Colt CoolShaft

Providing smoke ventilation and corridor cooling

Colt CoolShaft is a combined smoke and climate control ventilation shaft system which cleverly uses evaporative cooling technology to provide active pre-cooling of the incoming air, without compromising the ability of the shaft system to ventilate the common area in a fire – and this with exceptionally low energy consumption

What are the issues?

The quest for energy efficiency has led to very good insulation in residential buildings. While this is very good for the environment and for electricity bills, it is having unintended consequences in stair lobbies, corridors and entrance halls, which can tend to get warm and stuffy.

The solution: Colt Coolshaft

Since CoolShaft is a combined smoke and day-to-day shaft system, our design ensures that if there is a fire there is no compromise in its ability to ventilate the common area and allow smoke to escape.While a ventilation system supplying untreated outside air is able to achieve temperatures in the corridor at typically 3-5°C above the outside ambient, a CoolShaft system is able to reduce temperatures to below the outside ambient by providing active cooling in the corridors.

Sizing and selection of components

Each CoolShaft system is designed for the client's indiviudal application and is sized to suit that building's heat loads

Features and benefits

  • Cooling of corridors
  • Economical
  • Low energy use
  • High cooling capacity
  • No refrigerants
  • Hygiene certificate
  • A space saver
  • Lightweight

Read more


  • Type
  • Fan type
  • Controls
  • Connection
  • Accessories
  • Approval

Read more


CoolShaft shaft ventilation system

The many benefits of CoolShaft begin with low energy cooling

It doesn’t need to cost the earth to cool a building: using the cooling power of water, it’s possible to achieve low energy cooling. Here are some of the features and benefits of Coolshaft:

Cooling of corridors. Whereas basic day-to-day ventilation systems for common corridors and lobbies use outside air to ventilate the space, the CoolShaft provides active cooling of incoming air, providing highly desirable conditions for the residents. If the ambient air is 30°C or above, the supply air can be cooled down adiabatically by at least 10°C. In general, the hotter the weather, the more efficient the cooling is.

Economical. CoolShaft systems offer cooling that is up to 7 times more economical than conventional air conditioning systems, with lower initial costs. CoolShaft runs much of the year in free cooling mode, with evaporative cooling brought on-line when temperatures rise. CoolShaft units consume only around 1 kW and 50 litres of water per 10,000 m³/h of supplied air, equivalent to more than 30 kW cooling power, depending on the configuration chosen.

Low energy use. Evaporative cooling is up to 90% efficient. CoolShaft only needs a small quantity of electricity for the fan that circulates the air and for the water pump. As standard CoolShaft is available with a 400 V highly energy-efficient EC motor.

High cooling capacity. One CoolShaft unit can cool multiple floors, and often the complete building, owing to its inherent high cooling capacity.

No refrigerants. CoolShaft is free from refrigerants, thus there are no F-gas compliance issues, and there is no need for refrigerant / water pipework in the building.

Hygiene certificate. It provides safe circulation with temperature control and regular renewal of water to avoid the growth of bacteria and scale. It has been extensively tested and certified hygienically in compliance with VDI 6022 (“Hygienic Requirements for Ventilation Systems and Units for Internal Spaces”). This is a rigorous standard for air conditioning systems and confirms the high quality of supply air.

A space saver. CoolShaft has a smaller rooftop footprint and saving on rooftop ductwork compared to conventional air conditioning systems, thereby freeing up space.

Lightweight. CoolShaft is more lightweight than conventional air conditioning systems.



The system is selected specifically to suit the characteristics of the building– e.g. its heat loads and the number of storeys. Please contact Colt for system sizing.

Fan type

400V highly energy efficient EC motor.


Fully integrated control system with temperature sensors on each floor.


Integrated with smoke ventilation plant for reduced roof footprint. Roof plant connects to smoke ventilation shafts to supply and exhaust air.


G4 filters for improved air quality.

Noise attenuators to meet any requirements to limit noise either within the building or externally.


Tested and certified compliance with the VDI 6022 hygiene standard.