Page 402 - Industrial Ventilation Design Guidebook

6,! DEFINITIONS AND CONNECTION TO DESIGN METHODOLOGY 357

reconsidered. The target level assessment is a feedback process, as explained in
Chapter 3.
Target levels can be utilized at many levels and areas of technology. Some
examples from industrial air technology follow:
* Energy efficiency given as a percentage
* Energy usage per cubic meter or square meter of a building, such as for
the heat consumption in buildings
* Energy usage per produced unit of final product(s), for example, energy
use for each produced ton of stainless steel
* Indoor air quality
* Reliability, for example, how many breaks are accepted per day
* Emission rate
* Capture efficiency of the local exhaust
* Investment cost and maintenance cost
* Expected lifetime of a plant and its components
* Ecological issues
Because the goal of industrial air technology, as defined in Chapter 1, is
to control indoor environmental conditions and emissions, special attention
must be paid to the indoor conditions and contaminant content of the ex-
haust air. The need to define target levels for indoor conditions and exhaust
air blown outdoors originates from legal requirements, human health re-
quirements, production processes and equipment, and is also related to the
type of premises and construction. Target levels should be defined for ventila-
tion systems as well as many other items in the construction process. Target
levels should always be dealt simultaneously with design methodology. A de-
cision tree for the target level steps and design methodology is provided in
Chapter 3.

6.1.2 Use of Target Levels
It is the responsibility of the end user and the contractor to determine tar-
get levels. It is essential that the target levels be specified in such a way that
they can be unambiguously measured. It is also important that the respon-
sibilities of each stakeholder be clearly defined, particularly in case some-
thing goes wrong. This includes financial responsibilities. In addition to
the designer and end user, other stakeholders are involved in the construc-
tion of a plant or building. In the simplest case, the overall contractor
takes care of the design and construction of the plant or system, and then
the end user buys it. In this case only two stakeholders are involved. In
more complicated cases, the number of stakeholders may total 10. For in-
stance, the supplier side may be represented by the consulting engineer,
manufacturer, ventilation contractor, and building contractor, and the end
user side by the real estate company, plant owner, plant engineers, and
other occupants.
The use of clearly defined target levels has become more and more im-
portant in industrial ventilation. The targets must be realistic and verifiable