KENYA STANDARD       KS 2553: 2018 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Anaesthetic airways — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
© KEBS 201 8         First Edition 201 8 
 KS 2553: 2018 
 
ii      © KEBS 201 8 — All rights reserved   
TECHNICAL  COMMITTEE REPRESENTATION  
 
The following organiz ations were represented on the T echnical Committee.  
 
Association of Me dical Engineers of Kenya (AMEK)  
Nursing Council of Kenya  (NCK)  
Ministry of Health , Chief Nursing Officer’s Office  
Government Chemist ' Department  
Consumer International Network (CIN)  
Coast Provincial Hospital  
County  Government  of Nairobi , Department of Heal th 
Association for the Physically Disabled of Kenya  (APDK)  
Christian Health Association of Kenya  
Kenyatta National Hospital  (KNH)  
Kenyatta University (KU)  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast o f 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, 201 8 
 
Copyright. User s are reminded that by virtue of section 6 of the Copyright Act, Cap. 130 of the laws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under section 7 of this Act, no Kenya Standard produced by 
Kenya Bureau of Standards may be rep roduced, 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 2553: 2018  
 
 
© KEBS 20 18 — All rights reserved           iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Anaesthetic airways — 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 2553: 2018 
 
iv      © KEBS 201 8 — All rights reserved   
Foreword  
 
Kenya Bureau of Standa rds 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 r epresented 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 o f 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 mem bers 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 . 
During the preparation of this standard, reference was made to the following documents:  
 
IS 3392:  1965 Specification for anaesthetic airways.  
 
This assistance is hereby acknowledged.  
 
 KENY A STANDARD        KS 2553: 2018  
 
 
 © KEBS 20 18 — All rights reserved           1  
 
 
 
Anaesthetic airways — Specification  
 
 
 
1  Scope  
 
This Kenya Standard prescribes  the requirements for anaesthetic airways of the following types:  
 
a) Birt’s  
 
b) Guedel’s  
 
c) Phillip’s, and  
 
d) Water’s.  
 
2  Shape and dimensions  
 
The general shape, dimensions and range of nominal sizes of anaesthetic airways shall be in accordance to 
Table 1 and Figures 1 to 4.  
 
Table 1 — Dimensions of anaesthetic airways  
 
Commercial  
 designation  Size description  Dimension, L ,  
mm Mini. effective  
area of lumen, mm  Accepted colour  
 codes  
(1) (2) (3) (4) (5) 
0000/20  Infants  20 20 Violet  
000/40 Infants  40 20 Violet  
00/50 Infants  50 30 Blue 
0/60 Infants  60 40 Black  
1/70 Children  70 50 White  
2/85 Young adults  85 60 Green  
3/100  Adults  100 70 Orange  
4/115  Large adults  115 110 Red 
5/115  Large adults  120 110 Yellow  
 
3 Materials  
3.1  Anaesthetic airways shall be made of metal complying with the requirements of 3.2 or from suitable 
elastomeric materials complying with the requirements of 3.3 and 3.4 or 3.5.  KS 2553: 2018  
2      © KEBS 201 8 — All rights reserved  
 
     
Figure  3  —Phillip ’s Airway  KS 2553: 2018  
© KEBS 201 8 — All rights reserved           3 
 
 
3.2  Metal  
 
Water’s airways and metal fittings for Birt’s, Guedel’s and Phillip’s airways shall be made from suitable 
corrosion resistant metal or from metal finished with durable and corrosion resisting metal. If plating is done it 
shall be c hromium over nickel conforming to Grade ‘d’ of Annex A.  
 
3.3  Elastomeric materials  
 
Compound elastomeric material shall not include in its composition any substance known to have harmful 
effect on human tissue.  
 
3.3.1   Compounded elastomeric materials sha ll be subjected to accelerated ageing test by oven method. 
The ageing period shall be 168 hours and the temperature of oven shall be maintained at 70  ºC ±1 ºC.  
 
3.4  Compounded rubber  
 
Airways made of compounded rubber shall be vulcanized and after manufac ture shall be capable of being 
autoclaved in a saturated steam at a temperature of 120 ºC - 121 ºC (1.055 kg.cm2 gauge) for not less than 
two hours without showing appreciable stiffening, softening or cracking.  
 
3.5  Plastic materials  
 
Airways made of plas tics shall be capable of withstanding immersion in continuously boiling water for not less 
than 36 h without loss of shape or other significant deterioration . 
 
4  Manufacture, workmanship and finish  
 
4.1  The flanged end of airways made of elastomeric mate rials shall be reinforced with metal insert. This 
insert shall be flanged or otherwise made incapable of moving down the airway and shall remain immovable 
under ordinary conditions of use. The edges of the airways shall be smooth and rounded off to prevent  injury 
to patient during use.  
 
4.2  The airways shall be sufficiently rigid at the flanged end to withstand compression by teeth . KS 2553: 2018  
4      © KEBS 201 8 — All rights reserved   
4.3  Anaesthetic airway shall have sufficient rigidity to keep the base of the tongue of the patient in a 
forward position a nd shall be so designed that they function reliably and safely under normal condition of use. 
The external surfaces shall be smooth.  
 
5 Pack aging 
 
The anaesthetic airways shall be wrapped in suitable material and pack aged in cardboard boxes.  
 
6 Labelling  
 
The following information shall be imprinted, legibly and indelibly  on the package:  
 
a) the size, on each product ; 
b) manufacturer’s name, initial or trade -mark ;; 
c) Country of origin ; 
d) Date of Manufacture and expiry date ; 
e) Batch number ; 
f) Product Na me as, “Gaudel’s, Birt’s, ... airway” ; and  
g) Storage instructions . 
 
7 Instructions for use, inserts, and accompanying documents  
 
Airways and components shall be accompanied by instructions for use, inserts, or accompanying documents  
 KS 2553: 2018  
© KEBS 201 8 — All rights reserved           5  
Annex  A 
(normativ e) 
Requirements of metal for Water’s airways and fittings for Birt’s, Guedel’s and 
Phillip’s airways  
 
 
A.1 Nickel deposit  
 
A.1.1  The type of nickel shall be indicated by the following symblols placed after the chemical 
symbol  Ni followed by figures denoti ng thickness of nickel deposit . 
 
‘b’ for nickel deposited in  fully bright condition. This type of deposit usually  contains a little  
 sulphur  derived from brighteners.  
 
‘p’ for dull or semi -bright nickel requiring polishing to give ful l brightness, containi ng less than 
0.005 %  sulphur1, and passing the ductility test given in KS ISO 8401:1986.  
 
‘d’ for a double -layer nickel coating, of which the bottom l ayer contains less that 0.005 % 
sulphur3) and passes the ductility test given in KS ISO 8401:1986 and the  top layer contains 
more than 0.04 % sulphur3); the thickness of the bottom and top layers shall not be less than 
60 percent and 20 percent respe ctively of the total nickel thickness..  
 
A.1.2  Thickness of nickel deposit   
 
This is specified in microns and d enotes the minimum thickness of the nickel measured by the 
stripping method given in KS ISO 1461  which shall be present at any point of the significant surface 
that may be.  
 
A.2 Chromium deposit  
 
A.2.1  The type of chromium deposit shall be designated by th e follo wing symblols placed after the 
chemical symbol Cr;.  
 
‘r’ for regular or common type of chromium having a minimum thickness of 0.3 micron.  
 
‘f’ for chromium free from cracks, when checked by the microscopic method (except for cracks 
extending from th e edges of the component to 25  % of the width of the component or 10 mm 
whichever is the less) and havin g a minimum thickness of 0.8 micron.  
 
A.2.2  Thickness of chromium deposit   
 
This is specified in microns and denotes the minimum thickness of the chrom ium deposit, measured 
by the  stripping  method given in KS ISO 1461, which shall be present at any point of the significant 
surface that may be touched  by a ball 20 mm in diameter.  
 
A.2.3  Example of complete classificatin number  
 
For example, ‘S Ni40b Cr r ’ shall denote a coating on steel consisting of 40 microns (minimum) of 
bright nickel followed by 0.3 micron (minimum) regular chromium.  
 
A.2.4  Coatings appropriate to each service grade number   
 
                                                 
1 The sulphur contents are specified in order to indicate the type of nickel platin g solution that is to be used. No simple method ex ists for 
determining the sulphur content of a nickel deposit on a coated article An accurate determination is possible on a specially prepared 
test specimen.  
 KS 2553: 2018  
6      © KEBS 201 8 — All rights reserved   
Table 1 gives the Classification Numbers corresponding to e ach Service Grade Number for nickel -
chromium plating on iron and steel.  
 
Table 1 — Nickel -chromium plating on iron and steel  
 
 
 
  Servicer Grade No.     Classification No  
 
   4     S Ni40p Cr r  
        S Ni40d Cr r  
        S Ni40d Cr.f  
 
        S Ni40b C r r 
        S Ni30p Cr r  
   3     S Ni30d Cr.r  
        S Ni30d Cr.r  
   2*     S Ni20b Cr.r  
   1*     S Ni10b Cr.r  
 
*p- or d-nickel and f -chromium may be substituted for b -nickel and r -chromium in Service Grade 
Numbers 2 and  1. 
 
 
 
A.3 Adhesion  
 
Adhesion  of the coating  shall be tested by the method given in KS ISO 4522 -2. The coating should 
continue to adhere to the basis metal when subjected to this test.  
 
A.4 Corrosion resistance   
 
The plated article should be subjecyted for the specified duration to one o f the corrosion tests shown 
in Table 2 to be appropriate for the particular Service Grade Number .  The coating shall not show 
appreciable corrosion as indicated by the development of rust spots.  Unless other wise agreed 
between the purchaser and the suppl ier, appreciable corrosion shall be defined as the presence of 
more thant two corrosion spots per square decimeteres and not more than 10 corrosion spots in 
asny single area covering 25 cm2, as seen with the naked eye.  
 
 
 
 KS 2553: 2018  
© KEBS 201 8 — All rights reserved           7 Annex B 
(informative)  
 
Ductility  property  
B.1 Definition  
 
In materials science , ductility  is a solid material's ability to deform under tensile  stress; this is often 
characterized by the material's ability to be stretched into a wire. Malleability , a similar property, is a 
material's ability to deform under compressive  stress; this is often characterized by the material's ability to 
form a thin sheet by hammering or rolling. Both of these mechanical properties are aspects of plasticity , the 
extent to which a solid material can be plastically deformed without fracture . Also, these material properties 
are dependent on temperature an d pressure.  
 
Ductility and malleability are not always coextensive – for instance, while gold has high ductility and 
malleability, lead has low ductility but high malleability.  The word ductility  is sometimes used to embrace both 
types of plasticity.   
 
B.2  Importance of ductility  
 
Ductility is especially important in metalworking , as materials that crack, break or shatter under stress cannot 
be manipulated using metal forming processes, such as hammering , rolling , and drawing . Malleable 
materials can be formed using stamping  or pressing , whereas brittle metals and plastics  must be molded . 
High degrees of ductility occur due to metallic bonds , which are found predominantly in metals and lead s to 
the common perception that metals are ductile in general. In metallic bonds valence shell  electrons  are 
deloc alized and shared between many atoms. The delocalized electrons  allow metal atoms to slide past one 
another without being subjected to strong repulsive forces that wo uld cause other materials to shatter.  
 
B.3  Quantification  
 
Ductility can be quantified by the fracture strain 
 , which is the engineering strain  at which  a test specimen 
fractures during a uniaxial tensile test . Another commonly used measure is the reduction of area at fracture 
. The ductility of steel  varies depending on the alloying constituents. Increasing levels of carbon  decreases 
ductility. Many plastics and amorphous solids , such as Play-Doh, are also malleable. The most ductile metal 
is platinum and the most malleable metal is gold  
 
Ductility . The ability to defor m before braking. It is the opposite of brittleness . Ductility can be given either 
as percent maximum elongation e max or maximum area reduction.  
 
%EL = e max x 100 %  
 
%AR = ( A0 - Af)/A0 
 
These are measured after fracture (repositioning the two pieces back  together).  
 
Resilience.  Capacity to absorb energy elastically. The energy per unit volume is the area under the strain -
stress curve in the elastic region.   
 
 KS 2553: 2018  
8      © KEBS 201 8 — All rights reserved   
 
 
 
 
a) Brittle fracture  
 
b) Du ctile fracture  
 
c) Completely ductile fracture  
 
Figure  5 — Schematic appearance of round metal bars after tensile testing