News From Wesco

February 28, 2017


Six years ago we wrote about the decision made by Brianna Lozano, daughter of Wesco’s Karen Zukarfein, to enter the U.S. Air Force.  How time flies! We were so proud of her then and even prouder now that she has completed a six year stint with the Air Force – including two years in Turkey. Brianna is, without doubt or hesitation, the positive answer to the age old question, “What is happening to today’s youth?”

Welcome home Brianna!!
Brianna in 2010

Brianna in 2010

Brianna entered the Air Force’s Basic Military Training on December 14, 2010 and graduated basic training on February 11, 2011. She began Phase 1 of Surgical Tech training at Ft. Sam Houston, San Antonio, TX and continued with Phase 2 training at Travis AFB, California, gaining much hands-on experience in the operating room. Brianna returned to San Antonio to complete Phase 3 training, specializing in becoming an orthopedic technician. She graduated 2nd in her class and was assigned to Lackland AFB, San Antonio, TX, where she performed various Orthopedic specialty duties at Wilford Hall and Brook Army Medical Center.


Brianna in 2016

Brianna in 2016

Since March 2015 she has been assigned Incirlik Air Base, Turkey, managing the Surgical Specialty Clinic. She recently returned home and is excited to resume civilian life in FL.
Her list of accomplishments/awards include:
  • Orthopedic Specialty Course Honor Graduate
  • Airman of the quarter Jan to March 2012
  • Airman of the quarter July to September 2013
  • Surgical services airman of the year 2014 for Air Education and Training Command
  • Non Commissioned Officer of the Quarter for July to September 2016, 39th Air Base Wing (Incirlik Air Base, Turkey)
  • Non Commissioned Officer of the Year 2016, 39th Medical Group
  • United States Air Forces in Europe Surgical  Services NCO of the Year 2016
  • United States Air Force Surgical Services NCO of the Year 2016
  • Air Force Achievement Medal
  • Air Force Commendation Medal


Trump Supports Obama HFC Crackdown

February 27, 2017
Then-Secretary of State John Kerry delivers remarks about the Montreal Protocol in Kigali, Rwanda, last fall. (Photo by U.S. Department of State, courtesy of Flickr.)

Then-Secretary of State John Kerry delivers remarks about the Montreal Protocol in Kigali, Rwanda, last fall. (Photo by U.S. Department of State, courtesy of Flickr.)


By Amanda Reilly, E&E News reporter
E&E News

A window into the administration’s support of Kilgali Amendment to phase-down HFCs and whether or not EPA will continue to change the SNAP status of HFCs?

The Trump Justice Department defended an Obama administration rule for phasing out potent heat-trapping chemicals.

Two manufacturers of the chemicals, hydrofluorocarbons, have asked the U.S. Court of Appeals for the District of Columbia Circuit to kill the rule.

President Obama’s 2013 Climate Action Plan called for cutting HFC use at home and abroad. The 2015 U.S. EPA regulation at issue eliminated some uses for HFCs, which were previously accepted as alternatives to ozone-depleting substances, and approved substitutes for the chemicals.

“This isn’t a stretch of the statute,” DOJ’s Dustin Maghamfar told a three-judge panel in the D.C. Circuit.

Judge Brett Kavanaugh appeared to side with the companies at times, saying EPA’s rule would force firms that switched from ozone-depleting substances to HFCs to “spend a lot more money.”

EPA’s regulation — and a similar rule last year phasing out other uses of HFCs — was issued in the runup to the October international agreement to amend the Montreal Protocol to phase down HFCs globally.

The Trump administration has broadly pledged to undo Obama climate regulations. But while there are concerns with specific rules to eliminate HFCs, global efforts to phase down the chemicals have industry support.

Industry leaders want Congress to ratify the Montreal Protocol amendment and are worried the deal will get caught up in the politics of climate change (Greenwire, Jan. 12).

Two U.S.-headquartered companies that produce alternatives to HFCs are backing EPA in the lawsuit. The companies — DuPont spinoff Chemours Co. and Honeywell International Inc. — and the Natural Resources Defense Council intervened in the case on the agency’s behalf.

Chemours and Honeywell have “invested hundreds of millions of dollars” in replacements, said Thomas Lorenzen, a partner at Crowell & Moring and a former DOJ attorney who represents the companies. “This is significant to them, too.”

The legal question in the lawsuit is whether EPA can use the Significant New Alternatives Policy (SNAP), which is geared toward phasing out ozone-depleting substances, to replace HFCs.

EPA first issued its SNAP regulations in 1994, listing HFCs as acceptable replacements for ozone-depleting substances like chlorofluorocarbons. Since that rule took effect, HFC demand has increased dramatically, thanks in part to growing demand for refrigeration and air conditioning in developing countries.

With increased demand has come awareness of HFCs as potent greenhouse gases, leading to President Obama’s inclusion of HFC cuts in his 2013 plan to address climate change.

The EPA rule in 2015 effectively banned 38 individual HFCs or HFC blends in 25 uses in four industrial sectors: aerosols, air conditioning for new cars, retail food refrigeration and foam blowing.

In their lawsuit, Mexico-based Mexichem Fluor Inc. and France-based Arkema SA argue EPA can’t use SNAP to limit substances that themselves do not deplete ozone. The SNAP program, they argue, can only be used to replace ozone-depleting substances — not previously approved replacements for those substances.

Once industrial sectors have moved away from ozone-depleting substances, “the SNAP program no longer has any work to do,” said Dan Himmelfarb, a partner at Mayer Brown who is representing Mexichem.

“EPA has turned a limited program into a limitless one,” he told judges.

The Justice Department maintained that EPA has authority to revisit its list of replacements for ozone-depleting substances. The rule is lawful, the agency argues, because HFCs pose an overall risk to humans and the environment due to their effects on climate change.

And the Clean Air Act, DOJ’s Maghamfar told the judges, says it’s illegal for EPA to replace ozone-depleting substances with substitutes that may adversely affect human and environmental health.

“The statute requires EPA to compare alternatives to each other,” Maghamfar said.

‘I’m still stuck’

But Kavanaugh, a George W. Bush appointee, said that while the statute does seem to give EPA authority to decide that “some substitutes are OK and some are not OK,” the agency’s 2015 rule “does seem to pull the rug out” from under companies that invested in HFCs.

“I guess I’m still stuck,” he said. “Maybe I’m unique in seeing the problem that I’m seeing.”

Like Kavanaugh, Judge Robert Wilkins, an Obama appointee, questioned what promises EPA made to companies in its 1994 regulations about potential updates to the list of accepted alternatives.

But Wilkins said a petition process that Congress established “wouldn’t make sense” if lawmakers didn’t expect EPA to update the list in the future.

Maghamfar argued the agency was clear in its 1994 regulations that it may make changes to the list of accepted substitutes in the future.

“We are not promising that once you’re on the acceptable list, you get to stay there forever,” he said.

Judge Janice Rogers Brown, a Bush appointee, heard the case with Kavanaugh and Wilkins. The judges will likely issue a decision in the coming months.

Mexichem is a member of the Air-Conditioning, Heating & Refrigeration Institute, the major trade group for the heating and cooling industry. A spokesman said the group had its eye on the case.

“We are watching this case closely as it involves one of our member companies and an issue — refrigerants and the SNAP program — we care a lot about,” said Francis Dietz, the spokesman. “We did not intervene in the case but are paying close attention to how it plays out.”

The ruling will likely affect a pending lawsuit in the D.C. Circuit over EPA’s 2016 HFC rule brought by the National Environmental Development Association’s Clean Air Project.

The Natural Resources Defense Council, Chemours and Honeywell are also seeking to intervene in that case on behalf of EPA.

The original article can be found here.

Oxygen Reduction Fire Protection 101: An Introduction and Case Study

January 31, 2017

Reprinted with permission from Fire Protection Engineering QT3 2016 issue –

By Adam Barowy and Scott Creighton, F(PE)

For approximately 20 years, oxygen reduction fire protection systems have been developing  as a new approach to providing a primary means of fire protection for enclosed spaces. The design concept of these systems is to reduce the oxygen concentration within a space (by constant inerting with nitrogen) sufficiently to prevent ordinarily combustible materials from igniting in the presence of a typical ignition source. Oxygen reduction systems should not be confused with gaseous extinguishing systems, which discharge extinguishing agents after a fire starts in response to detection. Oxygen reduction systems provide constant control over the gaseous makeup of the enclosure while online.

As of 2014, more than 700 installations have been constructed outside of North America by just one manufacturer.[1] Common applications for oxygen reduction systems include data centers, cold storage, museum storage areas and archives, and electrical rooms. Few installations currently exist in North America. However, two notable examples are a system that protects the Betsy Ross American Flag at the Smithsonian National Museum of American History,[2] and a system in Richland, Washington that protects the largest cold storage warehouse in North America (as of September 2015).[3]

What is an Oxygen Reduction Fire Protection System?

Nitrogen producing equipment is the backbone of any oxygen reduction fire protection system. The nitrogen supply is produced onsite from ambient air. The systems employ technology originally developed in the 1980’s for the industrial gas industry in a process known as “air separation.”[4] The development of air separation equipment for use in fire protection applications began approximately 20 years ago,[1] though this is not to suggest that controlling the gaseous environment within an enclosure is a new concept. The first published research into the feasibility of mitigating fire hazards by continuous inerting an enclosed space was conducted by the U.S. Navy in the late 1960s,[5] and continued with research into the medical hazards of flame-suppressing atmospheres in 1990s.[6] Oxygen reduction systems referred to as On Board Inert Gas Generating Systems (OBIGGS) have been deployed for explosion prevention in the fuel tank ullage spaces of military aircraft for approximately 30 years.[7]

Manufacturers of oxygen reduction systems use three different air separation technologies to produce nitrogen: selectively permeable gas membranes, pressure swing adsorption (PSA), and vacuum pressure swing adsorption (VPSA). The membrane systems work much like a filter: as compressed air flows through a membrane, smaller oxygen molecules pass through the porous membrane walls. This allows oxygen and nitrogen to be collected into separate pipework. The PSA and VPSA systems work similar to each other, by passing compressed air through pressure vessels containing a carbon material that selectively adsorbs oxygen and allows nitrogen to pass through. Flow through a vessel is discontinued when the carbon material becomes saturated, and nitrogen flow is continued from another vessel. A saturated vessel “regenerates” when it is depressurized back towards atmospheric pressure. A continuous effluent of nitrogen is typically produced using two vessels.[8]

Figure 1 demonstrates the basic operation of an oxygen reduction fire protection system. Membrane, PSA or VPSA, air separation technologies are represented in the box labeled “air separation.”


The potential for ignition and fire growth within the enclosed space(s) is reduced because of two basic phenomena: 1) less oxygen is available for combustion and 2) a greater amount of thermal energy is lost during combustion due to the additional nitrogen. The oxygen concentration required to establish fire protection is primarily determined by the flammability characteristics of the materials to be stored within the enclosed space, but also depends on ambient temperature and pressure. Figure 2 shows how temperature, pressure, and the addition of nitrogen affect the gaseous composition of a fixed volume of air. The atmospheres illustrated in Figure 2 provide insight into the variables considered at the installation described in this article’s case study.

The reduced oxygen concentration referred to as the “ignition threshold” by guideline documents that restrict burning, must be empirically determined for all materials stored within the space protected by the system. The design oxygen concentration that any system maintains is principally determined by the stored material with the lowest ignition threshold oxygen concentration. By the test methods currently used in ­European oxygen reduction system guidelines, ignition thresholds for common plastics and cellulosics typically fall within 14 to 17 percent, and within 11 to 16 percent for solvents.[9, 10] When determining a design oxygen concentration, European guidelines recommend reducing the lowest ignition threshold by 1 percent (volume concentration) as a safety margin.[9] It is anticipated that the first European installation standard, due to be published in 2016, will require a safety margin of 0.75 percent with a further allotment based on the precision of the oxygen sensing equipment.[11]


Case Study: Richland, Washington

In July 2015, construction of the largest public refrigerated warehouse in North America was completed in Richland, Wash. An oxygen reduction system is the primary means of fire protection for this facility. The warehouse employs an automated storage and retrieval system (ASRS) and has three common wall freezer spaces that are each 475 ft (145 m) long by 225 ft (69 m) wide by 116 ft (35 m) tall. Each freezer encloses approximately 12,000,000 ft3 (340,000 m3) and has a capacity of approximately 115,000 pallet stalls for 9 ft (2.8 m) high pallet loads. The racking has eleven 9.5 ft (2.9 m) tier levels for a total storage height of 106 ft (32 m). Further details of the building construction are available in the January 2015 issue of Construction Today.[12]

The fire protection engineer for this project provided the stakeholders with a complete array of prescriptive and performance-based options for this complex and unusual facility. The performance objectives established for the fire protection system in this facility included:

  • Provide a system that is least likely to result in the contamination of the stored commodity.
  • Provide redundancies of equipment to assure that a single point equipment failure cannot cause loss of protection.
  • Provide a system that reduces risk to emergency responders (reduce fire frequency or severity).
  • Provide a system that does not require water or chemical (e.g., antifreeze) cleanup.

The stakeholders were most concerned with smoke contamination that can result in a complete loss of the food product. Because fire sprinkler activation is dependent on the heat generated from a fire, the stakeholders chose to pursue an oxygen reduction system using a performance-based approach.

There was an early consensus that oxygen reduction would be a reasonable substitute for fire sprinklers. The stakeholders were already familiar with the oxygen reduction system equipment used in controlled atmosphere food preservation. Oxygen reduction systems (that maintain ≤ 3 percent O2)[13] are frequently deployed in apple storage warehouses within the geographical area surrounding Richland.

The proposed design of the oxygen reduction system for this application needed to meet the safety criteria of Verband Der Schadenversicherer (VdS), a German testing, inspection and certification company, as well as the Fire Engineer of Record and the local building and fire department criteria. VdS has developed design and installation guidelines as well as a certification program for oxygen reduction systems. In addition to the details required in the guideline document VdS 3527en,[14] VdS conducted fire testing on the commodity anticipated to provide the greatest challenge to the oxygen reduction system and concluded that an oxygen concentration of 17.4 percent provided the necessary “ignition threshold.” The final design oxygen percentage of 16.1 percent was derived by applying a 1 percent safety margin recommended by VdS and a 0.3 percent safety margin recommended by the oxygen reduction system manufacturer.

In the United States, the Occupational Safety and Health Administration (OSHA) regulations require employees to wear self-contained (or supplemental) breathing apparatus to enter and work in the freezer spaces because the oxygen concentration is less than 19.5 percent.[15] Entry points are monitored with position switches and display notifications of the reduced oxygen hazard within the freezer space.

After system installation, equipment was individually tested for function and performance. With the system operational, the oxygen concentration was reduced by approximately 0.25 percent per day. Reducing the oxygen concentration to 16.1 percent required three weeks. The system control panel indicates operational status locally as well as remotely to the building control room and to the manufacturer.

These systems, as with other fire protection systems, require ongoing inspection, testing, and maintenance to ensure reliability of operation.

Advantages, Limitations and Challenges

Oxygen reduction fire protection systems have advantages and limitations. As a new fire protection approach, oxygen reduction faces several implementation challenges, particularly within the United States. Table 1 summarizes the advantages, limitations, and challenges facing oxygen reduction systems.

It is important to understand the advantages and limitations of any means of fire protection, but the growth potential for oxygen reduction system deployment within the United States lies in addressing the challenges identified in Table 1.



The greatest challenge for oxygen reduction systems is that there is currently no installation standard in the United States. Fire protection engineers pursuing oxygen reduction fire protection will need to rely on either VdS guidelines or the EN installation standard until a U.S. installation standard is developed. Development of an installation standard in the United States is not yet underway.

UL issued a product safety certification document in January 2016 for oxygen reduction systems titled as, UL 67377, Outline of Investigation for Oxygen Reduction Fire Protection System Units.[17] The UL certification document evaluates the capability of a system to develop and maintain a reduced ­oxygen atmosphere within an enclosure. The document includes requirements for fire, electrical, and mechanical safety of oxygen reduction system equipment, and uses a functional safety approach to evaluating the reliability of the system control hardware and software.

Limited data is available for the ignition thresholds of materials.[16] In practice, this is not a significant challenge, as existing installation standards for oxygen reduction systems require that material test data form the basis for determination of the design oxygen concentration. This is similar to the practice of commodity classification testing. However, Nilsson and van Hees suggest further developments to the test method currently used in Europe should be based on research into the dependency of ignition threshold oxygen concentration on material orientation and reradiation.[16] Research data is also limited to the effect of reduced oxygen concentrations on smoldering behavior and the production rates of pyrolyzates and other gasses.[16]

Internationally, occupational safety and health regulations establish required oxygen concentrations within working environments. These regulations determine whether an AHJ will permit employees to work within a reduced oxygen space. Regulations may require employees to wear supplemental breathing apparatus or to take mandatory breaks within a normoxic environment. Regulations are based upon an occupational safety regulator’s interpretation of health risks at sub-atmospheric levels of oxygen and differ internationally.

For example, Germany has established four risk classes for reduced oxygen atmospheres. Each class requires employee awareness training. As oxygen concentration decreases, each increase in risk class requires reduced exposure durations. Below 13 percent O2, supplemental breathing apparatus are required.

In the United States, OSHA maintains that an oxygen deficient atmosphere contains less than 19.5 percent O2 . In practice and for the indefinite future, installations in U.S. are likely to be limited to normally unoccupied spaces that require breathing apparatus for entry, similar to the warehouse in Richland.

Adam Barowy is with UL.

Scott Creighton is with Womer & Associates.



  1. P. Clauss, “Fixed Firefighting Systems – Oxygen Reduction Systems: Active fire prevention vs. passive fire protection,” in SUPDET, Orlando, FL, 2014.
  2. Smithsonian Institution, “Visited the Star Spangled Banner,” 2015. [Online]. Available:
J. Harris, “Cold Front: Victory Unlimited is Building North America’s Largest Refrigerated Warehouse,” Construction Today, no. January, pp. 152–163, Januar 2015
S. Ivanova and R. Lewis, “Producing Nitrogen via Pressure Swing Adsorption,” June 2012. [Online]. Available:
C. Huggett, “Habitable Atmospheres Which Do Not Support Combustion,” Combustion and Flame, no. 20, pp. 140–142, 1973.
  6. D. R. Knight, “The Medical Hazards of Flame Suppressant Atmospheres,” Naval Submarine Medical Research Laboratory, Bethesda, MD, 1991.
  7. H. W. Wyeth, “Aircraft Fire Safety,” North Atlantic Treaty Organization, London, 1982.
A. R. Smith and J. Klosek, “A review of air separation technologies and their integration with energy conversion processes,” Fuel Procesing Technology, vol. 70, pp. 115–134, 2000.
  9. VdS, “3527en : 2007-01 Inerting and Oxygen Reduction Systems, Planning and Installation,” VdS, Köln, Germany, 2007.
  10. British Standards Institution, “PAS 95:2011 Hypoxic air fire prevention systems – Specification,” British Standards Institution, London, 2011.
  11. Comité Européen de Normalisation, “Fixed firefighting systems – Oxygen reduction systems – Design, installation, planning and maintenance,” Comité Européen de Normalisation, Brussels, May 2014.
  12. J. Harris, “Cold Front: Victory Unlimited is Building North America’s Largest Refrigerated Warehouse,” Construction Today, vol. 2015, No. January, pp. 152–163, January/February 2015.
  13. P. G. Levesque, J. R. DeEll and D. P. Murr, “Food Preservation by Modified Atmospheres Food Preservation by Modified Atmospheres,” HortScience, vol. 41, no. 5, pp. 1322–1324, 2006.
  14. VdS Schadenverhütung GmbH, “Guidelines for Inerting and Oxygen Reduction Systems: Planning and Installation,” VdS Schadenverhütung GmbH, Köln, Germany, 2015.
  15. Occupational Safety and Health Administration, “Respiratory Protection. – 1910.134,” 23 February 2016. [Online]. Available:
  16. M. Nilsson and P. van Hees, “Advantages and challenges with using hypoxic air venting as fire protection,” Fire and Materials, vol. 38, pp. 559–575, 2014.
  17. Underwriters Laboratories Inc., “UL 67377 – Outline of Investigation for Oxygen Reduction Fire Protection System Units,” Underwriters Laboratories Inc., Northbrook, IL, 2016.

Data Center Fire Protection: Adapting to a Constantly Changing Environment

January 31, 2017

Reprinted with permission from Fire Protection Engineering QT3 2016 issue –

By Lee A. Kaiser, P.E.

Data center designs have become a playground for creative problem solvers and new products. The areas of information technology, electrical power, and equipment cooling — The Big Three — seem to be reinvented every five years. This constant reimagining of the data center is driven by the need for a larger capacity to address software and data demands as consistently as possible with zero downtime.

Building designs have become a secondary consideration, adapting to serve the needs of The Big Three. Some building designs have become more complex to reduce size while other designs remain simple but larger.

Despite all these changes, the goals of data center fire protection remain the same: warn early of a fire, give the occupants options, and do no additional harm. If you select fire protection systems with these precepts, then they will parallel the mission of the data center.

A Well-Developed Fire Protection Strategy

The architecture and engineering team for any new data center project must design with these three fire scenarios in mind:

  • A fire outside the data center is indirectly threatening it.
  • Smoke inside the data center requiring immediate investigation before escalation (with the option for manual extinguishment).
  • A fire inside the data center too large to be extinguished manually.

Some examples of solutions include continuous walls surrounding the data center, air sampling smoke detection arranged for Very Early Warning Fire Detection, clean agent-type manual fire extinguishers placed near all room exits, and clean agent fire extinguishing systems. Engineers should remember to focus on asset protection—life safety will be a convenient byproduct of that focus.

NFPA 75 and Enforcement by AHJ Community

The section concerning risk considerations (Chapter 4) is one of the most important parts of NFPA 75, Standard for the Fire Protection of Information Technology Equipment. Fire protection engineers should judge risk assessments against NFPA 551, Guide for the Evaluation of Fire Risk Assessments.

The standard is voluntary in most cases, and many data center designers skip over its usefulness. AHJs also have trouble applying the prescriptive portions when they run into an IT facility. Many are confused by how NFPA 75 applies to the size of IT room. The scope states it is for “…the protection of information technology equipment and information technology equipment areas.” This is admittedly a broad definition, but the broad scope points to the importance of a risk assessment. The smaller an IT room, the less equipment it can hold. If loss of the equipment presents a risk to the business, the prescriptive requirements should be followed. But if there is little risk, then the standard may not apply to that room. It should then stand to reason that any large IT rooms or data centers should perform a risk assessment to determine fire protection requirements.

Raised Floors Present Unique Firefighting Challenges

A risky proposition for any firefighter is battling a fire underfoot. Many data centers continue to use raised floor systems to act as an air supply plenum and to conceal power and communications cabling. The 2013 edition of NFPA 75 requires either automatic sprinklers or a gaseous fire extinguishing system below raised floors when one or both of these conditions exist:

  • There is a critical need to protect data in the process, reduce equipment damage and facilitate a return to service.
  • The area below the raised floor contains combustible material.

Raised floors are an important, but often overlooked requirement that bears more explanation. If a fire occurs in a raised floor space, it will be difficult to access. Manipulating tiles for access is tough and regularly causes injuries in non-fire conditions including sprains, strains, and cuts on sharp corners of the metal framing system. Fill the room with smoke and firefighters now have a new risk not usually found in other structural firefighting conditions.

Virtualization IT Solution Increases the Cost of Fires

Virtualization is the consolidation of multiple computer servers into one device. The concept of virtualization is purely IT-related but increases the value of the equipment inside the data center. The virtualized server has much more computing power, energy consumption, and heat rejection. Servers operate multiple software applications simultaneously and more efficiently than individual servers, but have created a market with server costs of $1–1.5 million (U.S.)—much more expensive than the industry is used to.

Because of the rising costs, virtualization is changing the loss equation. In the mainframe days, the equipment was worth more than the data. Then equipment became cheap, and the data explosion made data loss more expensive than the equipment. Virtualized servers are bringing the two into balance with equal worth.

Fire Ignition Sources

Many in the gaseous suppression industry believe data center fires are under reported for a variety of reasons. A large concern is a fire can damage a company’s brand image, exposing vulnerabilities.

The actual number of incidents per year in any given country is unknown, but the reality is data centers have fires. It is this author’s experience that there are about two fires per month in the U.S. resulting in a suppression system discharge. The ignition source varies. About 10 percent of the time it is in the IT equipment, but manufacturers have made great strides in making equipment more resistive to causing fires. A little more than a third of the time the ignition source is the power distribution equipment—either inside the IT room or outside in a power or battery room. Uninterruptible power supplies are a frequent source of small fires and smoke events. The remaining causes are less common and can include foreign objects in the data center, human error, or even arson.[1,2]

HVAC and Cabling Designs Should Lead Fire Protection Decisions

Do not develop final designs for fire protection systems until there is a complete understanding of both the HVAC system and electrical raceways present in the space. Without accommodating the HVAC system, performance will inevitably suffer.

Today, air change rates for most data centers require spot smoke detector spacing of 125 Ft2 per detector, as dense as required by NFPA 72, National Fire Alarm and Signaling Code. Also, facilities use aisle containment systems that complicate installation of both detection and suppression systems. NFPA 75 and NFPA 76, Standard for the Fire Protection of Telecommunications Facilities have requirements for installing fire protection when aisle containment is at play, but the components must be understood early in design. Without adjusting for aisle containment partitions, sprinklers may not work properly, or clean agent systems may not develop concentrations as fast as possible.

Locations of electrical cable trays and bus ducts must be known for proper placement of sprinklers and clean agent nozzles. Improper coordination can impact fire system performance. Furthermore, recent Factory Mutual Research has shown how difficult cable bundle fires can be to extinguish.[3] A fire involving a cable bundle can threaten the entire data center if not extinguished.

Placement and Type of Smoke Detection Key to Detecting an Impending Fire

Large, uncontrolled smoke production causes increased damage, an additional difficulty in response and equipment failures from corrosion of printed circuit boards. Early detection of smoke depends on knowledge of the HVAC system in the space.

For very early warning, locate detectors where the smoke will travel—along the air circulation path. Smoke must arrive in sufficient density to be detectable. If there are not sensors along the airflow paths, smoke may not be detected in time to avoid a larger fire event.

Air sampling smoke detectors can warn data center operators of a smoke condition well before humans can perceive it. A notification scheme using mobile communication devices should be part of a well-thought-out very early warning fire detection system.

Once notified, a facility should have trained personnel search for the source of the smoke. Statistically, the most probable cause of a smoke event is overheated equipment. Personnel investigating should have thermal imagers available to search the space.

When the source of smoke is found, the associated equipment should be powered down according to IT procedures. To extinguish any flaming or active combustion, make sure a manual fire extinguisher is available to address the problem before any suppression system activates.

Specifying the appropriate type and number of manual fire extinguishers in the data center can be overlooked. Many times specifying extinguishers is left to architects, but engineers should take a more active role in IT facility designs so the correct type is specified. Chapter 8 of NFPA 75 has requirements to follow for extinguishers. Facilities should steer clear of powdered extinguishers in IT rooms.

After Detection Data Center Operations Impact Fire System Decisions

Automatic power and HVAC shutdown is a very hot topic for IT personnel. The NFPA codes and standards generally require powering down equipment in an IT room when a fire is detected as well as turning off HVAC units and closing dampers serving the room. This is not popular with many IT operators.

Within the past five years, it is become en vogue to “ride through” the event because the reality of an immediate shutdown of server equipment is too risky for the primary mission of the data center. NFPA allows exceptions for these “critical operations data centers” if proper justification can be made to the AHJ. Furthermore, this new reality has been realized by the NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems Technical Committee that more Class C fires will be part of the data center fire experience. System designers must make accommodations for this including higher Class C extinguishing concentrations and planning for continual mixing during the agent retention period.

Non-Traditional Data Center Fire Suppression Systems

Clean agent fire extinguishing systems should be selected if the risk analysis shows a low tolerance for an outage. However, several fire protection systems have been marketed for installation in data centers besides clean agent systems including aerosol systems that generate fine particulate which interrupts flame chemistry for extinguishment. The concern with aerosol, however, is the cleanup effort of the particles after a discharge and the high heat during discharge causing secondary fires.

There is a lot of interest in water mist systems for data centers and several examples of water mist being used as the primary fire suppression system. Water mist should be viewed as an alternative to water-based sprinkler systems, not clean agent systems. It is important to remember that they still use water and activate using heat like a sprinkler system as water will pool on any horizontal surfaces. The advantage of water mist over sprinklers is they use less water, typically 50-90 percent less depending on the system.

Data center operators and specifying engineers continue to select very different strategies for fire protection of new data centers. In large part, decisions about the appropriate level of suppression protection and detection are made by showing the data center owners a menu of available options and letting them select at their risk without performing the risk analysis required by NFPA 75. In some cases, selection of the fire protection system is made by the construction manager/general contractor who is delivering the finished space for a certain unit price. Often, the owner believes they have a “critical operations” data center even though the fire systems weren’t installed for critical operations.

Many system selection decisions are based on the cost first, what worked the last time, and a hope that no fire will occur, but the reality is the stakes for major IT facilities have never been higher. The public’s demand for service with little to no interruption, additions to data consumption, and the significantly increased cost of virtualized servers make the risk of fire exposure to data centers significantly higher today than even just five years ago.

The best strategies for fire protection today are integrated with the operating model of the data center and the disaster recovery plan. A multi-layered approach to fire protection assures that fires and other small thermal events can be dealt with early causing minimum impact to the data center and delivery of service.

Lee A. Kaiser is with ORR Protection Systems.



Hirschman, Dave (, ‘ATC Zero’: Inside the Chicago Center Fire, (November 6, 2014)
Judge, Peter (, Modular data center survives arson attack, (February 3, 2015)
  3., Small-Scale Testing, Large-Scale Benefits, (August 25, 2015)

An Update on Water Mist Fire Protection Systems

January 31, 2017

Reprinted with permission from Fire Protection Engineering QT3 2016 issue –

By Magnus Arvidson

A new technical report 
from SP (Technical Institute of Sweden) presents the results of the development of water mist fire protection systems over the last few years. This report a) describes new technology and presents the results of confirmatory trials for various applications, b) describes installation regulations together with test methods and their applications; and c) presents examples of both good and bad experiences from real installations.

New Applications

Roadway tunnels are a particular application in which sprinklers are not, and have not been, particularly common. Increasing traffic on the European road network, ever more tunnels, and, not least, several serious tunnel fires, have paved the way for the use of sprinklers. Water mist systems have been launched as an alternative to traditional sprinklers or water spray systems, and, in recent years, several largescale tests have shown positive performance.

A similar application can be found in multi-story parking garages. A series of tests have shown that the performance of water mist is comparable with that of traditional sprinkler systems, despite the fact that the distances between nozzles are often greater, and the overall water delivery density is lower.

Another application in which water mist fire protection systems can be used is that of subfloor and above ceiling areas, in which the primary fire hazard, and potential fire load, consists of electric cables on cable trays.

Prison cells represent a further application for which water mist is particularly suitable, both in the form of permanently installed automatic systems and systems for manual firefighting. A problem specific to prisons is that of the risk of intentional damage to the nozzles, or of their potential use for securing a rope or noose. Automatic nozzles (with glass bulb elements) are available on the market for prison cells or areas where persons might be suicidal or at risk of self harm. An example of such a nozzle is shown in Figure 1. The design is such that it is difficult to dismantle it. If the yoke carrying the glass bulb is subjected to a load of about 150 Newton (about 15 kg), the nozzle will operate. This type of nozzle is suitable for wall or ceiling mounting.

The primary fire hazard in aircraft hangars is that of fuel spillage on the hangar floor. The use of high-expansion foam systems is common, but their use necessitates filling the area with foam. Another alternative is that of ceiling mounted foam-water spray or foam nozzles, but the presence of an aircraft fuselage and wings screens the water spray from covering a burning fuel spill running underneath an aircraft. Several manufactures, therefore, developed what are known as ‘pop-up’ nozzles for installation in the floor. In the interests of rapid activation, these systems often use flame detectors and are divided into zones, each representing a stand position for an aircraft. Service and maintenance of aircraft often require electrical equipment, cables and connections to be directly exposed. Common aircraft fuels are JP8 or other hydrocarbons. As hangars are often large, the primary fire-suppression mechanism is therefore direct cooling of the fuel, rather than evaporation of the water and internalizing the fire by water vapor. In order to improve fire protection, end-users often elect to install ceiling mounted nozzles over and around aircraft stands. An example of a water mist system in operation is shown in Figure 2.

Smaller Water Droplets with New Technology

New technologies available on the market include systems in which the water droplets are generated by a patented method, of 
which one of the elements consists of an oscillating sheet. The water droplets produced in this way are considerably smaller than those produced by a system depending on hydraulic atomization of the water, of the order of smaller than 10 µm, as compared with 50–150 µm. The result is that the water droplets behave more like a gas, being carried by air currents and capable of flowing around obstructions. Other systems combine water mist with an inert gas, usually nitrogen. The gas has several functions:

  1. compressed, it ejects the water from a pressure vessel into the system pipes;
  2. it breaks the water into very small droplets at the nozzle; and,
  3. finally, it assists fire suppression by reducing the oxygen concentration in the area.

Velocity through the nozzles is high, ensuring good mixing of the mist with the air in the protected area. As the quantities of water are very low, the risk of water damage is reduced.

Additives Can Improve Efficiency

Although water is a very effective fire suppressant, the use of additives can considerably improve its performance. ­Smaller-scale trials[1] with various additives have shown that alkali metal salts are very effective, even at low concentrations. Antifreeze additives are another application where the fears are instead that the additive will reduce the fire suppression performance. All antifreeze additives have both benefits and limitations. In some cases, the limitations are such that some particular antifreeze additive at a particular concentration cannot be used in a water mist system. In other cases, it is the specific application and design of the system that determines whether an antifreeze additive can be used. In general, antifreeze additives increase the density, viscosity, volumetric expansion and corrosivity in comparison with those of pure water, as well as reducing the surface tension. Propylene glycol, glycerine, and betaine supply energy to a fire, thus increasing the heat release rate, while potassium acetate improves the fire suppression performance in comparison with that of pure water.[2]

System Reliability

The reliability of water mist type systems is often discussed, and there are extensive and detailed fault tree analyses that provide at least an indication of the reliability of different system designs. These analyses involve a number of simplifications and assumptions. Although they use input data for components used in the systems, these data are taken from the components when used in other applications.

An analysis performed by FM Global[3] shows that errors with great impact on the probability of a system failure include; the water supply has no water, the pressure is too low in the drive gas reservoir, incorrect control settings, errors in the fire control panel or transmission errors, and closed water main valves. Human error, such as that the propellant or water tank is empty or the control settings are set wrong, are common.

Studies have also been conducted on the reliability of the various fire suppression systems on ships[4]. The analysis shows that traditional automatic sprinkler systems on passenger ships have high reliability. Water mist systems are judged to have an equivalent level of reliability if properly maintained. According to the source, the strength of a fault tree analysis is that, in principle, it can be applied to any system, regardless of its complexity. Its weakness is that it does not consider the interaction between components or any domino effects. The reliability of various components of a system is not necessarily determined by the components alone, as a fault in one component can carry over to another. For this reason, a fault tree analysis presents a result that is only an approximation of the real reliability of a system. Nevertheless, the methodology does yield useful results when no other source material is available. It is recommended that results should be compared with those from trials or historical data in order to verify the calculation model.

Experience from Actual Installations

The risk of clogging filters and nozzles was one of the fears to which particular attention was paid when the use of water mist systems began to be widely introduced in the early 1990s, and in several cases, in Swedish on-shore installations, these fears have been found to be partly justified. As a result, this calls for frequent inspection of nozzles, filters, and the water quality as well as regular flushing of piping and water tanks. Another experience is that system applications are sometimes not covered by the system’s certificate, or that one particular system design has been tendered, but a different one has been installed. Two serious incidents show that closed areas with no direct access to the open air are unsuitable for storage of pressurized inert gasses used for the atomization or pressurization of water. If instead, the area has a boundary with the open air, pressure relief valves can be installed and would open in the event of an escape of gas and ventilate the area. Opening a door to the area also assists ventilation when somebody needs to enter.

There are also examples from passenger ships of cases when automatic nozzles (i.e. with glass bulbs) have not operated when tested in the field. This underlines the importance of regularly testing the performance of all parts of the system (i.e. including the automatic nozzles). Traditional sprinkler systems in onshore installations are subject to a testing regime by which some sprinklers from each system are dismantled and performance tested. Naturally, this should also be applied for water mist systems.

The SP Report

This project was financed by the Swedish Fire Research Board, with the results published in SP Report 2014:30, ‘Water mist fire protection systems—an updated state-of-the-art report, Swedish Fire Research Board project no. 500-121’. The report is only available in Swedish.

 Magnus Arvidson is with SP Technical Research Institute of Sweden.



Joseph, Paul, Nichols, Emma and Novozhilov, Vasily “A comparative study of the effects of chemical additives on the suppression efficiency of water mist,” Fire Safety Journal, Volume 58, 2013, pp. 221-225.
Connolly, Matthew S., Jaskolka, Stephen M., Rosen, Jeffrey S., Szkutak, Michael D., “Engineering Performance of Water Mist Fire Protection Systems with Antifreeze,” Worcester Polytechnic Institute, 26 April 2012.
Xu, Shuzhen and Fuller, David, “Water Mist Fire Protection Reliability Analysis,” FM Global.
Lohtmann, Phillip, Kar, Apurba, Breuillard, Antoine, “Probabilistic Framework for Onboard Fire Safety—Reliability and Effectiveness Models of Passive and Active Fire Safety Systems,” January 13, 2011.

Special Hazards Fire Protection: Developments Since Halon 1301

January 31, 2017

Reprinted with permission from Fire Protection Engineering QT3 2016 issue –

By Jeff L. Harrington, P.E., FSFPE

It has been nearly 22 years since the production of halon 1301 ceased 
in the United States and many other developed and developing countries. This article will reflect on that time in history and examine many of the significant developments in fire and explosion suppression that were a direct result.

Halogenated hydrocarbons have been in commercial use as fire extinguishing agents since the early 1900s. Their use began to decline and had all but ended by the 1950s due to their relatively high toxicity coupled with the increasing popularity and availability of dry chemical agents. In the late 1940s, halon 1301 was verified to possess effective fire extinguishing capability while also having the lowest toxicity of all known halons. In the 1960s, halon 1301 received renewed interest as a means to extinguish fires in computer rooms without collateral damage from the agent itself with the added benefit of low toxicity.

Halon 1301 grew in popularity for the next 20 to 25 years becoming the extinguishing agent of choice in fixed fire extinguishing systems protecting a majority of electronic equipment facilities, including electronic data processing and communications equipment rooms. Halon 1301 also grew in popularity as an option for protecting a variety of other high-value and high-criticality assets benefiting significantly from the absence of direct damage by the agent, including vital records and priceless artifacts in museums. In 1989, it was reported that halon 1301 was in use according to estimates shown in Table 1.[1]


Halon 1301 Phases Out

The National Fire Protection Association (NFPA) formed a committee on Halogenated Fire Extinguishing Systems in late 1966 for the purpose of writing a new standard on halon 1301 extinguishing systems. In 1968, the first edition of the new standard was adopted in tentative form by the NFPA membership, and in 1970 it was officially adopted as NFPA 12A, Standard on Halon 1301 Fire Extinguishing Systems.[2] Just 27 years later, the continued viability of halon 1301 would be forever changed due to its particular effectiveness in depleting ozone in the earth’s stratosphere.

On September 16, 1987, the United States and 23 other nations signed the Montreal Protocol, which was adopted into US law through the Clean Air Act Amendments of 1990.[3] These new laws scheduled the phase-out of the production of ozone-depleting substances (ODS) that were causing the destruction of stratospheric ozone, including substances used as fire extinguishing agents. Stratospheric ozone is an essential minor atmospheric constituent responsible for the absorption of harmful UV-B radiation. The ODS chemicals are primarily chlorine and bromine-containing gasses, each of which has a characteristic potency for destroying ozone called the Ozone Depletion Potential (ODP). Halon 1301, as it turns out, has the highest ODP of any man-made ODS. Halon 1301 was targeted for the cessation of production in developed countries by ­January 1, 1994.

Since the cessation of production of halon 1301 in 1994, new fire extinguishing agents have been developed to serve as alternatives. Many of these new gaseous agents have attributes similar to those of halon 1301 including low toxicity to humans, nil electrical conductivity, and “clean” extinguishment (i.e., they cause no direct damage to the protected assets). These new “clean” agents are addressed by NFPA 2001, Clean Agent Fire Extinguishing Systems,[4] first published in 1994.

The phaseing out of halon 1301 not only prompted a search for alternative gaseous agents with characteristics similar to it, but also motivated a renewed interest in the further development of other fire extinguishing technologies, including water mist[5] and powdered aerosols.[6] Water mist fire protection systems are addressed by NFPA 750, Water Mist Fire Protection System,[7] first published in 1996. Powdered aerosol extinguishing systems are addressed in NFPA 2010, Standard for Fixed Aerosol Fire-Extinguishing Systems,[8] first published in 2006.

The Clean Air Act Amendments provided the authority to the EPA (Environmental Protection Agency) to develop and enforce rules and create a program that would facilitate the replacement of ODS including halon 1301 with alternative chemicals that reduce the overall risk to human health and the environment. In 1994, the EPA developed the Significant New Alternatives Policy (SNAP) program as a result. Under the Clean Air Act, Title VI regulations on ozone layer protection and Section 612 that is the basis for the SNAP program, all new alternative substances developed to replace Halon 1301 must be submitted to EPA for review and determination of acceptability. The submitted information must include the submitter’s health and safety studies for the alternative being proposed. EPA categorizes all listed substitutes for ozone-depleting substances by use sector. Substitutes for halon 1301 are listed in the Fire Suppression and Explosion Protection use sector.


Agency review of SNAP program submissions includes the following criteria:[9]

  1. Atmospheric effects and related health and environmental impacts.
  2. General population risks from ambient exposure to compounds with direct toxicity and to increased ground-level ozone.
  3. Ecosystem risks.
  4. Occupational risks.
  5. Consumer risks.
  6. Flammability.
  7. Cost and availability of the substitute.

The Clean Air Act also required the EPA (Agency) to publish and maintain a list of substitutes that are unacceptable for specific uses and a corresponding list of substitutes that are acceptable for specific uses. This is commonly referred to as the SNAP List. Upon review, the submitted substitute will be placed on the SNAP List in one of five categories as shown in Table 2.

The EPA completes a risk screen on all substitutes submitted for inclusion on the SNAP List using the submitter’s health and safety studies. The information required to be submitted for halon 1301 substitutes is detailed in the EPA’s risk screen guide and is categorized as follows:[10]

  1. Physical-Chemical Properties.
  2. Conditions of Manufacture, Installation, Maintenance, and Use.
  3. Toxicological Effects.
  4. Additional Considerations for Powdered Aerosols Used in Occupied Spaces.

The purpose of the risk screen is to evaluate the human health and environmental risks of the proposed substitute and analyze its acceptability. The EPA further asks for information specific to the type of substitute being proposed. The EPA defines two substitute types in the Fire Suppression and Explosion Protection sector:

  • In-kind Halon Alternatives:
    • Halocarbons
    • Inert Gas
    • Carbon Dioxide
  • Not-in-kind Halon Alternatives:
    • Powdered Aerosols
    • Foam
    • Water Mist

Substitutes are further distinguished by their proposed use as follows:

  1. Flooding Agent
  2. Streaming Agent
  3. For Occupied Spaces
  4. For Unoccupied Spaces

For total flooding substitutes, a SNAP listing of “Acceptable” means that the substitute can be used in occupied areas and also unoccupied areas. EPA approval of a substitute for use in occupied areas clears the way for its use as a replacement for halon 1301 in the predominant share of the market. This approval offers the greatest potential return on investment for a new substitute, which often provides the necessary justification to develop the substitute fully and bring it to the marketplace.


Gaseous Agent Alternatives to Halon 1301

Numerous collaborative efforts to find suitable alternatives to halon 1301 were undertaken in the years immediately following the signing of the Montreal Protocol in 1987. These efforts shared funding, expertise, and other resources from various government and private organizations. One such effort led to the publication of a report by NIST (National Institute of Standards and Technology) that presented an exploratory list of 103 chemicals in 9 chemical families for the purpose of helping to facilitate the search for halon alternatives.[11]

Candidate chemicals would need to possess performance characteristics in three major categories to be considered a viable replacement for halon 1301, including:

  1. Environmental impact,
  2. Agent Performance, and
  3. Toxicity.

Environmental impact considerations for a gaseous agent alternative include an assessment of its ozone depletion potential (ODP) and global warming potential (GWP), which are both related to the agent’s atmospheric lifetime (ALT). A candidate agent’s ODP value must be zero or near zero and the GWP must be very low to have commercial viability.

Agent performance is determined primarily by its effectiveness in extinguishing fires. Secondary factors include an agent’s form factor (weight and volume), total cost (installation, maintenance, and refill), and discharge effectiveness (evaporation and mixing).

Toxicity considerations are dependent on the agent’s chemical family. Halocarbon agents must be tested to determine their cardiotoxicity. When a person inhales halocarbons, it can cause an increase in the heart’s sensitivity to elevated levels of adrenaline, which can lead to cardiac arrhythmia and possibly a heart attack. Inert gasses have no toxicity effect; however, their use in total flooding applications creates the potential that a person could be exposed to low oxygen concentrations at high agent concentrations with the risk of asphyxiation.

Both halocarbon and inert agents can be used to extinguish fires in total flooding applications under conditions considered safe for humans. Rules to ensure safe exposure limits are contained in NFPA 2001,[12] which includes design requirements that define safety limits including an agent’s NOAEL (no observed adverse effect level) and LOAEL (lowest observed adverse effect level).

Enormous progress in the search and validation for new gaseous alternatives to halon 1301 was made during the late 1980s and the first half of the 1990s. By 1995, five commercially available halocarbons and three commercially available inert gasses were determined to be acceptable for total flooding applications in occupied spaces.[13] Since that time, additional agents have been commercialized and added to the SNAP List as acceptable for total flooding applications in occupied spaces and to the list of clean agents in NFPA 2001. Also, several have been discontinued. Table 3 includes the gaseous agents concurrently listed on the SNAP List as acceptable for total flooding use in occupied spaces and the current edition of NFPA 2001. Carbon dioxide is also included because it is a gaseous agent on the SNAP List; however, it is addressed in NFPA 12.[14]

Listing and approval agencies have developed standards and guidelines for validating the design, performance, and reliability of the new alternative gaseous clean agent systems. Standards organizations in addition to NFPA have also developed clean agent system standards addressing design/performance, installation, testing and maintenance. These documents provide a means to achieve uniformity in design, quality of components and installation, and performance effectiveness and reliability. Key examples are shown in Table 4.


Water Mist Alternatives to Halon 1301

Advances in water mist technology since the signing of the Montreal Protocol in 1987 have been significant for two primary reasons. The lack of a drop-in replacement for halon 1301 motivated renewed interest in water mist technology to fill the void and improved the economics resulting in more research funding. Also, in 1995, the International Maritime Organization implemented a new requirement mandating the installation of automatic marine sprinklers on all ships capable of carrying 35 or more passengers. This new requirement motivated interested parties globally to develop water mist technology further as a means to comply with the objectives of the sprinkler requirement with much less water and overall additional weight.[26] By 1996, nearly 50 agencies worldwide were engaged in some form of fundamentals research or applications development involving water mist technologies.[27]

Water, as an extinguishing agent, was approved by the EPA as an acceptable alternative to halon 1301 and placed on the SNAP List with its first publication in 1994. The general category of water mist systems was added to the SNAP List in 1995.

EPA did raise several concerns regarding the lack of evaluation of the health risks associated with exposure to water mist.[28] The primary risks of concern included respiration of water mist with an unknown droplet size distribution with and without water additives, and the physical properties of mist which may reduce visibility, interfering with safe evacuation from the protected space. In response to these concerns, the water mist industry facilitated the process of assembling an expert panel to evaluate the health risk concerns raised by the EPA. The panel report states that water mist systems using potable water do not present a toxicological or physiological hazard, and are safe for use in occupied spaces. EPA included the use of natural seawater as an acceptable alternative to potable water in the SNAP Listing for water mist systems. Furthermore, the panel report states that water mist with additives should be evaluated on a case-by-case basis, and the EPA has included this requirement in its process for SNAP program assessments of new water mist system proposals.

By the late 1990s, water mist system research and development efforts had made substantial progress in understanding and documenting the fundamental extinguishing mechanisms involved as well as the role of spray characteristics in suppression performance.[29] Three distinct types of water mist systems have evolved in the marketplace, defined by the operating pressure:[30]

  1. Low Pressure: operating pressure ≤12.1 bar (175 psi);
  2. Intermediate Pressure: operating pressure >12.1 bar (175 psi) but ≤34.5 bar (500 psi); and
  3. High Pressure: operating pressure >35.4 bar (500 psi).

Water mist systems have solidified market share in the protection of turbine and diesel powered machinery, protection of machinery spaces aboard ships, and the protection of passenger cabins aboard ships.[31] They continue to make inroads into other market areas protecting diverse hazards including industrial hot oil cookers, flammable liquid storage, and computer data/communication rooms.

Listing and approval agencies have developed standards and guidelines for validating the design, performance, and reliability of water mist systems. Standards organizations in addition to NFPA have also developed water mist system standards addressing design/performance, installation, testing, and maintenance. These documents provide a means to achieve uniformity in design, quality of components and installation, and performance effectiveness and reliability. Key examples are shown in Table 5.


Hybrid Inert Gas-Water Mist Alternatives to Halon 1301

During the last decade, a distinct variant of water mist and inert gas fire extinguishing systems has emerged and is actively being further defined and developed. These systems are being called Hybrid (Water and Inert Gas) Fire Extinguishing Systems, from now on called hybrid systems. Hybrid systems employ a larger quantity of inert gas in combination with water than traditional twin-fluid type water mist systems.

The EPA, as of this writing, has added one manufacturer’s hybrid system to the SNAP List, effective January 2, 2009, as acceptable for use in occupied spaces.[38] EPA recommends that the use of this manufacturer’s system conform to the safe exposure guidelines for inert gas systems in the latest edition of NFPA 2001 (clean agent systems), specifically the requirements for residual oxygen levels, and should conform to the relevant operational requirements in NFPA 750 (water mist systems).

Research by FM Global determined that one hybrid system tested extinguished the test fires at a dry-basis oxygen concentration ≥12.5 percent and ≤16.0 percent, providing a strong indication that fire extinction was accomplished by contributions from both the inert gas and water components.[39] This research further suggests that a twin-fluid water mist system should be treated as a gaseous system if the dry-basis oxygen concentration at fire extinction is <12.5 percent, and as a water mist system if the dry-basis oxygen concentration at fire extinction is >16.0 percent.

FM Global has published an approval standard for hybrid systems (Class No. 5580[40]), which borrows heavily with from their water mist system approval standard (Class No. 5560). It is likely that other listing and approval agencies will follow suit, but this may take some considerable time. Two manufacturers have received FM approval of their twin-fluid water-inert gas extinguishing systems by FM Global’s Hybrid Systems approval standard Class No. 5580.

NFPA, in the latter part of 2014, initiated the development of a new document on hybrid systems, and approved the roster for the new Technical Committee (TC) in April 2015. The TC has held two pre-first draft development meetings as of this writing. It is estimated that the first edition of this document may be ready for approval approximately in 2019, preliminarily named NFPA 770, Hybrid (Water and Inert Gas) Fire Extinguishing systems.

Powdered Aerosol Alternatives to Halon 1301

Research and development efforts related to powdered aerosol fire extinguishing systems increased dramatically, as with most other alternative fire suppression technologies, subsequent after the signing of the Montreal Protocol in 1987.[41] Powdered Aerosol agents are typically one or a mixture of several solid salts and oxides of alkaline metals (dry chemicals) that are dispersed rapidly into a protected space by one of the several mechanisms. The dry chemical particles that are dispersed are typically <10 µm in diameter. Condensed aerosols exist as a solid, which is a mixture of the dry chemicals in powder form, an oxidizer, a reducer, and a binding resin. This solid mass is thermally ignited, and the ensuing combustion reaction ejects the combustion reaction products as a dispersion aerosol. The dry chemical particles produced in this manner are in a size range that provides maximum fire extinguishing effectiveness, and would be very challenging to create and deliver by other means.

Some testing has shown that condensed aerosol systems may not be effective extinguishing deep-seated Class A type fires.[42]

The EPA, as of this writing, has added several powdered aerosol extinguishing systems to the SNAP List as acceptable for total flooding of occupied spaces. The EPA recommends that the use of these systems conforms to the safe exposure guidelines for inert gas systems in the latest edition of NFPA 2001 (clean agent systems), specifically the requirements for residual oxygen levels, and should conform to the relevant operational requirements in NFPA 2010 (aerosol agent systems). The EPA has added several other powdered aerosol agent systems to the SNAP List as acceptable for total flooding of unoccupied spaces.

NFPA publishes a design/performance standard addressing powdered aerosol extinguishing systems.[43] NFPA 2010 was first published in 2006. The standard defines two types of aerosol extinguishing systems: Condensed Aerosol and Dispersed Aerosol. Condensed aerosols are finely divided dry chemical powders in the form of a solid aerosol forming compound that requires a combustion process to generate and disperse the aerosol. Dispersed Aerosols are finely divided dry chemical powders that are resident in a pressurized agent storage container, suspended in a halocarbon or an inert gas.

Underwriters Laboratories (UL) has published a listing standard for validating the design, performance, and reliability of fixed condensed aerosol extinguishing system units. The scope of this standard evaluates performance on surface fires involving Class A, Class B, and Class C hazards. Four manufacturers have fixed condensed aerosol extinguishing system units listed by UL by UL 2775 as of this writing. Several standards organizations have developed powdered aerosol system standards addressing design/performance, installation, testing, and maintenance. These documents provide a means to achieve uniformity in design, quality of components and installation, and performance effectiveness and reliability. Key examples of the listing and design/performance standards for powdered aerosol systems are shown in Table 6.



Oxygen Reduction Fire Prevention Systems

Oxygen reduction fire prevention systems are also commonly referred to as hypoxic air fire prevention systems. These systems were developed in the 1990s and have gained market share in many countries as alternatives to conventional fire suppression systems of all types. There are several manufacturers of these systems and their reach in the global marketplace continues to expand.

Oxygen reduction systems work by ventilating a protected volume continuously with a supply of air that has been modified such that the oxygen volume percent has been reduced[48]. The manufacturers commonly refer to this as the hypoxic air supply to the protected space. Hypoxic air is supplied and oxygen sensors in the protected space provide information to the control system to enable a specified design level of oxygen to be achieved and maintained. Typically, this design level will be in the range between 14 percent and 17 percent, and will be based in part on an evaluation by the designer of the combustible fuels present. The manufacturers claim that such a system will prevent fire ignition in the protected space. Many also claim that the hypoxic atmosphere maintained by these systems is safe for human exposure. This claim has been challenged and debated in various countries by the authorities having jurisdiction and addressed by the organizations that have written design/performance standards. This concern must be addressed on a case-by-case basis since each country will have some health standards that address human exposure to hypoxic environments in some manner, and there will be differences that will impact on how these systems will be allowed to be configured.

In the U.S., for example, The U.S. Occupational Safety & Health Administration (OSHA) Respiratory Protection Standard[49] defines as oxygen deficient any atmosphere that contains less than 19.5% oxygen and requires, generally, that all oxygen-deficient atmospheres be considered immediately dangerous to life or health (oxygen-deficient IDLH). Certainly, any country or jurisdiction with similar health and safety laws will have concerns about workplace environments that are maintained at oxygen volume percent levels between 14 percent and 17 percent for indefinite periods of time. Safety procedures would have to be developed and implemented that meet the approval of the health and safety enforcement authorities.

The EPA, as of this writing, has received no applications to review oxygen reduction fire prevention systems for inclusion on the SNAP List as an acceptable halon 1301 replacement. There is currently no NFPA design/performance standard for oxygen reduction fire prevention systems, nor is there a standard under development. Likewise, FM Global has no current plans to develop an approval standard for oxygen reduction fire prevention systems.

UL has published a listing standard for validating the design, performance, and reliability of oxygen reduction fire protection system units. The scope of this standard covers oxygen reduction fire protection system units, intended to separate oxygen and nitrogen from the ordinary air to produce a flux of reduced-oxygen (elevated nitrogen) air for limiting the potential for ignition and fire spread of combustibles in a protected volume. The standard applies specifically to oxygen reduction fire protection system units intended for design, installation, operation, and maintenance under prEN 16750. One manufacturer has oxygen reduction fire protection system units listed by UL in accordance with UL 67377 as of this writing. Several standards organizations have developed oxygen reduction system standards addressing design/performance, installation, testing, and maintenance. These documents provide a means to achieve uniformity in design, quality of components and installation, and performance effectiveness and reliability. See Table 7.

Jeff L. Harrington is with Harrington Group, Inc.



  1. Final Report of the Halons: Technical Options Committee, August 11, 1989, UNEP Technology and Economic Assessment Panel, 1997.
  2. NFPA 12A, Standard on Halon 1301 Fire Extinguishing Systems, National Fire Protection Association, Quincy, MA, 2015.
The Clean Air Act Amendments of 1990, Public Law 101-549, 42 U.S. Code 7401, et seq.
NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems, National Fire Protection Association, Quincy, MA, 2015.
  5. Mawhinney, JR and Back III, GG, Water Mist Fire Suppression Systems, Chapter 46, p. 1588. In: “SFPE Handbook of Fire Protection Engineering, 5th edition,” Society of Fire Protection Engineers, 2016.
  6. Kibert, CJ and Douglas Dierdorf, “Solid Particulate Aerosol Fire Suppressants,” Fire Technology, November 1994; vol. 30, issue 4: pp. 387-399.
NFPA 750, Standard on Water Mist Fire Protection Systems, National Fire Protection Association, Quincy, MA, 2015.
NFPA 2010, Standard on Fixed Aerosol Fire-Extinguishing Systems, National Fire Protection Association, Quincy, MA, 2015.
  9. Agency Review of SNAP Submissions, Code of Federal Regulations, title 40, vol. 14, sec. 82.180(a)(7).
  10. U.S. EPA, 1994. A Guide to Completing a Risk Screen: Collection and Use of Risk Screen Data: Fire Suppression Sector, Stratospheric Protection Division, April 1994.
  11. Pitts, William M., Marc R. Nyden and Richard G. Gann, NIST Technical Note 1279: Construction of an Exploratory List of Chemicals to Initiate the Search for Halon Alternatives, National Institute of Standards and Technology, August 1999.
  12. NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems, National Fire Protection Association, Quincy, MA, 2015.
  13. Su, Joseph Z., Andrew K. Kim, and Jack R. Mawhinney, Review of Total Flooding Gaseous Agents as Halon 1301 Substitutes, “Journal of Fire Protection Engineering,” May 1996; vol. 8, no. 2: pp. 45-63.
  14. NFPA 12, Standard on Carbon Dioxide Extinguishing Systems, National Fire Protection Association, Quincy, MA, 2015.
  15. DiNenno, PJ and Forssell, EW, Clean Agent Total Flooding Fire Extinguishing Systems, Chapter 44, p. 1484. In: “SFPE Handbook of Fire Protection Engineering, 5th edition,” Society of Fire Protection Engineers, 2016.
  16. NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems, National Fire Protection Association, Quincy, MA, 2015.
  17. U.S. EPA, Significant New Alternatives Policy (SNAP) Program, Acceptable and Unacceptable Substitutes, Fire Suppression and Explosion Protection, Total Flooding Agents, (accessed March 2, 2016).
  18. UL 2166, Standard for Halocarbon Clean Agent Extinguishing System Units, Underwriters Laboratories, Northbrook, IL, 2012.
  19. UL 2127, Standard for Inert Gas Clean Agent Extinguishing System Units, Underwriters Laboratories, Northbrook, IL, 2012.
  20. ISO 14520, Gaseous Fire Extinguishing Systems: Physical Properties and System Design, International Organization of Standardization, 2015.
  21. Approval Standard for Clean Agent Extinguishing Systems, Class No. 5600, FM Approvals, LLC, Norwood, MA, April 2013.
  22. VdS 2381 (2009-06), Fire Extinguishing Systems using Halocarbon Gases, Planning and Installation, Verband der Sachversicherer e.V., 2009.
  23. VdS 2381-S1 (2014-06), Guidelines for Fire Extinguishing Systems using Halocarbon Gases, Amendment 1, VdS, 2014.
  24. VdS 2380 (2014-06), Fire Extinguishing Systems using non-liquefied Inert Gases, Planning and Installation, Verband der Sachversicherer e.V., 2009.
  25. VdS 2381-S1 (2011-07), Fire Extinguishing Systems using non-liquefied Inert Gases, Amendment 1, VdS, 2011.
  26. Mawhinney, JR and GG Back, III, Water Mist Fire Suppression Systems, Chapter 46, p. 1589. In: “SFPE Handbook of Fire Protection Engineering, 5th edition,” Society of Fire Protection Engineers, 2016.
  27. Mawhinney, JR and JK Richardson, A Review of Water Mist Fire Suppression Research and Development, Fire Technology, January 1997; vol. 33, issue no. 1: pp. 54-90.
  28. Rubenstein, Reva, Halon Alternatives Health Effects Assessment: U.S. Environmental Protection Agency, Halon Options Technical Working Conference, New Mexico Engineering Research Institute, Albuquerque, New Mexico, May 9, 1995, pp. 29-35.
  29. Su, Joseph Z. and Andrew K. Kim, “A Review of Water Mist Fire Suppression Systems: Fundamental Studies,” Journal of Fire Protection Engineering, August 1999; vol. 10, no. 3: pp. 32-50.
  30. NFPA 750, Standard on Water Mist Fire Protection Systems, National Fire Protection Association, Quincy, MA, 2015.
  31. Wickham, RT, Status of Industry Efforts to Replace Halon Fire Extinguishing Agents, Wickham Associates, March 16, 2002.
  32. UL 2167, Standard for Water Mist Nozzles for Fire Protection Service, Underwriters Laboratories, Northbrook, IL, 2002.
  33. Approval Standard for Water Mist Sprinkler Systems, Class No. 5560, FM Approvals, LLC, Norwood, MA, November 2012.
  34. VdS 3188 (2015-05), Guidelines for Water Mist Sprinkler Systems and Water Mist Extinguishing Systems (High Pressure Systems), Planning and Installation, VdS, 2015.
  35. ISO 6182-9, Fire Protection – Automatic Sprinkler System – Part 9 – Requirements and Test Methods for Water Mist Nozzles, International Organization of Standardization, 2005.
  36. MSC/Circ. 668, Alternative Arrangements for Halon Fire Extinguishing Systems in Machinery Spaces and Pump Rooms, International Maritime Organization, London, England: 1994.
  37. MSC/Circ. 728, Revised Test Method for Equivalent Water-Based Fire Extinguishing Systems for Machinery Spaces of Category A and Cargo Pump Rooms, International Maritime Organization, London, England: 1996.
  38. Determination of Acceptability, Protection of Stratospheric Ozone: Notice 23 for Significant New Alternatives Policy Program, Federal Register, vol. 74, no. 1 (January 2, 2009): 21-29.
  39. Yu, Hong-Zeng, Robert Kasiski and Matthew Daelhousen, Characterization of Twin-Fluid (Water Mist and Inert Gas) Fire Extinguishing Systems by Testing and Modeling, Fire Technology, August 2014; vol. 51, issue 4: pp. 923-950.
  40. Approval Standard for Hybrid (Water and Inert Gas) Fire Extinguishing Systems, Class No. 5580, FM Approvals, LLC, Norwood, MA, November 2012
  41. Kibert, Charles J. and Douglas Dierdorf, Solid Particulate Aerosol Fire Suppressants, Fire Technology, November 1994; vol. 30, issue 4: pp. 387-399.
  42. Back, Gerard, Michael Boosinger, Eric Forssell, David Beene, Elizabeth Weaver, and Lou Nash, An Evaluation of Aerosol Extinguishing Systems for Machinery Space Applications, Fire Technology, March 2009; vol. 45, issue 1: pp. 43-69.
  43. NFPA 2010, Standard on Fixed Aerosol Fire-Extinguishing Systems, National Fire Protection Association, Quincy, MA, 2015.
  44. UL 2775, Standard for Fixed Condensed Aerosol Extinguishing System Units, Underwriters Laboratories, Northbrook, IL, 2014.
  45. ISO 15779, Condensed Aerosol Fire-Extinguishing Systems: Requirements and Test Methods for Components and System Design, Installation and Maintenance-General Requirements, International Organization of Standardization, 2011.
  46. MSC/Circ. 1270/Corr. 1, Revised Guidelines for the Approval of Fixed Aerosol Fire-Extinguishing Systems Equivalent to Fixed Gas Fire-Extinguishing Systems, as Referred to in SOLAS 74, for Machinery Spaces, International Maritime Organization, London, England: 2008.
  47. AS 4487, Condensed Aerosol Fire Extinguishing Systems: Requirements for System Design, Installation and Commissioning and Test Methods for Components, Standards Australia, July 17, 2013.
  48. Oxygen Reduction versus Inerting or Gas Extinguishing Systems, Tech Talk, vol. 11, pp. 1-4, Allianz Risk Consulting
  49. OSHA Respiratory Protection Standard, Code of Federal Regulations, title 29, std. 1910, sub. I, sec. 134.
  50. UL 67377, Standard for Oxygen Reduction Fire Protection System Units, Underwriters Laboratories, Northbrook, IL, 2016
  51. prEN 16750 Draft, Fixed Firefighting Systems: Oxygen Reduction Systems-Design, Installation, Planning, and Maintenance, European Committee For Standardization (CEN), May 2014.
  52. VdS 3527 (2015-05), Oxygen Reduction Systems: Planning and Installation, Verband der Sachversicherer e.V., 2015.
  53. PAS 95:2011, Hypoxic [air] Fire Prevention Systems for Occupiable Spaces: Specification, British Standards Institute, 2011.

EEA Releases Report on Fluorinated Gases

January 23, 2017



A report was released in December 2016 by the European Environment Agency (EEA) that summarizes the data reported by companies in 2015 on the production, import, and export of fluorinated greenhouse gases in the European Union.

The key findings of the report are as follows:

  • Production of F-gases in the EU declined by 5 % (as CO2-eq) in 2015.
  • F-gas imports to the EU decreased by about 40 %, compared with the exceptionally high amounts reported in 2014 (both by weight and as CO2-eq).
  • EU exports of F-gases decreased by 2 % (by weight) or 1 % (CO2-eq) compared with 2014. However, compared with 2013, exports in 2015 increased by 18 % (by weight) and 23 % (CO2-eq).
  • Supply of F-gases in the EU decreased by about 24 % (by weight and as CO2-eq) since 2014.

Of the total supply of F-gases in the EU in 2015, the amount intended for fire protection applications was 1% by weight and 2% in CO2 equivalents.

You can see the full report by clicking here.