China
Africa
Explore chapters and articles related to this topic
Electrical installations
Published in Derek Worthing, Nigel Dann, Roger Heath, of Houses, 2021
Derek Worthing, Nigel Dann, Roger Heath
Smoke detectors are normally one of two types – either an ionisation chamber (working by physical process) or an optical chamber (working via photoelectric process). In the former, any smoke entering the ionisation chamber interrupts a small current between two electrodes and sets the alarm off. The optical chamber is basically a light sensor; when smoke enters the chamber, some light is scattered by the smoke particles, interrupting the sensor and triggering the alarm. This type is generally considered more reliable than an ionisation detector as the latter is likely to give more false alarms. Combination alarms incorporating both types of detection are also available and are considered to offer the best protection. Alternatively, it is possible to install a multi-sensor alarm that incorporates both an optical and a heat sensor.
Typical fire safety design strategy for tall buildings
Published in Feng Fu, Fire Safety Design for Tall Buildings, 2021
A smoke detector is a device that senses smoke, typically as an indicator of fire. It is an important tool in fire safety design of tall buildings. Smoke detector usually is directly connected or powered by a central fire alarm system to ensure that notification can be passed to occupants in the building. All lift lobbies shall be provided with smoke detectors. Smoke detectors can be divided into two types: photoelectric smoke detectors and ionization smoke detectors.
Specific Maintenance Procedures and Requirements
Published in Ryan Cruzan, Manager’s Guide to Preventive Building Maintenance, 2020
Multi family residences, hotels, and other buildings with individual sleeping rooms or apartments will often have single station battery operated smoke detectors. Just like the smoke detectors that are part of a building’s fire alarm system, these detectors need to be tested monthly. Smoke detector batteries also need to be changed on a regular schedule. Fire investigations show that 25% of homes have smoke detectors that do not work. The primary reason is dead or disconnected batteries.
Understanding the influencing factors of heritage building maintenance management: findings from developed and developing regions
Published in Building Research & Information, 2023
Mayowa I. Adegoriola, Esther H. K. Yung, Joseph H. K. Lai, Edwin H.W. Chan, Sitsofe K. Yevu
The rigidity of applying building regulations concerning HBs needs to be addressed. These regulation demands often lead increase in renovations and refurbishment expenses, in many cases to unaffordable levels. In addition, it may also compromise or even destroy the heritage integrity of the properties (HHK, 2007). To help curb issues emanating from legislative requirements, the government may adjust building ordinances according to the exceptional circumstances of individual cases. Such consideration has been applied in the case of the former Tai O police station (grade 2 HB), which was revitalized as the Tai O Heritage hotel in Hong Kong. The building department considered and accepted the application for the alteration process based on specific circumstances. For example, the actual means of escape, fire resistance structures and emergency vehicular access of the Former Tai O Police Station do not meet the current standards under the Buildings Ordinance and its associated regulations. Therefore, the Building Department accepted the fire engineering approach (such as sprinkler and smoke detector systems) as the performance-based alternative approach to achieve the performance prescribed by law.
Experimental and Numerical Investigation of a Room Fire in a Wooden-Frame Historical Building
Published in International Journal of Architectural Heritage, 2020
Shu-Fen Tung, Hung-Chi Su, Chun-Ta Tzeng, Chi-Ming Lai
Figure 7 illustrates the layouts of the measurement points. There were five thermocouple trees symmetrically distributed in the fire compartment for temperature measurement. Each thermocouple tree was composed of five sets of type K thermocouples tied vertically to thin iron chains with thermal isolation materials wrapped outside. These five thermocouples were positioned 0.6 m, 1.2 m, 1.8 m, 2.3 m, and 2.9 m away from the floor level. Each smoke detector tree consisted of 3 photoelectric detectors connected to a fire alarm control panel, positioned at 1.8 m, 2.3 m, and 2.9 m above floor level.
Transient heat flux measurement analysis from coaxial thermocouples at convective based step heat load
Published in Numerical Heat Transfer, Part A: Applications, 2019
Sanjeev Kumar Manjhi, Rakesh Kumar
In this work, the K-, E-, and J-type surface junction coaxial thermocouples have been fabricated and calibrated in the laboratory. The static calibration has been carried out to determine the thermal coefficient resistance (TCR) and sensitivity (S) of these handmade coaxial thermocouples. The oil-bath technique unit provides a gradual step variation in voltage corresponding variation in temperature. This calibration refers to act of calculating and adjusting the exactness and accuracy of these coaxial thermocouples. After confirming these handmade coaxial thermocouples are performing as designed in order to rationalize the efficacy of these handmade coaxial thermocouples in the application of convection it is vital to calibrate in the analogous environments. Transient heat flux has been measured at the low temperature and at low velocity on force convective flow environments to analyzed that these handmade coaxial thermocouples are suitable to measure transient heat flux at low temperature and low velocity or not. Thus for the implementation the calibration technique of CSJTs (K-type, E-type, and J-type coaxial thermocouple) on connective based transient heat transfer, an experimental set-up has been developed. The three different known input velocity and temperature have been applied to these handmade coaxial thermocouples one by one. A simple laboratory experimental set up has been designed in which these three CJSTs (K-type, E-type, and J-type) are exposed to heated air flow engender by a “hot air gun.” The experiment has been done by exposing these handmade coaxial thermocouples on the hot air flow field for short durations for 200 ms. Then, the transient temperatures history is recorded with the help of data acquisition system (DAS) with respect to time during the heated air flow over the coaxial thermocouples on the experimental period. The numerical simulation has also been done using commercial software (ANSYS-FLUENT v. 15.0) for the similar as mentions in experimentation conditions. The transient surface heat fluxes are estimated using one-dimensional heat conduction model for a semi-infinite body from transient temperature history captured by coaxial thermocouples for both experimentally as well as numerically subsequently compared between them to estimate the performance of these three (K-type, E-type, and J-type) handmade coaxial thermocouples. These handmade coaxial thermocouples can measure the heat flux at low velocity and low temperature. They can also be used to measured heat transfer rate in areas of non-nuclear application such as smokestack air monitoring, cooling towers in a coal plant, combustion of air for boiler, HVAC Duct fire, smoke detector where heat transfer rate change rapidly. Details of the experimental setup, estimation of sensitivity and TCR and calibration procedure are discussed.