Contents
(1) Smoke-proofing technique for escape route (stairway room, corridor, smoke-proof room) in multi-story building.
(2) Behaviour of smoke flow in corridor (Forced air supply or Forced exhaust system)-Model experiments (scale : 1/4).
2·1 Objectives of experiments.
2·2 Model of corridor (quarter-scale model).
2·3 Experiment I -Smoke-front and behaviour of smoke flow beneath ceiling (Forced exhaust), Fig. 1, Table 1.
2·4 Experiment II -Patterns of smoke flow and velocity profile in corridor with a windward screen (Forced air supply), Fig. 2, Table 2.
2·5 Experiment III-Patterns of smoke flow and velocity profile in corridor without screen (Forced exhaust), Fig. 3, Table 3.
2·6 Experiment IV-Patterns of smoke flow and velocity profile in corridor with smoke vent. (Windless or forced air supply), Fig.4, Table 4.
2·7 Experiment V-Patterns of smoke flow and velocity profile in corridor with two discharging openings (Forced air supply), Fig. 5, Table 5.
2·8 Experiment VI-Relation between U₀ and U₁ (comparison of forced air supply system with forced exhaust system), Fig. 6.
2·9 Experiment VII-Comparison of velocity profiles between forced air supply system and forced exhaust system. Fig. 7.
2·10 Scaling law ; Determination of necessary air velocity to be charged into corridor in case of forced air supply system.
(3) Experiment VIII- Vestibule for Safety : Natural ventilation through smoke-tower inducing air in-flow, Fig. 8, 9.
(4) Conclusion and Application to escape-route planning.
Nomenclature
U₀ ………velocity of supplied air at the opening below the screen, averaged (m/s or cm/s)
U₁ ………velocity of spurting hot gas (smoke) from burning room (m/s or cm/s)
m ; f (suffix) … model ; full-sized (corridor)
γ₀ ; γ_g … unit weight of air/hot gas (kg/m³)
θ₀ ; θ_g … temperature of air/hot gas (°C)
Δθ₁ …… θ₁ - θ₀, where θ₁ is temperature of spurting gas from a burning room.
T ……… absolute temperature (°K)
h or h₁ … height or vertical distance of spurting center of an opening from the neutral plane. (m, cm)
L ……… representative length.
Model for experiment (1/4-scale model, 6 mm thick glass plates) : corridor : 60 cm × 30 cm × 540 cm (length) ; hot gas (smoke) opening : 12 × 18 cm ; opening of vent shaft : 12 × 18 cm and 12 × 36cm ; vent shaft : 10 × 10 × 80 cm (height) ; burning room : 60 × 30 × 60 cm with a out-side air inlet : 15 × 15 cm
(i) Natural ventilation system and forced air supply-or exhaust-system
Merits of the forced air-supply system is described, comparing with the natural ventilation system. Considered the draft through the corridor which accompanies the natural ventilation throughout vertical routes such as stairway, air-conditioning vertical shaft and others alike, smoke flow spurting from a burning room may be resisted or checked by the draught, so that smoke venting from the smoke-tower may be reduced, resulting in an increase of smoke layer thickness beneath the corridor ceiling. The forced air supply system can overcome the resistance of the draught and lessen the smoke layer thickness, resulting in making escaping easy.

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The smoke ventilation due to ordinary smokeproof tower depends on the natural flow or motor fan. However, natural flow doesn’t occur if the inside of the tower is cool and motor fan won’t work normally, because of any trouble of electronic circuits. Therefore, we have planed the method of ventilating the smoke under enforced heating inside the tower. With the model tower，we have measured the effects of this method. The model tower is about 1/40 scale that is used for actual building, the most simple one, and placed nich-rohme heater inside it. We have obtained the following informations from this test. Smoke flow resistance was scarce and the effect was good. The best heating Place was under the 1/3 of tower’s height and the best heating efficiency was 80～100％ when we used plastic board as wall material. Minimum heat quantity was about 55.5kcal/s·m². We want to apply this new method for actual building, and we are going to examine practical Possibility shortly based on this data.

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