Aspirating Detection Systems
Aspirating smoke detection (ASD) systems are quite different from traditional point type smoke detectors. A typical aspirating detection system is comprised of a number of pipes laid out above or below a ceiling in parallel runs, some meters apart. Small holes, also some meters apart, are drilled into each pipe to form a matrix of holes ('sampling points'), providing an even distribution across the ceiling. Air or smoke is drawn into the pipework through the holes and onward to a very sensitive smoke detector mounted nearby, using the suction pressure of an aspirator. For specific object or cabinet protection, the sampling points can be fed into and around the equipment with flexible capillary tubes. When high air-flow movement is presence in the protection area like data center or cleanrooms, the sampling points can be located in the return air path to intercept the smoke.Actually the configuration of the sampling pipeworks and sampling points is very flexible. Compared with the traditional way to install point type smoke detector on the ceiling, the aspirating detection systems can be installed in any place where the fire or smoke presents.
10.2 Electronic Data Processing (EDP) Areas
Within this type of environment there are a number of issues to be considered in designing the ASD system. These being:
- High Airflow
- Lack of smoke energy
- Resultant low smoke temperature
- Dilution caused by airflow velocities
- Addition of clean air by ventilation systems
Due to these issues it is necessary to protect areas using primary and secondary detection principles. Detection is therefore required at ceiling level, floor void and return grilles of AHU. Ceiling (Roof) voids should also be taken into consideration where necessary.
Dependent upon the area being covered it may be necessary to use separate ASD systems to monitor the specific areas as identified in the preceding paragraph. However, in applications smaller than 150m2 it may be possible to use a single Class A detector to cover the area as identified above (refer to manufacturer for design implications).
Secondary detection spacing, at ceiling levels and within voids, will require the sampling points to be spaced in accordance with clause 8.3.3.2.
Primary detection of air return grilles can be used to overcome the effects of high airflows, which often prevent the smoke particles from being detected at ceiling level. The maximum number of air return grilles that can be monitored by a single ASD is generally limited to four depending on the air grille size, airflow and the specific ASD being used. Refer to the manufacturer’s recommendations when designing Primary Detection for such areas.
Sampling pipe is required to be installed across the grille with the sample points positioned at a typical angle of 30-60o off centre, into the airflow. Maximum spacing recommendations are given in clause 8.3.3.1. The use of a union socket is recommended to allow the selection of the final orientation during the commissioning of the system and allow maintenance access to the grilles of the AHU.
PARTIAL CUSTOMER LIST
Airport
- Taipei Songshan Airport Immigration: Computer Room
Bank
- Taiwan Stock Exchange Banqiao Data Center Project 1 & 2
- South China Insurance
- Taishin International Bank Neihu
- Industrial Bank of Taiwan Neihu
Judicial
- Hualien High Court
- Hualien District Court
- Hualien High Court Sindian Summary Court
- Hualien District Court Sindian Summary Court
Telecom/IDC
- Chunghwa Telecom Mobile ( Telecommunication Room Communication Branch)
Kaohsiung Shiquan/Juemin/ ErlingTa
Tainan Yongkang
Taichung Changer - Chunghwa Telecom Toufen site: Cloud Modular
- Taiwan Stock Exchange Yang De Building: Substation/Data Center/Electrical Room/UPS Room/Battery Room
- HWACOM SYSTEMS INC
- Bureau of Education,Tainan City Government
- China Telecommunications Group Co.,Ltd
