Nitrogen: Membrane vs PSA Technology

It has been established that replacing the Oxygen in your sprinkler pipes with Nitrogen will reduce, or even stop, corrosion; thus, significantly extending the service life of your sprinkler pipes, and reducing maintenance and repair costs.

Since the solution to corrosion is nitrogen, the question becomes how to produce and inject Nitrogen into your fire sprinkler system. There are two methods for Nitrogen generation, Membrane technology and PSA technology.

Membrane Technology
Nitrogen generating membranes line the fire sprinkler pipes and generates gaseous Nitrogen on-site. The polymeric hollow fiber, which makes up the membrane, permeates oxygen, water vapor, and impurities out of sidewalls, allowing Nitrogen to flow through its center. Membranes require a minimum of 125 PSI of clean, dry compressed air. A refrigerated air dryer will ensure clean and dry air is reaching the membranes. This is important for increasing the lifespan of the membrane, as properly designed and maintained membranes can have a lifespan of 8 to 13 years.

PSA Technology
Pressure Swing Absorption (PSA) technology has vessels full of Carbon Molecular Sieve (CMS). Under high pressure, CMS absorbs impurities, allowing Nitrogen to pass through and into the Nitrogen receiver tank. This is an efficient way to generate nitrogen as it has an air to nitrogen ratio of 2:1, while the ratio for membranes is 3:1. It has a greater longevity and performance as the lifecycle before re-nourishment is 20-25 years. It holds 98%+ purity for longer and outputs 39% more nitrogen production. PSA technology also requires 46% less air compressor load, which will significantly increase the life of your air compressor.

Complimentary Technology for Corrosion Protection
High purity Nitrogen must be equally distributed throughout the entire sprinkler piping system in order to effectively inhibit corrosion. An automatic, pneumatic vent should be installed at each riser of your fire sprinkler system to provide a low volume, constant purge of Nitrogen throughout each fire protection system. This vent also provides a testing point for monitoring Nitrogen levels in the system.

A portable, nitrogen purity sensor is a hand-held device that can be connected to your pneumatic vent or at any system sampling port to verify the desired levels of Nitrogen are being achieved throughout the sprinkler system piping.

For large systems, or systems that are monitored offsite, you have the option of utilizing an electronic manifold that can monitor each Zone of your system and track a daily sampling of Nitrogen levels. If purity does not meet specifications during a sampling phase, the manifold will cause the Nitrogen vents to remain open for a continual purge until the next sampling phase. You Nitrogen generator will provide the Zone with more Nitrogen until purity specifications are met.

You can learn about corrosion solutions for Wet and Dry/Pre-Action systems, or the length of service life for specific steel types at A1’s Blog.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane

Galvanized or Black Steel Pipe to Combat Sprinkler Pipe Corrosion?

Fire sprinkler systems experience corrosion due to the interaction of oxygen, an unprotected metal, and moisture. In 25 years, 35% of wet fire sprinkler systems have significant corrosion issues. In only 12.5 years, 73% of dry and pre-action systems have significant corrosion issues.

Corrosion will cause leaks in your sprinkler pipes, resulting in costly repairs which may include replacing piping, fittings, or even the entire system, facility or equipment damage from water leaks, and sprinkler head blockages.

To combat corrosion, fire sprinkler systems utilize either galvanized steel or black steel for pipes, as each type of steel has corrosion resistant properties.

Galvanized and Black Steel

Galvanized steel pipe is hot-dipped in zinc to have a protective coating on the walls of the pipe. The zinc coating, or galvanizing, acts as a sacrificial anode to reduce the corrosion of steel pipe. However, galvanized steel pipe does corrode in any pitted area or space where the galvanized coating is damaged or missing.

Black steel pipe has little to no protective coating. This is the most commonly used steel pipe for sprinkler systems. The oxygen within the water is quickly dissipated, thus reducing the corrosion potential. However, black steel pipe does corrode in a uniform thinning of the walls.

Corrosion Solution

Since neither type of steel is able to stop corrosion, one of the other agents in corrosion, either oxygen or moisture, must be addressed in order to stop the problem. While water is inevitable in sprinkler pipes (even dry system pipes will have condensation), Oxygen can be replaced with Nitrogen – effectively breaking the corrosion triangle.

Dry and Pre-Action systems can be pressurized with Nitrogen, instead of air. Wet systems can have the pipes charged with Nitrogen before being flushed with water, so that any “air” pockets are actually pockets of Nitrogen. Read more about corrosion solutions specifically for Dry/Pre-Action Systems and Wet Systems.

Testing Corrosion Rates in Steel Pipes

An independent lab has been conducting ongoing, long-term exposure tests to compare the performance of Nitrogen vs Oxygen, in both black steel (schedule 10) and galvanized pipe, and the effects on corrosion. Each pipe segment is subjected to compressed air or supervisory nitrogen, as they would be in a practical application of a dry pipe fire sprinkler. At regular intervals, the pipes are opened and the amount of corrosion is measured so that the rate of corrosion can be calculated.

The images below show pipe segments that have been exposed to either compressed air or 98% Nitrogen for 6.5 years, and in both the state the pipe was received and then that pipe segment cleaned. At the rate of corrosion found, the Black Steel Pipes would last 19.8 years with compressed air and 60.9 years with 98% Nitrogen. The Galvanized Steel Pipes would last 9.2 years with compressed air and 162.3 years with 98% Nitrogen. The results clearly show that a significant cost savings can be realized by using black steel pipe in combination with Nitrogen supervision.

Black Steel


Black Steel, filled with compressed air
Black Steel, filled with 98% Nitrogen






Galvanized Steel

Galvanized Steel, filled with compressed air
Galvanized Steel, filled with 98% Nitrogen






A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane

How to protect Wet Sprinkler Systems from Pipe Corrosion

Corrosion is a problem that must be addressed in both dry pipe and wet pipe sprinkler systems. In this article, we will discuss pipe corrosion in wet sprinkler systems and methods of preventing the corrosion.

The water that fills wet sprinkler pipes contains approximately 10 parts per million (ppm) of dissolved oxygen. All wet systems experience initial corrosion because of this dissolved oxygen. However, this corrosion is self-limiting as some of that dissolved oxygen will be consumed until the system is refilled with fresh, oxygenated water.

The primary catalyst of pipe corrosion in a wet system is air that has been trapped in air pockets of the pipes. These air pockets exist frequently within wet system pipes at high points of the piping. These trapped air pockets contain 20.9% oxygen, which can fully sustain electrochemical corrosion. As a result, pinhole leaks eventually develop at the location of the air pockets. These leaks have costly results including property and equipment damage, ongoing repairs to pipes or full system replacement, sprinkler head blockages, and an inoperable fire protection system that puts your people and assets at risk.

In order to prevent pinhole leaks, there must be less than 2% oxygen in the trapped space (reduced from the 20.9% that would typically be present). There are several preventative actions that can be taken: wet air vents, auto inert with nitrogen, and remove oxygen from the water. While each action can be taken individually, the best results occur when they are combined.

Wet Air Vents  wet air vent

Installing wet air vents is the most basic step you can take to reduce oxygen corrosion in your wet sprinkler pipes. Your Life Safety Partner will install the wet air vents at high points and other potential areas where air can be trapped, in order to provide a vent to remove the air. There are two types of wet air vents, single and dual. Both types remove the oxygen from the pipe, venting it outside the sprinkler pipe. A single vent removes the air and closes the valve when water reaches it, this water then drains back into the sprinkler pipe. The single vent will discharge any overflow so it should not be used in areas that are water sensitive. A dual vent will not discharge water so it is safe to install in water sensitive areas. As the pressure from the sprinkler pipe drops, any collected water in the air vents will automatically drain back to the sprinkler pipe through the secondary valve. The dual valve also creates redundancy, eliminating any failure concerns.


Auto Inert with Nitrogen

Filling the sprinkler pipes with high purity nitrogen gas prior to charging the system with water can ensure that corrosion in all trapped air locations is slowed. To do this to a wet sprinkler pipe system, you must first drain the fire protection system of all water and install an auto inert system. The fire sprinkler system is then filled with 98% pure nitrogen through the inert system. By displacing the trapped air with high-purity nitrogen, you minimize the source of oxygen to sustain electrochemical corrosion and corrosion cells have less chance of propagating.

You can use this technique in place of wet air vents, as installation of wet air vents may not always be possible due to lack of headroom or varying elevations, which make identification of trapped air pockets challenging or impossible. However, the best results for slowing corrosion occur when you combine the two solutions.

Removing Oxygen from a Wet Pipe Sprinkler System

Removing oxygen from a wet pipe sprinkler system is the best option to slow, or eliminate, internal wet system corrosion. In addition to the wet air vents, this method removes the oxygen from the trapped air pockets and reduces the dissolved oxygen in water to 1.0 ppm or less.

First, the wet pipe system is pre-purged with nitrogen. This changes the pockets of trapped air to pockets of trapped nitrogen gas, which does not act as a catalyst for corrosion like oxygen does. The sprinkler pipe is filled with deoxygenated water, 1.0 ppm or less of dissolved oxygen. This deoxygenated water, which is below the threshold of oxygen known to cause corrosion, stays in constant contact with the sprinkler piping. There is now not enough oxygen in the water to dissipate into the trapped nitrogen gas pockets, which protects the areas of pipe that would have corroded under normal circumstances.

Fully Oxygenated Water in a Wet Sprinkler Pipe
De-Oxygenated Water in a Wet Sprinkler Pipe








A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane


Stop Dry Sprinkler Pipe Corrosion

Understanding the correct cause can help you to slow or stop dry sprinkler pipe corrosion.

Microbiologically influenced corrosion (MIC) was once thought to be the primary threat to sprinkler pipe longevity. However, further research has found that oxygen is the primary factory in sprinkler pipe corrosion for both wet and dry pipe systems. In this article, we will discuss how corrosion occurs in a dry sprinkler system and the options for preventing or slowing this corrosion in order to maintain your system and extend the life of your sprinkler piping.

The corrosion triangle illustrates the three factors necessary for corrosion to take place: an unprotected metal, electrochemical potential in the form of oxygen, and electrolyte in the form of moisture. When all three factors are present, there interaction results in corrosion of the unprotected metal. To prevent corrosion, you must remove one factor in the corrosion triangle.

Removing the Unprotected Metal from the Equation

Galvanized steel prevents corrosion by having a protective surface between the metal and the water or air; Black steel pipe has little to no protective coating. However, both galvanized steel and black steel pipes present opportunities for corrosion – an issue we will go into further in a future blog.

Removing Water from the Equation

The definition of a dry sprinkler pipe system says that the sprinkler pipes are dry – without water. And this is true, the purpose of a dry sprinkler system is to provide piping without water in sensitive areas, such as areas where the water in sprinkler pipes would freeze or locations where any water leakage could cause serious damage. (Although, if your sprinkler system is located in an area where any water can cause serious damage to the facility or equipment, it is best to look at other fire suppression options such as aerosol based or clean agents.)

However, dry sprinkler pipes will still collect trace amounts of water due to hydrotesting, flow testing, and condensation. Even when you properly drain the system on a regular basis (read more on how to drain your dry system pipes here – drip drum blog), the water is present and can react with the pipe and oxygen to create corrosion. The remaining option is to remove the oxygen from the dry pipe system in order to prevent corrosion.

Removing Oxygen from the Equation

Dry sprinkler and pre-action system pipes are pressurized with air until the system is alerted that a fire is occurring, at which time the sprinklers activate releasing the air from the system and filling the pipes with water. Instead of pressurizing these pipes with air, however, you can pressurize them with nitrogen, which does not react with the water or pipes to create corrosion.

Ongoing, long-term exposure tests have been conducted, and have shown that nitrogen filled sprinkler pipes slow or stop corrosion and extend the life of the sprinkler pipes significantly. This preventative measure for your dry sprinkler system can save you money in costly repairs due to corrosion including property and equipment damage, ongoing repairs to pipes or full system replacement, sprinkler head blockages, and an inoperable fire protection system that puts your people and assets at risk.

Nitrogen arrests electrochemical, galvanic and MIC corrosion. The nitrogen also prevents ice plugs by ensuring a -40F to -70F dew point within the sprinkler system. As high purity nitrogen enters the sprinkler piping, corrosive oxygen is displaced – preventing corrosion, slowing corrosion that may already have occurred, and maintaining your sprinkler system for a longer life span.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane

Drum Drip Maintenance

What are Drum Drips?

Drum drips are drains on dry sprinkler systems, which are used to empty the dry sprinkler pipe of any water that has collected due to condensation or water draining within the system. Since dry pipe systems are utilized in areas where water may freeze, it is important to regularly remove any condensed water to prevent freezing and damage to the pipes.

Drum drips can also be called auxiliary drains, drip legs, and condensate drains. No matter what they are called, a drum drip consists of two, 1-inch valves with a short section of two-inch pipe between them. These are normally located at the lower points of the system or where piping elevation changes may occur.

Locating and Labeling Drum Drips

Systems may have multiple drum drips and it is important that each be drained on a regular basis to prevent costly damage from freezing water. NFPA standards require that drum drips within buildings be identified so that they are easier to maintain. You must also have an informational sign at the system’s control riser that includes the location of all drum drips.

When to Perform Drum Drip Maintenance

All drum drips should be operated weekly during the fall and winter months, even if no water is found on a regular basis. When preparing for cold weather, you should operate the drum drips daily and may decrease the operation based on the amount of water discharged.

After a dry sprinkler system operation, you should perform drum drip maintenance on a daily basis until several days pass with no discharge of water from the drain valve. At that time, you can decrease the frequency to weekly or longer intervals depending on the volume of water discharged.

In many cases, frequency of drum drip maintenance can decrease if the system is shown to be dry.

How to Perform Drum Drip Maintenance

  1. Locate all drum drips throughout the property.
  2. If a quick opening device is installed, temporarily remove it from service.
  3. At the drum drip, ensure both valves on the drum drip are closed.
  4. To catch any water that may discharge from the drum drip, place a container underneath the bottom valve. For interior locations, remove the plug from the bottom valve. (Exterior locations may not have a plug.)
  5. Slowly open the top valve to full open position and maintain this position for 10 seconds.
  6. Close the top valve. **You should never open both the top and bottom valve at the same time as this may activate your system.**
  7. Slowly open the bottom valve to discharge any water. If you cannot see the discharge point, allow water to drain for 10 seconds.
  8. Close the bottom valve.
  9. If water discharged when you opened the bottom valve, repeat steps 5 through 8 until no water appears when you open the bottom valve. This will ensure you have removed all water from the system.
  10. When the system has been completely drained, meaning no water appears when the bottom valve is opened, close the bottom valve. Then slowly open the top valve and, if applicable, replace the plug. This will return the drum drip to service.
  11. If you removed a quick opening device from service before beginning drum drip maintenance, re-install it at this time.

If your drum drip discharges to a location you cannot see, you can use a second person to watch the drain and notify you when there is no more water draining from the system. Another option to identify when all water has been removed from the system is to place a bucket under the drain and empty the bucket after each discharge.

If you are discharging water without using a bucket to collect it, be sure the water will not cause a safety hazard in traffic areas, or damage any surrounding areas or equipment.

Need more help? Check out A1’s video on how to perform drum drip maintenance.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Mike Rossman

Why have your sprinkler gauges checked?

The importance of pressure gauges on a fire sprinkler system can sometimes be overlooked. It is a common misconception that if a pressure gauge is registering pressure then it is operating properly. We must first take a look at what these gauges are and how they are used in order to completely understand their importance as a part of your sprinkler system.

Types of Pressure Gauges: Dry and Liquid Filled

Pressure gauges for a fire sprinkler system come in two basic types: dry and liquid filled. The dry gauge is most common; it consists of a numbered dial with an indicating needle that is attached to a spring loaded mechanism. This spring is compressed by pressure from the system, causing the needle to rise in relation to the amount of pressure. Liquid filled gauges operate under the same principle but are completely filled with liquid, usually glycerin. The liquid does a couple things, it lubricates and protects components in the gauge from wear and corrosion, while at the same time it dampens vibration and small spikes or jumps of the needle as pressures change. This creates a more sensitive precise gauge. For that reason, these gauges, which are higher in price, are usually used on testing or other more demanding applications.

Selecting the Correct Gaugegauge

Gauges can be manufactured for a specific application, such as fire pump readings and high pressure systems, or for a specific pressure type such as water pressure, air pressure, or a combination. Choosing the proper gauge for the application should be done by a trained Life Safety professional, as not just any gauge may be installed. NFPA 13 requires the gauge be approved for the application as well as have UL and FM approval. Your Life Safety Partner will also have the expertise needed to determine gauge location and correct installation procedures. Gauges are typically installed on ¼”, 3-way valves to allow easy replacement without taking the system out of service since fire sprinkler systems should always be functioning.

Gauge use in a Fire Sprinkler System

Fire sprinkler systems are always on, active, and supplied by an automatic water supply. Gauges help us ensure that the system is active, in service, and proper water supply and pressure is available. Located at various points in the system, they give us an indication of what the system status is and if anything has changed that may affect performance. Water pressure gauges at the control risers indicate the system is active and supplied by water pressure. This “resting active” pressure is known as static pressure. When the main drain on the system is opened completely, a water flowing pressure reading can be taken here which is known as a residual pressure. Your Life Safety Partner will track these readings during annual inspections, a change in this residual pressure can give warning to changes in the water supply or supply piping system. Gauges monitoring air pressure on dry systems are important for setting the correct air to water pressures on dry gaugesvalves and recording trip pressures. A system air pressure that is too high could result in delayed trip times, too little could cause false trips. Gauges are used too monitor pressures on standpipes, fire pump performance, and many other functions.

Inspection and Maintenance

As with any other critical component of a sprinkler system, gauges must be tested, inspected and maintained. Gauges are used in almost every stage of system testing. Quarterly, semi-annual and annual inspections all include testing that involves gauges. NFPA requires a monthly visual inspection of gauges noting any damage, leakage, or unusual readings. The date of the gauge should also be noted in inspections, as NFPA requires all gauges to be tested or replaced every 5 years. When gauges are tested, they must fall within a +/- 3% accuracy range or they have to be re-calibrated. Because the cost of new gauges is relatively low, it is common to have the gauges replaced rather than paying for the testing and re-calibrating.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane


Sprinkler Heads

Sprinkler heads are an important piece of your intricate sprinkler system. As such, it is necessary to understand how they work and what is required in maintaining them.

A fire sprinkler system is made up of a network of piping connected to a water supply. Individual sprinkler heads are placed along the piping to protect the area beneath them. These sprinklers individually activated by a heat source. Unlike in the movies, when a fire occurs only the sprinkler head above the fire activates, efficiently applying water only where it is needed.

How a Sprinkler Head works

Each sprinkler head consists of a plug held in place with a trigger mechanism. The most common type of trigger is a glass bulb filled with heat-sensitive, glycerin-based liquid. When the temperature around the sprinkler head is high enough to expand the glycerin-based liquid (most commonly designed at 155 degrees) the glass bulb breaks and the plug is forced out by the pressurized water or air in the pipes. This allows the water to flow out of the sprinkler and directly into the deflector plate of the sprinkler head which is designed to distribute water in an even pattern. Water will continue to flow until the main valve is shut off.

A less common trigger mechanism than the glass bulb is a two-part metal link which is held together with a solder point. When the ambient temperature is high enough to melt the solder point, the plug is released and water flows over the sprinkler head.  sprinkler heads

Smoke will not activate a fire sprinkler and only the sprinklers close enough to the heat source to reach the rated temperature activate. When a sprinkler activates, the water flows forcefully down over the flames, extinguishing them completely in most cases, or at least controlling the heat and spread of the fire and limiting the development of toxic smoke.

Sprinklers are so effective because of how quickly they react. They reduce the risk of death or injury from a fire because they dramatically reduce heat, flames and smoke which gives people time to evacuate.

Required and Recommended Inspections and Testing

As you can see, sprinkler heads are an important component of your sprinkler system. They must be inspected visually annually. Sprinkler head inspections ensure that water can discharge properly; they are checked for obstructions, damage, corrosion, and paint or other foreign material which may interfere with the sprinkler head operation.

Once your sprinkler heads are 50 years old, they should be tested at that time, followed by testing every 10 years after until they are 75 years old, at which point they must be tested every 5 years. Unlike plumbing, electrical, or HVAC systems, sprinkler systems can sit inactive for years if no fire emergency occurs. As a result of this idleness, proper testing is the only way to ensure the sprinkler system and the sprinkler heads are working correctly. To test your sprinkler heads, your Life Safety Partner will remove 1%, but at least 4, of your sprinkler heads from different areas of your sprinkler system and perform a plunge test. The plunge test measures the amount of time it takes for the sprinkler head to activate. If a sprinkler head fails, then all sprinkler heads in the area from where that particular head was taken must be replaced.

Dry-type sprinkler heads have a much higher failure rate than other types and must be tested every 10 years, starting at 10 years instead of 50. This is due to their susceptibility to corrosion both internally, when moisture condenses inside the device, and externally. In addition, dry-type sprinklers are usually installed in harsher environments which provide greater opportunity for damage to the sprinkler heads. In addition sprinklers with fast response elements should be tested every tested or replaced after 20 years and sprinklers exposed to a harsh environment every 5 years. You should consult with your Life Safety Partner about the costs of testing them versus replacing them.

Another requirement for sprinkler heads is that you have a cabinet with spare heads onsite.  A sprinkler head may need to be replaced for any number of reasons, it may have become coated with a foreign material or activated due to a fire. The area the sprinkler was protecting is now unprotected until it is replaced. Worse, if the sprinkler is damaged and cannot hold pressure, the entire sprinkler system must be shut down and is rendered inoperable which leaves the entire facility unprotected. Sprinkler heads need to be replaced as quickly as possible to keep your system running or get it back in service. There are many different sprinkler head types, depending on the availability of the type you need it could take days or even weeks to order a new one. Keeping extra sprinkler heads onsite is required and ensures uninterrupted fire protection of your business, life, and property. You can read more about spare sprinkler head cabinet requirements here.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane

Special Hazard Fire Suppression Systems

Our last article focused on Fire Sprinkler System types and how the different types are best used in particular structures or situations. The same variation is true for fire suppression systems used in special hazard applications. Here we will review the different technologies and their purposes.


A foam-water fire sprinkler system is a special application system which discharges a mixture of water and low-, medium-, or high-expansion foam concentrate. This results in a foam spray from the sprinkler. This is usually used with special hazard occupancies associated with high challenge fires, such as flammable liquids and airport hangars. The foam-water application can be used in wet, dry, pre-action or deluge system.

Water Spray

Water spray systems are operationally identical to deluge systems, but the piping and discharge nozzle spray patters are designed to protect a uniquely configured hazard, usually being three-dimensional components or equipment. The nozzles are selected for a specific spray pattern to conform to the three-dimensional nature of the hazard. Some typical spray patterns are oval, fan, full circle, and narrow jet. Examples of hazards protected by water spray systems are electrical transformers containing oil for cooling or turbo-generator bearings. Water spray systems can also be used on the surfaces of tanks containing flammable liquids or gases (such as hydrogen). In this case, the water spray is intended to cool the tank and its contents to prevent tank rupture and fire spread.

Water Mist

A water mist system works by creating a heat absorbent vapor. This type of system is used when water damage is a concern or where water supplies are limited. By using a mist, an equal volume of water will create a larger total surface area exposed to the fire. The larger total surface area better facilitates the transfer of heat, thus allowing more water droplets to turn to steam more quickly. A water mist, which absorbs more heat than water per unit time, due to exposed surface area, will more effectively cool the room, thus reducing the temperature of the flame. NFPA 750 defines water mist as a water spray with a droplet size of “less than 1000 microns at the minimum operation pressure of the discharge nozzle.” Water mist systems use a compressed gas as an atomizing medium, which is pumped through the sprinkler pipe. Instead of compressed gas, some systems us a high-pressure pump to pressurize the water so it atomizes as it exits the sprinkler nozzle. Water mist systems can operate with the same functionality as deluge, wet pipe, dry pipe, or pre-action systems.

Clean Agent (Gaseous Fire Suppression)

NFPA 2001 defines clean agent as, “Electrically nonconductive, volatile, or gaseous fire extinguishant that does not leave a residue upon evaporation.” Clean agents are used when protecting high dollar, mission critical assets that would be destroyed by water, such as IT systems, data storage rooms, and manufacturing equipment, or irreplaceable items like intellectual property, art, and antiques. There are three ways clean agents can extinguish a fire: reduction of heat, reduction or isolation of oxygen, and inhibiting the chain reaction of the heat and oxygen.

Clean agent fire protection systems are comprised of the agent, agent storage containers, agent release valves, fire detectors, fire detection system (wiring control panel, actuation signaling), agent delivery piping, and agent dispersion nozzles. Less typically, the agent may be delivered by means of solid propellant gas generators that produce either inert or chemically active gas. Clean agents are applied with either total flooding or local application. Total flooding systems apply an extinguishing agent to a three dimensional enclosed space in order to achieve a concentration of the agent (volume percent of the agent in air) adequate to extinguish the fire. These types of systems may be operated automatically by detection and related controls or manually by the operation of a system actuator. Local application systems apply an extinguishing agent directly onto a fire (usually a two dimensional area), or into the three dimensional region immediately surrounding the substance or object on fire. The main difference in local application from total flooding design is the absence of physical barriers enclosing the fire space.

Condensed Aerosol

Condensed aerosol fire suppression is one of the most efficient forms of fire suppression. It is a particle-based form of fire extinction similar to gaseous fire suppression or dry chemical fire extinction. The aerosol employs a fire extinguishing agent consisting of very fine solid particles and gaseous matter to extinguish fires. The condensed aerosol microparticles and effluent gases are generated by the exothermic reaction; until discharged from the device, the particles remain in vapor state. They are cooled and “condensed” within the device and discharged as solid particles.  Condensed aerosols release finely-divided solids of less than 10 micrometers in diameter, the solid particles have a considerably smaller mass median aerodynamic diameter than those of dry chemical suppression agents, remain airborne significantly longer, and leave much less residue within the protected area. Condensed aerosols are flooding agents and therefore effective regardless of the location and height of the fire. This system does not require a room integrity test as it is flooding the space at room pressure; this will save you money in sealing the room and annual testing.

Dry Chemical

Dry chemical fire extinguishing agents are primarily used for fast knock down of high risk gas and liquids such as dip tanks, paint booths and gas filling stations. The dry chemicals work by preventing the chemical reactions involving heat, fuel, and oxygen (combustion). The substances in dry chemicals can also stop the break-down of fuel in the fire to prevent the creation of highly reactive fragments of molecules.

Wet Chemical

Primarily used in kitchen fire suppression, the wet chemical agent suppresses fire by cooling and reacting chemically to produce a foam layer on the grease. The foam seals combustible vapors, stopping the flames from re-igniting.

Fire Extinguishers

Fire Extinguishers may not be a part of the fire sprinkler system, but they are an integral part of your fire safety system. If the proper fire extinguisher is used correctly and promptly, more than 90% of fires are extinguishable. Most work environments are required by OSHA to have an emergency action plan, functioning extinguishers, and trained extinguisher operators. OSHA requirements vary, but safety does not – be safe, provide fire extinguishers and fire extinguisher training to your staff.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Jack Menke
Jack Menke

Fire Sprinkler Systems

An estimated $14.3 billion in property damage occurred as a result of fire in 2015, an increase of 23.2 percent from the previous year. Because fire sprinklers react so quickly, they can dramatically reduce the heat, flames, and smoke produced in a fire. Properly installed and maintained fire sprinklers help save lives and property.

Fire sprinklers have been around for more than a century, protecting commercial and industrial properties and public buildings. Sprinkler systems are as varied as the structures they protect. In this article we will outline the various sprinkler system types, and in the next article we will review the special hazard fire suppression systems.

Fire Sprinkler System Types

Wet Systems

Wet pipe sprinkler systems are the most common type of fire sprinkler system. In a wet pipe system, the sprinkler pipes are filled with water under pressure. When the sprinkler head is activated, the pressurized water pushes the plug out of the sprinkler head when the head is activated. The advantage of wet pipe sprinkler systems is that water immediately available to flow out of the sprinkler head and onto the fire, however water sitting in pipes can be an opportunity for leaks so it is very important they are properly maintained.

Dry Systems

Dry pipe sprinkler systems have the sprinkler pipes filled with pressurized air and are the second most common type of fire sprinkler systems. The pressurized air releases the plug when the sprinkler head is activated. The air is replaced by water flowing into the pipes from the water supply. Dry pipe systems are used with the ambient temperature may be cold enough to freeze the water in a wet pipe system. Dry pipe systems are most often used in unheated buildings, parking garages, outside canopies attached to heated buildings, and refrigerated coolers. NFPA regulations require the use of a dry system in areas where the range of temperatures goes below 40 degrees Fahrenheit.


Pre-action sprinkler systems are designed for use in locations where accidental activation is especially undesired, such as in museums or data centers. A pre-action fire sprinkler system employs the same basic concept as the dry system, in that water is not contained within the pipes. The pipes are pressurized with air or nitrogen. The water source is restrained with an electrically operated valve, known as the pre-action valve.

For the pre-action system to discharge, two steps must be completed. First, the detection system identifies either smoke or heat (depending on which type of detection you have), and activates the pre-action valve to allow water to flow into the piping. Second, sprinkler head(s) are activated by heat releasing water onto the fire.


Deluge fire sprinkler systems are similar to pre-action systems in that the water is held back with an electronic deluge valve. The sprinkler heads in a deluge system are open, not plugged like they normally are. The system is directly connected to a water supply, when the detection system is tripped by smoke or heat the water is released throughout the entire system and through all open sprinkler heads. This rush of water is designed to quickly smother all varieties of chemical and mechanical fires, which is why the deluge fire sprinkler system is commonly used in high hazard industrial and commercial facilities where special hazards create a concern for rapid fire spread. The deluge system is designed to quickly cover the horizontal floor area of a room.


Keeping your fire sprinkler system running is essential to protecting your business, people, and assets. Regular inspections are required by law and checked by your Fire Marshal or AHJ.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane

Concealed Space Sprinkler Requirements

Attics: Determining if sprinklers are required

First, it is important to remember the difference between Code and Standards. Code tells us what needs to be done for fire protection and comes from the IBC, International Fire Code, or State Building Code. Standards pick up at this point outlining how the fire protection needs to be carried out; these are from the National Fire Protection Association.

While codes and standards are created to provide clarity on what is required, there can sometimes be varied interpretations on how a standard is applied. These interpretations can vary geographically or depending on the role of the interpreter in the life safety profession. To avoid this confusion, the NFPA technical committees work to ensure the language of the codes and standards is clear and can be enforced only in the intended manner. However, there are still cases where various interpretations exist and one such area is the idea of providing automatic sprinkler protection in attics.

NFPA 13, Installation of Sprinkler Systems, the standard for the installation of automatic sprinkler systems never specifically addresses whether or not an attic requires sprinkler protection. Section 8.1 states that all spaces should be protected unless there is a specific exemption somewhere in the standard. Since there is no specific “attic sprinkler exemption” in NFPA 13, many people think that all attics require sprinklers.

The real answer is a bit more complicated. Since there is no outright exemption for attics, the NFPA various standards on concealed spaces must be read to determine whether or not each particular attic space is considered a concealed space that does not require sprinklers. Currently, there is even some confusion on whether attics are even considered to be concealed spaces. NFPA 13 does not declare attics to be concealed spaces because not all attics are created the same from a fire development and fire spread perspective. Because of this, the standard is written to take into consideration hazards present in an attic when determining if it is a concealed space and if it requires sprinkler protection.

Adding to the confusion are two different staff interpretations from NFPA staff members in the last five years. The first interpretation stated that attics cannot be considered concealed spaces and so always require sprinklers. The second interpretation attempted to clarify that attics can be concealed spaces, and therefore may not always require sprinklers.

To determine if your attic requires sprinklers, your sprinkler system designer and reviewing authority should consider the following:
* what are the construction materials?
* can the space be occupied?
* are goods stored in the space?
* what is the quantity of combustible material?
* what level of access is provided to the space?

The answers to these questions will allow them to determine whether or not the space qualifies as a concealed space and if it needs sprinklers.

A1 is a leading expert on the latest technology in life safety. To find out more information or to ask a question, click here or call us at 1-800-859-6198.

Greg Lane