Understanding Visible Signals

1. Definitions & Industry Trends

2. Physics of Visible Appliances

3. Visible Appliances Building Code Requirements

4. "Strobe” Layout Design Practices

5. Mircom Solutions for Difficult Environments


A visible signal device which utilizes high intensity flashing
light to notify occupants of a building on the activation of the
fire alarm system.

NEEDS

“In Canada, the number of seniors aged 65 and
over increased 14.1% between 2006 and 2011
to nearly 5 million”

“According to a new Census Bureau
report, there were 40.3 million people age 65
and older on April 1, 2010, up 5.3 percent from
35 million in 2000”


CANADA

UNITED STATES
•

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2. Physics of Visible Appliances
Candlepower is an obsolete scientific unit of luminous intensity
based on the light emitted from a candle made to a specific
formula

The candlepower as a scientific measure was replaced in 1948 by
the international unit (SI) known as the candela

Measures only the “PEAK”

• Candlepower and Candela have an equal ratio 1:1
INTENSITY

• Peak candlepower measures only the peak

PEAK
AREA
100 200 300 400 500
TIME IN MICROSECONDS

Effective candela rating is calculated by the total area under the light
intensity curve and includes all of its light energy
INTENSITY

Light
CANDELA
Intensity
Curve

100 200 300 400 500
TIME IN MICROSECONDS

• Measures the intensity in candela and the distance from the
light source
• This is called illumination and can be calculated by the following
formula

INTENSITY OF LIGHT DIVIDED BY THE DISTANCE SQUARED
SOURCE

1. Peak Candlepower measures only the peak and looks at the
performance over a short period of time.

2. Effective Candela measures the total light energy, but does
not take into consideration the distance from the light source.

3. Illumination (Lumens or Foot-Candles) takes both factors
into consideration by measuring the power of the light and the
distance from the light source.


NFPA 101 & NBCC require strobes in the following areas…..
•Where Ambient Sound Levels Exceed 87dB
(Noisy manufacturing plants or diesel generator areas)

•Where ear protection is worn


NBCC & NFPA 101 require strobes in the following areas…..
•Sound insulated or audiometric booths
(Recording Studios or Sound Testing Rooms)

•Entertainment areas where sound levels may exceed 100dB
(Night Clubs & Concert Halls)


NFPA 101 & NBCC require strobes in the following areas…..

•Building or portions of a building for persons with hearing impairment

•Minimum 10% of Hotel Rooms


Installation of strobes in public corridors for
B Occupancy (Health Care) A Occupancy (Assembly
Strobes permitted in lieu of audible Areas)
signals in compartments including Strobes are required in
operating rooms and recovery corridors used by the
areas such as ICU and CCU public, and also floor areas
where public may congregate


Installation of strobes in public corridors for

D Occupancy (Office) E Occupancy (Mercantile)


OBC Not Required
•In classrooms •In care occupancy for up to 10
(A Occupancy) persons (B Occupancies)
•3.2.4.18.(6) (a) •3.2.4.18.(6) (b)


NFPA72-2010 Table 18.5.4.4 – Corridor
CAN/ULC-S524-06 Table 7 – Corridor

NFPA72-2010 Table 18.5.4.3.1(a) – Wall
CAN/ULC-S524-06 Table 5 – Wall

NFPA72-2010 Table 18.5.4.3.1(b) – Ceiling
CAN/ULC-S524-06 Table 6 – Ceiling


Corridor Length (m) Minimum # of 15 Candela Strobes
6m less in width

0-9 1
10 - 40 2
41 – 70 3
71 – 100 4
101 - 130 5
131 - 160 6

39.2 meter corridor

4.6 m 4.6 m

30 m

Corridor Length (m) Minimum # of 15
Minimum 2 (15 Candela) Strobe
6m less in width Candela Strobes for corridor installations
0-9 1
Additional strobes placed not
10 - 40 2
more than 30m apart
41 – 70 3
71 – 100 4
Strobe must be located no
101 - 130 5 more than 4.6m from end of
131 - 160 6 corridor

20.4m
4.6 20.4m
50 meter corridor

4.6 m 4.6 m

40.8m

Corridor Length (m) Minimum # of 15 Candela
Minimum 3 (15 Candela) Strobe
6m less in width Strobes for corridor installations
0-9 1
10 - 40 2 Additional strobes placed not
41 – 70 3 more than 30m apart
71 – 100 4
101 - 130 5
Strobe must be located no
more than 4.6m from end of
131 - 160 6
corridor

38m

4.6 22m

4.6m
4.6m
4.6m
5.4.5.14 Where there is an interruption
of the concentrated viewing path, such 4.6m
as a fire door, an elevation change, or
any other obstruction, the area shall be 22m
treated as a separate corridor. Minimum 2 (15 Candela) Strobe for
corridor installations per corridors
Corridor Length Minimum # of 15
(m) Candela Strobes
6m less in width Strobe must be located no more
0-9 1 than 4.6m from end of corridor
10 - 40 2
41 – 70 3
71 – 100 4
101 - 130 5
131 - 160 6

5.4.5.3 Wall-mounted visible signal
devices shall be installed such that the
entire lens is not less than 2000 mm
and not more than 2400 mm above
the finished floor.

Mircom offers FS-340 (“Potter”) and the “System Sensor” models
for wall mounted applications

LIGHT OUTPUT FOR WALL-MOUNTED VISIBLE SIGNAL DEVICES FOR VARIOUS ROOM SIZES

Maximum Area 1 Strobe per area 2 Strobes per area 4 Strobes per area
Coverage in (m)

6.10 X 6.10 15 N/A N/A
8.53 X 8.53 30 15 N/A
9.14 X 9.14 34 15 N/A
12.2 X 12.2 60 30 15
13.7 X 13.7 75 60 30
15.2 X 15.2 94 60 30
16.5 X 16.5 110 60 30
18.3 X 18.3 135 95 60
21.3 X 21.3 185 95 60
24.4 X 24.4 240 135 60
27.4 X 27.4 304 185 95
30.5 X 30.5 375 240 95
33.5 X 33.5 455 240 135


Application: 6m X 5m Room
6m
ULC-S524-06 Table 5 for wall mounted
devices requires a 15 Candela strobe for
a maximum room size of (6.10m X
6.10m)
5m
? Intensity Maximum Area
Coverage in (m)
1 Strobe
per area
2 Strobes
per area
4 Strobes
per area

6.10 X 6.10 15 N/A N/A

ONE 15 Candela Strobe will meet this
application

Do we mount the strobe on the short or long side of the wall?
Installation Tip -Spacing
allocation for wall
Long Side Coverage? mounted strobes are to be
located (at the mid-point
of the longest side of the
6m area served) NFPA 72
5m
Short Side
Coverage? 15 Candela

The mid-point of the longest side is the preferred method

Application - Four 15
Maximum Area
Coverage in (m)
1 Strobe
per area
2 Strobes
per area
4 Strobes
per area
Candela Strobes in a 12.2m
X 12.2m Room
12.2X 12.2 60 30 15

12.2 m In this example, we are
meeting minimum Candela
rating (illumination) but
the strobe allocation is
incorrect

Area Coverage of each
appliance is not maximized
12.2 m Moreover, if these were
(Horn/Strobe or Speaker
Strobe) combination units
the result may be
conflicting sound waves or
sound cancellation

Maximum Area 1 Strobe 2 Strobes 4 Strobes The correct method is by
Coverage in (m) per area per area per area following clause 5.4.5.8 in
CAN/ULC-S524-06
6.10 X 6.10 15 N/A N/A
Subdivide the room into multiple
12.2 m squares (6.1m x 4)
5.4.5.8 Where multiple wall-mounted visible
6.1m signal devices are used within a room, the room
shall be subdivided into multiple squares and
the selection of the device output and location
6.1m shall be in accordance with Table 5 and Figure 3.

• ULC-S524-06 Table 5 - room
12.2 m
size of 6.1m X 6.1m requires a 15
candela strobe
6.1m • Install four 15 candela strobes
(one for each 6.1m area)
Utilize Maximum Area
6.1m Coverage

• Application – Room size is 14m X 28m 5.4.5.8 WhereArea
Maximum multiple wall-mounted visible signal devices are
1 Strobe 2 Strobes 4 Strobes
used within ain (m) the room shall be per area into per area
Coverage room, per area subdivided multiple
• Divide the room into two 14m X 14m squares and the selection of the device output and location shall
15.2 X 15.2 94 60 30
be in accordance with Table 5 and Figure 3.
• Two 60 Candela or four 30 Candela strobes can be substituted
• Note that the two visible signal devices are located on opposite walls

28 m

14 m

14 m

14 m

If there are two appliances in a protected area, they must
be located on opposite walls

Maximum Area Size Maximum Mounting One Strobe Light
Height (Rated Candela)

6.10 X 6.10 3 15
9.14 X 9.14 3 30
12.2 X 12.2 3 60
15.2 x 15.2 3 95

6.10 X 6.10 6 30
9.14 X 9.14 6 45
12.2 X 12.2 6 80
15.2 x 15.2 6 115

6.10 X 6.10 9 55
9.14 X 9.14 9 75
12.2 X 12.2 9 115
15.2 x 15.2 9 150


• Ceiling mounted strobes have a different polar distribution than wall
mounted versions.
• The strobe’s reflector has to be designed to disperse the light 180
degrees.
• Mircom offers “System Sensor” models for ceiling mounted applications.

180 Degrees
Distribution

• Application 9.14 X 9.14 Room @ 3 meter Ceiling Height
• Ceiling Appliance Centered
• ULC-S524-06 Ceiling Mount Table 6 requires a 60 Candela Strobe for room
size 9.14m X 9.14m

• At 6m ceiling height, a 45 Candela is required
• At 9m ceiling height, a 75 Candela is required

9.14 m

Maximum Area Size Maximum Mounting Height One Strobe Light
(Rated Candela)

12.2 X 12.2 3 30
9.14 X 9.14 6 45
9.14 X 9.14 9 75
9.14 m

30 Candela
Strobe @ 3m
height


• Application 9m X 4.5m Room @ 3 meter Ceiling Height

• Ceiling Appliance Not Centered
Where the ceiling-mounted visible signal
4.5 m device is not located at the center of the
room, the effective intensity (candela) shall
One 95 or 2 be determined by doubling the distance
from the device to the farthest wall to
60 Candela
obtain the maximum room size.
Strobes can
be used We have a 7m distance from device to the
9m furthest wall - Doubling the distance gives
us 14m. The next closest room size is
7m 15.2m X 15.2m. The table shows that a 95
candela strobe is required
Maximum Area Size Maximum Mounting Height One Strobe Light
(Rated Candela)

15.2 X 12.2 3 95
12.2 X 12.2 3 60


Longitudinal
flue space

37
End View

NFP2-2010 18.5.4.5
Performance Based Alternative
Any design that provides a minimum of 0.4036 lumens/m2
(0.0375 lumens/ft2) of illumination at any point within the
covered area at all angles specified by the polar dispersion
planes for wall or ceiling-mounted visual appliances in
ANSI/UL 1971, Standard for Safety Signaling Devices for
Hearing Impaired

0.4036 lumens/m2

Understanding Visible Signals

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