Vesda system manual

Revision A7. VESDA aspirating smoke detectors buy the critical time needed to investigate an alarm and initiate an appropriate response to prevent injury, property damage or business disruption. VESDA detectors have multi-level warnings and a wide range of sensitivity where minute levels of smoke can be detected before a fire has time to escalate. Using unique detection principles, the VLP has an alarm sensitivity range of.

It provides the designer with tools to speed the design process and ensure optimum network performance and quality. Page Preliminary Systems Check. This guide introduces you to the VLP features, technical specifications and gives an understanding of its components and their function.

Document No. The airflow within a protected area carries the air samples to the sampling holes. The input is isolated from the system by an opto-coupler device. Table Of Contents. Quick Links Download this manual. Fire Suppression Applications. With ever increasing environmental responsibilities, it is essential that a fire suppression system should deploy unnecessarily.

VESDA smoke detection use in conjunction with conventional smoke detection is a perfect match. Preferably VESDA detection samples the air across the return plenums of the air conditioning systems which provide primary smoke detection! An alert alarm can be raised and human intervention can prevent the gas from discharging! VESDA smoke detection is a suitable replacement for conventional smoke detection where accessibility is limited.

For example, VESDA detection will be better suited to a warehouse with smoke detectors situated at high levels. Conventional smoke detectors can become faulty and access equipment will need to be deployed, this can be extremely disruptive to operation and it is also dangerous. Aspirating pipe will replace the smoke detectors at high level, with holes in the aspirating pipe replacing the smoke detectors.

Cold Storage. VESDA smoke detection is commonly used where temperatures are not suitable for other types of smoke detection. Cold temperatures will ice up the optical chambers of conventional smoke detectors rendering the system useless. VESDA detectors are located outside the cold environment, with aspirating pipe work located within the risk or outside the risk with capillary smoke sampling heads located within the risk!

The ASD monitors the air used in equipment cooling. ASD monitoring systems should be analyzed and reviewed by well-trained engineers. They should have a piece of sound knowledge in smoke detection systems.

The main factors affecting the sensitivity of ASD systems are the number of sampling holes drilled in the piping network and smoke detection thresholds. The dilution of the air coming into the sensing chamber depends on the number of sampling holes drilled in the piping network. When a cloud of smoke is drawn into a single sample hole which results in the dilution of smoke concentration due to the passage of smoke through other sampling holes aspirating clean air.

When the volume of clean air is mixed with smoke-filled air in the detection chamber the smoke-filled air is diluted.

When the smoke is transported through the pipe, it combines with clear air, thus diluting the smoke density. The dilution effect is directly linked with the number of sampling holes in the piping network. The more sampling holes, the more volume of air is sent to ASD and that results in dilution of smoke in the air. While setting an alarm for the smoke detection system, the dilution effect needs to be considered.

Experimentation is done by creating a smoke near one of the sampling holes. The same amount of air will be let in through all the sampling holes. At the one end of the pipe, there is a smoke source, which prevents any other smoke to enter in any of the sampling holes. Issues that are affecting the dilution effect is the number of sampling holes, the number of bends, elbows, and fittings used in the piping system. The transport time is the time taken for the smoke to reach the sensing chamber.

The time measured in seconds for the particles to reach the sensing chamber from the sensing point. When discussing transport times, various factors are taken into consideration. Hope you got an idea after reading the blog until the end. Select Course H. Follow Us On for updates.

Enquire Now. Principles Of Aspirating Sample Detection A central detection unit in the aspirating smoke detection system, which helps to bring air from the pipes and detects smoke. The aspirating detector consists of Sampling pipe network which can gather air through sampling holes and send it to the detector. Aspirating smoke detector: It consists of a sensing chamber having a highly sensitive sensor to detect even the micro smoke particle. A fan is installed to draw air from a protected area to the sensing chamber.

Optical fiber to remove large particles from entering the sensing chamber. Exhaust pipe to remove the sampled air from the detector. Aspirating Detection System Piping The Aspirating smoke detector is connected with a sampling piping network through the port from the top or bottom.

Aspirating Smoke Detector Aspirating smoke detection systems can be classified according to the type of detection technology Laser-based systems filtered : This system works on laser technology.

The air passes through the filter to remove all large particles and the filtered air passes in front of the laser. A photo collector is used to sense the light scatter caused by smoke. The detectors can analyze the quality of smoke detectors.

Non-filtered laser-based systems: This method purely uses a laser detection system. Here the air is passed to the sensing chamber without passing through the filter. The photo collector counts the number of micro air particles and it can differentiate between dust particles and smoke particles.