Warehouses and large buildings in which activity is constantly taking place may have a number of concerns regarding air quality:

• Controlling the influx of contaminants (from vehicles or industrial sources outside the building or people, equipment and materials inside)
• Exhausting odours, vapours and fumes and excess heat from the building
• Air filtration for the removal of pollutants such as particulates
• Controlling humidity
• Providing sufficient fresh air (depending on the pollution levels and occupation density) while avoiding unwanted draughts. Guidelines vary, but are often around five to eight litres of air per person per second. Insufficient fresh air is associated with “sick building syndrome” (SBS) in occupants.

Typically, these issues are addressed by the use of wall-mounted or roof-mounted exhaust fans and air inlets. In the case of wall-mounted fans, the inlets are usually positioned on the wall opposite the fans.

Airflow and Temperature Control

Proper air circulation is an important part of a functional ventilation solution. Obstructions in the warehouse or badly-positioned ventilation equipment can lead to poor airflow and stagnant “dead air” zones where polluted air remains.

Apart from regulating airflow, warehouse fans can also improve temperature control. In winter, cold conditions in buildings are exacerbated by the fact that the warmer air rises to the top of the space. By mixing the air, fans eliminate this effect, improving comfort for workers and potentially saving on heating costs that would otherwise have been incurred. Up to 70% of heat transmission losses occur through the roof. Equalizing air temperatures helps to prevent the problem of condensate dripping down from beams and roof areas onto the floor and working areas. In summer, the increased airflow helps keep occupants cool. Thorough mixing of the air circulating in the building, together with (possibly conditioned) make-up air introduced from the outside, is important to ensure that air is properly exchanged and filtered.

Choosing the Type of Ventilation System

While natural ventilation is sometimes used, its limited nature usually presents the need to supplement it with well-placed fans and other ventilation equipment. In particular, buildings with only natural ventilation are very dependent on external temperature and humidity, making these factors difficult to control. Temperature and humidity are not independent, so that when the building cools at night, condensation often occurs on concrete in naturally ventilated buildings. The effectiveness of natural ventilation is also heavily dependent on the orientation and structure of the whole building.

The various available options have different initial, operating or maintenance costs. A seemingly attractive solution may result in higher costs later, whether there are unforeseen efficiency losses because of poor design or ventilation needs and fan sizing have not been adequately assessed. High-efficiency equipment that is correctly sized is critical to keeping costs down.

The chosen solution depends on the costs involved and the desired results. For close control, carefully designed HVAC systems may be needed, whereas in other cases a fan-only solution may be chosen to keep costs down.

The number of variables involved in HVAC design for warehouses (and buildings in general) calls for an integrated approach to improve energy efficiency while providing high quality air. Building orientation and layout, the expected number of occupants, possible sources of pollution and the type of activities taking place are all important variables. When installing fans, noise levels must also be considered.

CFW Turnkey Ventilation Systems

CFW ventilation systems can be designed from scratch for reliable operation, with integrated ducting, exhaust fans, and temperature and humidity control systems as required. The performance and installation parameters are specified by our clients – custom design means that compatibility between system components is assured and unforeseen maintenance problems and efficiency losses are avoided.

Thorough testing of all fans is conducted in CFW’s test laboratory, ensuring component reliability and accuracy of airflow performance.

Fan components and spare parts are readily available from stock, and are assembled to order.

HVAC Equipment Offered by CFW

CFW’s designers have a thorough and detailed knowledge of the industry. Our engineers provide on- and off-site coordination of the project, working closely with customers to understand their needs.

The possibilities include:

• Heat recovery systems: control temperatures in your building for a productive and comfortable environment while cutting costs. Heat recovery reduces the burden carried by air conditioning and uses energy which would often be lost for maximum efficiency. Heat exchangers
• Evaporative cooling or air conditioning: Evaporative cooling offers a temperature control and humidification solution for dry climates with low costs (see www.evapcool.co.za to view our standard evaporative cooling units). Air conditioning provides more temperature control and some dehumidification with higher running costs.
• Exhaust ducting, fans, vents and accessories: Ensure proper air exchange and remove excess heat and contaminants with a carefully constructed exhaust system constructed from heavy-duty materials resistant to corrosion.
• Refrigerative and desiccant dehumidification: Remove excess moisture that can lead to condensation, damage buildings, materials or equipment and adversely affect the health of occupants. We install the appropriate dryer for your environment, depending on the temperature, the size of the space etc. (Our dehumidifier units can be seen at www.dampcontrol.co.za).
• Fire safety measures: CFW provides tried and tested fans designed for smoke ventilation and reliable operation in high temperatures, for integration into the building ventilation system.
• Fan accessories: Our ventilation systems are equipped with cowls, louver shutters, weather louvers and other ancillary equipment as needed. Accessories can also be ordered for existing systems.
• Airflow control and energy-saving devices: Fans can be equipped with a variable speed drive (VSD) or otherwise customised to avoid efficiency losses.