freezing in the pipes.

Aluminum sign reading "main drain" in red letters.

This sign marks a main drain, used in maintenance and repairs of sprinkler systems.

For a deep dive into draining fire sprinklers, check out our article on Draining a Fire Sprinkler System.

In addition, NFPA 13 adds an additional sign requirement for dry pipe or preaction sprinkler systems:

From the 2016 Edition of NFPA 13 Systems with low point drains shall have a sign at the dry pipe or preaction valve indicating the number of low-point drains and the location of each individual drain.

The Sprinkler Age article mentioned earlier notes that many contractors fail to include this sign and detailed an example of the consequences:

Lack of providing this sign has caused numerous installing contractors to lose legal claims that were brought against them when systems experienced freeze damage. In one case that I personally know, a maintenance crew drained all the low points that they saw but the system still experienced pipe damaged due to freezing. There were seven low points but two of them were not obvious. The low points were shown on the “as-built” drawings, but because the required signage was not provided, the installing contractor was still found liable.

Venting valves signs

Venting valves are used to vent air that is trapped in a wet sprinkler system. Doing so fights corrosion in the interior of the pipes by reducing the amount of oxygen dissolved in the water, which in turn reduces the chances of blockages or leaks. Some vents are automatic, shutting off when water reaches the vent, whereas others are manual, requiring the valve to be closed after removing excess air. These fire sprinkler system signs ensure that they are identified and closed during normal system operation, and used to vent air when required.

Test connection valve signs

The inspector’s test valve can be opened to simulate water flow through the sprinkler riser. These tests are performed for a variety of reasons: ensuring that the water flow alarm works, testing the opening of a dry-pipe or pre-action valve, or assessing how long it takes for water to arrive at an average sprinkler head at system working pressure. The valve should be marked so that it can be easily found to conduct a test and fully closed when not in use.

Rectangular sign with red text reading "inspectors test"

Inspector's test signs hang near inspector's test valves.

Anti-freeze sprinkler system signs

Antifreeze systems need specific signs explaining the location of systems that are remote from the riser, as well as the specifications of the antifreeze used in them.

From the 2016 Edition of NFPA 13 Where antifreeze systems are remote from the system riser, a placard shall be mounted on the system riser that indicates the number and location of all remote antifreeze systems supplied by that riser. A placard shall be placed on the antifreeze system main valve that indicates the manufacturer type and brand of the antifreeze solution, the concentration by volume of the antifreeze solution used, and the volume of the antifreeze solution used in the system.

The latter requirement was added because antifreeze solutions with too much glycerin or propylene glycol relative to water were found to actually feed a fire. In response, NFPA requires “a mixture of an antifreeze material with water that is prepared by the manufacturer with a quality control procedure in place that ensures that the antifreeze solution remains homogeneous.” Essentially, all antifreeze that is used must be premixed by the manufacturer, with signage detailing that supplier as well as the concentration and volume of the antifreeze in the system. That said, most current antifreeze options are being phased out by NFPA until new, non-flammable mixtures are developed. To read more about this issue, check out our blog: "The Use of Antifreeze in Fire Protection Systems."

Rectangular sign reading "anti-freeze system"

This sign indicates the location of antifreeze system components. Other, more detailed signs are required by NFPA 13.

Additional fire sprinkler system signage is required for fire department connections, hydraulic systems, general information, and signaling

NFPA-compliant fire sprinkler systems require signs marking each connected fire department connection (FDC), and they must include the following information:

  • The service design of the FDC
  • Which part of the building an FDC serves (if it serves only a portion)
  • The "pressure required at the inlets to deliver the greatest system demand" – if the system demand pressure is 150 psi or greater.

In addition, Section of NFPA 13 requires marine sprinkler systems to have an 18" × 18" sign showing the FDC symbol “placed at the connection so that it is in plain sight from the shore access point.”

From the 2016 Edition of NFPA 13 Where a fire department connection services only a portion of a building, a sign shall be attached indicating the portions of the building served. Each fire department connection to sprinkler systems shall be designated by a sign having raised or engraved letters at least 1 in. (25 mm) in height on plate or fitting reading service design — for example, AUTOSPKR., OPEN SPKR., AND STANDPIPE. A sign shall also indicate the pressure required at the inlets to deliver the greatest system demand. The sign required in shall not be required where the system demand pressure is less than 150 psi (10.3 bar).

Hydraulic design information signs

As part of NFPA 13 sprinkler system acceptance requirements, all hydraulically designed sprinkler systems must be appropriately labeled as such "with a permanently marked weather-proof metal or rigid plastic sign secured with corrosion-resistant wire, chain, or other approved means. Such signs shall be placed at the alarm valve, dry pipe valve, preaction valve, or deluge valve supplying the corresponding hydraulically designed area." [25.5.1]

A blank hydraulic calculation sign hung on a fire sprinkler system

While this hydraulic system sign is properly placed, the contractor failed to complete it, resulting in a code violation. Source: Fire Protection Deficiencies.

There are two basic designs for a sprinkler system: the older pipe schedule method and the hydraulic design. Pipe schedule requires a specific number of sprinklers to be fed off of a specifically-sized pipe at system pressure, whereas hydraulic systems allow the use of a flexible number of sprinklers based on a certain area’s hazard classification. NFPA restricts the use of pipe schedule systems for new installations, so the vast majority of sprinkler systems will be hydraulically designed and require appropriate signage.

From the 2016 Edition of NFPA 13

25.5.2 The sign shall include the following information:

1. Location of the design area or areas.
2. Discharge densities over the design area or areas.
3. Required flow and residual pressure demand at the base of the riser.
4. Occupancy classification or commodity classification and maximum permitted storage height and configuration
5. Hose stream allowance included in addition to the sprinkler demand
6. The name of the installing contractor

General Information signs

All sprinkler systems require a general information sign that details the "system design basis and information relevant to the inspection, testing, and maintenance requirements required by NFPA 25" [25.6.1]. As with certain other signs, it must be "a permanently marked weather-proof metal or rigid plastic sign, secured with corrosion-resistant wire, chain, or other acceptable means"[25.6.2]. The sign must be present at the "system control riser, antifreeze loop, and auxiliary system control valve" and must have up to 19 different pieces of information.

From the 2016 Edition of NFPA 13

25.6.2 The sign shall include the following information:

(1) Name and location of the facility protected
(2) Occupancy classification
(3) Commodity classification
(4) Presence of high-piled and/or rack storage
(5) Maximum height of storage planned
(6) Aisle width planned
(7) Encapsulation of pallet loads
(8) Presence of solid shelving
(9) Flow test data
(10) Presence of flammable/combustible liquids
(11) Presence of hazardous materials
(12) Presence of other special storage
(13) Location of venting valve
(14) Location of auxiliary drains and low point drains on dry pipe and preaction systems
(15) Original results of main drain flow test
(16) Original results of dry pipe and double interlock preaction valve test
(17) Name of installing contractor or designer
(18) Indication of presence and location of antifreeze or other auxiliary systems
(19) Where injection systems are installed to treat MIC or corrosion, the type of chemical, concentration of the chemical, and where information can be found as to the proper disposal of the chemical

Signaling System Signs

Finally, if a structure has a central station, auxiliary, remote station, or proprietary protective signaling system in addition to a local alarm, NFPA 13 directs that a sign should be installed "near the device" and suggests the following wording: "SPRINKLER FIRE ALARM — WHEN BELL RINGS CALL FIRE DEPARTMENT OR POLICE." [A.8.17.1]

Round sign reading "sprinkler fire alarm when bell rings dial 911"

This round "dial 911" sign installs on a fire alarm bell.

While most fire sprinkler system signs must be metal or plastic, those not covered by NFPA rules may be made from other materials

NFPA 13 is very specific about the physical design of signs that are required for certain areas. All valve signs, hydraulic design signs, and general information signs must be a "permanently marked weather-proof metal or rigid plastic identification signs secured with corrosion-resistant wire, chain, or other approved means." In addition, the sign showing the Fire Department Connection must have "raised or engraved letters at least 1 in. (25 mm) in height on plate or fitting" that spell out the service design of the system. Beyond those specific signs, a fair interpretation of NFPA code is that any other markings can be decals, stickers, or placards, as long as they are durable and convey the necessary information.

Keep your fire sprinkler system compliant and safe

Making sure a fire sprinkler system is properly marked doesn’t simply keep it compliant with code – identifying crucial components also helps contractors and building owners avoid liability and reduce the risk of system failure during an emergency. At QRFS, we offer a variety of signs, decals, and stickers to help you satisfy NFPA 13 and other safety signage requirements.

Click here to browse our selection of fire protection system signs, including valve signage, drain signs, stickers, decals, and more.

Do you have more questions about fire sprinkler system signage? Comment here, call us at +1 (888) 361-6662, or email us at [email protected].

This blog originally published at on December 14, 2017, and updated on January 1, 2019. Like what you've read? Check us out at or on Twitter @QuickResponseFS.