Sharp JX-9400 Información técnica descargar pdf (Pagina 138)

pollution of concentrations of 2-propanone unknown to them by making

comparison with the milestones. On the third, fourth and ﬁfth days, training

includes 2- propanone concentrations and other sources of pollution. Since

the pollutants have diﬀerent characters to 2-propanone it is of great importance

that the subjects understand that they are exposed to the intensity by

comparing the intensity of the milestones. Up to 12 diﬀerent concentrations

of pollutants are presented each training day.

After the evaluation of each unknown concentration of 2-propanone, the

panel member is given the correct answer and their performance is discussed

with the experiment leader. The panel members write their votes on a form

where it is possible to follow their performance during the training. Panel

members are submitted to a test similar to the selection test at the end of the

third and ﬁfth training days. If they do not succeed, they should either quit

the panel or train for two additional days.

Experimental day

On each experimental day, the panel members are retrained for approximately

15–20 minutes per group of three to four people. During this training the panel

members are exposed to two or three diﬀerent concentrations of 2-propanone

and two diﬀerent materials, on which they receive feedback.

Also on each experimental day, the panel members are exposed to six

diﬀerent concentrations of 2-propanone corresponding to the values 1, 3, 7,

12, 16 and 19. The concentrations of 2-propanone should be meas ured just

before the sensory assessments of each group of panel members. These expo-

sures make it possible to compare diﬀerent sensory panels and to calculate

performance factors.

The panel members are placed in a well-ventilated waiting room. During

each round of assessments, one by one the subjects assess the intensity of the

perceived air pollution of the air sample (fro m a material in a PAP meter, in

a walk-in climate chamber, air from a ventilation system and so on) by

making comparison with the intensity of the milestones. The panel members

are allowed to go back and forth between the milestones and the polluted air

sample. The members write down their assessment on a voti ng sheet , which

is handed to the experiment leader before making the next assessment.

The time between assessments or each panel member should not be less

than three minutes. An experienced panel member can assess an air sample

within 30–45 seconds. With a panel of 12 subjects the time between assessments

for a panel member will be approximately nine minutes, and for a group of four

panel members three minutes.

Contaminant transport in rotating heat exchangers

Principle of the method

A heated VOC mix is injected in the extract duct (star in Figure 6.10), in such a

way that the VOCs are well evaporated and mixed into the air at location C

Contaminants in Air Handling Units 117

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