Page 38 - Industrial Ventilation Design Guidebook

i .3 AIR TECHNOLOGY SYSTEMS 3

tion in energy consumption (a ratio of 5:1) in technically similar welding halls;
this study showed the best indoor air quality was achieved in the hall with the
lowest energy consumption. With commercially available high-level design
concepts it is possible to decrease the contaminant load by about 90% and the
heat load by about 60% compared with medium-level applications.
The above results show the need to increase the level of knowledge from
"rules of thumb" to a more rigorous scientific procedure based on validated
data and design methods.

1.2 DEFINITION AND PURPOSE OF INDUSTRIAL AIR TECHNOLOGY

Figure 1.1 (see color insert) is a schematic representation of the principles of
IAT, Industrial air technology (IAT) can be defined as

Air flow technologies that control workplace indoor
environment and emissions
A longer definition is

1. Air flow technologies that achieve and maintain a safe, healthy, pro-
ductive and comfortable indoor environment in premises and occupied enclo-
sures where this need is determined not only by human occupancy, normal
human activities, and construction and finishing materials but also, and often
primarily, by other factors, for example, production processes
2. Process air technology, such as air and gas purification, drying, or
pneumatic conveying
3. Safety air technology, including risk assessment, that minimizes dam-
ages and hazards caused by accidents, fire, and explosion
It is typical for industrial premises to have, in one space, zones with different
target levels. The target levels may be determined for the whole area or locally. Of-
ten only a part of the space requires controlling of the indoor environment param-
eters. In addition to the main controlled zone, there may be one or more local
controlled zones with target levels different from those in the main controlled zone.
In addition to measures to control the indoor environment, industrial air
technology also includes measures to prevent harmful emissions from indus-
trial processes from being discharged outdoors, such as conveying and clean-
ing technologies and controlled discharge of exhaust air. Other systems
include, drying (pulp drying, milk drying, crisp-bread drying, etc.), process
ventilation, and safety air systems.
The scope of IAT includes premises other than traditional industrial pro-
cess buildings, such as hospitals; underground car parks; mining, railroad, and
vehicle tunnels; livestock buildings; and other premises and processes.

13 AIR TECHNOLOGY SYSTEMS

Industrial air technology systems can be classified into two categories: indus-
trial ventilation and process air technology. A brief description of each type of
system follows. More details are presented in Chapter 2.