【 Weak current College 】 VESDA system construction specification

Section 1 General provisions
1. in order to improve VESDA early smoke detection alarm system installation quality, ensure system uptime, harm reduction and prevention of fire, protect life and property safety, especially formulates this specification.
2. this standard applies to VESDA early smoke detection alarm system construction and acceptance.
3, VESDA early smoke detection alarm system construction, must be under the supervision of public security fire agencies, the system must pass before the delivery of public security and fire fighting supervisory body acceptance.
4, VESDA early smoke detection and alarm system, acceptance of construction, in addition to the implementation of this specification, you must comply with existing relevant standards and norms.
The General provisions of section II

Section III cabling
1. very early smoke detection alarm system cabling, should meet national standards for the electrical installations existing construction and acceptance.
2, wiring, according to the existing national standards of the automatic fire alarm system design code of conductor types, voltage level.
3, in tubes or trunking of threading, it should be in the building plaster and adjournment of ground works. Before the thread, tubes or trunking of stagnant water and debris.
4. the different systems and different voltage level, different current categories of line, and should not be put on the same pipe or Groove within the same slot.
5, wire in tubes or trunking, should not have a connector or kink. Wire connectors, junction boxes in welding or Terminal.
6, laying in dusty or damp place pipe nozzle and pipe joints, sealing treatment should be made.
The length of the pipe over the following should be convenient for wiring office connection box:
Pipe length per 1) for more than 45 m, no bending;
2) pipe length exceeding 30 m, a bending;
Pipe length 3) over 20 meters, has two bending;
4) tubes of more than 12 m length, there are three bending;
7, the tube into the box, the box should set lock out, inside the mouth guard should be mounted in the ceiling installation, inside and outside of the box should be set lock.
8, in the ceiling and underfloor installation trunking for various types of pipe and shall adopt the separate fixtures lifting or supporting structure.
9, pipeline after deformation joint Department of buildings, compensatory measures should be taken, traverse across both sides of deformation seams should be fixed, and have the appropriate allowance.
10, traverse laying, respond to each loop of conductors of a megohmmeter measurement resistance 500V, the insulation resistance is not less than 20 M Ω.
11, protection wire for plastic pipe and fittings must be fire-retardant materials, plastic pipe should be spaced no greater than the width of continuous fire retardant tag and label manufacturers.
12, plastic pipe should not be laid at high temperatures and vulnerable to mechanical damage. Ming piping in through the floor in vulnerable areas should be used in pipe protection.
The fourth section very early smoke detection alarm system sampling network installation
1. standard sampling pipeline construction
Since the very early smoke detection alarm system network there are several installation modes, the following will be will be described in different ways:
1.1 sampling tubes fixed
Sampling of fixed according to the actual situation at the scene the flexibility to ensure that the sampling tube firmly fixed and beautiful.
1.1.1 the ceiling down sampling, the sampling tube should be at least 25 mm distance from the ceiling, but no more than 100 mm, and the sampling point to the room. Every 1.5 m or more distance should adopt pipe clamp fixed. The entire pipeline should not be bending stress. For longer than 2 m above the sample tube, vacancy should be fixed installation of metal suspenders. For longer vacant sampling tubes, or ceiling unevenness, the installation of metal horizontal bracing beams. And sampling of reliable fixed on the beam.
1.1.2 the ceiling in the sample, you must use the Standard PVC pipes or nylon self-locking ties will pipe fixed to the roof or on the other pillars. Ceiling sampling, you can use a ceiling hanging bar fixed sampling tubes, or use a placement level support, fixed. Take advantage of the lifting rods on the ceiling and beams fixed sampling tubes, should ensure the soundness of the beam frame itself. Fixed sampling tube is strictly prohibited in the active object; no no proper fixtures, forced to bend sampling of its proximity to fixed objects. Recommendations from the ceiling using metal horizontal bracing beams fixed sampling tubes.
1.1.3 ceiling and Underfloor air sampling, the sampling tube placed under the floor, for monitoring the safety of the cable under the floor. Installed in the floor, in order to avoid very early smoke detection and alarm system of trunk pipe and cable staggered under the floor, more suitable for vertical pipe sampling. In the placement of the sampling distribution network under the floor, first of all you should make sure that the cables are not under the floor was damaged, mess. Prohibition to forcibly pull mobile cable wiring. Sampling of not fixed in movable objects, should generally be indepent, fixed, sampling of non-close to the floor joist.
1.2 sampling of connection
Sampling tubes including pipe and tubes, pipe and tube end cap, and capillary connections between the connection and other places, the above connection should use special PVC adhesive, adhesive bonding surface should be clean and uniform glue, ensure that connections and reliable seal. In order to maintain the sampling line system is easy to install and test phase, suggesting changes to adjust the system detects the end and finalize forming, in sealed or permanent bonding pipeline interfaces. The sampling tube and hosts connections is not binding.
1.3 sampling of choice
Recommended sampling tube inner diameter of outer diameter 25mm should select flame retardant PVC pipe 21mm. Metal tube used for the following special cases: special extended, specific requirements, long time exposure to light, heat, cold, or encounters a PVC can be dissolved gas. The drop-down sampling tube or a walking stick-type sampling tube should be used for the outer diameter PVC pipe 16mm.
1.4 sampling of bending
Change sampling pipe direction applied arc elbow, do not use the right elbow. MiningSample tubes need to change direction when doing the design in advance, cannot force perverted sampling tube to change the direction of the pipe to avoid loading pipe for a long time, causing broken or cracked.
1.5 sampling point of processing and mark
1.5.1 in drawings specified local predrilled holes for sampling, convenience and security reasons, this operation should be carried out on the ground.
15.2 sampling drill should be cleared after each sampling hole Burr, ensure that every part of the pipe. Also check the pipe surface, clear the drilling of debris. Drilling of Burr, easy attachment to dust, debris may clog filters. In addition, you should replace the obvious defective sampling tubes.
The sampling points identify the sampling tube and Center holes sampling hole.
All sampling points processing completes, then assemble the entire network, and in the pipeline before the formal access host, use the vacuum cleaner to thoroughly clean the inside of the pipe network.
2, subtle sampling network installation specification
2.1 covert sampling distribution system is the use of a capillary tube, or a drop-down for detection.
2.2 backbone placement in most of the sampling distribution system on the ceiling, the installation should comply with the ceiling of the relevant provisions on sampling.
2.3 in uses standard capillary, capillary tube length should not exceed 8m. Capillary minimum diameter is 5 mm. Although the capillary maximum length can reach 8 meters, but increased capillary length 2 m, diameter 1 mm needs to increase. In order to ensure air flow speed, balanced sampling network. For example: 2-4 meters long by 6 mm diameter, as required, and so on.
2.4 drop down sampling of adopting internal diameter 12.5 mm PVC pipe through "T" type reducer tee branch from trunk pipelines. Pipe length must not exceed 4 metres. End plug for sampling hole punch.
2.5 without configuring the capillary sampling head, capillary must configure dedicated Terminal.
2.6 capillary sampling head should have clear instructions (with special requirements other than the application places).
2.7 covert sampling usually competent Internet terminal hole and capillary sampling point is not in the same area, and when these two different regions have large air pressure difference, should take appropriate measures exist.
2.8 although trunk pipelines connected capillary length may be (or need), but this will cause irregular reaction time. Therefore, it is recommended that you connect to different sampling point capillary length consistent as possible.
3, return air sampling network
3.1 return air ducts sampling
3.1.1 return air ducts sampling probe should be the detection of samples air rushed huihui duct.
3.1.2 the sampling tube and the exhaust pipe between the minimum distance of 300 mm.
3.1.3 return air tube usually work under negative pressure condition. Therefore to ensure that the sampling tube and exhaust pipes and their intersection closed to ensure sealed State.
3.1.4 sampling and exhaust pipe is placed to avoid diagonal air into the exhaust pipe to confusion.
3.2 back style gate sampling
3.2.1 sampling hole to airflow. A sampling of place on the best airflow. Sampling of recommended sampling hole on the diameter of 3 mm, sampling hole spacing is 100 mm. Sampling tube through the grill surface.
3.2.2 in air flow speed higher, be careful not to apply sampling pipe stuck Grill surface placement as this can cause the sampling hole around an area of low pressure, affect the normal operation. The grill at the end of the sampling tube required closed to avoid inhalation of gas loss from the end of the pipeline. In this case you want to use a non-porous end cap.
3.2.3 the larger grid requires at least two of the sampling tube to cover the entire area.
3.2.4 in order to ensure that the probe to be able to smoke conditions make the right response, improve response time, a single detector can only monitor the four air conditioning unit. In high-risk areas one detector can only monitor the two air conditioning unit. In addition, a sample pipeline can only monitor a air handling unit.
3.2.5 sampling line installed at a distance of air-conditioning unit on the edge of the main grille 100 ~ 200 mm bracket, sampling point is on the main airflow direction. High air flow velocity in place, this is the most basic. Sometimes you may need to rotate the sampling of the wind speed calculation best airflow measured out.
The fifth section equipment installation
5.1 very early smoke detection and alarm equipment should be in the sampling of arrangement completed the installation, the installation before the function check, unqualified, not installed.
5.2 very early smoke detection and alarm equipment installed on the wall, the bottom margin to (f) surface height easy 1.5 m. You should install solid, not italic. Installed in a light wall, the reinforcement of measures to be taken. Introduced very early smoke detection and alarm equipment wire, should meet the following requirements:
Wiring should be neat, avoid cross.
Wire end shall identify the number.
Cable core and conductors, should have not less than 20 cm of the allowance of bunched cables, conductors should be binding.
Power Inlet, should direct and fire power connections, is strictly prohibited to use the power plug.
Power cable and network line ground wire should be firmly and clearly marked.
5.3 sampling tube and device connection, no adhesive.