Fire Safety (Common Design Issues)

1. Limitation Imposed By Code/Standard
• Monitoring Integrity of Installation Conductors and
Other Signaling Channels.
• Circuit Pathways and how they behave
• Devices installation location, general spacing
• General requirements of how a fire detection and alarm
system will function
Limitation Imposed By Manufacture on their specific product
• Protocol of the system
• Internal compatibility among different parts
• Panel/System’s physical feature (no of Loops, Auxs, NACs and other peripheral
parts)
• Electrical Features of panel including internal and external wiring
• Charging Capacity & Maximum battery Size
• For SLC-Maximum Loop current, No of devices, Maximum cable length & allowable
maximum resistance
• For NAC- Maximum current, In some cases maximum voltage drop across a circuit
• For Networking- No of maximum networking, Networking type, Maximum length among
panels
• Maximum Coverage area of devices, their specific Wiring, Specific installation
requirement like backboxes, environmental condition, detector orientation etc.
Limitation
Imposed By
Listing Authority
• Listing conditions
• Listing standard
• Listing Intended use
• Compatibility
Design Guidance for FADS: Know your Limitations

2. Selection of
Sprinkler system
Selection
of Design
Philosophy
Requirement
determination
following
Building Code
Design
Occupancy
selection as
per NFPA-13
Determine
the Design
criteria
(ESFR/CMDA/CMSA/SS
U)
Selection of
sprinkler based
on the
characteristics
(Suitable for
installation)
There is another
step that is
selecting the
type of function-
Wet, Dry, Pre-
action, Deluge
system
Check the
datasheet, if
sprinkler selected
is appropriate to
use in selected
design occupancy
K-
Factor
Temp.
rating
Response
Type
Orifice
Size
Installation
orientation
Design Notes:
• Check Design occupancy
• Design hydraulic
requirements
• Check Ambient ceiling
temp.
• Ceiling geometry
Spray
Pattern
Listing
certificate
must
Reflect some of
the
characteristics
mentioned here.

3. Calculation of
Sprinkler system
Design Notes:
• Remote Area Selection
• Most Demanding
• Min working pressure
• Design Area & Density
or Other design
criteria
• Maximum Working
Major
Issues
Hydraulic calculation done in a software program is a simulation
demonstration of how the system will work in case of sprinkler activation.
So, inclusion of all nodes in drawing with adequate information (pipe length,
size, elevation) through isometric and Nodal diagram is very important. As
inclusion of all fittings and pipes in calculation input. Ensure hydraulic
calculation summary address this issues.
Min Working pressure
for CMDA sprinkler
is 7 Psi. However,
ESFR sprinkler are
designed with much
higher min.
operating pressure
as high a 3 BAR
Hydraulic calculation with fixed flow
(same) in all sprinkler is not
acceptable, because it is impossible
that all sprinkler will operate with
minimum required working pressure at
a same time
Remote area selection shall be made with
rectangular area with the larger length dimension
parallel to the branch lines, that captures as
many sprinklers as it can along the branch line.
Check fire pump churn
pressure. Check static
pressure (Maximum
working pressure)
working at a sprinkler
system at any point.

4. Major Sprinkler system
Installation Issues-1
Long sprigs been used in
sprinkler installation
with severely deflected
condition from its
perpendicular position to
the branch line causing it
to have a different
discharge pattern
development than the
design intended.
Additionally, long sprigs
are often found
unsupported/unrestrained
against lateral movement.
Design Notes:
Sprigs 4 ft (1.2 m) or longer
shall be restrained against
lateral movement
Design Notes:
Upright sprinklers shall be installed with the frame
arms parallel to the branch line, unless specifically
listed for
other orientation.
Upright sprinklers are installed with the frame arms not
parallel to branch line causing double obstruction in
discharge pattern.

5. Major Sprinkler system
Installation Issues-2
Sprinkler head has been installed without any reducer inserted in the end
of the branch line to reduce the pipe size from the larger tapered fitting
to the smaller diameter pipe increasing the friction loss and turbulence
in the pipe which affects water distribution onto a fire from a sprinkler.
Design Notes:
6.4.7.1 Unless the requirements of 6.4.7.2 or
6.4.7.3 are met, a one-piece reducing fitting
shall be used wherever a change is made in
the size of the pipe.
6.4.7.2 Hexagonal or face bushings shall be
permitted in reducing the size of openings of
fittings when standard fittings of the required
size are not available.

6. Major Sprinkler system
Installation Issues-3
Return bends were not used during the installation
of pendant sprinklers
Design Notes:
8.15.19.1 Unless the requirements of
8.15.19.3, 8.15.19.4, or8.15.19.5 are met,
return bends shall be used where e pendent
sprinklers are supplied from a raw water
source, a mill pond, or open-top reservoirs.
8.15.19.2 Return bends shall be connected to
the top of branch lines in order to avoid
accumulation of sediment in the drop nipples
in accordance with Figure 8.15.19.2.
8.15.19.3 Return bends shall not be required
for deluge systems.
8.15.19.4 Return bends shall not be required
where dry pendent sprinklers are used.
8.15.19.5 Return bends shall not be required
for wet pipe systems where sprinklers with a
nominal K-factor of K-11.2 (160) or larger are
used.
Did you
know?
Design Notes: (Additional)
• For new systems, outlet size shall be minimum of 1 in, and we can use hexagonal bushings to accommodate sprinklers
attached directly to branch line fittings to allow for future system modifications.
• For existing systems (pipe schedule) riser nipples less than 1" are allowed but shall not exceed 10 cm in length.
• For existing systems (Hydraulically calculated) riser nipples less than 1" are allowed but shall not exceed 10 cm in
length and shall be considered in hydraulic calculations.
• Hangers are required to prevent upward movement on the arm over piping when:
• the arm over is steel, exceeds 12 inches, and system pressure exceeds 100 psi (NFPA 13
2002/2007/2010/2013/2016 9.2.3.5.2)
• the arm over is steel and exceeds 24 inches (NFPA 13 2002/2007/2010/2013/2016 9.2.3.5)

7. Major Sprinkler system
Installation Issues-4
To be considered obstructed, the construction elements must be composed of “beams, trusses, or
other members” that will impede heat flow, water distribution, or otherwise affect the ability
of the sprinkler to control or suppress the fire. [3.7.1]
Obstruction
to impede
heat flow
reaching the
sprinkler
Obstruction
to sprinkler
discharge
pattern
development.
Obstructions
that Prevent
Sprinkler
Discharge
from
Reaching
Hazard

8. Major Sprinkler system Installation
Issues-4. Continue

9. Major Sprinkler system
Installation Issues-5
Design Notes:
• Floor control valve assembly shall be
provided in buildings exceeding two stories.
(16.9.11.1)
• For isolation, control, and annunciation of
water flow on each floor level.
Where Not Required?
• Floor control valve assembly shall not be
required where sprinklers on the top level of
a multistory building are supplied by piping
on the floor below. (16.9.11.1)
• Floor control valve assembly shall not be
required where the total area of all floors
combined does not exceed the system
protection area limitations. (16.9.11.3)
System Protection Area Limitation:
The maximum floor area on any one floor to be protected by sprinklers supplied by
any one sprinkler system riser or combined system riser shall be as follows:
• For light hazard occupancies:52,000 Sft.
• For ordinary hazard occupancies: 52,000 Sft.
• For Extra hazard occupancies: 40,000 Sft.
• For high piled storage: 40,000 Sft.
• For in-rack storage: 40,000 Sft.
Check Valves are not included as a part of
Floor/Zone control valve assembly