Abstract

According to ISO 7730:2005, classification is a mandatory precondition for thermal comfort assessment since the appropriate criterion depends on which category the specific work situation (SWS) investigated belongs to. Unfortunately, while the standard does include three different comfort criteria, it does not indicate how the appropriate criterion should be selected. This paper presents a classification scheme that allows thermal comfort assessment to be reliably performed in any environment. The model is based on an algorithm that calculates a score by means of a weighted product of three quantities, each one taking care of a specific, highly relevant element: the subject's thermal sensitivity, the accuracy required for carrying out the task and the practicality of thermal control. The scheme's simple modular structure can easily accommodate both changes and additions, should other hypothetical elements be identified to be as relevant to the classification scheme. The model presented allows a modulation of comfort levels across different social groups. It is so possible to provide extra care for children, elderly, pregnant women, disabled and other ‘weak’ categories, as required by ISO/TS 14415:2005, by setting the highest comfort level. Finally, it also widens the options for simultaneously establishing comfort conditions for different individuals performing different tasks in the same area and clarifies whose comfort should be pursued with the highest priority.

INTRODUCTION

Thermal comfort is unique among all specifications of comfort for physical and chemical risk factors, in that a long-standing technical regulation exists, which allows its assessment on solid objective bases. A single criterion for acceptability of global thermal comfort has been developed for use in any kind of environment, which may be expressed in terms of either the predicted mean vote (PMV) 

(1a)
graphic
or the predicted percentage of dissatisfied (PPD) 
(1b)
graphic

PMV is an index that predicts the mean value of the votes of a large group of persons on the seven-point thermal sensation scale ranging from cold (−3) to hot (3), based on the heat balance of the human body. PPD is an index that predicts the percentage of thermally dissatisfied, that is people who will vote hot, warm, cool or cold (−3, −2, 2 and 3) on the seven-point thermal sensation scale (ISO 7730:2005; ISO, 2005a).

Equations (1a) and (1b) were included in the international standard on thermal comfort ∼25 years ago (ISO 7730:1984; ISO, 1984) and has represented a universally accepted reference thereafter. This simple framework that most thermal ergonomists had become familiar with has been shattered by the latest edition ISO 7730:2005 (ISO, 2005a) which has removed the acceptability criterion [equation 1] from the main text, relegating quantitative comfort assessment to Annex A (informative) and introducing three fundamental changes:

  • there are now three criteria of acceptability instead of one. They have the usual form 

    (2)
    graphic

  • but Xj takes on different values (XA = 0.2, XB = 0.5 and XC = 0.7) under different circumstances;

  • the identification of the criterion to be applied to a specific work situation (meaning a given individual performing one or more tasks in a given thermal environment, hereafter SWS), depends on the category (A, B or C) it has been assigned to;

  • classification of the SWS into one of these three categories is not addressed in ISO 7730:2005 (ISO, 2005a).

This classification task is delegated to national or local regulations, which are requested to take on the responsibility of arranging a classification scheme, taking into due consideration their priorities, technical developments, as well as the climatic details of the interested area. In Olesen's (2006) original words: ‘The level of thermal comfort (at which to set thermal acceptability) may be influenced by what is technically possible, economy, energy use, environmental pollution and performance. Individual countries or a contract between client and designer can then specify which levels must be used’.

After >3 years, this has proven wishful thinking more than anything else, as neither individual states or regions nor European or national bodies have shown any enthusiasm over the drafting of rules for classification of thermal environments. The acceptability of thermal comfort in a given environment is today suspended in a sort of no-man's land.

In the absence of official indications, it is highly unlikely that contracts drafted between private parties will guarantee protection of workers at a level other than the minimum (Category C), with an effective regression compared to the pre-2005 situation.

This paper makes an attempt to draft a classification scheme which might represent a useful basis for future technical or legal documents on thermal comfort.

LITERATURE

The (limited) existing literature shows the existence of two lines of thought on the classification of thermal environments in the context of comfort assessment. Some documents (for example, Markov, 2002) support an a posteriori approach, in which the appropriate category is assigned based on the examination of existing conditions. This approach might be acceptable if the objective is to provide an energy performance class to the investigated building. However, it becomes meaningless in the context of comfort assessment. An individual performing a given task in a given environment should see his/her thermal comfort pursued regardless of how carefully the building is thermally managed. In simple words, classification is a prerequisite for assessment, and therefore it must be carried out a priori, not a posteriori.

Elsewhere (for example, Paevere and Brown, 2008), the approach consists in grading different categories in terms of higher or lower comfort, such as:

  • Grade A whole body PPD = good thermal comfort

  • Grade B whole body PPD = satisfactory thermal comfort

  • Grade C whole body PPD = poor thermal comfort

The two terms ‘satisfactory’ and ‘poor’ implicitly set the threshold of acceptability at the border between Category B and Category C. Given that the threshold of acceptability for Category B coincides with the classical limit [equation 1], this approach seems largely dictated by the desire to keep the evaluation framework unchanged, if not in form, at least in substance.

This approach is equally unsatisfactory. The three criteria included in ISO 7730:2005 (ISO, 2005a) are not aimed at quantifying different levels of comfort in the same environment, but rather at setting different comfort limits in environments with different requirements. In simple words, they all are acceptability criteria with equal strength.

DEVELOPMENT OF A CRITERION FOR CLASSIFICATION

Generalities

In this paper, a novel scheme for classification of thermal environments has been assembled, by recognizing and taking into due account three key elements, namely the ‘thermal sensitivity’ of the individual, the ‘accuracy’ required for the tasks which are carried out and the ‘practicality’ of thermal manipulation.

Thermal sensitivity of individuals

The thermal sensitivity of an individual is quantified through the descriptor FS. The quantity of FS is exclusively associated with the exposed subject and takes on higher values for individuals with a lower tolerance to non-ideal thermal conditions (ISO/TS 14415:2005; ISO, 2005b), including pregnant women, the disabled, as well as individuals whose age is outside the adult range (14 < y < 60 years).

The existing literature provides consistent evidence that sensitivity to hot/cold surfaces declines with age. How thermal sensitivity to environmental parameters (air temperature, radiant temperature and humidity) evolves with age is somewhat more controversial. However, there is some evidence of a gradual reduction in the effectiveness of thermoregulation above age 60 (Criqui et al., 2003; Kenney and Munce, 2003). This is mostly due to a more sluggish response of the counterreaction mechanisms that can be used by the human body to maintain the core temperature close to ideal values.

The evolution of thermal sensitivity with age (y) has accordingly been modelled with a hyperbolic functional form 

(3a)
graphic
for y >60. The same profile has been used for children (y < 14) 
(3b)
graphic

The shorter timescale that appears in equation (3b) simply reflects the more limited duration of the process in young individuals, where it is forcibly limited to 14 years, compared to old individuals. Table A1 lists the values of FS assigned to the various groups identified as entitled to special safeguarding.

The accuracy of the task

The accuracy of the tasks to be carried out is quantified through the descriptor FA. The quantity FA is exclusively associated with the activity undertaken and takes on higher values when higher work quality is required. In order to select the appropriate value of FA, we have adopted EN 12464-1:2002 (CEN, 2002) on lighting of indoor environments, as the primary basis.

The first three elements quoted by EN 12464-1 to support higher scores are as follows: ‘visual work is critical’, ‘errors are costly to rectify’ and ‘accuracy or higher productivity is of great importance’. Apart from purely visual aspects, which have been removed from consideration, the elements quoted by EN 12464-1 represent exactly the same rationale that we would like to see applied to thermal environments.

Table B1 lists the values of FA assigned to the various tasks identified.

The practicality of thermal manipulation

The practicality of solutions for thermal manipulation (air conditioning or heating) of the environment is quantified through the descriptor FT. The quantity FT is exclusively associated with the exposure location.

An articulation of the factor FT over several levels, although technically justified and indeed desirable, is also very discretional as are opinions on the higher or lower manipulability of any specific thermal environment. We have accordingly opted for a simple two-level scheme: FT = 10, if no serious hurdles to the establishment of comfort exist and FT = 5 wherever such hurdles do exist (see Table C1). The former is typical of newly built or planned buildings where the predicted needs of future occupants can be taken into due account, provided the building's destination of use is known. The lower values FT = 5 is more typical of existing buildings, where constraints often exist in the installation of heating, ventilation and air-conditioning systems.

Furthermore, in recognition of the fuzzy border between the two typologies of buildings, a two-step strategy is followed: the calculation is initially performed using the higher value FT = 10, assuming a fully adjustable environment. Then

  1. if this leads to classification of the SWS in Category A, this signals the existence of a highly sensitive case which we do not want to miss out; classification is confirmed and the process comes to an end;

  2. if this leads to classification of the SWS in Category C, any further lowering of the value of FT would be inconsequential (Category C is the lowest); the process also comes to an end;

  3. if this leads to classification of the SWS in Category B and there are well-founded elements supporting a limited thermal manipulability, a new calculation is carried out assuming the lower value FT = 5, and its outcome is then used for the final classification.

If thermal manipulation is impossible, then FT = 0, that is we are dealing with a ‘constrained’ thermal environment (Lenzuni and del Gaudio, 2007). These cases fall outside the scope of this paper since comfort cannot be realistically pursued and health protection becomes the dominant issue. Possible examples relevant to this paper's context are those buildings of particular historic interest where legislation explicitly prohibits any disruption or modification which may damage the historic and natural value of the property. In such buildings, thermal manipulation is forcibly very limited. It is recommended that any activity which is not strictly linked to the building itself should be carried out in other locations where thermal comfort could much more easily be achieved.

Classification algorithm

The overall score associated with any SWS is calculated by means of the algorithm 

(4)
graphic
where k = S, A and T (see sections Thermal sensitivity of individuals, The accuracy of the task and The practicality of thermal manipulation) and Pk is the weight associated to Fk. A weighted product has been selected as it shows a more acute sensitivity to individual variables compared to a weighted sum. In a weighted product, a single contribution close to zero determines a final result of similar small size, which is not the case for a weighted sum.

Each of the three quantities FS, FA and FT varies on a scale from 0 to 10. Because we are addressing comfort assessment, elements related to the individual have been given higher weights (see Table 1).

Table 1.

Quantities and weights included in the criterion for classification of thermal environments

 Descriptor Weight 
Thermal sensitivity of the individual 0 < FS ≤ 10 PS = 5/3 
Accuracy required for the task 0 < FA ≤ 10 PA = 4/3 
Practicality of thermal adjustment 0 < FT ≤ 10 PT = 1 
 Descriptor Weight 
Thermal sensitivity of the individual 0 < FS ≤ 10 PS = 5/3 
Accuracy required for the task 0 < FA ≤ 10 PA = 4/3 
Practicality of thermal adjustment 0 < FT ≤ 10 PT = 1 

It follows from equation (4) and from Table 1 that FC varies in the range (0–10000). Based upon the score FC, classification takes place as illustrated in Table 2.

Table 2.

Classification scheme

Category Criterion 
3000 < FC ≤ 10000 
500 < FC ≤ 3000 
0 < FC ≤ 500 
Category Criterion 
3000 < FC ≤ 10000 
500 < FC ≤ 3000 
0 < FC ≤ 500 

DISCUSSION

The pros

The key features of the scheme presented in this paper are:

  1. each of the three quantities FS, FA and FT carries information on a different element of the SWS, namely the individual, the task (or activity) and the environment, independently of one another. The modular structure of the model makes it simple to modify one element, should the treatment given be perceived as unsatisfactory or even adding a new descriptor if required, without affecting the others. In this sense, we have striven to keep with Albert Einstein's famous precept ‘a model must be as simple as possible but not simpler’;

  2. through the factor FS, it takes special care of specific groups, for whom of a higher level of thermal comfort is required.

  3. it is easier to manage situations which see the coexistence in the same physical environment of individuals who, owing to different clothing and/or different metabolic activity, have different thermal requirements. The problem has traditionally been 2-fold; it was not clear if there should be a privileged individual on whose comfort the thermo-hygrometric set-up of the environment had to be based, and, if so, how this individual should be identified; in addition, once this decision was made, the leverage to bring the others within the −0.5 ≤ PMV ≤ +0.5 range was limited.

In this new scheme it is the comfort of the individuals in Category A (or B, if A is absent) that dictates how the thermo-hygrometric parameters should be set. In addition, the margin to keep any hypothetical Category C individual within the borders of acceptability is somewhat wider.

The cons

None of the values shown in Tables A1, B1 and C1 is the result of a rigorous analysis based on physical or physiological considerations. Accordingly, such values are fully open to debate and may be subjected to future revision. It has to be kept in mind, however, that the relation between the factors FS, FA and FT and any physiologically or physically relevant quantity in the context of thermal comfort is very indirect; therefore, even our crude description of phenomena, such as the ageing of thermoregulation, might be adequate.

Borders between categories have been set so to match the expected results for some reference cases. On the other hand, it is hard to see any other guidance on this issue, which is of critical social relevance, but technically unapproachable.

Summary

Figure 1 shows how the activities listed in Table B1 distribute themselves among the three categories, with three different assumptions about FS and FT.

Fig. 1.

Fractional population of categories under different hypotheses (see text).

Fig. 1.

Fractional population of categories under different hypotheses (see text).

When dealing with individuals who do not belong in special groups (S = standard subjects, FS = 5) and in environments with high thermal manipulability (H = high), the overwhelming majority of SWS fall into Category B (∼92%), with a very small fraction in Category A (6%) (SH in Fig. 1). A close match to the outcome of a pre-2005 analysis is precisely what we expect in a case with no peculiarities.

The same subjects (S) in environments with low thermal manipulability (L = low) mainly fall into Category B (75%) with the remaining 25% fall into Category C (SL in Fig. 1). The impact of low manipulability is seen to be appreciable, but not overwhelming, as desirable, given that it would be inappropriate to massively downgrade comfort requirements just because of architectural constraints.

Finally, subjects who are entitled to particular protection (P = protected, FS = 10) operating in environments with high thermal manipulability (H) mainly fall into Category A (73%) and to a lesser extent into Category B (27%), with none falling, as expected, in Category C (PH in Fig. 1). This is where the impact of allowing extra protection of specific groups is most evident. While a fraction >73% in Category A, and indeed close to 100%, would be desirable, the result is an acceptable match to expectancies.

Table 3 gives some examples of classification, obtained from the data shown in Tables A1, B1 and C1.

Table 3.

Examples of classification

Subject/thermal manipulability SWS FS FA FT FC Category 
Standard/full Researcher 10 2339 
Standard/low Warehouse worker 464 
Standard/full Student in library 10 10 3150 
High protection/full 50-year-old patient with invalidating illness 10 1626 
High protection/full Pregnant box office assistant 10 5120 
Subject/thermal manipulability SWS FS FA FT FC Category 
Standard/full Researcher 10 2339 
Standard/low Warehouse worker 464 
Standard/full Student in library 10 10 3150 
High protection/full 50-year-old patient with invalidating illness 10 1626 
High protection/full Pregnant box office assistant 10 5120 

EXAMPLES

Example A

Several employees work in office, performing mostly sedentary work. Their age range is 30–65 years old. The building is new, and thermal control is easy to implement. Table 4 summarizes the values of all the relevant quantities in the classification scheme.

Table 4.

Office

Quantity Subjects
 
 30-year-old employee 65-year-old employee 
FS 5.45 
FA 
FT 10 10 
FC 1594 1840 
Category 
M (met) 1.2 1.2 
Icl (clo) 0.8 + 0.1 = 0.9 1 + 0.1 = 1.1 
ta = tr (°C) 22.7 21.5 
Final ta (°C) 22.0 22.0 
Final PMV −0.17 0.12 
Compliance OK OK 
Quantity Subjects
 
 30-year-old employee 65-year-old employee 
FS 5.45 
FA 
FT 10 10 
FC 1594 1840 
Category 
M (met) 1.2 1.2 
Icl (clo) 0.8 + 0.1 = 0.9 1 + 0.1 = 1.1 
ta = tr (°C) 22.7 21.5 
Final ta (°C) 22.0 22.0 
Final PMV −0.17 0.12 
Compliance OK OK 

The small difference introduced by the age spread does not alter the final classification which is Category B for all employees (Table 4, line 5).

Clothing resistance includes the effect of chairs (0.1 clo) and is assumed higher for older employees. Making standard assumptions on humidity and air velocity (RH = 50%, va = 0.1 m s−1), the temperatures that leads to PMV = 0 for each subject have been calculated (ISO 7730:2005; ISO, 2005a) and are shown in line 8.

The bottom part of Table 4 (lines 9–11) displays the temperature that provides the best overall compromise among the subjects’ requirements, the implied PMV and compliance (or lack of) with the appropriate limits.

Because the relevant parameters show limited variability, thermal acceptability can be easily achieved for all employees, by setting the temperature half-way between the individual preferences, possibly closer to the older individuals, who have a slightly higher FC score.

Example B

A nurse operates in a hospital room where a few 60- to 70-year-old individuals are seated. Table 5 summarizes the values of all the relevant quantities in the classification scheme, for each of the three different typologies of subjects (nurse, younger individuals and older individuals).

Table 5.

Hospital room

Quantity Subjects
 
 Nurse at work Seated 60-year-old patient Seated 70-year-old patient 
FS 5 + 2 = 7 6.7 + 2 = 8.7 
FA 10 
FT 10 10 10 
FC 3150 1626 2337 
Category 
M (met) 1.6 
Icl (clo) 0.8 0.9 1.1 
ta = tr (°C) 21.1 23.8 22.7 
Final ta (°C) 22.0 22.0 22.0 
Final PMV 0.18 −0.52 −0.19 
Compliance OK See text OK 
Quantity Subjects
 
 Nurse at work Seated 60-year-old patient Seated 70-year-old patient 
FS 5 + 2 = 7 6.7 + 2 = 8.7 
FA 10 
FT 10 10 10 
FC 3150 1626 2337 
Category 
M (met) 1.6 
Icl (clo) 0.8 0.9 1.1 
ta = tr (°C) 21.1 23.8 22.7 
Final ta (°C) 22.0 22.0 22.0 
Final PMV 0.18 −0.52 −0.19 
Compliance OK See text OK 

Two of the three SWS are classified in Category B and one in Category A. Similarly to Example A, the building can be easily air conditioned, so that the recalculation with a lower thermal control factor FT (section The practicality of thermal manipulation) is not implemented.

The temperatures that leads to PMV = 0 for each subject (line 8) have been calculated making standard assumptions on humidity and air velocity (RH = 50%, va = 0.1 m s−1), and show a larger variability (total range 2.7°C compared to 1.2°C in Example A). The bottom part of Table 5 shows that, since the nurse is the only one in Category A, the final thermo-hygrometric parameters are closer to her ideal set-up than to the average of other subjects. Thermal acceptability can be achieved for all the three investigated SWS, possibly requiring some marginal adjustment for the 60-year-old patient, whose PMV is very slightly above the threshold.

Example C

A theatre is populated by spectators, actors and technical/professional staff. Table 6 summarizes the values of the relevant quantities for classification, for the three associated SWS. If the initial assumption of full thermal manipulability is made (FT = 10), all three SWS fall into Category B. However, the structural characteristics of a theatre make it hardly amenable to thermal manipulability: there is no physical separation between the audience, backstage and the stage, and the stage is the only part of the entire open-space which is heated by lights/projectors.

Table 6.

Theatre

Quantity Subjects
 
 Actor Technical staff (backstage) Spectator 
FS 
FA 
FT 10 10 10 
FC 2339 1594 928 
Category 
FT 
FC 1170 797 464 
Category 
M (met) 1.8 1.4 
Icl (clo) 0.8–1.4 0.8–1.2 
ta = tr (°C) 15.0–20.0 20.8 22.2–24.4 
Final ta (°C) 18.5 18.5 21.0 
Final PMV −0.27 to 0.48 −0.46 −0.25 to −1.00 
Compliance OK OK See text 
Quantity Subjects
 
 Actor Technical staff (backstage) Spectator 
FS 
FA 
FT 10 10 10 
FC 2339 1594 928 
Category 
FT 
FC 1170 797 464 
Category 
M (met) 1.8 1.4 
Icl (clo) 0.8–1.4 0.8–1.2 
ta = tr (°C) 15.0–20.0 20.8 22.2–24.4 
Final ta (°C) 18.5 18.5 21.0 
Final PMV −0.27 to 0.48 −0.46 −0.25 to −1.00 
Compliance OK OK See text 

Accordingly, as detailed in section The practicality of thermal manipulation, the calculation of FC is repeated assuming a thermal control factor FT = 5, so to take into account the limited practicality of technical solutions. As summarized in the central part of Table 6 (lines 6–8), two of the three SWS remain in Category B, while one (spectators) slides to Category C.

The very large discrepancy between on-stage and off-stage requirements implies that two thermal zones must be created. On stage, a temperature of 18.5°C allows both staff and actors (for Icl up to 1.4 clo) to stay within the PMV limits.

Depending on the actual mean clothing, in consideration of the higher radiant temperature on the stage due to lights, a temperature tr 1–2°C lower in this area might also be considered.

Because of a lower metabolic activity and lighter dresses, spectators (women particularly) require higher temperatures, of order 22.5–24°C. A reasonable compromise is reached by setting initially ta = 21°C, which keeps PMV > −1 for all individuals. The heating effect induced by the concentration of individuals is expected to lift PMV during the performance, to fully compliant values.

CONCLUSIONS

The classification of the thermal environment where an individual performs a specific task is a fundamental prerequisite for comfort assessment. Only after an appropriate category (A, B or C) has been assigned to the (individual + task + location) ensamble, the correct acceptability criterion can be selected among those listed in ISO 7730:2005 (ISO, 2005a) and comfort assessment be pursued. Unfortunately, ISO 7730:2005 (ISO, 2005a) does not tackle the issue of classification, which leaves the entire process suspended in some sort of limbo.

This paper tries to fill the void, by proposing a classification scheme which can hopefully represent a basis for the development of future normative documents.

The classification algorithm takes into account the individual thermal sensitivity, the task accuracy and the thermal manipulability of the building. Thanks to its modular structure, this scheme is open to future changes and/or additions.

THERMAL SENSITIVITY OF INDIVIDUALS

Table A1.

Classification of individuals

Individual Sensitivity factor FS 
Age y <14 years forumla 
Age y >60 years forumla 
Disabled and affected by motor disabilities 10 
Pregnant women 
All others 
Affected by pathologies which reduce thermoregulation 
Individual Sensitivity factor FS 
Age y <14 years forumla 
Age y >60 years forumla 
Disabled and affected by motor disabilities 10 
Pregnant women 
All others 
Affected by pathologies which reduce thermoregulation 

ACCURACY REQUIRED FOR THE TASK

Table B1.

Classification of activities

Activity Accuracy factor FA 
Artisans  
    Manual worker 
    Specialist manual worker 6/8a 
    Manual worker in health-threatening activities 
    Cleaner 
    Wardrobe assistant 
    Main room assistant 
    Doorman/guard 4/6a 
    Security guard 6/8a 
    Warehouse worker/goods loader 
    Barber 
    Beautician 
    Designer 
    Hairdresser 4/6a 
    Goldsmith 6/8a 
    Tailor 6/8a 
    Florist 
    Decorator/restorer 6/8a 
    Baker/patisserie 
    Optician 
Commercial activities  
    Shop/sales assistant 
    Cashier 6/8a 
    Technical investigation expert in health-threatening activities 6/8a 
    Customer 
Industrial activities  
    Manual worker 
    Specialist manual worker 6/8a 
    Manual worker specializing in processes which bring particular health risks 
    Laboratory/production staff 
Services, public administration, research bodies  
    Highly intellectual, scientific and specialist professions 10 
    Driver/bus, tram, metro, taxi driver 8/10a 
    Manager/entrepreneur/director 8/10a 
    White collar staff 6/8a 
    Staff in direct contact with general public 6/8a 
    Technician in sciences, engineering etc. 
    Secretary 4/6a 
    Switchboard operator 4/6a 
    Bank employee 6/8a 
    General public/customers 
Shows, theatres, cinemas, recording studios, TV  
    Actor/journalist 
    Specialist artisan (e.g. costumier/make-up artist etc.) 6/8a 
    Spectator 
    Director/scenographer/sound recordist/director's assistant/editor 
    Room security/guide/hostess 
    Ticket office staff 
Schools and studies  
    Librarian 6/8a 
    Student/teacher (library) 10 
    Teacher/pupil 
    Cleaner 
Hospitals, healthcare centres  
    Family doctor 6/8a 
    Specialist doctor 6/8a 
    Surgeon (operating theatre/emergency ward) 10 
    Specialist nurse 8/10a 
    Nurse/stretcher bearer 4/6 
    Physiotherapist 6/8a 
    People waiting for treatment 
Airports, stations, metro  
    Check-in staff/security staff/ground staff 10 
    Ticket office staff /information points 
    General public 
Accommodation  
    Receptionist/tour guide 
    Customers/tourists/guests 
Entertainment centres/sports events  
    Spectator/customer 
    Sports person 
    Sports coach 6/8a 
Prisons  
    Prison guard 6/8a 
    Prisoner 
Canteen, restaurants, bars  
    Cook/kitchen staff 6/8a 
    Customer 
Activity Accuracy factor FA 
Artisans  
    Manual worker 
    Specialist manual worker 6/8a 
    Manual worker in health-threatening activities 
    Cleaner 
    Wardrobe assistant 
    Main room assistant 
    Doorman/guard 4/6a 
    Security guard 6/8a 
    Warehouse worker/goods loader 
    Barber 
    Beautician 
    Designer 
    Hairdresser 4/6a 
    Goldsmith 6/8a 
    Tailor 6/8a 
    Florist 
    Decorator/restorer 6/8a 
    Baker/patisserie 
    Optician 
Commercial activities  
    Shop/sales assistant 
    Cashier 6/8a 
    Technical investigation expert in health-threatening activities 6/8a 
    Customer 
Industrial activities  
    Manual worker 
    Specialist manual worker 6/8a 
    Manual worker specializing in processes which bring particular health risks 
    Laboratory/production staff 
Services, public administration, research bodies  
    Highly intellectual, scientific and specialist professions 10 
    Driver/bus, tram, metro, taxi driver 8/10a 
    Manager/entrepreneur/director 8/10a 
    White collar staff 6/8a 
    Staff in direct contact with general public 6/8a 
    Technician in sciences, engineering etc. 
    Secretary 4/6a 
    Switchboard operator 4/6a 
    Bank employee 6/8a 
    General public/customers 
Shows, theatres, cinemas, recording studios, TV  
    Actor/journalist 
    Specialist artisan (e.g. costumier/make-up artist etc.) 6/8a 
    Spectator 
    Director/scenographer/sound recordist/director's assistant/editor 
    Room security/guide/hostess 
    Ticket office staff 
Schools and studies  
    Librarian 6/8a 
    Student/teacher (library) 10 
    Teacher/pupil 
    Cleaner 
Hospitals, healthcare centres  
    Family doctor 6/8a 
    Specialist doctor 6/8a 
    Surgeon (operating theatre/emergency ward) 10 
    Specialist nurse 8/10a 
    Nurse/stretcher bearer 4/6 
    Physiotherapist 6/8a 
    People waiting for treatment 
Airports, stations, metro  
    Check-in staff/security staff/ground staff 10 
    Ticket office staff /information points 
    General public 
Accommodation  
    Receptionist/tour guide 
    Customers/tourists/guests 
Entertainment centres/sports events  
    Spectator/customer 
    Sports person 
    Sports coach 6/8a 
Prisons  
    Prison guard 6/8a 
    Prisoner 
Canteen, restaurants, bars  
    Cook/kitchen staff 6/8a 
    Customer 
a

The adequate score should be selected, taking into account the degree of attention and accuracy which is actually required for the specific task undertaken.

PRACTICALITY OF THERMAL CONTROL

Table C1.

Classification of buildings

Environment Thermal control factor FT 
Full manipulability 10 
Limited manipulability 
Environment Thermal control factor FT 
Full manipulability 10 
Limited manipulability 

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