CD13/SERV/  2018 
© KEBS 20 18 – All rights reserved             First Edition  2018  
 
 
DRAFT  KENYA STANDARD  
 
 
 
 
 
 
Dial thermometers - Specification  
 
 
 
 
 
Public Review  Draft      March  2018 
 
 
 KENYA BUREAU OF STANDARDS (KEBS)  
 
 
 
  
© KEBS 20 18 – All rights reserved             First Edition  2018 WORKING GROUP REPRESENTATION  
 
The following organizations were represented  on the Technical Committee.  
 
Assoc iation  of Persons living with Disability of Kenya (APDK)  
Christian Health Association of Kenya (CHAK)  
Nairobi County  
Ministry Of Health  
Kenyatta National Hospital (KNH)   
Nursing Council of Kenya (NCK)   
Kenya Bureau of Standards (KEBS) - Secretariat  
 
 
 
REVISION OF KENYA STANDARDS  
 
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© Kenya Bureau of Standards, 20 18 
 
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© KEBS 20 18 – All rights reserved             First Edition  2018  
 
  
DRAFT KENYA STANDARD  
 
 
 
 
 
 
 
 
 
 
 
 
Dial thermometers - Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
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© KEBS 20 18 – All rights reserved             First Edition  2018  
Foreword  
Kenya Bureau of Standards is a national standards bod y (NSB). The work of preparing Kenya  Standards is 
normally carried out through national  technical committees. Each member body interested in a subject for which 
a technical committee has been established has the right to be represented on that committee. National  
organizations, governmental and non -governmental, in liaison with KEBS , also take part in the work.  
Kenya  Standards are drafted in accordance with the rules given in the KS ISO/IEC  Directives, Part  2. 
The main task of technical committees is to prepare National  Standards. Draft Kenya  Standards adopted by the 
technical committees are circulated to the technical committee member s for ballo ting. Publication as a Kenya  
Standard requires approval by at least 2/3 of the member s casting a vote.  
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent 
rights. KEBS  shall not be held responsible for identifying any or all such patent rights.  
This Kenya Standard  was prepared by Technical Committee KEBS /TC 136, Medica l Tools, devices and 
Equipment . 
During the development of this standard, reference was made to the following documents.  
EN 13190:2001, Dial thermometers.  
This assistance is hereby acknowledged.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
© KEBS 20 18 – All rights reserved             First Edition  2018 KENYA STANDARD  
Dial thermometers  - Specifications  
 
 
1. Scope  
This Kenya Standard  specifies requirements and testing for indicating thermometers using sensing methods of 
gas expansion (symbol GE), liquid expansion (symbol LE) and bimetallic s trip (symbol BM). Nominal  sizes are 
from 40 to 160 , and temperature measurement from – 100 ºC to +700 ºC.   
Thermometers specified have circular scales, and are for industrial use only.  
Thermometers of square form are also covered by this Kenya Standard except for case and pointer dimensions.  
Annex A inclu des recommendations for selection and installation.  
This standard does not apply to thermometers for medical use nor to thermometers with electrical limit contact 
devices  
 
2. Terms and definitions  
For the purpose of this standard, the following terms and d efinitions apply.  
2.1 
dial indicating thermometer  
instrument consisting of head and temperature detecting element or stem connected together by a rigid 
stem or, except for bimetallic thermometer, by a flexible capillary.  
 
2.2 
bimetallic thermometer  
dial indicating thermometer operated by differential expansion strip, helix or coil.  
 
2.3 
gas expansion thermometer (GE)  
dial indicating thermometer operating on the principle of change in pressure of a fixed volume of gas in 
response to temperature change.  
 
2.4 
liquid expansion thermometer (LE)  
dial indicating thermometer operating the principle of liquid volume expansion in response to 
temperature change.  
 
2.5 
temperature detecting element  
that part of a thermometer which supports and includes the sensitive port ion. 
 
2.6 
sensitive portion of temperature detecting element  
that part of the temperature detecting element which contains the major portion of the temperature 
sensitive fluid or bimetal strip.  
 
 
2.7 
thermometer insertion length  
distance the temperature de tecting element is inserted into process medium  
 
2.8 
thermometer movement  
assembly by means of which the expansion of the fluid used or bimetallic strip are transformed and 
enlarged into an angular variation  
 
  
© KEBS 20 18 – All rights reserved             First Edition  2018 2.9 
thermometer connection  
part by which the d ial indicating thermometer can be coupled to the temperature tapping of the plant, 
pipework or equipment  
 
2.10 
thermometer compensation  
apparatus fitted inside head and/or capillary to minimize errors due to ambient temperature variations.  
 
2.11 
adjustable  pointer  
pointer with an adjustable device  
 
2.12 
thermometer nominal size  
conventional alpha -numerical designation relating to the size of the thermometer  
 
3 Nominal sizes  
Nominal sizes of the thermometers are as follows : 40, 50, 63, 80, 100, 130, 150 and  160 mm (see table 
1 for dimensions).  
 
4 Nominal ranges  
The degree Celsius  abbreviated to ºC is the preferred unit of temperature measurement. The following 
nominal ranges are specified:  
From  0 ºC to  60 ºC     From  -20 ºC to +40 ºC  
From  0 ºC to  80 ºC     From  -20 ºC to +60 ºC  
From  0 ºC to 100 ºC     From  -20 ºC to 120 ºC  
From  0 ºC to 120 ºC     From  -30 ºC to +30 ºC  
From  0 ºC to 160 ºC     From  -30 ºC to +50 ºC  
From  0 ºC to 200 ºC     From  -30 ºC to +70 ºC  
From  0 ºC to 250 ºC     From  -40 ºC to +40 ºC  
From  0 ºC to 300 ºC     From  -40 ºC to +60 ºC  
From  0 ºC to 400 ºC     From  -100 ºC to +60 ºC  
From  0 ºC to 500 ºC  
From  0 ºC to 600 ºC  
From  0 ºC to 700 ºC  
From  50 ºC to 650 ºC   
From  100 ºC to 700 ºC  
NOTE – Not all types of thermometers are suitable for all ranges ( al so see Table A.1).  
 
5 Accuracy classes  
The following accuracy classes are defined: class 1 and class 2.  Class 1 may be used with nominal 
sizes 63 to 160, class 2 may be used with nominal sizes 40 to 160.  
 
6. Dimensions  
6.1 General tolerance  
General toleran ces: Tolerance class m according to  
  
© KEBS 20 18 – All rights reserved             First Edition  2018 6.2 Cases and flanges  
The user will have to determine the dimensions for panel cut -out according to the manufacturer’s data.  
Figure 1 – Dimensions of thermometer cases and flanges  
Nominal 
size d1min. 
Mm d2, max.  
mm d4 
mm d5 
mm 
40 38 61 51 3.6 
50 48 71 60 3.6 
63 61 88 75 3.6 
80 77 110 95 5 
100 97 134 118 6 
130 125 - - - 
150 147 186 168 6 
160 157 196 178 6 
NOTE: Elongated holes can be accepted to ensure interchangeability with previous standards  
 
6.3 Thermometer  connection  
The type of connections in figure 2 are used for  both rigid stem thermometers and thermometers with 
capillarity. The connections in figure 3 are for rigid stem thermometers only. The length of “l5” of 
thermometers connection form 4 depends on the length of the threaded part of its thermowell and shall 
be longer than the latter.  
 
The minimum height of the hexagon, square or flats shall be compatible with the use of standard 
spanners according to KS ISO 10102.  
 
6.3.1  Screw threads  
Parallel pipe t hreads (symbol G) according to KS ISO 228 -1. 
Taper pipe threads (symbol NPT) according to ANSI/ASME B1.20.1.  
ISO general purpose metric screw threads (symbol M) having basic profile according to KS ISO 68 -1. 
Other threads specific to certain industries are  acceptable.  
 
6.3.2  Temperature detecting element  
The diameter of the temperature detecting element “d 5” and its length “l 1” (see figures 2 and 3) will be at 
manufacturer’s discretion or should be by agreement between purchaser and supplier.  
 
6.3.3  Sensiti ve portion of the thermometer detecting  element  
The length of the sensitive portion of the temperature detecting element “l 2” (see figures 2 and 3) shall be 
stated by manufacturer.  
 
7 Requirements  
The test methods for these requirements are given in clause  9. 
 
  
© KEBS 20 18 – All rights reserved             First Edition  2018 7.1 Accuracy  
The limits of error in Table 5 correspond to the measuring range of the thermometer and shall apply in 
the range ± 2 ºC above and below the reference value given for the ambient temperature and for the 
mounting attitude specified in 7.5.  
 
The hysteresis error shall not exceed half value specified for the limits of error in Table 5.  
 
The measuring range of dial thermometers is set of values of the measurand for which the errors of 
measurement must lie within the specified or agreed limits of error. It is a part of the nominal range and 
may be coincident with it.