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27 

(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 

Sensitivity 

Area of high risk in fire event 

and normally no people in 

there. 

Intend detecting flame of a 

small area in the screen. 

Intend detecting flame of a 

small area in the screen 

  Default 

Not crowded, normal indoor 

space. 

No limitation 

 

No limitation 

Smoke 

High 

Sensitivity 

Area of high risk in fire event 

and normally no people in 

there. 

Area under supervision with 

some smog happening( The 

height of smog in the screen / 

the height of screen < 0.2) 

Supervision from long 

distance (>50 M) and intend 

detecting the happening of 

some smog (The height of 

smog in the screen / the height 

of screen < 0.2) 

Default 

Not crowded, normal indoor 

space. 

No limitation 

 

No limitation 

 

Summary of Contents for VFDS

Page 1: ...VFDS Video Fire Detection System System Design Manual V3 1 English GKB SECURITY CORPORTATION...

Page 2: ...arget setup 4 2 2 Detection environment investigation 5 2 3 Hazards analysis and scenario Design Considerations setup 7 2 4 Detection time definition 10 2 5 Hazard Detection Definition 11 2 6 Fire smo...

Page 3: ...s the VFDS provides many extra advantages 1 Early stage alarm VFDS may prevents serious damage and millions of lost by recognizing fire and smoke at an early stage VFDS detects both flame and smoke co...

Page 4: ...figuration 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 Vide...

Page 5: ...ed protecting area design flow chat as follows Set protection areas Investigate field space Illumination conditions Fire hazard analysis and set fire scenario Decide VFDS reaction time Define and esti...

Page 6: ...nvironment such as high ceiling hall or wide open space Define the protection area where usually is high risk Please refer to Pic 2 1 1 Generally VFDS system designers position the system as the early...

Page 7: ...level of object and unit measure is Lux Averagely each square meter with one lux light on is defined as 1Lux Field illumination control There are specific cameras for VFDS to achieve precious detectio...

Page 8: ...ht spread 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...

Page 9: ...d their alloy Ignition Sources factor analysis Investigate possible ignition sources in the environment Some possible ignition sources are as follows Energized electrical sources include short circuit...

Page 10: ...ft meters high 6 12 moisture Medium Fast Wood pallets stacked 10 ft meters high 6 12 moisture Fast Wood pallets stacked 16 ft high Meters 6 12 moisture Fast Mail bags filled stored 5 ft high meters F...

Page 11: ...9 Gasoline Ultra fast Kerosene Ultra fast Diesel Oil Ultra fast...

Page 12: ...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 S...

Page 13: ...th rate of fire ignition kW s2 Refer to Table 2 5 1 t g Effective ignition time s the alarm trigger time Table 2 5 1 T Squared Fires Growth Rate Coefficient Item description Growth rate kW s2 Slow 0 0...

Page 14: ...lculation The smoke volume and height has a lot of to do with VFDS smoke detection limit Hence the system designer needs to predict or define the minimum size height of possible smoke arose or need to...

Page 15: ...13 Pic 2 6 2 Smoke height calculation Height m Width m...

Page 16: ...w 2 8mm 4 mm 6 mm 8 mm 12 mm Camera viewable angel and coverage calculation Different focal lengths in the camera lenses provide different viewable angle and coverage Usually it is present in the form...

Page 17: ...ession angle 2 degree 2 tan 1 Dv 2f Camera image vertical viewable angel Dv is CCD vertical length f is focal length value Pic 2 7 3 Parameters of camera installation Image detection distance calculat...

Page 18: ...for each camera will be the smaller value of either Df or Ds According to the shortest and farthest detection distance the detection area can be drawn out as sector shape Please refer to the yellow r...

Page 19: ...the whole region to be set as the required protection region is highly recommended Pic 2 7 4 Camera focal length and viewable angel relation a Wide viewable angle but short detection distance inadequa...

Page 20: ...e the camera cover all the range overlapping cameras view angle is a safer way for installation Fig 2 7 5 Recommended cameras installation in rectangular space Fig 2 7 6 Recommended cameras installati...

Page 21: ...Horizontal angles a Correct Angle 45 b Prohibited Angle 45 c Correct Angle 45 d Prohibited Angle 45 Pic 2 7 7 Interior space Height 4 meters camera depression angel Avoid the camera looking directly t...

Page 22: ...low as a factor for correct detection on the fire and smoke 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...

Page 23: ...21 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: ...ead zone settings Above the dead zone demarcation it is no moving object area and under the demarcation it is the area with moving objects Appropriate setting of demarcation will shorten detection tim...

Page 25: ...affect the accuracy of detection Also refer to Pic 2 8 4 a In Pic 2 8 3 b the camera is set to 3 4 level of ALC the image is with appropriate brightness and more stable It causes little variation by...

Page 26: ...rent 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 Setu...

Page 27: ...917DVFP C If using a none GKB CCTV camera the suggested settings are as below Camera Option Camera with IR Camera_with_IR Camera w o IR Camera_without_IR Note It would affect the detection accuracy if...

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 conditi...

Page 29: ...area in the screen Intend detecting flame of a small area in the screen Default Not crowded normal indoor space No limitation No limitation Smoke High Sensitivity Area of high risk in fire event and n...

Page 30: ...he area close to the ceiling due to the thermal buoyancy as shown in the photo The red area stands for an area where the smoke is accumulated Others refer to areas which are used as the normal detecti...

Page 31: ...ection 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 i...

Page 32: ...e 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...

Page 33: ...r chemical Part failure leak or break Unclassified or unknown type mechanical failure or malfunction Cutting or welding too close Unclassified or unknown type operational deficiency Ultra fast Wood or...

Page 34: ...cal length Calculate horizontal viewable angle is 43 6 vertical viewable angle is 33 4 Detection nearest limit dead angle estimation CCD 3 1 Width 4 8mm Height 3 6 mm Camera vertical viewable angel 2...

Page 35: ...e to detect smoke CCD 3 1 with width 4 8mm height 3 6 mm Real smoke reflection height Hp Hs cos 1 13 4 m cos 30 11 6 m VFDS smallest smoke detection limit height ratio 30 240 0 125 CCD hf VFDS height...

Page 36: ...cording 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 terr...

Page 37: ...a rod 1 inch in diameter until the paper level is 4 inches below the top edge of the receptacle A hole 1 inch in diameter is to be formed through the center from top to bottom of the paper The tempor...

Page 38: ...per 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 di...

Page 39: ...denatured alcohol consisting of 190 proof 95 percent ethanol to which 5 percent methanol is added as a denaturant The alcohol is to be placed in a 1 1 2 inch 38 mm diameter 1 inch 25 4 mm deep metal c...

Page 40: ...9 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: ...m stainless steel 6 1 4 inches 158 mm in diameter and 1 1 4 inch 32 mm deep rounded bottom formed by 1 2 inch 12 7 mm radius Located 3 feet 0 9 m above the test room floor and centered with a ring sup...

Page 42: ...id 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 o...

Page 43: ...1 4 inch 6 4 mm thick the top most portion of which is to be 8 inches 200 mm above the floor The temperature of the hotplate is to be monitored by an iron constant an No 30 AWG 0 05 mm2 Type J thermoc...

Page 44: ...ve 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...

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