NFPA 15 Standard for Water Spray Fixed Systems for Fire Protection

Fire safety is of prime importance while designing any building to ensure the protection of occupants as well as the facility. Fire safety equipment is installed in almost every building in America, but it does not mean that fire will never happen.

Fire is an unpredictable catastrophe that can start at any time. So, one needs to be always ready to combat such contingencies. To handle the fire at the most appropriate time, one 'requires adequately installed and functional fire safety equipment such as Water Spray Fixed Systems.

What is Water Spray System?
Water Spray System is a fixed pipe system that is connected with a water source and spray nozzle. The system is associated with the automatic detection system or fire alarm to get activated in case of fire.

Upon activation, it supplies water at a high pressure to control the fire. Water Spray System is employed to protect from fire caused by flammable liquid, gases, oil switches, electrical equipment such as transformers, etc.

NFPA 15: Standard for Fixed Water Spray Systems

All the instructions relevant to the water spray system are provided by NFPA 15. NFPA 15: Standard for Water Spray Fixed Systems for Fire Protection helps control fire by giving guidance about water spray system layout and proper testing and maintenance of the system.

Selection of a nozzle according to NFPA 15

NFPA 15 contains all the instructions for selecting the correct spray nozzle to achieve the proper coverage area and water density requisite to extinguish the fire.

The nozzle selection under NFPA 15 involves considering different factors such as the purpose of the system, discharge characteristics of the nozzle, thermal draft condition, equipment configuration, and atmospheric conditions.

NFPA 15 provides the method to determine the range of water spray by measuring velocity and water droplet size. Velocity is an important factor while selecting a proper nozzle for a fixed water spray system, and no one can change a nozzle without fulfilling the requirements of NFPA 15 standard.

Requirements for proper pipes and hangers selection
Apart from nozzles, the standard covers all necessary recommendations regarding water spray system pipe, fittings, and hangers. According to NFPA 15, Pipe hangers and support should be designed to endure the impact of maximum operating pressure. The standard requires the pipes capable of withstanding at least 175psig water pressure so that they do not collapse in case of emergency.

All the pipes and fittings should be made of anti-corrosive material, and they should be galvanized to ensure maximum protection. If the galvanization is damaged at any point, the exposed steel should be covered with resistant paint.

Actuation valve for fixed water spray system
Under the recommendations of NFPA 15, each water spray system must possess system actuation valves (for opening and closing of the system) to control the flow of water. Actuation valves are required both for manual as well as automatic operation.

In a manual system, these actuation valves should be present on the access points, easy to identify in an emergency. In addition to these valves' locations, NFPA 15 covers all requirements for the types of valves.

System actuation valves that are required for automatic systems are known as deluge valves. NFPA 15 ensures that these valves are properly regulated hydraulically, electrically, or mechanically to spray water when needed.

Instructions for proper inspection and maintenance of fixed water spray system

Apart from proper design and fitting of fixed water spray systems, NFPA 15 makes sure the appropriate maintenance and inspection of the system to avert the fire danger.

It ensures :

· Adequate water supply
· Annual inspection and cleaning of nozzles and strainers
· Proper cleaning and calibration of values and detectors


Fixed water spray systems provide safety and protection against fire, but they can only work effectively when they comply with the requirements of NFPA 15. NFPA 15 covers all instructions and requirements for optimal functioning and maintenance of fixed water spray systems.

NFPA 17A Standard for Wet Chemical Extinguishing Systems


Cooking has become the leading cause of fire-related causalities worldwide. According to NFPA's 2020 report" U.S Home Cooking Fires," almost 49% of home fires in America are caused by unattended cooking. The report highlighted that nearly 173,000 cooking fires occur in homes every year, resulting in 550 deaths and 4,820 civilian injuries.

That is quite appalling!

Considering the escalating Kitchen related fire cases in the country, NFPA provides necessary instructions and recommendations regarding the Wet chemical extinguishing systems to control cooking-related fire accidents.

Wet chemical extinguishing systems

Wet chemical fire extinguishing systems are most commonly used to provide fire protection in commercial cooking operations. These commercial cooking operations include restaurants, plenums, institutional hoods, ducts, filters, and other cooking appliances.

NFPA 17-A Standard for Wet Chemical Extinguishing Systems

NFPA 17A: Standard for Wet Chemical Extinguishing Systems contains necessary information about the design, installation, maintenance, and inspection of wet chemical extinguishing systems. The standard provides all recommendations required for proper selection of :

· Minimum and maximum pipe lengths
· Quantities of agent used
· Specific pipe sizes
· Nozzles size and pressure
· Flow rate

In case of fire, a specific liquid agent is sprayed by extinguishers with a pre-determined flow rate and pattern from the nozzle. Upstream of the nozzle, a Stainer shall be present along with a protective cover cap to prevent the entry of contaminants or foreign particles in pipes.
Requirements for Wet Chemical Extinguishing Systems installation.

According to NFPA 17A, wet chemical extinguishing systems shall be approved by an authorized person. Before the installation, the installing contractor shall ensure that appliances, pipes, hoods, and ducts are correctly positioned and protected according to the standard. The team shall verify that accurate nozzle and pipes are used and fastened in the system to protect against the fire.

Piping integrity test.

After verifying these parts, the next step required, according to NFPA 17 A, is the piping integrity test to ensure the continuous flow of liquid. For this purpose, NFPA 17A includes four main steps :

· Physical examination of pipes to check tightness.
· To check the normal operating pressure of the system using nitrogen or dry air.
· Confirmation that the nitrogen or dry air is discharged out of the nozzle properly
· Verification shall be done by the authority having jurisdiction.

After the verification is completed, all the devices need to be appropriately labeled with specific instructions given by NFPA 17A. If any other fire suppression system is already installed in the building, the AHJ will check the system to ensure its compliance with the wet chemical fire extinguishing system.

NFPA 17A requirements for the selection of proper nozzles

The nozzle should be accurately marked to assist in the selection of the proper nozzle requisite for operation. NFPA 17 A also ensures that the entire structure comprises anti-corrosive, non-combustible material such as steel or brass.

While selecting the proper nozzle for the system, the nozzle coverage area and its purpose are considered. For example, for duct xx-tr nozzle with 2 flow point shall be used while xx-ed nozzle with 4 flow point is required for Plenum.

Appropriate tanks that comply with nozzles

NFPA 17 A covers recommendations about selecting tanks with appropriate capacities based on Flow point in addition to nozzle requirements. Flow point actually refers to nozzle flow capacity, which determines the tank capacity.

Characteristics of Wet Chemical extinguishing systems
Wet Chemical fire extinguishing system shall have the following characteristics according to NFPA 17A.

· Shutoff devices having the ability to shut down all heat and electrical sources automatically.
· Manual activation even in case of the automatic system except for the systems for common exhaust ducts
· Monitoring devices for electrically controlled automated systems to provide an audio or visible signal in case of dysfunction.
· If any other fire suppression system is present in the building, such as a fire alarm system, the two systems need to be connected so that both can respond in an emergency.

Proper testing of Wet Chemical Fire Extinguishing Systems
Apart from the proper design and installation of wet chemical fire extinguishing systems, proper maintenance and testing are also crucial to ensure the protection you need.

According to NFPA17A:

These systems need to be tested once a month to confirm that all parts are correctly located and protected. Make sure that nothing is obstructing the actuators and they have not been tempered. Thoroughly examine the system to check all the tags and certificates are in place.

NFPA 17-A requirements for inspection of Wet Chemical Fire Extinguishing Systems

NFPA 17A requires a comprehensive and detailed inspection of the system twice a year and after every activation according to its instructions. The inspection involves the examination of the system to check whether the hazard has changed the system or not.

It includes assessing all parts, including nozzles, pipes, and other devices, to ensure that there isn't any obstruction and the agent is properly flowing.

The Technical Committee responsible for NFPA 17A formulated 11 minimum requirements with the objective of providing a thorough procedure for approval, testing, and maintenance of systems. All the instructions provided by NFPA 17-A are necessary to follow before and after the installation of Wet Chemical, fire extinguishing systems to ensure fire protection and safety.

NFPA 17 Standard for Dry Chemical Extinguishing Systems


Fire is one of the most devastating humanmade disasters, occurring frequently and engulfing thousands of lives every year. Losing your beloved one and property in front of your eyes is the scariest thought. But, it is not impossible to combat.

Fire can be controlled through adequately installed and functional fire suppression systems. In this regard, Dry Chemical Extinguishing Systems are a great choice, especially when the sprinkler system is not available.

Dry Chemical Extinguishing Systems

These systems are effective against class ABC fire, and for industrial applications, they act as automatic fire suppression systems.

Dry chemical extinguishing systems release a composition of dry chemical powder to extinguish the fire. The most common fire extinguishing powders used in Dry chemical extinguishing systems include:

  • sodium bicarbonate
  • potassium bicarbonate
  • monoammonium phosphate
  • and urea complex.

Their only disadvantage is that they throw a lot of powder at the hazard site, which needs to be cleaned up, but that does not matter when compared to these life-saving systems' significance.
NFPA 17: Standard for Dry Chemical Extinguishing Systems

Like the other fire suppression systems, dry extinguishing chemical systems must comply with NFPA standards. In this regard, NFPA 17:Standard for Dry Chemical Extinguishing Systems provides all essential requirements for purchasing, designing, installing, approving, and inspecting these systems.

According to NFPA 17, Dry chemical extinguishing systems are designed to provide maximum protection against the fire in the following cases:

  • Combustible liquids and gases
  • Combustible solids that melt in the fire
  • Electrical hazards such a transformers and circuit breakers
  • Combustibles including cloth, paper, and wood
  • Kitchen hazards

Selection of appropriate Operating devices

NFPA 17 provides recommendations for operating devices as well. The standard illustrates that all operating devices used for dry chemical extinguishing systems should encounter the hazard. They should be marked with their minimum and maximum temperature limits, and they should at least withstand the temperature range of 0°C to 49°C.
Requirements for Discharge Nozzles

Discharge nozzles made up of corrosion-free material such a brass or stainless steel shall be used for the system. While selecting discharge nozzles, ensure that they are of adequate strength and capable of enduring fire exposure malformation. They should be of noncombustible material with permanent identification marks.

Another vital point that must be kept in mind while selecting discharge nozzles is blow off caps or devices to hinder the entrance of moisture in piping.

NFPA 17 instructions for manual actuators

NFPA 17 specifies that all devices, including the manual actuators, shall be designed to protect in case of fire. For this purpose, all manual actuators of Dry chemical extinguishing systems can have pictographs, but the lettering size should be at least size 6.35 mm in height.

Guidelines for selection of pipes and fittings

All the pipes and fittings required for the system shall be according to the requirements of NFPA 17. According to NFPA 17 requirements, pipe and fittings, all be of noncombustible material, and they shall be capable of withstanding maximum expected pressure in the piping system.

They should be appropriately galvanized and made up of corrosion-resistant stainless steel, brass, or copper material.

Quantity of dry chemicals for dry chemical extinguishing systems

According to NFPA 17, if the area is mostly enclosed with less than 15% openings, a total flooding system can be used. But if the area of unclosable spaces is less than 1%, no extra dry chemical is needed. If the unclosable openings are present between 1-5 %, an extra dry chemical suppressant can be employed.

Other NFPA 17 requirements for Dry Chemical Extinguishing Systems

Other requirements of NFPA 17 include:

Only trained personnel shall design, install, and maintain dry chemical systems. It specifies that only Authorities having jurisdiction shall be competent to approve the fire protection system.

Under the supervision of NFPA 17, all the equipment or materials used in dry extinguishing chemical systems should be appropriately labeled with the identification mark of the authorizing organization.

Automatic detectors used in the system should be listed. They should be capable of detecting heat, flame, smoke, vapors, or other fire-related hazardous conditions.

Proper coiling of hose around the hose reel to ensure easy uncoiling in case of emergency.

Hose nozzle shall be devised in such a way that one person can easily handle it. It should have an incorporated shutoff device to regulate the flow of dry chemicals.

The dry chemical used in this fire suppression system shall not be replaced with another until approved by the testing laboratory and recommended by AHJ. Different types of dry chemicals should not be mixed without authorized personnel's permission, as they may cause bodily harm.

The carbon dioxide used as expellant gas shall not have a vapor pressure of less than 99.5%, and its water content should not exceed 0.01 %.In the case of nitrogen gas as an expellant, it should have a dew point of (-52.2°C) or lower.


Dry chemical extinguishing systems are designed to control the fire immediately. The sooner the fire can be contained, the lower the chances of causalities and property damage. However, these fire suppression systems' designs and installation conditions are not the same for all the buildings. They can work effectively only when they are installed according to the structure and requirements of NFPA 17.


How Visual Cues Help In Fire Safety

boy aiming for shot the billiard ball, black and white

Visual communication has become a proven and worldwide famous tool for the workplace's safety in fire hazards. The tool helps employees understand all essential safety measures and practice them at the workplace to ensure the vicinity's safety that provides the facility's safety and improves the employees' emergency response at the time of emergency.

Employees should attend safety training in visual communication tools. If the employees are not trained on the visual signals, they won't follow the visual signals in case of any emergency, leading to a disaster. To effectively implement these visual signals at the workplace, the employees must know what they mean and how to use them. The effective use of visual communication will help the organization create better workplace safety and standardization of 5S at all levels.

Examples of Fire Safety

There are different forms of visual communication companies can use for workplace safety. Wall signs are the most important type of visual communication. These signs are primarily used for fire safety and to alert people to use emergency exits. These signs help people identify necessary safety equipment like fire extinguishers and PPE or any other available equipment at the facility. Wall signs are proven useful against fire safety as they are easy to approach, eye-catching due to their contrasting colors, mostly having red text with white background to make anyone alert.

Companies can use floor markings as another tool of visual communication for the fire safety of their facility. Floor markings can include signs like fire extinguishers, electrical panels, and potentially dangerous areas identification using the red floor tape. Floor markings are more useful than wall signs because they can cover more area and give a complete track to follow in an emergency. For floor markings, the use of tape markings is quite useful to chalk out plans for emergency response, particularly the use of glow-in-dark tapes. This type of tape is used to mark emergency exits and set a pathway to follow in a power failure.

Machine and pipe labeling is another type of visual communication that ensures fire safety concerning devices and pipelines. However, it is quite dull but essential to mark all the machines and pipes in a factory or manufacturing unit to prevent potential fire hazards. Every device must carry labels conveying the information on how to use it and what safety equipment to use for operating a particular machine. Especially machines used for welding/cutting must be handled with care using the safety equipment as they can result in fire eruption. Similarly, pipelines carrying potentially dangerous gases and liquids must-have a label on them for compliance with ANSI and OSHA regulations and prevent employees from accessing or opening them without SOPs. It will help employees to report any spilling or leakage to the emergency teams.

Employees and Management can make the workplace safe if they are appropriately trained in using the different forms of visual communication that can help prevent fire hazards.


Is NFPA 25 Mandatory


Complying with NFPA 25 is mandatory for businesses to ensure their fire protection systems operate optimally and avoid hefty penalties upon violating the code.


NFPA 25 is a globally recognized compliance baseline for inspection, testing, and maintenance (ITM) of water-based fire suppression systems. This standard's objective is to verify the integrity and efficacy of the systems and ensure they operate optimally in case of a fire breakout. It specifies the minimal care and amount of work required to maintain the systems. In the US, this standard has been adopted in most states through either the building code or the fire code.


What is the Importance of NFPA 25?

Once you install a system, the NFPA 25 standard provides a suggested timeline and frequency to conduct specific requirements - Inspection, Testing, and Maintenace.
Inspection: A meticulous examination of the system to detect physical damages and signs of corrosion, deep dents, or any other flaw.
Testing: A physical testing of the system ensures it withstands immense pressure during operation and has no leakage.
Maintenance: Experts perform jobs to repair or maintain the system, like replacing disposable components or reinstalling the hose and tamper seal.


It is mandatory to conduct ITM monthly, quarterly, or annually. According to NFPA 25, the property owner or designated representative is accountable for the fire protection system's overall maintenance. During monthly inspection, the on-site fire protection person should examine the pipe system gauges, ensure water pressure maintenance, and inspect the alarm valves.

However, you must outsource quarterly and annual ITM services to licensed fire protection experts. They will determine the facility's safety by identifying areas or processes that could jeopardize people or property during a fire breakout. In case hazardous conditions are determined to exist, recommendations will be made to fix the issues in a reasonable time frame. Thus, you will ultimately take your facility's safety to the next level while complying with the NFPA 25.

You are also advised to retain all the recent inspections and test records and be prepared to show them to the service provider when requested. Keeping these inspections up-to-date will help you avoid fire protection system failures and code violations.


NFPA 25 Inspection – Things to Keep in Mind

Preparing for an NFPA 25 inspection can be stressful if it's your first time. This is especially true for premises that have gone through significant remodeling and require a completely new look at their safety systems. While it's not always a mandatory part of running any property, it's a good idea to follow the guidelines laid out in the regulation as closely as possible. This can not only save lives if something eventually goes wrong, but it can also contribute positively to your bottom line in terms of time and money invested in the maintenance of your buildings.


Is an NFPA 25 Inspection Mandatory?

The NFPA 25 inspection standard is just that – a standard. It's not a legal regulation that dictates how often your premises should be inspected, contrary to what some believe. However, it may still be mandated on a local level through various laws and regulations, and it's essential to pay attention to those if you want to ensure that you're compliant. Check your local building codes, get a consultation with a specialist – or even submit an inquiry to the fire marshal, depending on how these regulations are structured in your region. But as we mentioned above, it's a good idea to submit your premises for an NFPA 25 inspection regularly, even when it's not a strict legal requirement.


How Frequently Do I Need to Have My Systems Inspected?

NFPA 25 provides various suggested inspection frequencies for the different components of your fire suppression system. Many elements can be checked quarterly or even annually – such as pipes and fittings, sprinklers, spare emergency sprinklers, and more. However, others require a much more systematic approach, such as control valves (which have to be checked weekly or monthly depending on their type). Your sprinklers will typically have to be sample-tested every five years, and there are also 10- and 20-year testing periods for different types of sprinkler systems. Some system components depend on their manufacturer's guidelines for their testing frequency, so you'll have to consult them to ensure that you're compliant.


NFPA 25 Testing Requirements

Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems

NFPA 25 is the baseline for inspection, testing, and maintenance of water-based fire protection systems. Compliance helps maximize system integrity to avoid failure and ensure fast, effective response in a fire emergency.


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Usually, only parts of a system must be tested to validate the fundamental component for passing the inspection. For example, with sprinklers, you're generally required to test around 1% of the ones connected to a specific system. However, the number must not be less than four. You should consult with an inspection specialist to ensure that you're not missing any important details, which is a real risk when it comes to something as complicated as an NFPA 25 inspection. There are also specific requirements that might prompt further inspection – such as the presence of corrosion on certain elements. Leaks should be reported before the inspection so that additional attention can be paid to their area.


How do I prepare for a fire inspection?

It isn't much you should do specifically to get things ready for an NFPA 25 inspection other than to do a rudimentary check on your sprinklers, valves, and pipes to ensure that there are no obvious signs of corrosion or leaks. If you are dry-testing individual components, make sure that you know where the shutoff valve is. Sometimes you may need to kill the flow in advance to ensure that the system will be in a proper condition for testing when it comes. If in doubt, consult a specialist in advance to be sure that everything will be prepared adequately.

It's a good idea to take notes during the inspection to ensure that you'll be better prepared in the future. This is the kind of process where you can benefit from prior knowledge, even when you support a dedicated specialist assisting you through it. Don't leave any doubts hanging in the air either, because it's better to resolve those questions well in advance rather than finding out that you have to modify the test – or postpone it all together – in the middle of the whole ordeal. When done right, this is a relatively hassle-free process that will ensure that everything is in order with your building in the long term when it comes to fire safety.


Final Words

Fire protection systems minimize the risk of damage and loss of lives by quenching fire within seconds. These systems suffer wear and tear issues like any other building system. The regular, timely inspection and testing of the fire protection systems as per NFPA 25 will ensure that they are optimal and provide your facility with an extra protection level.

Additionally, NFPA 25 is regularly being enforced by the fire department of Orange County. So you must perform mandated inspections to avoid any violations and save yourself from hefty penalties.