Blog

23 Nov
Fire Sprinklers…Silver Bullet?

Most visibly effective mitigation measure in fire and life safety in buildings is the provision of fire sprinklers. When fire sprinklers are provided is like having, sometimes, hundreds of fire fighters at the ready and around the clock. Each sprinkler is capable to detecting potential fire and automatically activating to suppress the fire. Yet, fires are still occurring every day.

One may wonder why. Indeed, despite continual improvements of design requirements, many fires do overwhelm fire sprinklers. Every fire does present an opportunity to evaluate sprinklers effectiveness. The National Fire Protection Association (NFPA) has been collecting data on fire sprinklers. Statistical data, even though it is far from being perfect, it is still providing lots of useful information on fires and fire sprinklers effectiveness.

Fire Sprinklers: Most Bang for the Money

  • Heat detection
  • Localized suppression
  • Hazards paired to protection
  • Hydraulically calculated
  • Water flow detected
  • Water flow triggers alarm
  • Life Safety bonus
  • Life safety bonus

Standard Continually Improved

It is hard to believe that the original standard for the installation of fire sprinklers in buildings was only a 25 pages document in 1896. The standard for the installation of fire sprinklers in buildings evolved to become todays standard with over 430 pages documents. In addition to common chapters found in most of the NFPA Standards, NFPA 13 goes into a great effort to classify and describe different fire hazards for the purpose to providing appropriate and sufficient suppression level to be effective at controlling the fire. For each type of fire hazards, the standard prescribes a corresponding design criterium is mandated for effective fire suppression.

The ultimate measure of a design Standard effectiveness is the successful control of fires. Indeed, fire sprinkler systems are designed to control fires in lieu of extinguishment. This may trigger questions as to the difference between fire control and fire extinguishment. Fire sprinklers were always intended to control the fire. That means that once fire sprinklers activate, the fire would be expected to not grow beyond the area of origin. Fire fighters, who are expected to be notified shortly after detection of water flow, extinguish the fire manually.

Fire Sprinklers Limitations

Many limitations of fire sprinklers are reflected in the requirements found in the standard. These, generally, emanate from observed performance of fire sprinklers during full-scale fire tests. These fire tests are critical for evaluating the performance of sprinklers in a realistic setting.

Given that humans are constantly creating new materials with new and often different properties. These properties may end up being more fire challenging. Indeed, despite testing performance of fire sprinklers, we still are surprised once and while when fire sprinklers are overwhelmed by a fire.

For those familiar with fire behavior of different materials may not be surprised. Indeed, we have learned lots about lots of fire behavior of fire behavior of many materials. However, what is often not appreciated is that the combination of different materials may present combined behavior that is more challenging than materials burning alone. Shapes and configuration of fuels in a space play both important roles.

Key Design Decisions

Fire sprinkler designers must make key decisions to properly classify fire hazards, especially when it comes to storage of goods. Not only the nature of the goods is important but also the storage arrangement as well as the height of storage. Cold storage presents a different additional hazard of freezing. Special measures are required by the Standard to address subfreezing temperature while providing fire protection to the facility.

All designers have a great responsibility for pairing hazards and fire protection. NFPA Standards come with explicit requirements but also annexes. Annexes are explanatory language and clarifications of explicit requirements.

It must be stated that generally fire sprinkler systems require a fire pump if the water quality is not enough. Fire pumps are not necessarily required for every sprinkler system. If the required pressure cannot be provided by City water supply system, then a fire pump would be needed. Due to the height of tall buildings, fire pumps are used to provide the pressure to the top levels.

Compounded Challenges: Installations

Given that fire sprinklers performance is critical to control a fire, nearly all fire sprinklers are required to be hydraulically calculated to provide appropriate flows and pressures for every sprinkler. These metrics are of a paramount importance as well as other metrics such as coverage.

These are the simplest metrics to inspect and verify their compliance with NFPA 13. It all involves installation of fire sprinkler systems. Indeed, the design of the fire sprinkler system can be flawless, but its installation is sometimes problematic. It is expected to find deviations from exact requirements found in regulations. It is however expected that the Industry Standard to be met, otherwise deviations may not be acceptable to the Authority Having Jurisdiction (AHJ).

Differences in several fire sprinkler systems are always present. It is the nature of workmanship is ever inconsistent. It should not be surprising if those differences are acceptable per sprinklers regulations and the AHJ.

Seismic Consideration

Another key engineering requirement in the design of fire sprinklers is hanging, bracing, restraint of fire sprinkler systems. This is especially important in earthquake prone regions. The goal of the design is to allow fire sprinkler piping to move independently from the structure. The result would minimize failure of the sprinkler piping.

Special Requirements

At times fire sprinkler requirements are more stringent than requirements found in NFPA 13. Indeed, Factory Mutual Global has its own requirements for the design fire sprinklers. This is due to the fact the Factory Mutual Global is known to insure high risk properties. Examples of such properties would be manufacturing facilities, aircrafts hangars, special amusement facilities. As such FM Global has developed their own criteria of pairing hazards and protection.

Climatic Change Consideration

With the undeniable climate changes, we have seen sprinkler system failures due freezing temperatures. Locations where failures occurred were not normally prone to freezing conditions. It is affecting both dry and wet fire sprinkler systems. This will force many building owners to consider mitigating measures. It is equally undeniable that there is will be a financial penalty to upgrade existing fire systems.

Summary

Fire sprinklers have revolutionized the use of buildings. Indeed, with fire sprinklers, we build taller and larger. With fire sprinklers, we mitigate known hazards. Fire sprinklers do indeed minimize the loss of life and property. They also reduce business interruptions. This is so if fire sprinklers are appropriately paired with well identified hazards. In addition to appropriate design, fire sprinklers need to be installed per both Industry Standards and design requirements. Then, as for every physical system is appropriate inspections, testing, and maintenance per regulations.

 

26 Jul
High-Rise Fires – Sprinklers Lacking.

The high-rise fires, that recently have captured the attention of news media, have also triggered a progressive and positive reaction from Home Owner Associations (HOA) and residents. Indeed, the 36 story Marco Polo condominium fire in Honolulu claimed the lives of four (4) residents and caused several injuries. The building was constructed in the late seventies and not provided with fire sprinklers. To the surprise of many, we have still lots of high-rise buildings in this country without fire sprinkler systems. It’s not just Hawaii, the Trump Tower in New York City had no fire sprinkler system in 2018 when fire broke out. The Trump Tower fire had one fatality and several injuries. A more horrifying fire was the Grenfell Tower fire in London in 2017. Adding insult to injury, on top of having no fire sprinkler system, this building surprisingly had only one (1) exit and yet it was Code compliant according to standards in the United Kingdom.

Many cities with residential high-rise buildings erected in the 70s did not require fire and life safety features we routinely see in more contemporary high-rise buildings.

Minimum Requirements for High-Rises:

  • Minimum acceptable egress system
  • Exit stair pressurization systems
  • Fire detection, alarm, and notification systems
  • Fire Sprinkler systems
  • Acceptable Fire Department access
  • Acceptable building fire resistance

 

The above Homeowners Associations Dilemmais just the minimum expected features that should be provided for a typical high-rise building. There are lots other requirements such as a plan for a fire emergency and other stipulations AHJ may require. Other than for the stairs pressurization feature, all other five (5) standards are typically required for all buildings for public occupancy.

 

Homeowners Associations are always struggling to balance conflicting goals. These goals are generally around maintaining condominium buildings while minimizing cost increases to owners. Budgets are decided and agreed upon for routine maintenance expenses and major fire safety upgrades are not minor building expenses. These costs can amount to millions of dollars, as upgrades are generally more costly than if they were part of the original design of the building.

After learning the news of catastrophic fires in similar condominiums, HOAs first panic as they quickly realize their buildings have similar attributes and the same deficiencies as the building in the news. There are two important realizations. The first is that the buildings lack fire safety features. The second is that installing these crucial fire safety features will probably cost more than the reserves of the association. After much internal debate, the HOA and owners settle into a decision that improvements must be made. The debates are not about what needs to be done but rather about how much it will cost for each owner of the building.

Are these structures compliant

Are these structures non-compliant with regards to fire safety Most vintage buildings are generally considered existing non-complying, in order words, they are grandfathered in. Moreover, many of the vintage high-rise buildings were not required to provide many standard fire and life safety features such as smoke control, stairs pressurization, fire sprinklers, fire alarm system with voice evacuation, etc. Our building regulations have always left room for judgment decisions by the Authorities Having Jurisdiction (AHJ) At any time, the AHJ could step in if they judge a building not safe and declare the building as non-compliant.

Existing Non-Conforming: Compromise

To improve the general fire and life safety features of vintage residential high-rise building, one would have to embrace the spirit of compromise. Indeed, it would be cost-prohibitive to design and install fire and life safety features to match the level of safety provided in the plans of newly designed high-rise buildings. Most Authorities Having Jurisdiction are sensitive to the issue of technical difficulties and the financial hardship it poses to the HOAs. As such, AHJs generally agree to prioritize life safety over property protection. Fire and life safety compromises and trade-off are on a case by case basis.

Is it Enough Fire and Life Safety

Cost is always in the center of all discussions and debates of fire and life safety for a myriad of reasons but cost-cutting efforts from developers stem from the desire to increase profits.

Fire events such as the Marco Polo fire in Hawaii and Trump Tower in New York have raised many questions regarding the compliance with local regulations. Fire sprinklers are proven to be a highly effective and reliable part of a building’s fire protection system. And with potential lawsuits on the rise after events like these, there are concerns about fire safety features and questions of why fire sprinklers haven’t been implemented in older residential buildings.

Nowadays, high-rise buildings are required to have common safety features such as fire sprinklers, fire stairs, smoke control systems, a reliable water supply, and fire alarm and notification systems. According to a National Fire Protection Association (NFPA) 2010-2014 survey, fire sprinklers were present in 10 percent of reported U.S. fires. The death rate per 1,000 reported fires was 87 percent lower in properties with sprinklers than in properties with no automatic extinguishing systems.

Fire accidents happen in all places regardless of the level of fire and life safety features implemented in the building. The only difference is that buildings with fewer fire and life safety features usually result in more physical damage, injuries, and casualties.

Historically, many older buildings are grandfathered by Authorities Having Jurisdictions (AHJ) allowing them to not comply with current regulations. However, AHJs often require a vintage building to comply with current regulations after a catastrophic fire that results in injuries or loss of life.

Unfortunately, fire and life safety requirements are numerous and expensive to implement in older high-rise buildings. These buildings present emergency ingress/egress challenges to both firefighters and occupants. It is sometimes mind-boggling that with all available tools and technology, so many tragedies are still occurring in this nation and elsewhere in the world.

The degree of difficulty in putting out a fire is a function of the height of the building and the level of fire and life safety features. It would seem obvious that the taller the building the more challenging it is to reach the level and extinguish it.

It may sound implausible with all the technological advances we have made; most fire service personnel do not use elevators to reach the fire floor. Firefighters prefer climbing the stairs. For decades, fire service has grown to not trust elevator systems to reach high floors. That distrust had a well-founded reason. There have been many occasions where controls for an elevator were negatively affected by fire incidents. Hence, this condition created a lack of trust as their lives depend on reliable equipment including elevators.

After the September 11, 2001 destruction of the twin towers in New York, Codes have addressed the reliability of elevators in high-rise buildings. Current regulations require that one (1) elevator be constructed in such a way that it can reliably be used by the fire service.

GrandFathering and Fire Safety Upgrades

As we say, the devil is in the details. For example, a mundane thing such as the shutting down of the ventilation when a fire condition is declared can make a world of difference in a fire situation. Indeed, we have learned long ago that adding air to a fire makes the fire grow larger and last longer. It does not take a lot of effort to equally understand that depriving a fire of air causes the fire potentially die out. Yet, that simple fact is sometimes ignored for the sake of saving money.

In the past, architects and designers have always looked to designing efficient buildings. That means there is not much thought given for future changes in regulations. It is unfortunately short-sighted. Many experienced designers have realized many things change during the life of a building. To be fair, the responsibility of anticipated safety requirement changes should not be solely on the designer’s shoulders. Indeed, all involved in the design of a new structure should accept the responsibility of the building’s future safe use.

Fires in general are statistically rare occurrences. Fires can have drastic and irreversible consequences.