Kenya Standard    KS 2551: 2018 
ICS 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sphygmomanometers , mercurial  —
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
©KEBS 201 8          First Edition 20 18 KS 2551: 2018  
 
ii  © KEBS 201 8 — All rights reserved  TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Nursing Council of K enya  
Ministry of Health  
Government Chemist ' Department  
Coast Provincial Hospital  
County of Nairobi, City Council of Nairobi  
Association for the Physically Disabled of Kenya (APDK)  
Christian Health Association of Kenya (CHAK)  
Kenyatta National Hospital  
Keny a Bureau of Standards — Secretariat  
 
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvements to published standards, addressed to the Managing Director , Kenya Bureau of Standards, 
are welcome . 
 
 
 
 
 
 
© Kenya Bureau of Standards, 20 18 
 
Copyright.  Users are   reminded that by virtue of section 25 of the Copyright Act, Cap. 12 of 2001 of the Laws of Kenya, cop yright 
subsists in all Kenya Standards and except a s provided under section 26 of this Act, no Kenya Standard produced by Kenya Bureau of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in  writing 
from the Managing Director.  
 
 Kenya Standard   KS 2551: 2018 
ICS  
© KEBS 201 8 — All rights reserved   iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
Sphygmomanometers, mercurial  —
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org  
 
Coast Region     Lake Region          Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814  
 KS 2551: 2018  
 
iv  © KEBS 201 8 — All rights reserved  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 subj ect 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 accorda nce 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, Medical Tools, devices and 
Equipment . 
Recent surveillance have indicated that these products are still useful due to a number of reasons includi ng 
their being accurate relative to the digital ones, versatility as the parts can be replaceable and cheapness of 
technology.  
 
The term “normative” has been used in this standard to define the application of the annex A to which it 
applies. A “normative” annex is an integral part of this standard.  
 
During the development of this standard, reference was made to the following documents:  
 
IS: 3390 -1965 Sphygmomanometers, mercurial  
 
This assistance is hereby highly acknowledged.  
 
  
Kenya Standard    KS 2551: 2018 
 
 
© KEBS 201 8 — All rights reserved   1  
 
 
Sphygmomanometers, mercur ial — Specification  
 
 
 
1 Scope  
 
This National Workshop Agreement  lays down the requirements for mercurial sphygm omanometers used for 
measuring arterial blood pressure of human beings.  
 
2  Nomenclature  
 
2.1  For the purpose of this standard, the nomenclatur e for var ious parts, as indicated in Figure  1, shall 
apply.  
 
3 Types, f asting and scale range  
 
3.1 The sphygmomanometers shall be of the types, fastening and scale r anges as specified in 3.1.1 to 
3.1.3.  
 
3.1.1   Types  
 
a) Type 1 — Portable,  
 
b) Type 2 — Mountable /fixed, and  
 
c) Type 3 — Inclined.  
 
3.1.2  Fastening  
 
The fastening arrangement of the cuff shall be such that the cuff should be capable of being held in position.  
The arrangement may be of bandage  type, hook a nd rib type or any other convenient type.  The fastening 
arrangement shall also satisfy the requirements given in 3.1.2.1  
 
3.1.2.1  The cuff shall be tied round a rigid cylinder of appropriate si ze and then pressurized to 50 mm (6.66 
kN/m2) of mercury in stages and kept at each stage for 3 minutes, there shall be no sign of slip or failure of 
cuff, stitching or the fastening arrangement.  
 
3.1.3  Scale range  
 
Lower range;  0 mm of mercury  
 
Upper range:  260 (34.66 kN/m2) to 300 (40.0 kN/m ) mm of mercury  
 
 
 KS 2551: 2018 
 
2  © KEBS 201 8 — All rights reserved   
 
 
 
Figure  1 — General Assembly of Sphygmomanometer , Mercurial Type  
 
Table 1 — Dimensions of inflating bag cuff pocket  
Dimensions  
Sl.no. Sizes  A B 
i) Thigh, large  550 190 
ii) Thigh, small  400 190 
iii) Adult arm  240 140 
iv) Child arm  200 115 
v) Infant arm  135 75 
vi) New-born baby arm  95 40 
 
NOTE. La rger sizes of the inflating bags may be acquired as agreed upon between the manufacturer and the buyer.  
  KS 2551: 2018 
 
© KEBS 201 8 — All rights reserved   3 4 Material  
 
4.1 Metal parts  
 
The metal parts shall be fabricated from brass, aluminium alloy, steel or any other suitable metal inte nded. 
The metal p arts shall be given a suitable corrosion resistant finish.  If plating is done, it shall satisfy the 
corrosion resistance test specified in 7.5  
 
4.2 Rubber parts  
 
The rubber parts shall be made of natural or synthetic rubber.  The inflating bulb, with its  inlet valve in 
position, shall be capable ageing in an air -oven for 168 h at 70  0C ± 1 0C without showing appreciable 
stiffening, cracking or other change in condition.  Rubber tubing shall have a minimum tensile strength and 
elongation at break before ag eing a s 105 kgf/cm2 and 400 respectively . A reduction of 20 percent shall be 
permitted on tensile strength and 20 percent on elongation.  The tensile strength and elongation shall be 
tested in accordance with KS ISO: 37-2011.  
 
4.3 Glass Parts  
 
The glass pa rts shall be made of clear glass.  G lass shall show no evidence of corrosion, scumming, 
chipping or cracking, when subjected to the boil test as specified in 7.4.  
 
4.4 Plastics   
 
The plastics used shall be suitable for the purpose intended and shall not fl ake, peel or otherwise disintegrate 
in normal use.  The plastics tube shall remain clear like glass after subjecting to boil test as specified in 7.4  
 
4.5 Fabric  
 
 the fabric shall be of suitable cloth having minimum breaking  load specified against in acco rdance with 
Annex A.  
 
4.6 Sewing thread   
 
the sewing thread used shall be such that it satisfies the requirements given in  3.1.2.1.  
 
4.7 Mercury  
 
The mercury used shall be clean, double distilled and of 99.9 percent purity.  
 
4.8 Component p art  
 
4.8.1  Sphygmomanometers  shall consist of an inflation system , a pressure measuring device 
(manometer), a housing for the manometer and its inflation system.  These  individual devices or replacement 
parts or complete sphygmomanometers - may be ordered by the purchase r. 
 
4.8.2  Inflation system shall consist of a cuff, inflating bag, inflating bulb and a control valve.  
 
4.8.2.1 . Cuff 
 
The cuff shall be of the material specified in 4.5.  Cuff shall be of two layers of material.  A pocket shall be 
provided for the inflati ng bag made according to dimensions A and B (see fig 1).  It shall have an opening of 
about 50 mm on the side for entry of inflating bag and to accommodate its tubes.  The cuff shall be long KS 2551: 2018 
 
4  © KEBS 201 8 — All rights reserved  enough to give proper fastening to the required size of thigh or arm. The deviation on dimensions shall be as 
given in 4.8.3.2.  
 
4.8.3  Inflating  bag  
 
The inflating rubber bag shall be capable of withstanding an internal pressure of 450 mm of mercury without 
leaking, when tested as specified in 7.3.  
 
4.8.3.1  The bag sha ll be of the following sizes:  
 
         Length    Breath  
         mm   mm 
   Large thigh      500   175 
   Small thigh      380   175 
   Adult arm      225   125 
   Child arm      180   100 
   Infact arm      120     60 
   New-born baby arm       80      25 
 
4.8.3.2  Deviation as given below shall be applied on the dimensions given in 4.8.3.1. and Fig. 1:  
           mm 
    Below 100 mm    Bag    +0 
            -3 
        Cuff pocket   - 0 
           +3 
    Above 100 mm and   Bag    +0 
    Below 200 mm       -5 
 
        Cuff pocket   -0 
           +5 
    Above 200 mm    Bag   +0 
           +10 
  
        Cuff pocket    -0 
            +10 
 
 
4.8.4  Tubing  
 
 Two lengths of rubber tubes, approximately 460 mm long each shall be attached to one long side of the bag 
and shall provide air  entry from one end and exit from the other.  These tubes shall be fitted with female Luer 
fittings conforming to IS O 594 -2 to make leak -proof connections with the male Luer fitting attached to the 
extension tubes. The internal diameter of  the tubes shall be 3 ± 0.5 mm and external diameter shall not  be 
less than 8.0 mm for fitting to inflating bags of child and adult sizes, and not less than 6.0 mm for infant sizes.  
 
4.8.5  Inflating bulb   
The inflating bulb shall be made of natural rubber or plastics and shall be ovoid in shape.  One end shall be 
securely fitted with an air inlet non –return valve.  The other end shall be fitted over the proximal end of the 
control valve.  
 
4.8.6  Control value    KS 2551: 2018 
 
© KEBS 201 8 — All rights reserved   5  
 Control valve shall have a knurled thumb cont rol device which shall be attached such that it does not 
become completely unscrewed when the cuff is tied round a rigid cylinder of appropriate diameter, control 
valve shall be effective in holding a pressure of 300  mm, 150  mm and 50 mm of mercury with a leakage rate 
not exceeding 10 mm of mercury per minute.  The valve shall be tested at these points and at any 
intermediate points between 50  mm and 300 mm of mercury as may be deemed necessary to meet 
compliance (see also 7.2)  
 
4.8.6.1  Control valve shall be capable of giving complete control by hand to give a reduction in pressure at 
the rate of 1 mmHg/s to free release.  
 
4.8.6.2  One end of control valve shall be attached to the inflating bulb and the other end to one of the tubes 
of the inflating bag.  
 
4.9 Pressure measuring device  
 
4.9.1  The manometers shall consist of a graduated glass tube, a reservoir, a connection from reservoir to 
manometer tube, a rubber tube extension with a male Luer fitting and sufficient mercury for proper operation 
of the instr uments. The manometer tube shall be of adequate length for the purpose inte nded and shall have 
an inside diameter of 4  mm ± 0.2 mm and wall thickness of not less than 2.0 mm.  The manometer tube shall 
be calibrated and so  designed in conjunction with the d esign of the remaining instrument as to be 
interchangeable, without calibration on the instruments of the same scale range of the same manufacturer.  
The scale markings and graduations shall be engraved and filled with pigment, etched and filled with pigme nt 
or accomplished by silk screening and fus ing in or fusing on a pigment. The pigment shall be red, brown or 
black in colour and shall be permanent, meeting the requirements of boil test as given in 7.4. Any loss of 
pigment shall be a cause of rejection. The graduation shall extend from zero to full scale in 2 -mm divisions 
with proportionately longer markings at ea ch 10 -mm division  on the tube. The longer divisions shall be about 
30 % to 40 % longer than the shorter ones. The numer als on a scale plate may also be affixed in the back of 
the glass or plastics tube, if required by the purchaser.  The colour, in which the numerals are marked, shall 
be in clear contrast to the background in order to be easily read.  The pressure unit, that is, ‘mmHg’ shall  be 
marked on the scale plate (see 71.and 74)  
 
4.9.2  Tube m ounting and fittings   
 
Tube shall be recess -mounted to prevent breakage and shall provide a leak -proof channel for the mercury 
and shall be easily removable for cleaning and replacement.  The upper end of the tub e shall be fitted with a 
removable device  containing a filter which shall prevent loss of mercury while still allowing the tube at all 
times to be open to atmospheric pressure and which shall also serve to prevent rapid oscillation and 
fluctuatio ns of the mercury column, that is, damped column.  This device shall be easily removab le and 
replaceable to allow the  addition of mercury, when necessary.  
 
4.9.3  Reservoir and connecting tube  
 
The reservoir, trap and connection to the manometer shall be mad e from suitab le material, such as cast iron, 
steel or high impact resistant plastics, which shall have no  deleterious effect on mercury.   The reservoir shall 
be of uniform cross -section, its diameter shall be at least four times that of the manometer tube and its 
design shall be such as to allow interchangeability of the manometer tubes within instruments of the same 
scale range of the same manufacture.  The reservoir shall be fitted with the safety trap at the top to prevent 
passage of mercury to the exten sion tube which will be f itted to the top of the reser voir making a leak -proof 
connection.  The connection from reservoir to the manometer tube shall be air -tight, and mercury -tight, an 
“On’ and “Off” tap shall be provided in the connection from the reserv oir to the manometer tube.  
 
 KS 2551: 2018 
 
6  © KEBS 201 8 — All rights reserved  4.9.4  Extension t ube  
 
A rubber extension tube shall be fitted to the reservoir with a length not less than 300 mm and its end 
opposite to the reservoir shall be fifed with a mal e Luer fitting fitted to one of the tubes of the inflating bag.  
 
4.10 Housing   
 
 For Type 1, the case shall be of robust design and suitable material.  It shall give ample room to house the 
inflation system without damage. It shall be fitted with a device for setting and holding the lid at right angles.  
This device shall also prevent the accidental dropping of the lid when the instrument is in use.  All parts shall 
be re placeable in case of breakage. The housing of the Type 2 shall be of wood or metal, and shall be of 
robust design.  
 
4.11 Accessories   
 
Besides an adult size cuff and inflating bag, the sphygmomanometers may be provided with one set of cuff 
and inflating bag of sizes specifica lly required by the purchaser. A cleaning brush to clean the manometer 
tube and a set of spare washers may be provid ed with each sphygmomanometer.  
  
4.12 Accuracy   
 
The assembled instrument shall be tested with the mercury column vertical for Type 1 and Type 2 and at the 
designed inclination for Type 3, and descending at an average rate of 2 mmHg approximately in 5 seco nds, 
but the pressure shall be held constant while readings are being taken.  
 
4.13 Leakage   
 
The air leakage of the completely assembled sphygmomanometer, when tested in accordance with 7.2, shall 
not exceed 10 mmHg per minute . 
 
5 Workma nship and f inish . 
 
5.1 Workmanship shall be of high grade . 
 
5.2 Sphygmomanometer shall be free from defects which detract from the appearance and may impair 
their serviceability  
 
6 Marking  
 
6.1 Each sphygmomanometer shall be legibly and permanently marked with the name of tr ademark of 
the manufacturer and the manufacture’s serial number.  
 
6.1.1  The sphygmomanometer may also be marked with the Standard Mark.  
 
NOTE  The use of the Standard Mark is governed  by the provisions of the Kenyan Bureau of Standards Act, Cap 49 6 and the  Rules 
and Regulations made there -under.  The Standard Mark on products covered  by Kenyan Standard conveys the assurance that they 
have been produced to comply with the requirements of that standard under a well -defined system of inspection testing and qua lity 
control which is devised and supervised by KEBS and operated by the producer . Standard marked products  are also continuously 
checked by KEBS for conformity to that standard as a further safeguard .  Details of conditions under which a licence for the u se of the 
Standard Mark may be g ranted to manufacturers or producers, may be obtained from the Kenyan  Bureau of  Standards.  
 
7 Test p rocedures  
7.1 Calibration   
 
 All calibrations shall b e accomplished with a properly standardized and certified mercurial manometer .  One  KS 2551: 2018 
 
© KEBS 201 8 — All rights reserved   7 calibration shall be made without tapping and with decreasing pressure only.  Reading shall be take n at the 
highest  point of th e scale and at all other points which are multiples of 20 mm.  The readings shall be taken 
with the pressure falling at a rate of 2 mm/s approximately (see 4.9.1)  
 
7.2 Leak test   
 
 When the cuff of each completely assembled sphygmomanometer is tied round a rigid bar of appropriate 
diameter and each valve (when valves are purchased separately) shall be subjected to an i nternal air 
pressure of 50, 150 and 300 mmHg.  The instrument or the valve shall then be cut off from the air supply.  
The leakage as given in 4.8.6 and 4.13 shall be permitted.  
 
7.3 Leakage test (inflating bag)   
 
 The bag shall be subjected to a  pressure of 450 mmHg (gauge) for one minute.  The bag shall be prevented 
from ballooning by the use of sufficient strength to withstand the pressure.  There shall be no leakage (see 
4.8.2) . 
 
7.4 Boil test   
 
The graduated tube shall be completely immersed in distill ed water in a closed vessel having a steam vent 
and boiled continuously for six hours, boiling distilled water added when necessary to compensate for 
evaporation. The tube shall be suspended in water so that it does not come in contact with the containing 
vessel. The glass shall not show any evidence of corrosion, chipping or cracking and the graduation shall not 
have appreciably deteriorated in intensity. (see 4.9.1)  
 
7.5 Corrosion resistance test  
 
 the plated components shall be immersed in a 10 percent solution of citric acid at room temperature for 5 
hours.  They shall then be boiled in distilled water for 30 minutes and cooled while immersed in the same for 
48 hours.  The test shall be conducted in a glass container.  The components shall throw no sign  of 
corrosion.  
 
8 Packaging  
 
The sphygmomanometer shall be wrapped in a soft tissue paper and packed in a cardboard box or other 
equivalent box.  
 
9 Instruction manual  
 
Each sphygmomanometer shall be provided with a manual giving necessary instructions and precautions to 
be taken for its proper use.  The instruction manual shall include technical specification of the 
sphygmomanometer, list of accessories and spare components to be supplied with the equipment.   
 
 KS 2551: 2018 
 
8  © KEBS 201 8 — All rights reserved  Annex  A 
(normative)  
 
Fabric specification fo r inflation bag and cuff pocket  
 
Approximate count of yarn cotton 
(text)  Ends/cm  Picks/cm  Mass/m2 Breaking load on 
5.0X20 cm strips, min  
Warp  Weft    Warpway  Weftway  
24s(25 text)  24s (25 text)  38 28 170 510(52)N  375(38)N