Build Daily

Engineering Systems

August 12, 2017 18:07

Emergency ventilation - secured a peaceful sleep

main objective of emergency ventilation

During a fire, to eliminate smoke, use ventilation units that supply air evacuation passages and staircases.When the emissions of toxic substances in the room air flow occurs as a result of the overflow of his adjoining rooms.

To calculate the necessary air exchange in emergency mode, you need to take into account the non-stationary processes in the solution of the balance equation of gas in the room, which is written in the differential form.

emergency situation can occur due to various reasons: fire, self-ignition, the sudden release of gas, explosion, etc.To do this, there must be a special plan modes of auxiliary ventilation systems in case of an accident.

Typology emergency ventilation

There are several types of emergency ventilation :

  • Exhaust general ventilation system with additional fans for air flow in the accident;
  • Emergency exhaust system in addition to the main system (with a spare fan), if the air in the waste they do not provide air exchange in full;
  • Exclusively emergency exhaust ventilation system if the use of the main system is impractical or impossible;
  • Exclusively emergency Ventilation system for single-storey houses.

ventilation devices should be placed: to delete the selected gases and vapors, which have a specific gravity greater than the specific weight of the air - in the working part of the room, and a smaller proportion - in the upper zone.To prevent smoke suppressant used emergency ventilation to evacuate people from the premises with just ensuing fire.

In some cases, put the spare unit.It is associated with the working unit.When you turn off the desktop, backup is automatically activated.Devices that run extra ventilation must be installed at the entry door.

Such ventilation is always in a ready state, and it has two modes of operation:

  • active.Development of emergency ventilation is sufficient throughout the emergency, and the content of harmful substances in the air remains at a safe level;
  • Passive.The lack of development of emergency ventilation and the accumulation of vapors and gases in the air is constantly growing, and goes beyond a safe level.Safe operation in this mode is not guaranteed, because each pulse can cause an explosion resulting mixture of gases.

Features calculate

emergency ventilation calculation emergency ventilation is carried out based on the following parameters:

  • air velocity in ducts - m / s and operating pressure - Pa;
  • permissible noise level - dB;
  • air capacity - m³ / h;
  • heater power - kW.

index regulated sanitary and building regulations.It is better, if the calculation is carried out expert, as do it yourself is difficult.There are some requirements for emergency ventilation:

  • air that is drawn must go out through the roof, and the air tube can take place both outside and inside the building;
  • Fresh air must pass through the inside of the grille placed at least 2 meters above the ground;
  • air movement need to arrange so that it came out of the living rooms towards the toilet, kitchen or bathroom.