Understanding Visible Signals
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The document outlines the importance of visible signal devices, particularly strobe lights, in fire alarm systems and their requirements in various environments, especially for those with hearing impairments. It details the physics of light measurement, building code requirements, and layout design practices for optimal strobe light installation. Additionally, it discusses the impact of noise levels and specific areas where strobe lights are mandated by safety regulations.
Understanding Visible Signals
- 2. 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
- 3. 1. Definitions & Industry Trends A visible signal device which utilizes high intensity flashing light to notify occupants of a building on the activation of the fire alarm system.
- 4. 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”
- 5. 1. Definitions & Industry Trends CANADA UNITED STATES • • • • •
- 6. 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
- 7. 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
- 8. • 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
- 9. 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.
- 10. 3. Visible Appliances Building Code Requirements 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
- 11. 3. Visible Appliances Building Code Requirements 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)
- 12. 3. Visible Appliances Building Code Requirements 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
- 13. 3. Visible Appliances Building Code Requirements 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
- 14. 3. Visible Appliances Building Code Requirements Installation of strobes in public corridors for D Occupancy (Office) E Occupancy (Mercantile)
- 15. 3. Visible Appliances Building Code Requirements 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)
- 16. 4. "Strobe” Layout Design Practices 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
- 17. 4. "Strobe” Layout Design Practices
- 18. 4. "Strobe” Layout Design Practices 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
- 19. 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. 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
- 21. 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
- 22. 4. "Strobe” Layout Design Practices
- 23. 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
- 24. 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
- 25. 4. "Strobe” Layout Design Practices 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
- 26. 4. "Strobe” Layout Design Practices 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
- 27. 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
- 28. 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
- 29. • 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
- 30. If there are two appliances in a protected area, they must be located on opposite walls
- 31. 4. "Strobe” Layout Design Practices
- 32. 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
- 33. 4. "Strobe” Layout Design Practices • 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
- 34. 4. "Strobe” Layout Design Practices • 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
- 35. 4. "Strobe” Layout Design Practices • 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
- 36. 5. Mircom Solutions for Difficult Environments Longitudinal flue space 37 End View
- 37. 5. Mircom Solutions for Difficult Environments
- 38. 4. "Strobe” Layout Design Practices
- 39. 4. "Strobe” Layout Design Practices
- 40. 4. "Strobe” Layout Design Practices
- 42. 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
- 43. 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
Editor's Notes
- #4: strobe lightA high-intensity light flash: a high-intensity flashing beam of light produced by charging a capacitor to a very high voltage then discharging it as a high-intensity flash of light in a tubeA visible signal device which utilizes high intensity flashing light to notify occupants of a building to the activation of the fire alarm system.
- #5: The number of seniors aged 65 and over increased 14.1% between 2006 and 2011 to nearly 5 million. This rate of growth was higher than that of children aged 14 and under (0.5%) and people aged 15 to 64 (5.7%).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
- #22: Strobe must be located no more than 4.6m from end of corridorAdditional strobes placed not more than 30m apart15 Candela Strobes
- #23: Where there is an interruption of the concentrated viewing path, such as a fire door, an elevation change, or any other obstruction, the area shall be treated as a separate corridor
- #41: For example, in large warehouse spaces and large distribution spaces such as super stores, it ispossible to provide visible signaling using the appliances and applications of this chapter.However, mounting strobe lights at a height of 2030 mm to 2440 mm (80 in. to 96 in.) alongaisles with rack storage subjects the lights to frequent mechanical damage by forklift trucks andstock. Also, the number of appliances required would be very high. It might be possible to useother appliances and applications not specifically addressed by this chapter at this time.Alternative applications must be carefully engineered for reliability and function and wouldrequire permission of the authority having jurisdiction.Tests of a system in large warehouse/super stores designed using the prescriptive approach of7.5.4.3 showed that high ambient light levels resulted in both indirect and direct signalingeffects. The signal-to-noise ratio produced by the operating visible notification appliances waslow in many locations. However, with visible notification appliances located over the aisles orCopyright NFPAunobstructed by stock, indirect and some direct notification was sometimes achieved. Directnotification occurs even when occupants do not look up toward the ceiling-mounted visiblenotification appliances due to the extended cone of vision shown in Figure A.7.5.3(a). Thevisible notification appliance intensity and spacing resulting from the prescriptive design wasgenerally sufficient for occupant notification by a combination of direct and indirect signaling.Testing showed that the best performance was achieved where visible notification applianceswere directly over aisles or where visible notification appliances in adjacent aisles were notobstructed by stock. The performance-based design method will almost always result in aislesnot having a line of visible notification appliances in them, because the spacing of visiblenotification appliances can be greater than the spacing of aisles. Also, it is recognized thataisles might be relocated after installation of the system. Good design practice is to place visiblenotification appliances over aisles, especially those that are likely to remain unchanged such asmain aisles, and over checkout areas. Where reorganization of aisles results in visiblenotification appliances not in or over an aisle, or where that is the base design, it is important tohave a clear view from that aisle to a nearby visible notification appliance. See FigureA.7.5.3(b). Some spaces might have marginal visible notification appliance effect (direct orindirect). However, occupants in these large stores and storage occupancies move frequentlyand place themselves in a position where they receive notification via the visible notificationappliances. In addition, complete synchronization of the visible notification appliances in thespace produced a desirable effect.
- #43: Visible notification using the methods contained in 7.5.4.3 is achieved by indirect signaling.This means the viewer need not actually see the appliance, just the effect of the appliance. Thiscan be achieved by producing minimum illumination on surfaces near the appliance such as thefloor, walls, and desks. There must be a sufficient change in illumination to be noticeable. Thetables and charts in Section 7.5 specify a certain candela-effective light intensity for certain sizespaces. The data were based on extensive research and testing. Appliances do not typicallyproduce the same light intensity when measured off-axis. To ensure that the appliance producesthe desired illumination (effect), it must have some distribution of light intensity to the areassurrounding the appliance. UL 1971, Standard for Safety Signaling Devices for the HearingImpaired, specifies the distribution of light shown to provide effective notification by indirectvisible signaling.FIGURE A.
- #44: Any design that provides a minimum of 0.4036 lumens/m2 (0.0375 lumens/ft2) ofillumination at any point within the covered area at all angles specified by the polar dispersionplanes for wall or ceiling-mounted visual appliances in ANSI/UL 1971, Standard for SafetySignaling Devices for Hearing Impaired, or equivalent, as calculated for the maximum distancefrom the nearest visual notification appliance shall be permitted in lieu of the requirements