BRUEL & KJAER 1212 User manual

Instruction Manual
Thermal Comfort Meter Type 1212
A portable instrument for measuring the ef-
fect
of the thermal environment on human
comfort by simulating the thermal balance
of the human body. It consists of a heated
Transducer having the same ratio
of con-
vective to radiant heat emittance as a hu-
man body, and similar directional character-
istics. The Transducer surface is heated to
the same temperature as the clothing
of a
person clothed as set on the controls
of the
instrument. The heating power supplied
to
the Transducer is then used to compute
electronically PMV, PPD and other quanti-
ties related to comfort. The Thermal Com- .
fort Meter has a liquid-crystal digital display
and three outputs suitable for feeding to a
recorder. It is designed for taking measure-
ments quickly and easily
on site. It may be
powered from built-in batteries,
an optional
slide-in mains power supply,
or an external
DC supply.
+ Brliel & Kjcer

THERMAL COMFORT METER
TYPE 1212
From serial number 961484
Revision
November 1986

CONTENTS
1. INTRODUCTION AND SPECIFICATIONS {PRODUCT DATA) .............................................................................. 1
2. CONTROLS..................................................................................................................................................................5
2.1. FRONT PANEL........................................................................................................................5
2.2. REAR PANEL ..........................................................................................................................6
3. OPERATION .................................................................................................................................................................8
3.1. PRELIMINARY ........................................................................................................................8
Environment and Handling....................................................................................................8
Mounting ..................................................................................................................................9
3.2. CHOICE
OF POWER SOURCE ............................................................................................9
Alkaline Batteries...................................................................................................................9
Rechargeable Batteries.......................................................................................................10
Installing Battery Cells.........................................................................................................10
Mains Power Supply ZG 0199 ............................................................................................ 12
Battery Charger ZG 0113 .................................................................................................... 13
External DC .......................................................................................................................... 13
3.3. CHECKING THE CALIBRATION OF THE THERMAL COMFORT METER.................... 14
3.4. THERMAL COMFORT MEASUREMENTS ........................................................................ 15
Setting up the Transducer.................................................................................................. 15
Choosing Values for Preset Parameters .......................................................................... 15
Obtaining Readings ............................................................................................................. 19
Equivalent Temperature Accuracy..................................................................................... 21
Measuring Air Velocity and Mean Radiant Temperature................................................ 21
3.5. CLEANING THE THERMAL COMFORT TRANSDUCER MM 0023 ................................ 21
3.6. USING THE OUTPUT SOCKETS........................................................................................ 22
Portable Graphic Level Recorder Type 2317 ................................................................... 25
Portable Graphic Level Recorder Type 2309 ................................................................... 27
4. SERVICE AND REPAIR............................................................................................................................................ 28

type 1212
Thermal Comfort Meter
USES: FEATURES:
• Measurement of the quality of indoor thermal
environments • Combines
all thermal comfort factors: air
temperature, mean radiant temperature, air
velocity, humidity, and clothing and activity level
• Measurement
of PMV (Predicted Mean Vote)
• Measurement of PPD (Predicted Percentage of
Dissatisfied)
• Dial-in facilities for clothing, activity and water
vapour pressure levels
• Measurement of Operative and Equivalent
Temperatures
• Indication of PMV, PPD or Operative, Comfort,
Equivalent or Difference Temperature selectable
• Determination of heating and air-conditioning
system performance
• Measurements for standing or seated comfort
• Compact heated sensor with short setting-time
• Evaluation of thermal comfort conditions in
aircraft, trains, buses and other transport
environments
• 3-digit liquid crystal display
• Three recorder outputs
Introduction
The Thermal Comfort Meter Type
1212 is a direct-reading instrument for
determining the effect on human com-
fort
of the thermal characteristics of
indoor environments. It is suitable for
use
both in buildings and also in air-
craft,
trains and other vehicles with
their own enclosed thermal environ-
ments.
It conforms to the require-
ments of ISO 7730, "Moderate ther-
mal environments - Determination
of the thermal indices PMV and PPD
and assessment of thermal environ-
ments for comfort".
Thermal comfort is a function not
only of air temperature, but also of
five other, less obvious parameters:
mean radiant temperature, air veloci-
ty,
humidity, activity level, and the
thermal resistance of clothing. When
any combination of these factors satis-
fies
the Comfort Equation derived by
Prof. P.O. Fanger,
the thermal com-
fort
of a majority of individuals can be
stated to be neutral. The Type 1212
measures
three of these parameters
(air velocity, air temperature, and
mean radiant temperature), and com-
putes in usable form a quantitive mea-
sure
of comfort, taking account of di-
alled-in values
of the other three pa-
rameters.
BP 0251-13
• Powered from built-in batteries, with mains power
optional
The Thermal Comfort Meter is a
portable,
battery-powered instrument
which senses environmental condi-
tions via
the Comfort Transducer
MM 0023. This Transducer is elec-
tronic in its
operation and is connect-
ed by a cable. It may be mounted on a
normal lightweight
photographic tri-
pod (a
Tripod Adaptor is included and
a tripod can be supplied as an optional
accessory), and is used in one of two
orientations corresponding to stand-
ing and seated people. The MM 0023
incorporates a controlled heat source
and in this and other respects models
the static thermal properties of a hu-
man being. It is sufficiently compact
and fast-acting for every-day use on
site, away from
the laboratory.
Measurements made with the Ther-
mal Comfort Meter may be read di-
rectly on
its liquid crystal display or
logged on a
strip-chart recorder such
as
Types 2317 or 2309 from B & K.

A human being is said to be ther-
mally comfortable when he cannot
say whether he would prefer cooler or
warmer surroundings. In the range of
moderate environments which the
B & K Thermal Comfort Meter is de-
signed
to measure, this condition is re-
lated to the equilibrium resulting from
heat generated within the body and
transferred to the environment by con-
vection,
radiation and evaportation of
moisture. The principles on which the
Meter is founded have been developed
in a
number of independent laborato-
ries, most notably
the Heating and Air
Conditioning Laboratory
of the Techni-
cal University
of Denmark. A thermal-
comfort
meter patent taken out by the
University in the name of T.L. Madsen
is now held by B & K. Research into
thermal comfort has relied on extensive
and thorough tests with large numbers
of volunteers, including members of
both sexes and a variety of different
ethnic
and age groups.
The PMV (Predicted Mean Vote) scale
ranges from
-3 (Cold) to + 3 (Hot). The
Thermal Comfort Meter can calculate
the PMV valu~ in the range -2,2 to
+2,2 from the measured and preselect-
ed parameters , using methods based on
the Comfort Equation of Prof . P.O.
Fanger (Technical University of Den-
mark). An indicator
of additional prac-
tical value, also
computed by the Type
1212, is the PPD (Predicted Percentage
of Dissatisfied), which is derived from
the PMV as shown in Fig. 1 and also
owes
its origins to Fanger's work.
The Operative Temperature (°C) is
the value of air temperature which
Description
The system configuration of the
Thermal Comfort Meter Type 1212 is
shown in Fig.
2.
Display and Controls
The Type 1212 has a liquid crystal
digital display which
can be switch-
selected
to indicate one of the six dif-
ferent
quantities listed in Fig. 2.
These terms are explained in the box
above.
The two important parameters to be
preset
are the thermal insulation of
the clothing, expressed in clo, and the
activity level, expressed in met. A
Thermal Data Card to enable these
quantities to be estimated is supplied
with the 1212. The vapour pressure
should also be preset.
This is a func-
tion of the air temperature and the
relative humidity, and may be esti-
mated as its influence on the measure-
ment is secondary.
2
%
80
60
Q)
40
E
c:
CU-
30
~]
O...'t;
N · ~
20
(.)"'
:go
~0
0
0...
0...
10
"""
"'
/~
'
~
/ ,
" /
~i\.
/~
\ I
\. /
8
6
'"
/
5 - 2,0
Cool - 1,5
-0 ,5 ' v
0
Neutral 0,5 1,5 2,0
Warm
-1,0
Slightly
cool PMV (Predicted
Mean Vote)
1,0
Slightly
warm
811406
Fig. 1. The relationship between PPD and PMV
would result in the same heat loss from
a person by convection
and radiation as
in the actual environment, if the air
temperature and mean radiant tem-
perature were equal. It integrates the
influence of the air and mean radiant
temperatures.
The Equivalent Temperature (°C)
of an environment is the temperature of
the air and all the interior surfaces in a
reference environment in which
the air
is still
and the temperature has been
adjusted to obtain the same heat loss
from a person by convection
and radia -
tion as that person experiences in the
actual environment. When this condi-
tion is satisfied, then the Equivalent
Temperature of the actual environment
is
the same as the air temperature in the
reference environment.
The Comfort Temperature (°C) is
the value of Equivalent Temperature
required to achieve thermal comfort
when
the clothing, activity level and hu-
midity are given.
The Difference Temperature (K) is
a measure
of the amount by which the
temperature of the measured environ-
ment should be altered so that a person
with
the metabolic activity and clothing
insulation
set on the front panel con-
trols will feel thermally comfortable.
It
is equal to the Comfort Temperature
minus the Equivalent Temperature.
,---------------,
I s 7 I
.,.+---1!---J IOutputs
1-
I
I ing
Amplifier
Display
PMV
!Displayed
Value
I
I
I o
I I
~..-.-.. ________________ _
Comfort
Temperature
Function:
1-0ff; 2-0p _erative Temperature; 3-Comfort Temperature; 4- Equivalent Temperature;
5- Difference Temperature;
6- PMV;
7- PPD
811080
Fig. 2. System diagram of the Type 1212
Transducer
The Thermal Comfort Transducer
MM 0023 (Fig. 3) has a simple ellip-
soidal
shape with a circular section in
plan. It contains a surface tempera-
ture sensor, and a heating element
whose output is adjusted automatical-
ly to warm the surface to a tempera-

Fig. 3. The Thermal Comfort Transducer
MM 0023 in its mahogany case
ture similar to that of a thermally
comfortable human being clad as pre-
set on the instrument front-panel
Clothing switch. The rate of heat pro-
duction needed to attain this tempera-
ture is used as a measure of the envi-
ronmental conditions. Since the heat-
ing element is located in the surface
layer
of the Transducer, the device
reaches
rapid thermal equilibrium
with its environment and enables suc-
cessive
measurements under different
conditions to be taken fairly quickly.
The lower limiting value of clothing
thermal insulation for which measure-
ments may be made is shown in Fig. 4
as a
function of Equivalent Tempera-
ture (above 15°C, measurements can
be made with all available clothing
values).
Heat loss from a human being oc-
curs by
radiation, convection and
evaporation. The effective radiant
surface area is typically 30 % smaller
than the convective surface area be-
cause
of reciprocal radiation exchange
between
re-entrant parts of the body,
for example
between the insides of the
legs. The two effective areas are equal
for the Thermal Comfort Transducer,
but because it is smaller than a human
body, its convective heat emission per
unit area is greater. The size and sur-
face finish of the Transducer are
therefore carefully selected to achieve
the same ratio of convective to radiant
heat emission as for a human being.
Briiel & Kjcer
Measurement Object /.. 0 J(· nr. J I( 7
Outside
2,0 Minimum
Clothing
(clo)
measurement -t---'---t-':.....------t---t---1
range
0,5
0 so
Equivalent Temperature 817761
Fig. 4. Graph showing the lower limiting
value of clothing thermal insulation
for which valid measurements may
be taken with the Type 1212, as a
function
of Equivalent Temperature
The shape of the Transducer is de-
termined by the need to obtain the
same ratio of horizontal and vertical
projected radiant surface areas as for a
human being. For a standing person
these two areas are very different.
There are also likely to be significant
differences
between horizontal and
vertical radiation temperatures, for
example where lighting
makes a sig-
nificant contribution to the radiant
heat, or where the ceiling constitutes
an active part of heating or air-condi-
tioning
plant. On the other hand the
difference between the side and fron-
tal radiant surface areas do not justify
the extra complication in construction
and use of a transducer with three
differentiated axes.
Additional Facilities
The Thermal Comfort Meter is pro-
vided with
three analogue voltage out-
puts for connection to a strip-chart
recorder . Two of the outputs carry di-
rect voltages proportional to Comofrt
Temperature and PMV respectively.
The third carries a direct voltage pro-
portional to the quantity selected on
the display. The Comfort Tempera-
ture output is used for calibrating the
recorder. Suitable recorders are B & K
Type 2317 for single-channel record-
ing (Fig. 5),
and Type 2309 for two-
Fig. 5. Portable Graphic Level Recorder
Type 2317
channel work. An example of a record-
ing is shown
in Fig. 6.
The 1212 is supplied with six non-
rechargeable alkaline cells of a popu-
lar size, contained in a detachable bat-
tery-box (see Fig. 7).
These may be
replaced by rechargeable NiCd cells
(available
to order) if required, which
can be recharged in situ using Battery
Charger ZG 0113 (also available to or-
der)
or any suitable DC power source.
A
Mains Power Supply ZG 0199 is
available
to enable the Type 1212 to
be powered continuously from the AC
mains. This may be installed in the
rear panel Supply Compartment in
place
of the battery box, but it may
also be used externally, for powering
the 1212 and/or charging rechargeable
batteries. Provision is also made to
power the 1212 and/or recharge bat-
teries from a suitable DC supply.
Fig. 7. Rear panel of the Type 1212, show-
ing
the battery box installed
•••• •••••••••• • •••••• •• •••••••••••••••••••
Writing Speed~~/'
••••••• • ••••••
QP 0270 Calibration :
Upper Limit ,, '"k
Lower Limit - ~k Unit
oc 0
K@'
%0
toO teqO
tdifU{I>MvO PPD 0
8 Hour Recording 1 lei o16 clo 2
M~met3
Pa
1,.:>
kPa 4 tcomf .t0,3°C
5
Start Time 0100
6 Date .tl!lo/1/ 7 Signature
'l!.Jint436
Fig. 6. Example of graphic recording made using the Thermal Comfort Meter with the Type 2317 Recorder
3

Applications
The Thermal Comfort Meter has
wide application to the field of heating
and air-conditioning in buildings and
vehicles. With the help of the 1212,
maximum performance can be ob-
tained with minimum energy con-
sumption. It is ideal for measuring the
characteristics of existing system-s to
enable new designs to be optimised. It
can be used by installers to balance
newly-commissioned heating or air-
conditioning
equipement. · Plant engi-
neers will find a
Thermal Comfort
Meter of benefit in keeping a check on
the running performance of syste ms
for which
they are responsible, and for
arbitrating in disputes over comfort
conditions. Designers of window and
insulation systems can use the instru-
INDICATIONS:
Opetative Temperature: -1 oo to + 40°C
± 0,5°C
Comfort Temperature: -20 ° to + 32 °C
± 0,5 oc
Equivalent Temperature: -12 ° to + 32 °C
± 0,5 oc. Lower limit subject to conditions as
shown in Fig.4
Difference Temperature: -20 K
to + 20 K
PMV:
-2,2 to + 2,2
PPD: 5
to 90%, maximum resolution 0,1%
Display:
3-digit liquid crystal type , 16 mm
(5/s in) characters
PRESET QUANTITIES:
Clothing: 0,0
to 2,0 clo (0 to 0,31 m2° C/W).
For lower limiting value as a function of
Equivalent Temperature, see Fig. 4
Activity: 0,8
to 4,0 met (46 to 232 W/m
2)
Vapour 'Pressure: 0,3 to 3,6 kPa (3 to 36
mbar)
RECORDER OUTPUTS:
Comfort Temperature: 0,1 V per °C, -2,0 to
+3,2 v
Displayed Value: 0,1 V per °C, 0,1 V perK ,
0,05 V per %, 1 V per PMV unit
PMV: 1 V
per unit, -2,2 V to + 2,2 V
Impedance: Source <50 Q, minimum load
impedance 10 kQ
Connector: Standard BNC type, accepting
plug JP 0035
POWER SOURCES:
Battery: Approximately 10 hours' operation
from 6 alkaline batteries, QB 0004, to IEC
R 20 dimensions (D size), in plug -i n battery
ment to monitor the effectiveness of
their product s. It is especially valuable
in difficult
heating and air-condition-
ing
applications such as indoor sw im -
ming-pools,
indu st rial clean-rooms
and hospital o perating -t heatres. Em -
ployers who provide special clothing
for
staff such as electronics assembly
and food-processing personnel can use
the 1212 to optimise the garments for
the actual working conditions. Al-
though it is designed primarily for
taking mea s urements, some of the
voltages available on the outputs of
the Thermal Comfort Meter could be
used as control
inputs for heating or
air-co nditioning systems, on a trial or
experimental basi s.
Specifications 1212
pack ZG 0146 (all supplied), or rechargeable
NiCd batteries of the same dimensions such
as QB 0008 (available
to order). Battery
charger ZG 0113 for recharging from
100-130 I 200-240 V AC mains (50 to 400 Hz)
available to order
Mains: Mains Power Supply ZG 0199 for con-
tinuous operation from 100, 115, 127, 220 or
240 V AC mains (50 to 400 Hz) available to
order
External DC: + 6 to + 15 V DC, max. 1A, to
power the instrument. + 9 to + 12 V DC, 0,1 to
0,4 A to recharge installed rechargeable bat-
teries. Ext. supplies, i nternal batteries and
Transducer heater electrically isolated from
measuring circuits, outputs a.nd all other ac -
cessible metalwork
WEIGHT:
2,4 kg (5,3 lb)
DIMENSIONS:
Height: 133 mm (5,2 in)
Width: 210
mm (8,3 in)
Depth: 200
mm (7,9 in)
ENVIRONMENT:
Operating Temperature Range: + 5° to
+40 °C (+41 ° to+ 104°F). Transducer down
to -15 °C (+ 5° F)
Storage Temperature Range: -25 ° to
+70 °C (-13 ° to +158 °F)
Humidity: 0 to 90% non-condensin _g
Electromagnetic Compatibility: Complies
with U.S. FCC requirements for Class B Com-
puting Device
Fig. 8. The Thermal Comfort Meter being
used to meas
ur e conditions in a
public
swimming bath
COMFORT TRANSDUCER MM 0023:
Weight: 230 g (8 oz)
Length: 160
mm (6,3 in), excluding handle
Diameter: 54 mm (2 ,1 in)
Warm-up Time: Typically 10 to 15 minutes
after application of heating-power to the
Transducer; much less for small changes in
environment or clothing setting
Electrical: Connect ion to Type 1212 by 3 m
cable with plug JP 0408
ACCESSORIES SUPPLIED:
Thermal Comfort Transducer ............ MM 0023
Tripod Adaptor ......................................UA 0588
Battery Box .... ........ .... ....... .. .................... ZG 0146
6 Alkaline cells, IEC R 20 size .......... .. QB 0004
Standard 7-pin DIN plug for ext.
power connections .... . .. ....... .. .................JP 0703
2 spare 2 A fuses .. .... ............................. VF 0010
Thermal Data Chart ............................ .. BR 0231
ACCESSORIES AVAILABLE:
6 m Extension Cable for MM 0023..... AQ 0358
1 ,2 m BNC cable (for recorder
etc.)........................................................... AO 0087
Recording Paper.......................... ... ....... QP 0270
Rechargeable NiCd cell (6 re-
quired)
.. .. ................. .. ................. .. ........ .... QB 0008
Battery Charger .... ....... .. ........................ZG 0113
Mains Power Supply .. ........................... ZG 0199
Charge/Power cable .............................AQ 0035
Portable tripod ................................ .... ... UA 0587
Mahogany cabinet ................................. KA 0063

2.1. FRONT PANEL
0,5 0.6
0 ,3
0.2
Clothing
(clo1
CLOTHING:
ACTIVITY:
VAPOUR PRESSURE:
FUNCTION:
2. CONTROLS
nn~
- Lif.Lf ·.f:-
• o;,, ~·
BrUei&Kjar
,2
1.8 ~.0
o.a 4.0
Ac1Mty
(met)
0,.3 3,8
Vapour ,.,._,"'
(k Pa)
Fig. 2. 1. The front panel of the Type 1212
12-position switch for selecting the thermal insulation of the clothing.
Graduated in clo-values between 0 and 2,0.
12-position switch for selecting the activity level. Graduated in met
from 0,8 to 4,0.
12-position switch for entering the partial water vapour pressure in the
air. Graduated in kPa
from 0,3 to 3,6. (1 kPa = 10 mbar.)
7
-position switch for selecting the function to be indicated on the liq-
uid crystal DISPLAY and fed to the "Displayed Value" rear-panel OUT-
PUT, as listed below. The
terms are explained in Chapter 1. When any
of the five positions to the right (joined by a line) is selected, power is
fed
to the Transducer.
Power Off: The
instrument is switched off.
Oper. Temp.: Operative Temperature.
Comf. Temp.: Comfort Temperature (transducer is powered).
Equiv. Temp.: Equivalent Temperature
(transducer is powered).
5

DISPLAY:
2.2. REAR PANEL
Dif. Temp.: Difference Temperature
(transducer is powered).
PMV: Predicted Mean Vote (transducer is powered).
PPD: Predicted Percentage of Dissatisfied (transducer is powered).
3-digit liquid crystal display which reads out the quantity selected with
the FUNCTION switch. It also gives a warning
if the battery voltage is
low (5,6 V or less), or the indication is invalid because any of the pa-
rameters is out of range. (This will usually occur while the Transducer
is warming up.)
Fig. 2.2. The
rear panel of the Type 1212
TRANSDUCER INPUT:
Socket for connection of the Thermal Comfort Transducer MM 0023.
Accepts standard 4-pin DIN plug JP 0402. The connections are as
shown in Fig. 2.3.
6
Temperature
sensor
811159
Fig. 2.3. Pin connections for the TRANSDUCER INPUT socket, as
viewed from outside the cabinet

OUTPUTS: Three standard BNC sockets accepting plug JP 0035 for connection to
a
recorder or any other suitable device.
Comfort Temperature:
+100 mVfCC, -2,0 to +3,2 V. This output is al-
ways available when the instrument is switched on.
Displayed Value:
+100 mV/°C, +100 mV/K, +50 mV per% (max. valid
output +4,4 V), +1 V /PMV unit.
PMV: +1 V
/PMV unit. This output is disconnected whenever the combi-
nation of front-panel settings is such that it would not be valid.
SUPPLY COMPARTMENT:
Accepts Battery Box ZG 0146 (supplied) or Mains Power Supply
ZG 0199 (optional extra) for powering the instrument.
FUSE: Fuse-holder accepting 2 A slow-blow fuse to IEC 127 Ill, VF 0010. See
section 3.2.6.
POWER/CHARGE INPUT:
Socket accepting standard 7 -pin DIN plug JP 0703 or JP 0710 (with
screw-locking collar). For recharging NiCd batteries if these are in-
stalled in place of the alkaline types supplied, and/or powering the
instrument whether or not batteries are installed. The connections are
shown in Fig. 2.4. These
connections are electrically isolated complete-
ly from the measurement circuits, the OUTPUT sockets and all other
exposed metalwork, but not from pins 1 and 4 (the heater supply) of
the TRANSDUCER INPUT SOCKET. This isolation is provided in order
to facilitate the use of more than one instrument with the same power
source; no guarantee is given about its ability to withstand potentially
hazardous voltages. See section 3.2.6.
WARNING! Read the power supply instructions in section 3.2 before
attempting to use the Thermal Comfort Meter.
Charge Input
Max. 12 V 0,4 A External Power
6
to 12 V DC
8-____.__--8
811160
Fig. 2.4. Pin connections for the POWER/CHARGE INPUT socket, as
viewed from outside the cabinet. All connections are isolated
from chassis and other sockets
7

3. OPERATION
3.1. PRELIMINARY
3.1.1. Environment and Handling
8
Thermal Comfort Meter Type 1212 is a readily transportable instrument designed to be
operated in environments in which the temperature does not fall outside the range +5°
to +40° C (+41 o to +104 oF) and the humidity does not exceed 90% RH (non-condensing).
The Thermal
Comfort Transducer MM 0023 can be operated in ambient temperatures
down to -15°C (+5°F).
Other than observance of the instructions relating to power sources, no special handling
precautions are necessary for the Type 1212 itself. However the Thermal Comfort Trans-
ducer MM 0023 should be treated with care and returned to its mahogany case when it
is not in use. The validity of measurements taken with it depends on preservation of the
integrity of its surface, which should not be allowed to become excessively dirty, dusty,
oily or damaged by hard or abrasive objects. The cleaning procedure, which should only
be performed if essential, is described in section 3.5.
Fig.
3. 1. The Thermal Comfort Meter Type 1212 tilted for use on the
bench

3.1.2. Mounting
The 1212 is
designed to fit into the B & K Module System. It may be used free-standing
on
its four plastic feet or, more conveniently when it is used on the bench, tilted by
means of the metal stand attached to the front pair of feet (Fig. 3.1 ). It may be mounted
in an individual mahogany cabinet KA 0063, which includes a lid, provides additional
protection and helps to preserve the instrument in its as-new condition (Fig. 3.2); or
installed in carrying-case KA 2004 with other B & K instruments. In the case of the ma-
hogany cabinet, the feet should be unscrewed first, and then refitted after installation
with the adaptors YG 0160.
Tbennal Comfm M•t.,. TJ!l<' 1212
Fig. 3.2. The Thermal Comfort Meter installed in a mahogany cabinet
3.2. CHOICE OF POWER SOURCE
The Thermal Comfort Meter is supplied with non-rechargeable alkaline cells. The instru-
ment may also be powered from rechargeable NiCd cells, or a Mains Power Supply
capable of being used outside the instrument or installed in it. Alternatively it may be
powered and/or charged from an external DC source. These alternatives are explained
in the
following sections. Indication of when the supply voltage is low (5 ,6 V or less) is
given
by the DISPLAY.
3.2.1. Alkaline Batteries
The 1212 is
supplied with six alkaline (non-rechargeable) cells QB 0004 dimensioned to
comply with lEG Specification R20 (also known as "D" size). Approximately 12 hours of
measurement of Operative Temperature, or 8 hours of measurements of the other pa-
rameters available, may be taken before these cells become exhausted. Replacement
cells may be ordered from B & K, or other cells of the same size may be used. The use
of ordinary non-alkaline cells is not recommended because of the risk of damage to the
Battery Box and the instrument caused by chemical action in such cells after they be-
come exhausted.
9

Installation of cells is described below in section 3.2.3.
3.2.2. Rechargeable Batteries
The Battery Box supplied with the 1212 also accepts rechargeable nickel cadmium
(NiCd) cells QB 0008, which may be ordered separately from B & K. These are more
economical than non-rechargeable cells since they may be recharged up to 500 times
before they become unserviceable. Each charge will power the instrument for approxi-
mately 9 hours when the Transducer heating requirement is highest (i.e., PMV< -1 ), 11
hours when the Transducer heating requirement is low (PMV> 1 ), and 24 hours when
only the Operative Temperature is being measured. These times are all approximate and
apply to continuous operation.
QB 0008 cells take approximately 14 hours to charge at the maximum permitted charg-
ing-current (0,4 A) from complete exhaustion to full charge, and proportionately longer at
lower charging-currents. No harm will result from continuing to charge these cells after
they have
become fully charged. However, if the instrument is used only infrequently,
frequent unnecessary charging of the cells can shorten their long lifetime. The 0,4 A limit
is determined from thermal considerations, and may be exceeded in moderation for
short periods at the user's discretion. For details of how to charge NiCd cells, refer to
sections 3.2.4, 3.2.5 and 3.2.6, describing the various sources which may be used for
charging.
Installation of cells is described below in section 3.2.3.
3.2.3. Installing Battery Cells
10
Access is gained to the interior of the Battery Box ZG 0146 by removing the lid, which is
secured by
four fastenings, one at each corner of the lid. These fastenings may be
locked or unlocked using a screwdriver or small coin, and require not more than half a
turn
to lock or unlock. To install or replace the six cells in the Battery Box supplied,
proceed as follows:
1. Unlock the four fastenings, ensuring that the slots in them become parallel to the
long edge of the lid.
2. Lay the lid aside and empty the Battery Box of cells.
3. Load six replacement cells into the Box, in pairs, as shown in Fig. 3.3. Take care to
get each cell the correct way round. Just inside the Box are marked arrows indicat-
ing the direction the positive stud of each cell should face. If any of the cells is
reversed, the
instrument may function improperly or not at all.
4. Replace the lid of the Battery Box and lock it by turning the fastenings at each
corner of the lid half a turn.
5. Label the lid to indicate clearly whether the cells installed are rechargeable or non-
rechargeable.

Lid
WARNING! Batteries can be hazardous. It is possible for cells to explode if they are
abused, so
NEVER-
(a) Attempt to recharge cells the wrong way round;
(b)
Mix different makes or types of cells in one Battery Box;
(c)
Mix discharged cells with charged cells.
Fastening Screws for
Lid of Battery Box
Fig. 3.3. Orientation of cells in the Battery Box ZG 0146
To install the Battery Box in the SUPPLY COMPARTMENT in the rear panel of the 1212,
proceed as follows, referring to Fig. 3.4:
Fig. 3.4. Installing the
Battery Box in the Type 1212
11

1. Taking care to get it the right way up, slide the Battery Box into the SUPPLY COM-
PARTMENT, so that when almost completely inserted it comes to rest against the
· two spring contacts at the innermost end of the compartment
2. Use just sufficient pressure to push the Battery Box in so that the fastener marked
"Release" may be turned through 180° with a screwdriver, locking the Box in place
in the compartment.
3.2.4. Mains Power Supply ZG 0199
12
Fig. 3.5. Mains Power Supply ZG 0199
The Mains Power Supply ZG 0199 (Fig. 3.5), available to order, may be used fitted into
the Thermal Comfort Meter, or externally. It may be powered from 50 to 400Hz single
phase AC mains, and when adjusted as described in its Instruction Manual can accept
voltages of 100, 115, 127, 220 or 240 V.
The procedure for installing the ZG 0199 in the SUPPLY COMPARTMENT of the 1212 is
the
same as that described in section 3.2.3 for the Battery Box ZG 0146. Care should be
taken
to locate the ZG 0199 the right way up.
To use the Mains Power Supply externally for powering the instrument, and/or recharg-
ing NiCd cells if they are fitted, connect one end of control cable AQ 0035 to the rear
panel POWER/CHARGE INPUT socket, and the other end to the OUTPUT socket on the
ZG 0199. The ZG 0199
provides sufficient current both to charge NiCd rechargeable cells
and to power the instrument simultaneously. If non-rechargeable cells are fitted in the
Battery Box installed
in the instrument, the OUTPUT SELECTOR switch on the ZG 0199
should be set to "Drive Voltage 'On' -Charge 'Off'".
To charge rechargeable NiCd
cells installed in the 1212, set OUTPUT SELECTOR on the ZG 0199 to "Drive Voltage
'On' - Charge 'On'".
If a Mains Power Supply is connected externally to the 1212 and switched on, power will
automatically be taken from it in preference to any installed batteries so long as the
1212 is
switched on by means of its FUNCTION switch. If batteries are installed, switch-
ing off the Mains Power Supply will cause the 1212 to continue to run from its batter-
ies unless FUNCTION is set to "Off", so
remember to switch the FUNCTION SELECTOR
to "Off" after using the instrument.

3.2.5. Battery Charger ZG 0113
Fig. 3. 6. Battery Charger ZG 0113
Rechargeable cells installed in the 1212 may be charged by means of the Battery Charg-
er ZG 0113 (Fig. 3.6), available as an optional accessory. This Charger is suitable for use
with 50 to 400 Hz single-phase AC mains. A mains voltage range of either 100 to 130 V
·
or 200 to 240 V may be selected by the choice of colour-coded conductors in the mains
cable. There are three of these conductors, one of which should be cut back. To use the
Charger on 100 to 130 V, cut back the brown conductor and connect the supply between
the blue and
black conductors. To use it on 200 to 240 V, cut back the black conductor
and connect the supply between the blue and brown. Connect the 7-pin DIN plug on the
Charger to POWER/CHARGE INPUT on the 1212.
3.2.6. External DC
The ZG 0113 delivers approximately 0,4 A DC when used to recharge QB 0008 cells in-
stalled in the 1212. Approximately 14 hours is needed to recharge cells of this type
completely, from exhaustion, at this current. The 1212 may be used to take measure-
ments while the Charger is connected and supplying current provided rechargeable
cells are installed. This
arrangement can usefully extend the period for which the 1212
may be operated on its batteries. It must not be used like this with non-rechargeable
cells, and it should not be used with no cells installed.
An external DC source, such as a vehicle battery, may be used to power the Thermal
Comfort Meter via the POWER/CHARGE INPUT socket on the rear panel. This has the
pin
connections shown in Fig. 2.4 and accepts the 7-pin DIN plug JP 0703 supplied. This
may be used to make up a suitable cable. The FUSE fitted in the instrument protects
circuits inside the latter, but it is recommended that the connections from an external
source should be protected by a slow-blow fuse or other current-limiting device of not
more than 2 A rating.
Pin 1 carries current only to power the Type 1212 (not to charge any fitted batteries).
Internal power conditioning permits acceptance of a voltage range of +6 to +15 V DC.
The
current consumed may be greater at lower supply voltages than at higher voltages,
and does not normally exceed 0,5 A. Current consumption is only about 120 rnA for
measurement of Operative Temperature provided the supply voltage exceeds 8 V DC.
Pin 3
carries current to charge fitted batteries. Only rechargeable batteries should be
fitted if this pin is used. Provided the external supply fulfills with the requirements for
both charging and powering the instrument (12 V, 1 A), it may be connected to both pins
1 and
3. NiCd rechargeable batteries may be charged via pin 3 from a power supply
whose open-circuit voltage exceeds +12 V DC if it is current-limited to not more than
0,4 A when loaded to +12 V (current-limiting for supplies exceeding 12 V can easily be
achieved by wiring a suitable resistor in series with pin 3). At this current QB 0008 NiCd
batteries take approximately 14 hours to receive a full charge.
13

Pin 2 is common to both charge and power inputs. The battery and external power
circuits are completely isolated from the measurement circuits, outputs and all exposed
metalwork of the Thermal Comfort Meter, but not from pins 1 and 4 (heater supply
conductors) of the TRANSDUCER INPUT. This isolation prevents earth-loops occurring
when more than one instrument share a common supply source. It is not intended to
have to withstand potentially hazardous voltages: the mains-powered devices ZG 0199
and ZG 0113 mentioned in sections 3.2.4 and 3.2.5 provide their own isolation from the
mains.
When using the POWER/CHARGE INPUT socket connected to a vehicle battery, avoid
running the engine with only pins 1 and 2 connected, as voltage surges may damage the
instrument or cause measurement errors.
3.3. CHECKING THE CALIBRATION OF THE THERMAL COMFORT METER
14
The Thermal Comfort Meter Type 1212 is calibrated during manufacture, and no provi-
sion is made for adjustment by the user. However it is advisable to check from time to
time that it is performing correctly.
The carrying-case supplied for the Thermal Comfort Transducer MM 0023 may be used
as an isothermal chamber to
check the calibration of the measuring chain (Transducer
plus Meter). However, it is suitable only for checking Operative Temperature, since cali- '
bration for Equivalent Temperature and the other measurable parameters require a larg-
er chamber. Nevertheless, Operative Temperature calibration does validate the tempera-
ture-sensor, conditioning amplifier and DISPLAY.
Fig. 3. 7. Calibration of the Thermal Comfort Meter
To check the calibration, proceed as follows (Fig. 3. 7):
1. Place the Thermal Comfort Transducer in its carrying-case with the cable passing
through to the outside, and shut the case.
2. Insert a reliable mercury-in-glass thermometer into the carrying-case far enough to
ensure that the bulb is completely inside but not so far that the thermometer cannot
be read.
3. Connect the Transducer cable to the TRANSDUCER INPUT socket on the rear panel
of the Thermal Comfort Meter.
4. Provide a suitable power source for the 1212 as discussed in section 3.2.