Dangers of cable vaults and tunnels

Cable vaults and tunnels as in them it is difficult to create necessary ventilation, quite often contain the gases dangerous concerning explosion or poisoning. Especially it concerns wells and tunnels which are located near gas or sewer network.

Схема устройства кабельных колодцев

Scheme of the device of cable vaults.

Gases constitute double danger as at stay them in air they can be otravlyayushchiyom and explosive.

Before descent in the tunnel or the well it is necessary to be convinced of lack of gas first of all.

It is possible to find it by means of the normal miner's (petrol) bulb supplied with the corresponding grid. Opening carefully the well hatch so that there was no spark from mechanical blow, lower in it the lit lamp and watch its flame. Уве­личивающееся the flame demonstrates availability of the opasyonost on gas explosion (the lighting gas, methane), the pomerkyoshy or extinct flame indicates carbonic acid presence.

It is inadmissible to lower the lit paper in the well or the tunnel or I shine for gas verification of presence.

At gas detection the well is aired the special hose fan, and only after the second check the worker can fall to the well. The fan has to work during all working hours in the well as gases can appear suddenly again. The sleeve from the fan for forcing of the pure air has to be in the lower part of the well, without reaching the bottom on 0,25 m.

Схема протягивания кабеля.

Scheme of drawing of the cable.

At the open hatch the preduyopreditelny sign has to be established or barrier is made. In the well one worker can be and work with the kvalifiyokation not below group III. In this case about the hatch other worker from the structure of crew is on duty (installation of the sign or barrier in the presence of the person on duty are not obligatory).

During the works in collectors and tunnels two hatches or doors have to be open working were between them.

Kindling of blowpipes, warming up of mastic and solder have to be made only outside. It is possible to lower in the well the melted solder and the warmed weight only in the special ladles and the closed pans suspended by means of the carbine to the metal rope.

At special need of kindling of blowpipes and braziers for tunnels and collectors guards from fire-resistant material, ograyonichivayushchy distribution of the flame have to be applied and be had fabric from fireproof material for fire extinguishing.

In wells, tunnels and collectors working have to apply portable lamps of 12 V or accumulator lamps to illumination of jobs.

During the long works in wells, tunnels and collectors working have to come to some time for open air periodically.

If there is no need to apply fire and the tool able to cause the spark, and it is required to perform urgently work in the well filled with gas, it is necessary to use the hose or oxygen respirator.

At emergence of the fires in cable tunnels and channels the existing rules allowed to flood them with water.

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