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GKB VFDS System Design Manual

Video fire detection system
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VFDS™ (Video Fire Detection System)
System Design Manual
V3.1 English
GKB SECURITY CORPORTATION

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Summary of Contents for GKB VFDS

  • Page 1 VFDS™ (Video Fire Detection System) System Design Manual V3.1 English GKB SECURITY CORPORTATION...

  • Page 2: Table Of Contents

    2.5 Hazard Detection Definition ................11 2.6 Fire / smoke detected definition ..............12 2.7 Detection coverage definition ................ 14 2.8 Camera setup and parameter setup ..............22 Appendix 1 Design example ..............1 Appendix 2 VFDS™ Test on UL268 ............6...

  • Page 3: Chapter 1 Introduction Of Vfds

    Chapter 1 Introduction of VFDS VFDS™ (Video Fire Detection System) is an intelligent video system which is able to recognize fire and smoke through analyzing video signals and send alarm accordingly. VFDS™ server takes CCTV cameras or other compatible devices video images and analyzes whether there is smoke or fire, triggering visual or aural alarm.

  • Page 4: Vfds™ Specifications And Functions

    Detection territory：Please refer to Chapter 2.7 Programmable detection / none-detection areas Different detection modes configuration Alarm Output: VFDS™ window alarm, sound alarm, video recording, digital signal output and dry contact point output (alarm box) and mobile text message Processing log and alarm videos playback Video loss alarm * 1 - Under MIC instrument measures Smoke Density >...

  • Page 5: Chapter 2 Vfds™ System Design

    Chapter 2 VFDS™ system design VFDS™ is the system detects fire and smoke with videos from the cameras. Security cameras are the detectors in this system. This chapter describes how to choose, install and adjust cameras as detectors to cover the required protecting area; design flow chat as follows.

  • Page 6: System Protection Target Setup

    2.1 System protection target setup Position the protection target VFDS™ provides faster alarm compared to traditional smoke detectors. VFDS™ provides detection to special environment such as high-ceiling hall or wide open space. Define the protection area where usually is high risk.

  • Page 7: Detection Environment Investigation

    VFDS™ designers have to collect the field environment as below. Field scale (length, width, height) Field scale is the area that VFDS™ system applies detection to. In order to setup the VFDS™ system components correctly, designers have to measure the field dimensions, including length, width, height, special characteristics and so on.
  • Page 8 Field background color VFDS™ system bases on the image processing to detect fire and smoke. When the background color is similar color to the possible flame or smoke hazard, it may effect VFDS™ detection. For example: in figure 2.2 below, the color of the surrounding detection environment is black and gray, in a hazard that produces black smoke, the smoke detection will be effected.

  • Page 9: Hazards Analysis And Scenario Design Considerations Setup

    List the possible fire hazards as a consequence of your site survey, which shall consider the issues raised above and take the worst case as the possible Fire Scenario. Usually VFDS™ system designers could take the fire properties of the fastest burning combustibles in the environment and design the detection parameters based on this possible event.
  • Page 10 Release Rate for the target system Detect smoke? Detect fire? Detect both? VFDS is capable of both fire and smoke recognition. The system designer is able to decide whether to detect smoke or fire or both according to the combustibles variables.
  • Page 11 Gasoline Ultra-fast Kerosene Ultra-fast Diesel Oil Ultra-fast...

  • Page 12: Detection Time Definition

    Detection in early stage of the fire hazard and take steps to prevent the fire formation is the value of VFDS. Fire alarm should be triggered during the incubation period. In NFPA 92B, the recommend heat release rate is 1,055kW. Use the Ultra-fast, Fast, Medium and Slow growth curve of T-Squared Fires to calculate the flame growing time, referring to Table 2.4-1.

  • Page 13: Hazard Detection Definition

    Detection time definition; we can calculate what’s the smallest or minimum scale of fire hazard that VFDS™ is able to detect. In the NPFA 92B, it tells us the heat release rate in Ignition Period is rather low, though the heat release rate increases by time. VFDS™...

  • Page 14: Fire / Smoke Detected Definition

    Flame height calculation The flame size / height has a lot of to do with VFDS™ detection limit. Hence the system designer needs to predict or define the minimum size / height of possible flame that may arise or need to be detected. The actual flame height can be calculated according to Section 2.5, Hazard detection definition.
  • Page 15 Height(m) Pic. 2.6-2 Smoke height calculation...

  • Page 16: Detection Coverage Definition

    2.7 Detection coverage definition The focal range of the lens in the camera influences the object size in the picture (please refer to Figure 2.7-1), actual object height - H, object height on CCD - h, lens focal length– f and the distance between object and lens - D the formula is as below.
  • Page 17 Farthest detection distance of flame : D (m) = f × H f (mm)：Lens focal length (mm)：Object height in CCD (mm) equals to VFDS minimum height ratio of flame detection*CCD sensor height (mm) (m) = H cos(θ )：The flame reflection height...
  • Page 18 2.7-4(c) and (d). In general, using smaller focal length lens (small f value lens) could cover wider detection area. Note that when the focal length (f value) of the lens shrinks, the object forming in the VFDS™...
  • Page 19 image also shrinks; this may lengthen the flame detection time, or even fail to detect the flame. Please refer to appendix I to find the example of the whole design flow. The required protection region in picture 2.7-4 can either be the whole region, or only the region with combustible (smaller region).
  • Page 20 The performance of detection is closely related to camera installation. Therefore please refer to recommendations as follow: Optimize camera’s location Generally dead angle can be prevented by mounting two cameras on opposite side of wall in a specific space. For rectangular space, please refer to fig 2.7-5. If the detection area is square, in order to make sure the camera cover all the range, overlapping cameras view angle is a safer way for installation.
  • Page 21 The camera shall avoid looking directly at the strong light such as sunlight, which may cause detection faults Lighting environment factor The VFDS™ detection area has to be better with uniform illumination referring to picture 2.7-8(a). The unbalanced illumination condition may cause VFDS detection error, refer to picture 2.7-8(b).
  • Page 22 Lens clarity factor Lens is the eye to the camera as the eyes to human. The blemish on the lens blocks the image which affects the detection precision of VFDS. The clarify of lens is required for precious detection. Do not touch the surface of lens with polluted materials, such as fingers, towel or hard cloth, to avoid scratch, mist and stains.
  • Page 23 (c) Correct (High risk area) (d) Correct (Vacant area) (c) Correct (High risk area) (d) Correct (Vacant area) Pic. 2.7-9 Camera installation recommendation...

  • Page 24: Camera Setup And Parameter Setup

    For the indoor environment with ceiling height lower than four meters, it is suggested that the camera also takes view of the ceiling (Pic. 2.8-1). The VFDS™ server allows for smoke “dead zone” settings. Above the dead zone demarcation, it is no-moving-object area; and under the demarcation, it is the area with moving objects.
  • Page 25 <<Notice>> Very Important! Recommend position: 3/4 Pic.2.8-2 Camera ALC Adjustment Please refer to the image differences of ALC as Pic.2.8-3. In Pic.2.8-3(a), the camera is set to H level of ALC, and the image is too bright. The color variation by light compensation could affect the accuracy of detection. Also refer to Pic.2.8-4(a).
  • Page 26 Pic.2.8-4 Different ALC Levels with Black Object VFDS Camera Parameter Setup In this paragraph, VFDS™ system designer has to set up camera parameters in the server configuration pages. Enter VFDS main screen, click Setup to adjust camera parameters: (a) Detection Setting...
  • Page 27 (b) Camera Type Selection Choose correct camera type of GKB CCTV cameras. Indoor (Day & Night): Model No.CHQ-8986WTM(8) Outdoor (Day & Night): Model No.CHQ-8917DVFP(C) If using a none GKB CCTV camera, the suggested settings are as below:： Camera Option Camera with IR...
  • Page 28 (c) Detection Environment Setup 1. Please define the environment of the target area, an indoor place or an outdoor one by selecting the background option. 2. Please select the target area luminance condition.
  • Page 29 (d) Detection Sensitivity Setup Detection sensitivity is normally setting up default. The HIGH sensitivity is only recommended under the following circumstances as the summary table listed. Indoor High-Space Indoor Outdoor Flame High Area of high risk in fire event Intend detecting flame of a Intend detecting flame of a Sensitivity and normally no people in...
  • Page 30 The red area stands for an area where the smoke is accumulated. Others refer to areas which are used as the normal detection areas, i.e. tunnels, working sites and sidewalks. Appropriate setup can raise detection efficiency and lower down fake alarms. Relevant instruction regarding setting up smoke distribution area, please refer to VFDS guide book.
  • Page 31 Screen mask option can define areas where require detection or not. The main purpose of this option is to meet client’s requirements and to lower the false alarms. Users can make screen masks freely and decide the detection option for each mask. Relevant instruction regarding setting up screen mask, please refer to VFDS guide book.

  • Page 32: Appendix 1 Design Example

    Position VFDS™ as pre-detection system Detection environment investigation Filed name：F1 site Field dimension：Length 30m、Width 20m、Height 10m Field luminance: 100 Lux，meet VFDS requirements Field illumination condition：Interior with always opened illumination. Choose camera model CHQ-8986WTM(8) accordingly. Field background color：None monochrome, simple black-gray color...
  • Page 33 Medium - Slow Detection target: Both fire and smoke Detection time definition VFDS position as early stage alarm system. Select alarm reaction time as 30 seconds. Hazard detection definition T-Squared estimation -> Ultra-fast fire hazard，α = 0.1878，t = 30 seconds Fire Heat Release Rate Q(kW) = α...
  • Page 34 Detection territory definition Assume focal length is 6 mm (f=6mm)，tilt depression angle θ is 30°, camera installation height is 4m。 Viewable angle estimation θ (degree)= 2 tan Camera viewable angel (D/2f) D (mm) = CCD (horizontal, vertical, or diagonal) f (mm) = Camera focal length Calculate horizontal viewable angle is 43.6°, vertical viewable angle is 33.4°...
  • Page 35 =1.126 VFDS smallest flame detection limit (height ratio) =15/240=0.0625 CCD h = VFDS height ratio × CCD height = 0.0625 × 3.6 mm = 0.225 mm Farthest flame detection distance D (m) = f × H = 6 × 1.126 / 0.225 = 30.02 m (b) Farthest distance to detect smoke 1 ′...
  • Page 36 length decision. At last, the designer could calculate the camera width coverage according to the farthest detection distance and horizontal viewable angel: Camera width coverage W= 2 × 30.2 × tan(43.6°/2) = 24.2 m The final design for the field is to set two cameras across to cover most territories in the field.

  • Page 37: Appendix 2 Vfds™ Test On Ul268

    Appendix 2 VFDS™ Test on UL268 (Class A) Paper smoke generate method a) Combustible – Shredded newsprint (black printing only) is to be cut in strips 1/4 to 3/8 inch (6 to 10 mm) wide, 1 to 4 inches (25.4 to 102 mm) long, total weight 1-1/2 oz (42.6 g). The paper is to be poured into the receptacle, see (b), with the bottom covered temporarily by a flat plate.
  • Page 38 Smoke pattern of paper-oriented fire in different focal lenses (a) Distance 10m / f2.8mm lens (b) Distance 10m/ f4mm lens (c) Distance 10m / f6mm lens (d) Distance 10m / f8mm lens Pictures: Different paper-generated smoke pattern on different focal lenses...
  • Page 39 (Class A) smoke generate method a) Combustible – A wood brand formed of three layers of kiln dried fir strips, each strip 3/4 inch (19.1mm) square in cross section, 6 inches (152 mm)long with six strips in each layer, is to be used. Wood strips are to be nailed or stapled together with adjacent layers at right angles to each other.
  • Page 40 (b) Distance 10m / f2.8mm lens (b) Distance 10m/ f4mm lens (c) Distance 10m / f6mm lens (d) Distance 10m / f8mm lens Pictures: Different wood-generated smoke pattern on different focal lenses...
  • Page 41 (Class B) Liquid combustibles smoke generate method a) Combustible – Consists of a mixture of 25 percent toluene and 75 percent heptane (of sufficient quantity to generate curves within the limits specified by Figure 39.1 ) which is to be burned in a metal receptacle.
  • Page 42 Smoke pattern of liquid combustibles fire in different focal lenses (c) Distance 10m / f2.8mm lens (b) Distance 10m/ f4mm lens (c) Distance 10m / f6mm lens (d) Distance 10m / f8mm lens Pictures: Different liquid-generated smoke pattern on different focal lenses...
  • Page 43 (Class A) Wood-smoldered smoke generate method The combustible for this test is to be to ten Ponderosa pine sticks (non-resinous, free from knots or pitches) placed in a spoke pattern on the hotplate so that sticks are 36 degrees (0.63 rad) apart. The end of each stick is to be flush with the edge of the hotplate.
  • Page 44 Ignition site Shelter / Time Curve Wood-smoldered Smoke pattern in different focal lenses (d) Distance 10m / f2.8mm lens (b) Distance 10m/ f4mm lens (c) Distance 10m / f6mm lens (d) Distance 10m / f8mm lens Pictures: Different wood-smoldered smoke pattern on different focal lenses...

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