- Author
- Harada, K. | Terai, T. | Kadoya, M. | Miyagi, K.
- Title
- Study on Design Methodologies of Smoke Venting Systems. Part 2. Design of Air Supply Openings.
- Coporate
- Kyoto Univ., Sakyo-ku, Japan Okumura Corp., Osaka, Japan
- Journal
- Bulletin of Japanese Association of Fire Science and Engineering, Vol. 41, No. 2, 29-35, 1993
- Keywords
- smoke | venting | pressure reduction | exhaust systems
- Identifiers
- air supply opening
- Abstract
- [ABSTRACT IN ENGLISH] In order to prevent excessive depressurization and smoke inflow in the area where a mechanical smoke exhaust system is operating, it is necessary to supply air to the area. In this paper a method is proposed to determine the required size of the air supply opening. This method was verified using the experiments conducted in the same building as in the previous paper. It was determined an opening with 0.073 [m²] of the effective flow area is adequate to reduce excessive pressure to half in the case of an 80 [m₃/min.] exhaust rate for the 50.6 [m²] floor area. Two method were used to determine the required air supply opening area; one by a precise ventilation network and another by a simplified equation. The required area can be predicted accurately by using the precise network method, however it is relevant to know the full route including leakage from gaps in doors, ceilings, air ducts and pipe shafts. That is quite difficult in a practical design process, because often they are altered by many factors including methods of construction, alterations of design, etc. The simplified equation method also provides practical estimations of required air supply opening area if all the gaps are taken into account. If the door gaps only are taken into accounts, it gives somewhat large area, which will satisfy the safety requirements.