REQUIREMENTS DUE TO BUILDING CONSTRUCTION, EQUIPMENT, PROCESSES, AND TYPE OF PRODUCTION PREMISES

6.5.1 Introduction

Nonindustrial buildings are made as shelters for people and to create a proper in­door environment for the occupants. By contrast, industrial buildings are made around a process, and consequently nearly all decisions are based on the process needs. Due to these fundamental differences, the main targets in industrial build­ings generally differ from those of nonindustrial buildings. Of course, the process also consists of human beings in many industries, and therefore ventilation is de­signed and constructed based on the needs of the people working inside the build­ing. The requirements on target levels due to type of premises can be divided in two parts: the effect of the different parameters and their target levels on the building, and the building’s effect on the different parameters and their target levels.

Requirements on parameters that may influence the building and its per­formance and target levels to be determined for occupational zones and non — occupational zones are the following: temperature, humidity, air velocity, contaminant concentration (particles, gases), odors, biocontamination (in air and on surfaces), fire/explosion risk, noise, vibrations, radiation (IR, UV, ra­dioactive, etc.), sunshine, loading on floors, and pressure differences (inside­outside and between rooms).

Requirements on building parameters that may influence the performance of the ventilation system and target levels to be determined are the following: emis­sions from surfaces; heat transfer coefficients; diffusion and leakage through walls, floors, ceilings, and windows; thermal needs; pressure difference’s; layout; stack height; natural ventilation—orientation, place, wrind directions, height, sur­rounding environment—floors, walls, ceilings, windows, doors, gates; floor and ceiling heating systems; sunshielding load; spreading around and close to the building; process conditions; and interference of one parameter with another.

The process itself often sets requirements on the ventilation parameters, and it also affects the ventilation—for example, by secondary flows coming from moving wires or trucks. A very special case is clean rooms, where the high purity requirements set strict target conditions for ventilation.

Equipment inside the building also often influences the ventilation para­meters. For example, some electrical equipment needs especially precise in­door conditions. The requirements of these parameters can be one decade stricter than the target levels for people working inside the building.

In industrial premises it is also important that the target level values are guar­anteed and that the ventilation system operation can be secured so that the process is not violated because of the ventilation. There are many examples where impor­tant fans have failed or important components have corroded, causing extensive losses for the company. In many cases the whole production plant has stopped.

A summary of essential items to be taken into account in determining the target levels is presented in Table 6.20. The table shows that the process is the main determining factor for industrial ventilation.

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