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DESIGN CONSIDERATIONS Industrial ventilation can vary significantly from very simple supply air , supply and extract air , to supply and extract with conditioning and filtration flowing in and out with the inclusion of particulate management or direct process extraction ( such as what would be seen in printing press facilities where significant amounts of paper dust must be removed from the air to avoid spoilt products , machine faults and staff inhalation ).
Several sources may need to be identified from within the facility above the standard air changes required per hour according to our building codes . Additionally , in industrial settings the engineering team would possibly be required to design a multi-function system serving different zones – being offices with occupants , general work areas , specialised processing areas and very often large voids – common in factories and warehouses of all types . Design may also require that airflow be directed to a particular destination at a facility to manage contamination .
Sources of air-quality-affecting factors would further need to be identified on an individual basis before such contributors could be managed and controls applied . These could include the following as examples :
• Actual process equipment
• Employee tasks ( such as welding , grinding , sanding , or painting )
• Mobile equipment such as trucks or forklifts
• By-products such as steam , chemicals , gasses , or dusts
The purpose of ventilation is essentially the function of a reduction in exposure to such aspects , introduction of fresh air , to dilute concentrations in enclosed spaces , venting stale air safely outside of the space – generally to the outside air , or , all of the above .
Ventilation components for industrial applications could therefore include any of the following :
• Hoods
• Ducts / ducting
• Various types of filtration
• Fans
• Stacks
• Cupboards
• Air scrubbers
• General ventilation inclusion
• Evaporative cooling
• Cooling towers
• Drying , curing , and calcining
• Aeration of liquids
• Vacuum and pressure systems
• Heat recovery
• Etc
Tim Hüfner | Unsplash
The process would also involve the design considerations of how quickly air needs to be removed or replaced , venting air versus local regulations and laws , stacks , stack height and placement , type of appropriate ducting according to possible chemical reactions ( acidic environments require stainless steel as an example ), the impact and planning around maintenance requirements , the noise levels of the system / components , the inclusion of gates and dampers , and planning around possible duct and stack clogging .
Generally speaking , industrial ventilation must cater to “ hard / harsh ” environments and is subject to long operating hours as well as varying operating conditions in local industries such as :
• Mining
• Power generation
• Processing and food production
• General manufacturing and engineering works
• Agriculture related ( chemicals , nutrients and production of fertilisers )
• Marine operations
• Automotive
• Specialist facilities
FACILITY RESPONSIBILITY : WHAT THE SOUTH AFRICAN ACTS AND LAWS MANDATE For the industrial sectors , there are multi-pronged aspects that need to be addressed in ventilation today that may not be common knowledge , are ignored , or are disregarded . These aspects link the facility owners directly to not only the wellbeing of their plant and equipment , but mandate a firm responsibility towards employees and the environment .
The common sighting at many older facilities – the fan in the back wall of a factory .
www . refrigerationandaircon . co . za RACA Journal I September 2022 25