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8 Posts authored by: boconnor Employee

Corrosion is a costly problem for sprinkler systems. It can cause leakage which can lead to impaired sprinkler systems, water damage, and eventually replacement of the entire system. This blog looks at  what corrosion is, where we can find it, how it affects a sprinkler system, and how to spot and prevent it.

 

What is corrosion?

Generally, when we refer to corrosion we are talking about when a metal reacts with its environment which leads to deterioration of the metal. In sprinkler systems this is often when oxygen reacts with iron to form iron oxides, which we commonly refer to as "rust." This is further accelerated when it occurs in the presence of water, which helps the reaction. While this is the most common, there are other types of corrosion that can affect a sprinkler system such as microbiologically influenced corrosion (MIC) and galvanic corrosion. 

 

For any metallic component of a sprinkler system there is both external and internal corrosion. While both of these issues can lead to system failure, internal corrosion is more difficult to detect and causes more issues. Internal corrosion usually begins to form at the air/water interface while external corrosion is more dependent on the environment.

 

Where does corrosion occur?

There are many locations where piping and sprinklers are more susceptible to external corrosion. Most of these locations have different elements in the atmosphere that can speed up corrosion. A few common examples include:

  • Areas with fertilizer or manure (animal pens)
  • Pools or areas containing pool chemicals
  • Areas near the ocean that are exposed to outside salt air
  • Salt storage
  • Pipe is in contact with soil
  • Areas with excessive moisture (steam room)

 

Listed corrosion resistant sprinklers and corrosion resistant piping, fittings and hangars are required to be installed in places where corrosive conditions are known. Meanwhile all pipes and fittings installed on the exterior of the building are required to be corrosion resistant.

 

Internal corrosion on the other hand occurs most commonly where metal, water and air are in contact with one another. This occurs in both wet and dry pipe systems. For wet pipe systems, corrosion occurs most often near the pockets of air that could be trapped in high points. For dry and preaction systems the corrosion occurs most often at the low points because that is where any residual water builds up.

 

How does corrosion affect a sprinkler system?

Corrosion has a detrimental effect on sprinkler systems, causing the components to fail. For piping this can take the form of pinhole leaks or having rust buildup limit the flow of water (see image below). For sprinklers, corrosion can clog the water discharge orifice, affect the deflector and discharge pattern, or completely seal the plug, preventing water from reaching the fire. Other components such as piping hangers and fittings can also be susceptible to corrosion, which can lead to further complications. 

 

sprinkler

 

What can I do to minimize corrosion?

Completely eliminating the possibility of corrosion is nearly impossible, however there are some steps that can be taken to help reduce the amount of corrosion in a system:

  • Better pipe material: When trying to delay corrosion a great place to start is looking at the material used. Certain types of piping are more resistant to corrosion, such as plastic CPVC, copper or galvanized steel. There are also benefits to using thicker piping since rust will not eat through the wall of the pipe as quickly. Using higher quality material may cost more up front but it will extend the life of the system and increase reliability. 
  • Corrosion resistant sprinkler: When sprinklers are installed in areas susceptible to external corrosion, they need to be corrosion resistant. This means that they need to be either made out of corrosion resistant material, covered with a special coating such as wax, or plated with a corrosion resistant metal (see image below).
  • Water supply: NFPA 13, Sandard for the Installation of Sprinkler Systems, requires the water supply to be evaluated to determine if it contains any unusual corrosive properties or is likely to contain MIC. If it does, then you need to either install piping that is corrosion/MIC resistant, treat the water with water additives, implement a monitoring plan, or fill your system with nitrogen for dry or preaction systems.
  • Wet Pipe: Air Venting: NFPA 13 requires a vent to be located at a high point in the system to allow air to be removed by either a manual or automatic valve. This can be a reasonable approach on wet pipe sprinkler systems to reduce corrosion activity. The purpose of the air venting valve is to exhaust as much trapped air as possible from a single location every time the system is filled, thus having less oxygen for the metal to react with. 
  • Dry Pipe: Drain Water Out of System: Just like how in wet pipe systems you want to remove the air out of the piping, for dry pipe or preaction systems you want to remove the water. Dry pipe and preaction systems are required to be pitched to a low point drain so that water can be removed from the system. Since most corrosion occurs at the air/water interface this will help prevent corrosion.
  • Dry Pipe: Nitrogen: For dry pipe or preaction systems nitrogen can be used to fill the sprinkler piping network instead of air. When a system is filled with nitrogen it  contains very little oxygen, which is a vital ingredient in the corrosion process. Nitrogen can be provided through cylinders or a nitrogen generator.

 

sprinkler

 

How can I spot corrosion?

Some corrosion can be easily identified while others can be hidden. During your annual floor level inspection of piping, fittings and sprinklers be sure to keep an eye out for exterior corrosion which can be identified by its orange-brown color and rough texture.

 

Internal corrosion is more difficult to identify during your annual inspection so an assessment of the internal condition of piping is required to be conducted every five years. Outside of that assessment, the effects of both internal and external corrosion can be seen by looking for water stains or leaking pipe where corrosion could have created pinhole leaks in your system by eating through the wall of your piping (see image below).

 

sprinkler

 

 

 

What do I do if I see corrosion?

When there is significant corrosion buildup that is detrimental to sprinkler system performance, that section of piping, or sprinkler needs to be replaced. If corrosion is bad enough sometimes an entire system needs to be replaced.

 

Addressing these issues will help ensure the reliability of your sprinkler system, increase the life expectancy of your system and in the long run save you time, energy, and money. Share your experience working on a system that was installed in a corrosive atmosphere in the comments below. What was the biggest challenge or lesson learned?

 

If you found this article helpful, subscribe to the NFPA Network newsletter for monthly, personalized content related to the world of fire, electrical, and building & life safety.

Two reports from the Surprise, Arizona Energy Storage System (ESS) explosion that occurred in April, 2019 were published this week.  One report, titled, “Four Firefighters Injured In Lithium-Ion Battery Energy Storage System Explosion – Arizona” is written by the UL Firefighter Safety Research Institute and is part of a Study of Firefighter Line of Duty Injuries and Near ESSMisses. The other report, “McMicken Battery Energy Storage System Technical Analysis and Recommendations” by DNVGL, on behalf of Arizona Public Service, is an investigation report into the incident. The DNVGL report looks at how we can prevent this incident from happening again and the UL report analyzes first responder considerations with regards to the incident. Both documents are examples of how we can learn from past incidents to improve our codes and standards, increase the safety of our first responders, and build a safer environment.

 

The Incident

On April 19th, 2019 an explosion occurred at the McMicken Battery ESS in Surprise, Arizona injuring four firefighters. The battery ESS was placed into service in 2017, which is prior to the publication of NFPA 855. The system was comprised of 10,584 Lithium Nickel Manganese Cobalt (NMC) battery cells organized in modules and racks within an ESS specific walk-in enclosure. The system included a total flooding clean agent fire suppression system, a very early smoke detection apparatus, and an HVAC system. The entire system could supply 2MW over one hour (2MWh) and was used to supplement solar panels at the time of the incident.

 

While there was some information about the incident already known, these reports provide a great level of detail, insight and recommended paths forward.

 

Technical Analysis Report

The DNVGL report documents a thorough investigation that was conducted on the incident. It gives a lot of relevant background on the technology, the layout, and associated hazards. After building a foundation of knowledge about how batteries fail, the report analyses the factors that contributed to the failure and how we can prevent this from happening in the future. Some of the major conclusions reached in the report are as follows:  

 

  • The cause of the incident was most likely an internal failure in a single battery cell which was caused by a defect in the cell.
  • The clean agent fire suppression system that was installed was not designed to prevent or stop thermal runaway.
  • The absence of barriers allowed thermal runaway to propagate from cell to cell.
  • Flammable off-gases concentrated to create a flammable atmosphere and did not have a means to ventilate.
  • The emergency response plan did not address extinguishing, ventilation, or entry procedures.

 

Some of these items are addressed by NFPA 855, Standard for the Installation of Stationary Energy Storage Systems while others are included in the section of the report, “ Shortcomings that should be addressed in NFPA 855.” NFPA codes and standards are living documents that are constantly looking for ways to improve and keep up with new technology. Recommended improvements are always welcome in the form of Public Inputs or Public Comments

 

First Responder Report

This UL report gives an overview of the fire department and the incident. When addressing the responding fire departments, the document talks about their training, experience, equipment, and personnel. Regarding the Arizona incident, the report covers the building construction, the energy storage system, and responder PPE, and it walks through the timeline as well as provides a detailed incident narrative. This report does a great job addressing some of the contributing factors that led to the incident and firefighter injuries. Some of those factors include:

 

  • HAZMAT training curricula does not cover basic ESS hazards.
  • There was no way to monitor the conditions of the ESS container from a safe location.
  • The emergency response plan didn’t address mitigating ESS hazards and the plan was not provided to the responding personnel before the incident.
  • Deflagration venting and explosion prevention systems were not provided in the ESS unit.

 

The issue of training first responders on the basics of ESS hazards can be addressed through an updated NFPA online training course, Energy Storage and Solar Systems Safety Online Training for Fire Service Personnel.

 

It is encouraging to see that such a collaborative approach was taken in response to this incident to determine what happened and what could be done to prevent this type of equipment failure in the future. In the field of ESS, one of the major needs of the industry is better information like this or other publicly available test data to help guide our codes and standards. A number of related reports, articles, relevant standards, and other content can all be found on NFPA’s ESS webpage www.nfpa.org/ESS.

 

Let us know what your thoughts are on these reports or if you’ve had any recent experience with ESS installations by commenting below.

There are many different requirements for obstruction in NFPA 13 Standard for the Installation of Sprinkler Systems  based on the type of sprinkler being used as well as the distance, type, and size of the obstruction. This blog will address suspended or floor mounted vertical obstructions requirements from the 2019 edition of NFPA 13 since this is a topic NFPA has recently received several technical questions on.

 

What are suspended or floor mounted vertical obstructions?


An obstruction is something that affects the discharge pattern of one or more sprinklers. An example of what a discharge or distribution pattern looks like is provided below:

 

(This is from the 2019 edition of NFPA 13, Figure A.9.5.5.1)

 

NFPA 13 section 10.2.7.2.2 gives a few examples of things that could be considered suspended or floor mounted vertical obstructions which include privacy curtains, freestanding partitions, and room dividers.

 

The basic rule for these obstructions is simple. There are tables in NFPA 13 which contains horizontal distances and the required minimum vertical distance that the obstruction must be from the sprinkler deflector. There are also figures to help you understand how the table should be used. Below are the table and figures for standard spray upright/pendent and sidewall sprinklers but the same table and figures are located in the extended coverage and residential sprinkler chapters.

 

                     

(This is from the 2019 edition of NFPA 13 Table 10.2.7.2.2 and Figure 10.2.7.2.2)

 

 

(This is figure 10.3.6.2.2 from the 2019 edition of NFPA 13)

 

You will notice that the relationship between the horizontal and vertical distances forms an umbrella shape similar to Figure A.9.5.5.1 above. The intent of this is to make sure the obstruction doesn’t block the development of the sprinkler pattern which occurs within the first 18 vertical inches (450 mm) of the sprinkler.

 

What about non-light hazard occupancies?


You’ll notice that the requirements for suspended or floor mounted vertical obstructions only apply to light hazard occupancies. These requirements shouldn’t be applied for anything except light hazard occupancies because the testing that was done to justify the addition of this code section only evaluated sprinkler performance in a light hazard environment.

 

Well, what do you do when you are in something other than a light hazard occupancy? The answer is that you should follow the general obstruction rules of NFPA 13. For obstructions below 18 inches for standard pendent and upright spray sprinklers this means that as long as the obstruction is less than 4ft (1.2 m) wide that it is not considered an obstruction. For obstructions less than 18 inches (450 mm) below the sprinkler deflector there are additional diagrams and tables you need to follow because of the potential to disrupt the sprinkler pattern development. A common rule that is followed for obstructions within 18 inches of the sprinkler deflector is the “three times rule”. This requires sprinklers to be positioned away from obstructions a minimum or three times the maximum dimension of the obstruction.

 

Are there any exceptions?

 

Have you ever noticed that in healthcare facilities the privacy curtains are mostly solid except for the top 22 inches (550 mm)? According to NFPA 13, those privacy curtains are not considered obstructions if they follow three rules: 

 

  1. Curtains need to be supported by fabric mesh on a ceiling track
  2. The openings in the mesh part of the curtain needs to be at least 70% of the area
  3. The mesh portion of the curtain needs to extend at least 22 inches (550 mm) from the ceiling

 

Those rules allow heat from the fire and sprinkler water discharge to pass through the mesh portion of the curtain without having a major impact on the sprinkler discharge pattern development or sprinkler activation time. Once again this exception to the rule can only be applied to light hazard occupancies.

 

With all of this being said, it is also important to understand how the building will look when it is finished by reviewing all of the architectural, structural, and MEP drawings. Changes in any one of those drawings can create an obstruction to your once properly designed sprinkler system.


Let us know what your experience is with suspended or floor mounted vertical obstructions in the comments below.

 

If you found this article helpful, subscribe to the NFPA Network Newsletter for monthly, personalized content related to the world of fire, electrical, and building & life safety.

 

In my recent NFPA® Live session I focused on the location and placement requirements for portable fire extinguishers. I discussed the requirements of NFPA 10, Standard for Portable Fire Extinguishers, as well as the occupancies where NFPA 101®Life Safety Code®, requires portable fire extinguishers to be installed as well as the ratings for portable fire extinguishers and how that affects where they are required to be located.

 

During this live event I received this follow-up question from a member. I hope you find some value in it.
 

 

NFPA Live is an interactive video series in which members of NFPA staff address some of the most frequent topics they receive through the Member's Only Technical Question service. If you are currently an NFPA Member you can view the entire video by following this link. If you're not currently a member, join today!

 

The NFPA and Fire Protection Research Foundation are working on several projects related to Energy Storage Systems (ESS) including research reports, training for first responders, and the development of standards. These projects are highlighted in a recent article by Utility Drive, a utility news outlet that caters to busy industry professionals.


The piece looks at NFPA 855, the Standard on the Installation of Stationary Energy Storage Systems, as well as other efforts that NFPA, the Fire Department of New York City (FDNY), and UL are undertaking to help build a safety foundation for the ESS industry.


The article features comments from Davion Hill of DNVG who is involved with several of the NFPA projects listed above as well as insight from Ken Boyce from UL, who is collaborating with NFPA on the development of energy storage safety standards. Representatives from NFPA are also working closely with FDNY leaders on several different projects to optimize the well-being of the general public and champion first responder safety.


ESS is not new and it's certainly not going away. Feel free to use the comment box below to ask questions or to start a discussion. 

 

With the present growth of the energy storage industry, the National Fire Protection Association (NFPA) is actively engaged in a number of diverse initiatives including standards development, training, and research projects aimed at promoting the continued safe and sustainable expansion of this renewable technology. This presentation will talk about some of the standards that address energy storage systems as well as training that NFPA has developed to assist first responders who may encounter these unique hazards.

 

I presented on this topic during my latest NFPA Live. I got this great follow-up question at the end of the presentation. I hope you find some value in it.

 

NFPA 855 is now open for public input. What is a Public Input? This is a way for the public (anyone) to communicate the changes they would like to see in the standard and provide an explanation as to why the change should be implemented.

 

Public Input Closing Date is October 4, 2017. To participate go to www.nfpa.org/855 and click on the blue “Submit a Public Input for the Next Edition” link.

 

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NFPA Live is an interactive video series in which members of NFPA staff address some of the most frequent topics they receive through the Member's Only Technical Question service. If you are currently an NFPA Member you can view the entire video by following this link. If you're not currently a member, join today!

ESS el

For those of you who are unfamiliar, energy storage systems (ESS) are devices that can store energy for use as electrical energy at a later time. They are used in residential, commercial and utility applications listed below. These storage systems are important because they provide resiliency and reliability to our aging electrical grid system.


The most popular form of ESS are batteries and in particular, rechargeable lithium ion batteries. Other types of ESS include the following:
1. Flywheels
2. Pumped Hydro
3. Ultra Capacitors
4. Compressed Air
5. Thermal Storage (molten salts)


But I will concentrate on batteries for this article. Lithium Ion batteries are commonplace in today’s consumer electronics, usually found in your laptops, phones and even electric and hybrid vehicles. They are used in such a variety of applications because of their high energy density.


What do we use Energy Storage Systems for?
One huge application of Energy Storage Systems is to supplement renewable energy such as solar panels or wind turbines. The use of ESS allows any excess unused power generated to be stored for later use. This is important because it means you can use electricity from renewable power generation methods any time and not just when the sun it out or when the wind is blowing. Estimates have shown that residential solar systems will regularly include energy storage in the future.

 

When looking at what drives most industries forward one word comes to mind, money, and ESS is no different. A big driver of recent ESS installations is the cost saving benefit. For those of you who are unaware, electric companies vary their rates throughout the day based on demand. ESS allows a user to shift where their electricity comes from by drawing power from the system during the higher cost daytime hours then recharging during the lower cost nighttime hours. This way you are always paying the lower rate for electricity.


One last application is using ESS for Backup Power, which is a power supply used to provide alternating current power to a load for some period of time in the event of a power failure. This is often used in hospitals, data centers and homes.

 

ESS Hazards
So that was a little background as to what ESS are and how they are used, but along with this great technology comes some unique hazards. They are as follows:

 

1. Thermal Runaway. Thermal Runaway is a term used to describe the rapid and uncontrolled release of heat energy from a battery cell. Thermal runaway occurs when a battery creates more heat than it can dissipate which can result in a battery fire or explosion. Due to the configuration of batteries thermal runaway can often spread to adjacent cells, batteries and materials, causing fire to spread rapidly. Also, these ESS are often incased in many layers of protection and the visible signs of thermal runaway can be hidden in its early stages.


2. Stranded Energy. Something that is particularly tricky about Energy Storage Systems is that they often do not dissipate all of their energy when they are involved in a fire. This can be dangerous for the first responders who are navigating a fire scene. Once the fire is out that doesn’t mean the shock hazard is gone.


3. Re-ignition. ESS has an uncanny ability to reignite after the fire is thought to be extinguished. This is because of the stranded energy not dissipating in a fire, it can be cooled and the fire thought to be extinguished but if it doesn’t completely stop thermal runaway then the temperature will continue to increase and can reignite hours or even days later.


4. Off-Gassing. While involved in a fire, battery energy storage systems often let off different flammable and toxic gasses. These are dangerous while both fighting the fire and while cleaning up afterwards. Different ventilation techniques must be considered when installing these systems.


5. Toxic Runoff. Along with toxic gasses, while a first responder is trying to control the fire with their hose, water can create a toxic runoff that can effect surrounding areas. This is still a challenging problem to solve with no clear answer.


6. Lack of Information. There are a limited number of publicly available information on how these ESS behave in a fire. The industry is looking to the future for more large scale fire tests to be conducted.


7. Variety of Types. There are many different types, sizes and chemistries of energy storage systems that it is hard to have a “one size fits all” approach to fire safety.

 

Extinguishment
One popular myth about extinguishment is that you cannot put out a lithium ion battery fire with water. This conclusion is usually jumped to because pure lithium metal is reactive with water. Lithium ion batteries, however, do not have pure lithium in them but instead are made with lithium salts that can be safely extinguished with water.


The unique hazards listed above can make extinguishment of Energy Storage Systems quite difficult. A recent study by DNVGL and Con Edison recommend a two-tiered approach to fire extinguishment with a total flooding gaseous agent to control a fire early on that is followed up by ventilation and copious amounts of water being added to the fire if the fire gets too hot for the gaseous system to cool.


With the advancement of technology and the creativity of applications I do not see ESS going away anytime soon. With ESS here to stay the NFPA is working on the development of a Standard to address many of these safety issues, NFPA 855: Standard on the Installation of Stationary Energy Storage Systems.


If you need more information on regulations regarding ESS you can look into NFPA 70: National Electrical Code (NEC), Article 706, NFPA 1: Fire Code, Chapter 52 or our ESS resource page www.nfpa.org/ESS

Remembering When Conference 2016

Karen Berard-Reed and the NFPA have officially been recognized by the State Firefighters' and Fire Marshals' Association of Texas and the Texas Fire Marshals' Association for their Remembering When Program as a key program to keep Texans safe. This recognition includes an endorsement of Remembering When as a statewide fire and fall prevention program for older adults.

 

These recognitions were presented to the NFPA from John Erskine, Burnet, Texas Fire Marshal and Richard Zelade of the State Firefighters Marshals Office. 

 

Remembering When: A Fire and Fall Prevention Program for Older Adults, was developed by NFPA and the Centers for Disease Control and Prevention (CDC) to help older adults live safely at home for as long as possible.

Remembering When is centered around 16 key safety messages, eight fire prevention and eight fall prevention, developed by experts from national and local safety organizations as well as through focus group testing in high-fire-risk states.

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