The basic of warehouse sprinkler system design and application

1. The Basics of Warehouse
Sprinkler Design and
Application
Reference:
1) https://blog.qrfs.com/393-the-basics-of-cmda-cmsa-and-esfr-storage-sprinklers/
2) NPFA 13 - 2013
3) NFPA 13 - 2016

2. • specific issues of storage settings and how NFPA 13
categorizes them
• CMDA, CMSA, ESFR, and in-rack sprinkler
• the way different variables in storage occupancies direct
sprinkler system design in NFPA 13.

3. Unique challenge of warehouse fire
protection
• Commodity class and extra-flammable fuels
• the goods themselves and any packaging materials

4. four commodity classes, plus special groups
for plastics
• Class I and Class II both contain noncombustible goods, with
Class II generally having more
combustible packaging materials.
• Class III and Class IV both include flammable goods, with Class
III mostly involving wood, paper products, or natural fiber
textiles.
• Finally, Class IV, the most flammable category, involves
plastics.

5. plastics groups
• NFPA 13 further divides plastics into separate groups (Group A,
Group B, etc.), with Group A being the largest.
• In addition, special commodities like rubber tires and rolled
paper get separate consideration.

6. Encapsulation
• “Encapsulation” is a particular packaging that can apply to any
good that increases the fire hazard. It refers to palleted loads
enclosed on the top and sides by a plastic sheet (3.3.68)
• The NFPA 13 Handbook explains that encapsulation prevents
fuel from being wetted by sprinklers, allowing a fire to spread
more easily. Therefore, NFPA 13 requires increased water flow
for encapsulated commodities and limits how high they can be
stacked.

7. Storage layouts can impede water
spray
• Rack storage
• Open-rack
• Solid-shelf
• the space between shelves and racks affects fire spread and water flow
• Aisles between racks can create a fire break to control a blaze’s
spread, while flue spaces between different rack compartments allow
water to pass.

8. Storage layouts can impede water
spray
Solid-piled Storage
Palletized Storage

9. The effects of ceiling height and room
size
• Compared to warehouses, most commercial buildings have low
ceilings and small rooms.
• Low ceilings make it easier for sprinkler spray to reach fires,
and small rooms provide compartmentalization of fires, helping
keep them in one area.
• But in warehouses, distance creates fire protection challenges.

10. • Additionally, warehouses usually don’t have much
compartmentalization.
• Fire-resistant walls and ceilings typically help contain fires, and
their absence can let blazes spread freely.
• An example of compartmentalization’s importance is NFPA 13’s
provisions for storing unused plastic pallets—a major fire
hazard.
• If the pallets are separated from other storage, the dedicated
room must have three-hour-rated firewalls (20.17.2.2.4.1).

11. In-rack, CMDA, CMSA, and ESFR
sprinklers meet the challenges of storage
occupancies
• CMDA: control-mode density area sprinklers
• (CMDA) sprinkler refers to the fact that these heads provide
wetting and cooling to control a fire until first responders can
arrive.
• “Density-area” refers to how CMDA systems are designed.
• A set of density-area curves specifies the amount of water flow
required for a given area.
• The system and its water source are engineered based on them
to provide the necessary flow and pressure.

12. CMDA sprinkler
• CMDA sprinklers are almost identical to average fire sprinklers in both
shape and function
• The two things separating a CMDA sprinkler from a regular
sprinkler are
• larger K-factors and
• higher temperature ratings.
•Q=K√P

13. CMSA: Control-mode special
application sprinklers
• Like CMDA sprinklers, control-mode special application (CMSA)
sprinklers are designed for “control” functions: wetting and
cooling to prevent fire spread.
• CMSA sprinklers have unique sprinkler deflectors that produce
different water droplet sizes and spray patterns.
• to “special applications;” in other words, high-challenge storage
occupancies.

14. CMSA sprinkler
• CMSA sprinklers don’t use the design concepts employed by
CMDA sprinklers. No density/area curves are involved.
• Instead, different variables are analyzed to calculate the
necessary flow and pressure for a given system.

15. ESFR: Early-suppression fast
response sprinklers
• Unique among fire sprinklers, early-suppression fast-response
(ESFR) sprinklers provide fire suppression instead of fire
control.
• The goal of ESFR sprinklers isn’t to prevent fire spread until
firefighters can fully extinguish it.
• Rather, they are meant to activate quickly and attack a fire
directly.

16. ESFR sprinklers
• ESFR sprinklers have large K-factors and feature uniquely
designed deflectors meant to produce large, high-momentum
droplets that won’t evaporate before penetrating a fire plume.
• Another major distinguishing characteristic of ESFR sprinklers
is fast-response elements designed to operate sooner than
standard sprinkler elements.

17. • ESFR systems are typically used in warehouses with high piled
storage and
• are often used in place of in-rack sprinkler systems

18. Benefits of ESFR Systems
1. ESFR systems respond to fires faster than conventional sprinkler systems.
2. Conventional sprinkler systems have an output rate of 25-30 gallons per minute while the output
rate of ESFR systems is around 100 gallons per minute, releasing a high volume of water onto the
fire.
3. ESFR systems use larger water droplets than conventional sprinkler systems, making them faster at
suppressing fires.
4. Early Suppression Fast Response systems can be used in warehouses with ceilings as high as 45
feet.
5. These systems are less likely to have accidental discharges than in-rack sprinkler systems which
could leak if pipes are accidentally struck by material handling equipment.
6. Conventional sprinkler systems are designed to control fires. ESFR systems are designed to
suppress a fire at the point of its origin.
7. ESFR systems provide protection for high piled storage including palletized, solid pile, shelf, bin box
and rack storage.
8. Installing an Early Suppression Fast Response system is less costly than in-rack sprinkler systems.

19. ESFR systems require a large water supply which means
a fire pump is typically required for this type of system.

20. In-rack fire sprinklers
• All the storage sprinklers we’ve presented so far have been
ceiling-level sprinklers.
• But there are situations where tests have determined that
ceiling sprinklers—no matter how large the K-factor or water
pressure—can’t provide adequate control or suppression.
• Extremely flammable commodities, high ceilings, high-piled
storage, and obstructions to water are common culprits.
• In these cases, in-rack fire sprinklers are necessary.

21. In-rack Sprinklers
• sprinkler risers and branch pipes are installed with storage
racks to put sprinklers as close to potential fires as possible.
• Little distinguishes an in-rack fire sprinkler from a traditional fire
sprinkler.
• However, in-rack fire sprinklers are often installed with unique
accessories, including cage guards and water shields.

22. The design requirements for storage
sprinkler systems are complex
• designing most commercial sprinkler systems relies on density/area
curves that determine how much water flow and pressure is needed.
• Selecting a curve depends on the occupancy hazard of a
building.
• But while CMDA storage sprinkler systems use density/area
curves, CMSA and ESFR systems aren’t based on this concept.
• Moreover, the decision-making process for a storage sprinkler
system is much more complex.

23. The design requirements for storage
sprinkler systems are complex
• Based on extensive empirical testing by FM Global
• NFPA 13 guides the user through a decision tree based on the
situation for each storage sprinkler system.

24. The design requirements for storage
sprinkler systems are complex
This table from NFPA 13 (14.4.1)
provides an example of how CMSA
sprinkler system criteria are selected.
It is specifically for palletized storage;
users identify the appropriate
commodity class and other variables.
The table ultimately specifies the
minimum sprinkler operating
pressure.

25. This table from NFPA 13 (14.4.1)
provides an example of how CMSA
sprinkler system criteria are selected.
It is specifically for palletized storage;
users identify the appropriate
commodity class and other variables.
The table ultimately specifies the
minimum sprinkler operating
pressure.

26. ESFR Sprinkler

27. To understand what influences NFPA 13 rule,
check out this test of ESFR sprinklers
conducted by FM Global:
• https://youtu.be/2HOX_wDAB3A